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Wang Y, Chen Y, Lu S, Guo X. Development and trends of constructed wetland substrates over the past 30 years: a literature visualization analysis based on CiteSpace. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2024; 31:14537-14552. [PMID: 38308167 DOI: 10.1007/s11356-024-32139-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Accepted: 01/18/2024] [Indexed: 02/04/2024]
Abstract
Constructed wetland substrates (CWSs) have received considerable attention owing to their importance in adsorbing and degrading pollutants, providing growth attachment points for microorganisms, and supporting wetland plants. There are differences in the configurations and functions of constructed wetlands (CWs) for treating different water bodies and sewage, resulting in a wide variety of substrates. Research on the application and mechanism of CWSs is not sufficiently systematic. Therefore, the current research advancements and hotspots must be identified. Hence, we used CiteSpace to analyze 1955 English publications from the core collection database of the Web of Science to assess the current state of the CWS research field. Based on the cooperative network analysis, the roles of various countries, institutions, and authors in research on CWSs were reviewed. Keyword co-occurrence and cluster analyses were used to discuss the transformation of CWSs from removing traditional pollutants to emerging pollutants and the transition from incorporating natural substrates to artificial substrates. Finally, we underscored the need for more emphasis to be placed on the collocation and application of the CWSs at different latitudes. Furthermore, the substrate micro-interface process and its effects on the interaction patterns of pollutants and microorganisms should be thoroughly investigated to provide theoretical guidance for the development of wetland applications and mechanisms.
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Affiliation(s)
- Yongqiang Wang
- State Key Laboratory of Environmental Criteria and Risk Assessment, State Environmental Protection Key Laboratory for Lake Pollution Control, National Engineering Laboratory for Lake Pollution Control and Ecological Restoration, Research Centre of Lake Environment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, 150090, China
| | - Yi Chen
- Key Laboratory of the Three Gorges Region's Eco-Environment, Ministry of Education, College of Environment and Ecology, Chongqing University, Chongqing, 400044, China
| | - Shaoyong Lu
- State Key Laboratory of Environmental Criteria and Risk Assessment, State Environmental Protection Key Laboratory for Lake Pollution Control, National Engineering Laboratory for Lake Pollution Control and Ecological Restoration, Research Centre of Lake Environment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China
| | - Xiaochun Guo
- State Key Laboratory of Environmental Criteria and Risk Assessment, State Environmental Protection Key Laboratory for Lake Pollution Control, National Engineering Laboratory for Lake Pollution Control and Ecological Restoration, Research Centre of Lake Environment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China.
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2
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Mathews AP. Effectiveness of water softening residuals as components of road deicing chemicals: Model analysis of freezing point depression. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2021; 293:112888. [PMID: 34058451 DOI: 10.1016/j.jenvman.2021.112888] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/01/2021] [Revised: 05/22/2021] [Accepted: 05/23/2021] [Indexed: 06/12/2023]
Abstract
Water softening residuals disposal is a worldwide issue due to the lack of effective reuse alternatives. The current principal disposal methods of landfilling and land application are quite costly due to the dewatering and transportation costs involved, and these operations can also cause potential environmental harm from leaching of the additives used in the treatment process. This research is aimed at the use of water softening residuals in the production of biodegradable road deicers that would be beneficial in replacing the highly corrosive and environmentally harmful chloride salts that are currently used for road deicing. Experimental data developed show that calcium magnesium acetate (CMA) and calcium magnesium propionate (CMP) deicers produced using water plant sludges are effective in deicing applications. A mathematical model is developed for predicting freezing point depression of CMA and CMP deicers as a function of molal concentration. The model predictions are found to match well with the experimental data, providing confidence in the use of this model for the effective design water softening sludge based deicers. The information developed herein provides options for the sustainable management of softening residuals and the concommitant mitigation of environmental harm associated with road deicing operations.
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Affiliation(s)
- Alexander P Mathews
- Department of Civil Engineering, Kansas State University, Manhattan, KS, 66506, USA.
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3
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Yang Y, Ma C, He X, Li J, Li M, Wang J. Calcined Aluminum Sludge as a Heterogeneous Fenton-Like Catalyst for Methylene Blue Degradation by Three-Dimensional Electrochemical System. Electrocatalysis (N Y) 2021. [DOI: 10.1007/s12678-021-00684-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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4
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Tang C, Zhao Y, Kang C, He J, Yang Y, Morgan D. Creating tidal flow via siphon for better pollutants removal in a microbial fuel cell-constructed wetland. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2021; 290:112592. [PMID: 33895446 DOI: 10.1016/j.jenvman.2021.112592] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Revised: 04/07/2021] [Accepted: 04/09/2021] [Indexed: 06/12/2023]
Abstract
Oxygen is the electron acceptor in cathode chamber of microbial fuel cell-constructed wetland system (MFC-CW). The objective of the study lies in creating a "tidal flow" (TF) in cathode chamber via a siphon to enhance the oxygen diffusion, thus promoting the system performance. A laboratory scale MFC-CW with a siphon driven TF recirculation was proposed and designed. It allows the variable water level being created in four operational modes. The results demonstrated the significance of the siphon which was reflected by the attractive wastewater treatment performance. Compared with the tested four operational modes under the same hydraulic condition, the highest total nitrogen removal efficiency of 96.32% and COD removal efficiency of 92.37% were achieved, respectively, in 1st full siphon recirculation mode (FSR) and 2nd FSR operation mode. Indeed, the water level variation range played an important role in pollutants removal performance. Reduced water level variation of the TF in cathode chamber hindered excessive oxygen diffusion into MFC-CW and thus adversely affected the system performance. It is clear that the siphon is a wiser input to bring about the better treatment performance, but it is believed that the enhanced microbial activities behind the oxygen promotion is the driven force to exhibiting a better performance in the MFC-CW system.
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Affiliation(s)
- Cheng Tang
- State Key Laboratory of Eco-Hydraulics in Northwest Arid Region, Xi'an University of Technology, Xi'an, 710048, PR China; UCD Dooge Centre for Water Resources Research, School of Civil Engineering, University College Dublin, Belfield, Dublin 4, Ireland
| | - Yaqian Zhao
- State Key Laboratory of Eco-Hydraulics in Northwest Arid Region, Xi'an University of Technology, Xi'an, 710048, PR China; UCD Dooge Centre for Water Resources Research, School of Civil Engineering, University College Dublin, Belfield, Dublin 4, Ireland.
| | - Chun Kang
- State Key Laboratory of Eco-Hydraulics in Northwest Arid Region, Xi'an University of Technology, Xi'an, 710048, PR China
| | - Jintao He
- UCD Dooge Centre for Water Resources Research, School of Civil Engineering, University College Dublin, Belfield, Dublin 4, Ireland
| | - Yan Yang
- UCD Dooge Centre for Water Resources Research, School of Civil Engineering, University College Dublin, Belfield, Dublin 4, Ireland
| | - David Morgan
- UCD Dooge Centre for Water Resources Research, School of Civil Engineering, University College Dublin, Belfield, Dublin 4, Ireland
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Zheng Z, Duan X, Lu S. The application research of rainwater wetland based on the Sponge City. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 771:144475. [PMID: 33548728 DOI: 10.1016/j.scitotenv.2020.144475] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2020] [Revised: 11/25/2020] [Accepted: 12/08/2020] [Indexed: 06/12/2023]
Abstract
In order to promote the construction of the Sponge City and strengthen the utilization of rainwater resources, this paper attempts to design a wetland that can effectively purify the rainwater. The rainwater quality of Zhengzhou was monitored to provide actual data for follow-up studies. A variety of wetlands with different plants and substrates were constructed to analyze the purification of wetlands on rainwater. The wetland with optimal parameters was selected to ensure the effluent can be reused. The average concentrations of Chemical Oxygen Demand (COD), Total Nitrogen (TN), Nitrate Nitrogen (NO3--N) and Ammonium Nitrogen(NH3-N) in the initial rainwater were 140.25 mg/L, 13.31 mg/L, 5.77 mg/L and 6.82 mg/L, respectively. The experimental results show that the efficiency of COD purification in each wetland is great, and the differences between wetland are small. Compared with other substrates (gravel, activated carbon, vermiculite), zeolite effectively enhanced the purification effect of wetland on ammonia nitrogen. The purification efficiency of wetland with reed and zeolite is the best, and the removal efficiency of COD, TN, NO3--N and NH3-N is 86.54%, 89.46%, 95.87% and 80.88%, the nitrogen removal efficiency of this wetland is greatly improved. Based on various reuse standards in china, wetland with reed and zeolite can effectively purify initial rainwater, and the effluent can be used to urban miscellaneous water, landscape water and industrial water. This study has important reference significance and practical value for the construction of rainwater wetland in the process promoting the Sponge City.
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Affiliation(s)
- Zhihong Zheng
- School of Water Conservancy, North China University of Water Resources and Electric Power, Zhengzhou 450046, China; Henan Vocational College of Water Conservancy and Environment, Zhengzhou 450008, China
| | - Xiaohan Duan
- School of Water Conservancy, North China University of Water Resources and Electric Power, Zhengzhou 450046, China
| | - Shibao Lu
- College of Public Administration Zhejiang University of Finance and Economics, Hangzhou 310018, China.
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Xin L, Hu J, Xiang Y, Li C, Fu L, Li Q, Wei X. Carbon-Based Nanocomposites as Fenton-Like Catalysts in Wastewater Treatment Applications: A Review. MATERIALS (BASEL, SWITZERLAND) 2021; 14:2643. [PMID: 34070121 PMCID: PMC8158343 DOI: 10.3390/ma14102643] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Revised: 05/13/2021] [Accepted: 05/16/2021] [Indexed: 11/25/2022]
Abstract
Advanced oxidation (e.g., fenton-like reagent oxidation and ozone oxidation) is a highly important technology that uses strong oxidizing free radicals to degrade organic pollutants and mineralize them. The fenton-like reactions have the characteristics of low cost, simple operation, thorough reaction and no secondary pollution. Fenton-like reagents refer to a strong oxidation system composed of transition metal ions (e.g., Fe3+, Mn2+ and Ag+) and oxidants (hydrogen peroxide, potassium persulfate, sodium persulfate, etc). Graphene and carbon nanotube possess a distinctive mechanical strength, flexibility, electrical and thermal conductivity and a very large specific surface area, which can work as an excellent carrier to disperse the catalyst and prevent its agglomeration. Fullerene can synergize with iron-based materials to promote the reaction of hydroxyl groups with organic pollutants and enhance the catalytic effect. Fenton-like catalysts influence the catalytic behavior by inducing electron transfer under strong interactions with the support. Due to the short lifespan of free radicals, the treatment effect is usually enhanced with the assistance of external conditions (ultraviolet and electric fields) to expand the application of fenton-like catalysts in water treatment. There are mainly light-fenton, electro-fenton and photoelectric-fenton methods. Fenton-like catalysts can be prepared by hydrothermal method, impregnation and coordination-precipitation approaches. The structures and properties of the catalysts are characterized by a variety of techniques, such as high-resolution transmission electron microscopy, high-angle annular dark-field scanning transmission electron microscopy and X-ray absorption near-edge structure spectroscopy. In this paper, we review the mechanisms, preparation methods, characterizations and applications status of fenton-like reagents in industrial wastewater treatment, and summarize the recycling of these catalysts and describe prospects for their future research directions.
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Affiliation(s)
- Ling Xin
- Guizhou Provincial Key Laboratory for Information Systems of Mountainous Areas and Protection of Ecological Environment, Guizhou Normal University, Guiyang 550001, China; (L.X.); (Y.X.); (C.L.); (Q.L.)
| | - Jiwei Hu
- Cultivation Base of Guizhou National Key Laboratory of Mountainous Karst Eco-Environment, Institute of Karst, Guizhou Normal University, Guiyang 550001, China
- Research Center of Water Pollution Control Technology, Chinese Research Academy of Environmental Sciences, Chaoyang District, Beijing 100012, China;
| | - Yiqiu Xiang
- Guizhou Provincial Key Laboratory for Information Systems of Mountainous Areas and Protection of Ecological Environment, Guizhou Normal University, Guiyang 550001, China; (L.X.); (Y.X.); (C.L.); (Q.L.)
| | - Caifang Li
- Guizhou Provincial Key Laboratory for Information Systems of Mountainous Areas and Protection of Ecological Environment, Guizhou Normal University, Guiyang 550001, China; (L.X.); (Y.X.); (C.L.); (Q.L.)
| | - Liya Fu
- Research Center of Water Pollution Control Technology, Chinese Research Academy of Environmental Sciences, Chaoyang District, Beijing 100012, China;
| | - Qiuhua Li
- Guizhou Provincial Key Laboratory for Information Systems of Mountainous Areas and Protection of Ecological Environment, Guizhou Normal University, Guiyang 550001, China; (L.X.); (Y.X.); (C.L.); (Q.L.)
- Guizhou International Science and Technology Cooperation Base-International Joint Research Centre for Aquatic Ecology, Guizhou Normal University, Guiyang 550001, China
| | - Xionghui Wei
- Department of Applied Chemistry, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China;
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Van Truong T, Kim DJ. Phosphate removal using thermally regenerated Al adsorbent from drinking water treatment sludge. ENVIRONMENTAL RESEARCH 2021; 196:110877. [PMID: 33711322 DOI: 10.1016/j.envres.2021.110877] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Revised: 01/18/2021] [Accepted: 02/09/2021] [Indexed: 06/12/2023]
Abstract
Alum sludge (AS) is an abundant and ubiquitous residue generated from drinking water treatment plants. AS was thermally treated to use as an adsorbent for phosphate removal from wastewater. Organic matter in the AS was a potential competitor and can deter phosphate adsorption. Pyrolysis and drying of AS were adopted to enhance phosphate removal by eliminating organic matter and enriching Al content. Adsorption kinetics showed that phosphate removal was highest with the AS pyrolyzed at 700 °C followed by 500 °C, air-dried and oven-dried (105 °C). Adsorption kinetic modelling showed that chemisorption is the operative mechanism of phosphate removal in all the AS. Adsorption isotherms also showed that the pyrolyzed AS and air-dried AS had similar adsorption capacity of 30.83-34.53 mg P/g AS. Al dissolution was less than 2 mg/g Al in all the AS samples. COD release was significant in the dried AS, up to 8.0 mg COD/g AS, whereas the pyrolyzed AS released less than 1 mg COD/g AS. FTIR and SEM-EDS analyses of the AS after phosphate adsorption showed the formation of aluminum-phosphate complex. Overall, the pyrolysis of AS at 700 °C was most effective in removing phosphate without leaving secondary pollution.
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Affiliation(s)
- Tuan Van Truong
- Department of Environmental Sciences and Biotechnology & Institute of Energy and Environment, Hallym University, 1 Okcheon, Chuncheon, 24251, South Korea
| | - Dong-Jin Kim
- Department of Environmental Sciences and Biotechnology & Institute of Energy and Environment, Hallym University, 1 Okcheon, Chuncheon, 24251, South Korea.
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8
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Application of Alum Sludge in Wastewater Treatment Processes: “Science” of Reuse and Reclamation Pathways. Processes (Basel) 2021. [DOI: 10.3390/pr9040612] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Alum sludge (AlS) refers to the inevitable by-product generated during the drinking water purification process, where Al-salt is used as a coagulant in the water industry. It has long been treated as “waste”, while landfill is its major final disposal destination. In fact, AlS is an underutilized material with huge potential for beneficial reuse as a raw material in various wastewater treatment processes. In the last two decades, intensive studies have been conducted worldwide to explore the “science” and practical application of AlS. This paper focuses on the recent developments in the use of AlS that show its strong potential for reuse in wastewater treatment processes. In particular, the review covers the key “science” of the nature and mechanisms of AlS, revealing why AlS has the potential to be a value-added material. In addition, the future focus of research towards the widespread application of AlS as a raw material/product in commercial markets is suggested, which expands the scope for AlS research and development.
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9
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Qiu D, Peng H, Li T, Qi Y. Application of stabilized sludge to extensive green roofs in Shanghai: Feasibility and nitrogen leaching control. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 732:138898. [PMID: 32417550 DOI: 10.1016/j.scitotenv.2020.138898] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 04/20/2020] [Accepted: 04/20/2020] [Indexed: 06/11/2023]
Abstract
Extensive green roofs, in which commercial compost is usually used as organic component, have great potential to mitigate some environmental problems caused by urbanization, but carry risks of nutrients leaching into downstream aquatic. Stabilized sludge (SS) from wastewater treatment plants could be potentially used as nutrient component for green roof, but the effects on effluent quality are uncertain. To investigate the problem, a pilot experiment was conducted under field conditions, the effluent quality of green roof using SS was compared with green roofs using peat soil and controlled release fertilizer. In the field experiment, the nutrient concentrations in effluent of the green roof using SS (TN, NO3--N, NH4+-N and TP were 3.27 mg/L, 1.75 mg/L, 1.14 mg/L and 0.34 mg/L, respectively) were not significantly different from the green roofs using peat soil and controlled release fertilizer, and the chemical oxygen demand level (92 mg/L) was lower than the roofs using compost or commercial substrate. To reduce the environmental risks caused by the application of SS to green roofs, a laboratory test was carried out to analyze the effects of biochar and dual-substrate structure on nitrogen leaching. The results showed that both biochar and dual-substrate reduced nitrogen leaching, and nitrogen leaching from green roofs using SS was a combined effect of organic nitrogen mineralization during dry period and biological processes during wet period. A high temperature and low humidity environment which is common in green roofs reduced nitrate accumulation during dry period, and nitrate was transformed to other substances in gaseous form by denitrification, which tended to occur in long duration, low intensity rainfall events. The results suggest that the application of stabilized sludge to green roofs is feasible in area where average rain intensity is not high, preferably combined with amendment of biochar and a dual-substrate structure.
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Affiliation(s)
- Duanyang Qiu
- State Key Lab of Pollution Control and Resource Reuse, Tongji University, Shanghai 200092, China
| | - Hangyu Peng
- State Key Lab of Pollution Control and Resource Reuse, Tongji University, Shanghai 200092, China
| | - Tian Li
- State Key Lab of Pollution Control and Resource Reuse, Tongji University, Shanghai 200092, China.
| | - Yue Qi
- State Key Lab of Pollution Control and Resource Reuse, Tongji University, Shanghai 200092, China
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Shen S, Li X, Cheng F, Zha X, Lu X. Review: recent developments of substrates for nitrogen and phosphorus removal in CWs treating municipal wastewater. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2020; 27:29837-29855. [PMID: 32472508 DOI: 10.1007/s11356-020-08808-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Accepted: 04/07/2020] [Indexed: 06/11/2023]
Abstract
Substrates are the main factor influencing the performance of constructed wetlands (CWs), and especially play an important role in enhancing the removal of nitrogen and phosphorus from CWs. In the recent 10 years, based on the investigation of emerged substrates used in CWs, this paper summarizes the removal efficiency and mechanism of nitrogen and phosphorus by a single substrate in detail. The simultaneous removal efficiency of nitrogen and phosphorus by different combined substrates is emphatically analyzed. Among them, the reuse of industrial and agricultural wastes as water treatment substrates is recommended due to the efficient pollutant removal efficiency and the principle of waste minimization, also more studies on the environmental impact and risk assessment of the application, and the subsequent disposal of saturated substrates are needed. This work serves as a basis for future screening and development of substrates utilized in CWs, which is helpful to enhance the synchronous removal of nitrogen and phosphorus, as well as improve the sustainability of substrates and CWs. Moreover, further studies on the interaction between different types of substrates in the wetland system are desperately needed.
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Affiliation(s)
- Shuting Shen
- School of Energy & Environment, Southeast University, 2 Sipailou Rd, Nanjing, 210096, Jiangsu, People's Republic of China
- ERC Taihu Lake Water Environment Wuxi, 99 Linghu Rd, Wuxi, 214135, People's Republic of China
| | - Xiang Li
- School of Energy & Environment, Southeast University, 2 Sipailou Rd, Nanjing, 210096, Jiangsu, People's Republic of China
- ERC Taihu Lake Water Environment Wuxi, 99 Linghu Rd, Wuxi, 214135, People's Republic of China
| | - Fangkui Cheng
- School of Energy & Environment, Southeast University, 2 Sipailou Rd, Nanjing, 210096, Jiangsu, People's Republic of China
- ERC Taihu Lake Water Environment Wuxi, 99 Linghu Rd, Wuxi, 214135, People's Republic of China
| | - Xiao Zha
- School of Energy & Environment, Southeast University, 2 Sipailou Rd, Nanjing, 210096, Jiangsu, People's Republic of China
- ERC Taihu Lake Water Environment Wuxi, 99 Linghu Rd, Wuxi, 214135, People's Republic of China
| | - Xiwu Lu
- School of Energy & Environment, Southeast University, 2 Sipailou Rd, Nanjing, 210096, Jiangsu, People's Republic of China.
- ERC Taihu Lake Water Environment Wuxi, 99 Linghu Rd, Wuxi, 214135, People's Republic of China.
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11
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Numerical Models of Subsurface Flow Constructed Wetlands: Review and Future Development. SUSTAINABILITY 2020. [DOI: 10.3390/su12083498] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Numerical model as a simulation tool was used to describe the pollutants transformation and degradation process in constructed wetlands (CWs). It can help provide insight into the “black box” and increase the understanding of the complex processes in CWs. In the last few decades, several process-based numerical models were developed to depict the pollutants removal processes in CWs, which include biochemical model, hydraulic model, reactive-transport model, plants model, clogging model, and coupling model combining two or more sub-models. However, there was a long way to go before fully understanding the decontamination mechanisms of CWs. On the one hand, single or a composite model coupling a small number of sub-models cannot fully reveal the decontamination processes. On the other hand, a comprehensive model including all sub-models of current cognition involves numerous parameters, most of which are interaction and cannot quantitatively determined, thus making the model complex and leading to diffuse interaction. Therefore, in order to describe the reaction processes in CWs more accurately, it is expected that all parameters should be quantified as far as possible in the future model. This study aims to provide a review of the numerical models of CWs and to reveal mechanism of decontamination. Based on the advantages and disadvantages of existing models, the study presented the improvement method and future research direction: (1) new detection/monitoring technique or computing method to quantitatively assess the parameters in CWs models, (2) correcting the simulation errors caused by the assumption of Activated Sludge Models (ASMs) and developing a complete biofilm reaction sub-model, (3) simplification of the comprehensive model, and (4) need of emerging pollutants modeling.
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12
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The Effects of Plants on Pollutant Removal, Clogging, and Bacterial Community Structure in Palm Mulch-Based Vertical Flow Constructed Wetlands. SUSTAINABILITY 2019. [DOI: 10.3390/su11030632] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
In this study, the effects of plants on the performance and bacterial community structure of palm mulch-based vertical flow constructed wetlands was studied. The wetlands were built in August 2013; one of them was planted with Canna indica and Xanthosoma sp., and the other one was not planted and used as a control. The experimental period started in September 2014 and finished in June 2015. The influent was domestic wastewater, and the average hydraulic surface loading was 208 L/m2d, and those of COD, BOD, and TSS were 77, 57, and 19 g/m2d, respectively. Although the bed without plants initially performed better, the first symptoms of clogging appeared in December 2014, and then, its performance started to fail. Afterwards, the wetland with plants provided better removals. The terminal restriction fragment length polymorphism (T-RFLP) analysis of Enterococci and Escherichia coli in the effluents suggests that a reduction in their biodiversity was caused by the presence of the plants. Thus, it can be concluded that the plants helped achieve better removals, delay clogging, and reduce Enterococci and E. coli biodiversity in the effluents.
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Yang Y, Zhao Y, Liu R, Morgan D. Global development of various emerged substrates utilized in constructed wetlands. BIORESOURCE TECHNOLOGY 2018; 261:441-452. [PMID: 29627204 DOI: 10.1016/j.biortech.2018.03.085] [Citation(s) in RCA: 149] [Impact Index Per Article: 24.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Revised: 03/12/2018] [Accepted: 03/17/2018] [Indexed: 06/08/2023]
Abstract
Substrate selection is one of the key technical issues for constructed wetlands (CWs), which works for wastewater treatment based mainly on the biofilm principle. In recent years, many alternative substrates have been studied and applied in CWs, and a review is conducive to providing updated information on CW R&D. Based on the intensive research work especially over the last 10 years on the development of emerged substrates (except for the three conventional substrates of soil, sand, and gravel) in CWs, this review was made. The substrates are categorized depending on their main roles in pollutant removal as ion-exchange substrates, P-sorption substrates, and electron donor substrates. Among these, reuse of various waste products as substrates was suggested due to their competitive pollutant removal efficiency and minimized waste disposal. Regarding substrate development, future research on avoiding substrate clogging to extend their lifetime in CWs is needed.
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Affiliation(s)
- Yan Yang
- UCD Dooge Centre for Water Resources Research, School of Civil Engineering, Newstead Building, University College Dublin, Belfield, Dublin 4, Ireland; Department of Environmental Engineering, Anhui Jianzhu University, Hefei 230601, Anhui, PR China
| | - Yaqian Zhao
- UCD Dooge Centre for Water Resources Research, School of Civil Engineering, Newstead Building, University College Dublin, Belfield, Dublin 4, Ireland; State Key Laboratory of Eco-Hydraulic Engineering in Arid Area, Xi'an University of Technology, Xi'an 710048, PR China.
| | - Ranbin Liu
- UCD Dooge Centre for Water Resources Research, School of Civil Engineering, Newstead Building, University College Dublin, Belfield, Dublin 4, Ireland
| | - David Morgan
- UCD Dooge Centre for Water Resources Research, School of Civil Engineering, Newstead Building, University College Dublin, Belfield, Dublin 4, Ireland
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14
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Marguti AL, Ferreira Filho SS, Piveli RP. Full-scale effects of addition of sludge from water treatment stations into processes of sewage treatment by conventional activated sludge. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2018; 215:283-293. [PMID: 29574206 DOI: 10.1016/j.jenvman.2018.03.072] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Revised: 03/13/2018] [Accepted: 03/15/2018] [Indexed: 06/08/2023]
Abstract
An emerging practice for water treatment plant (WTP) sludge is its disposal in wastewater treatment plants (WWTP), an alternative that does not require the installation of sludge treatment facilities in the WTP. This practice can cause both positive and negative impacts in the WWTP processes since the WTP sludge does not have the same characteristics as domestic wastewater. This issue gives plenty of information in laboratory and pilot scales, but lacks data from full-scale studies. The main purpose of this paper is to study the impact of disposing sludge from the Rio Grande conventional WTP into the ABC WWTP, an activated sludge process facility. Both plants are located in São Paulo, Brazil, and are full-scale facilities. The WTP volumetric flow rate (4.5 m³/s) is almost three times that of WWTP (1.6 m³/s). The data used in this study came from monitoring the processes at both plants. The WWTP liquid phase treatment analysis included the variables BOD, COD, TSS, VSS, ammonia, total nitrogen, phosphorus and iron, measured at the inlet, primary effluent, mixed liquor, and effluent. For the WWTP solids treatment, the parameters tested were total and volatile solids. The performance of the WWTP process was analyzed with and without sludge addition: 'without sludge' in years 2005 and 2006 and 'with sludge' from January 2007 to March 2008. During the second period, the WTP sludge addition increased the WWTP removal efficiencies for solids (93%-96%), organic matter (92%-94% for BOD) and phosphorus (52%-88%), when compared to the period 'without sludge'. These improvements can be explained by higher feed concentrations combined to same or lower effluent concentrations in the 'with sludge' period. No critical negative impacts occurred in the sludge treatment facilities, since the treatment units absorbed the extra solids load from the WTP sludge.
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Affiliation(s)
- André Luiz Marguti
- Department of Hydraulic and Environmental Engineering, Polytechnic School, University of Sao Paulo, Brazil.
| | | | - Roque Passos Piveli
- Department of Hydraulic and Environmental Engineering, Polytechnic School, University of Sao Paulo, Brazil.
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15
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Wang Y, Ren B, Zhao Y, English A, Cannon M. A comparison of alum sludge with peat for aqueous glyphosate removal for maximizing their value for practical use. WATER SCIENCE AND TECHNOLOGY : A JOURNAL OF THE INTERNATIONAL ASSOCIATION ON WATER POLLUTION RESEARCH 2018; 2017:450-456. [PMID: 29851397 DOI: 10.2166/wst.2018.165] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
This study compares and contrasts the glyphosate removal efficiency of alum sludge (waterworks residue) and Irish peat in aqueous solution. Organic phosphonate of glyphosate aqueous solution was removed in pot tests separately filled with peat and alum sludge, while effluent samples were taken from each pot to analyse the concentration of phosphorus (P) and COD (chemical oxygen demand); physical and chemical analysis for both media before and after use was carried out subsequently. The results show that the P removal capacity of alum sludge was significant (>99%), while the removal capacity of peat was considerably less than 10% after 10 weeks. Both materials significantly reduced the levels of COD, but it was noted that peat had a marginally greater initial P removal capacity (68 ± 22%) and did perform better than alum sludge (57 ± 12%). Moreover, pre-treatment is a crucial step to harness the full potential of peat. Overall, this study provides a scientific clue for sorbents selection when considering alum sludge and peat to maximize their value in practice.
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Affiliation(s)
- Yae Wang
- School of Environmental and Municipal Engineering, Lanzhou Jiaotong University, Lanzhou, Gansu 730070, China E-mail:
| | - Baiming Ren
- UCD Dooge Centre for Water Resources Research, School of Civil Engineering, University College Dublin, Belfield Dublin 4, Ireland; Université de Toulouse, Mines Albi, CNRS UMR 5302, Centre RAPSODEE, Campus Jarlard, Albi, 81013 Cedex 09, France
| | - Yaqian Zhao
- School of Environmental and Municipal Engineering, Lanzhou Jiaotong University, Lanzhou, Gansu 730070, China E-mail: ; UCD Dooge Centre for Water Resources Research, School of Civil Engineering, University College Dublin, Belfield Dublin 4, Ireland
| | - Anthony English
- UCD Dooge Centre for Water Resources Research, School of Civil Engineering, University College Dublin, Belfield Dublin 4, Ireland
| | - Martin Cannon
- UCD Dooge Centre for Water Resources Research, School of Civil Engineering, University College Dublin, Belfield Dublin 4, Ireland
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16
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Li X, Cui J, Pei Y. Granulation of drinking water treatment residuals as applicable media for phosphorus removal. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2018; 213:36-46. [PMID: 29477849 DOI: 10.1016/j.jenvman.2018.02.056] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Revised: 02/10/2018] [Accepted: 02/14/2018] [Indexed: 06/08/2023]
Abstract
Recycling drinking water treatment residuals (DWTR) show promise as a strategy for phosphorus (P) removal; however, powdered DWTR is not an ideal practical medium due to clogging. This study granulates DWTR by entrapping powdered DWTR in alginate beads. Results show that granular DWTR has an appreciable amount of mesopores along with a Brunauer-Emmett-Teller (BET) surface area of 43.8 m2/g and total pore volume of 0.049 cm3/g. Most metals (e.g., Al, Ba, Be, Cd, Co, Cr, Mn, Ni, Pb, and Zn) in granular DWTR became more stable and granular DWTR could be considered non-hazardous material. Further analysis indicates that the granular DWTR has strong P adsorption capability with a maximum adsorption capacity of 19.70 mg/g as estimated by the Langmuir model. Good P adsorption may be attributed to the formation of Fe-PO4 and Al-PO4 associated with the amorphous state of enormous iron and aluminum in granular DWTR. More importantly, granular DWTR exhibits good mechanical stability and maintained its shape with weight loss below 12.49% after three recycling rounds. Overall, granular DWTR appears to serve as better media for phosphorus removal in water treatment structures such as wetlands.
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Affiliation(s)
- Xiuqing Li
- The Key Laboratory of Water and Sediment Sciences, Ministry of Education, School of Environment, Beijing Normal University, Beijing 100875, PR China
| | - Jun Cui
- The Key Laboratory of Water and Sediment Sciences, Ministry of Education, School of Environment, Beijing Normal University, Beijing 100875, PR China
| | - Yuansheng Pei
- The Key Laboratory of Water and Sediment Sciences, Ministry of Education, School of Environment, Beijing Normal University, Beijing 100875, PR China.
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17
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Zhao Y, Liu R, Zhao J, Xu L, Sibille C. A fancy eco-compatible wastewater treatment system: Green Bio-sorption Reactor. BIORESOURCE TECHNOLOGY 2017; 234:224-232. [PMID: 28319771 DOI: 10.1016/j.biortech.2017.03.037] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2017] [Revised: 02/27/2017] [Accepted: 03/05/2017] [Indexed: 06/06/2023]
Abstract
A novel concept was proposed and preliminarily investigated by embedding alum sludge-based constructed wetland into conventional activated sludge system in terms of Green Bio-sorption Reactor (GBR). This novel GBR inherited the aesthetic value of constructed wetland and owned the robust phosphorus (P) adsorption along with the benefit of carriers' addition (dewatered alum sludge). The preliminary demonstration was conducted in a lab-scale sequencing batch reactor (SBR) system without biological phosphorus removal process. The novel process achieved averagely 96%, 99% and 90% for BOD, TP and TN removal with piggery wastewater as influent, demonstrating for the first time of its promising performance. Moreover, the coexistence of biofilm and suspended sludge also achieved 55-88% simultaneous nitrification and denitrification efficiency, higher than biofilm only. Overall, alum sludge-based GBR could achieve reliable pollutants removal and provides a novel and sustainable pathway to upgrade conventional activated sludge system.
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Affiliation(s)
- Yaqian Zhao
- School of Civil Engineering and Architecture, Xi'an University of Technology, Xi'an 710048, Shaanxi, PR China; UCD Dooge Centre for Water Resources Research, School of Civil Engineering, University College Dublin, Belfield, Dublin 4, Ireland
| | - Ranbin Liu
- UCD Dooge Centre for Water Resources Research, School of Civil Engineering, University College Dublin, Belfield, Dublin 4, Ireland.
| | - Jinhui Zhao
- College of Urban Construction, Nanjing Tech University, Nanjing 211816, PR China
| | - Lei Xu
- UCD Dooge Centre for Water Resources Research, School of Civil Engineering, University College Dublin, Belfield, Dublin 4, Ireland
| | - Caroline Sibille
- Ecole des Mines de Nantes, Energy Systems Environment Department, 4 rue Afred Kastler, BP 20722, 44307 Nantes Cedex 3, France
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18
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Babatunde AO, Miranda-CasoLuengo R, Imtiaz M, Zhao YQ, Meijer WG. Performance assessment and microbial diversity of two pilot scale multi-stage sub-surface flow constructed wetland systems. J Environ Sci (China) 2016; 46:38-46. [PMID: 27521934 DOI: 10.1016/j.jes.2015.02.018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2014] [Revised: 01/30/2015] [Accepted: 02/16/2015] [Indexed: 06/06/2023]
Abstract
This study assessed the performance and diversity of microbial communities in multi-stage sub-surface flow constructed wetland systems (CWs). Our aim was to assess the impact of configuration on treatment performance and microbial diversity in the systems. Results indicate that at loading rates up to 100gBOD5/(m(2)·day), similar treatment performances can be achieved using either a 3 or 4 stage configuration. In the case of phosphorus (P), the impact of configuration was less obvious and a minimum of 80% P removal can be expected for loadings up to 10gP/(m(2)·day) based on the performance results obtained within the first 16months of operation. Microbial analysis showed an increased bacterial diversity in stage four compared to the first stage. These results indicate that the design and configuration of multi-stage constructed wetland systems may have an impact on the treatment performance and the composition of the microbial community in the systems, and such knowledge can be used to improve their design and performance.
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Affiliation(s)
- A O Babatunde
- Hydro-environmental Research Centre, Institute of Environment and Sustainability, Cardiff School of Engineering, Cardiff University, Queen's Buildings, The Parade, Cardiff, CF24 3AA, UK; UCD School of Civil, Structural and Environmental Engineering, Newstead Building, University College Dublin, Belfield, Dublin 4, Ireland.
| | - Raul Miranda-CasoLuengo
- UCD School of Biomolecular and Biomedical Science, Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland
| | - Mehreen Imtiaz
- UCD School of Biomolecular and Biomedical Science, Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland
| | - Y Q Zhao
- UCD School of Civil, Structural and Environmental Engineering, Newstead Building, University College Dublin, Belfield, Dublin 4, Ireland
| | - Wim G Meijer
- UCD School of Biomolecular and Biomedical Science, Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland
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19
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Wang C, Jiang HL, Xu H, Yin H. Variation of physicochemical properties of drinking water treatment residuals and Phoslock(®) induced by fulvic acid adsorption: Implication for lake restoration. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2016; 23:351-365. [PMID: 26308919 DOI: 10.1007/s11356-015-5209-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Accepted: 08/10/2015] [Indexed: 06/04/2023]
Abstract
The use of phosphorus (P) inactivating agents to reduce internal P loading from sediment for lake restoration has attracted increasing attention. Reasonably, the physicochemical properties of P inactivating agents may vary with the interference of various environmental factors, leading to the change of control effectiveness and risks. In this study, the effect of fulvic acid (FA) adsorption on the properties of two agents, drinking water treatment residuals (DWTRs) and Phoslock®, was investigated. The results showed that after adsorption, there was little change for the main structures of DWTRs and Phoslock®, but the thermostability of Phoslock®, as well as the particle size and settleability of the two agents decreased. The specific surface area and pore volume of DWTRs also decreased, while those of Phoslock® increased. Further analysis indicated that aluminum and iron in DWTRs were stable during FA adsorption, but a substantial increase of lanthanum release from Phoslock® was observed, in particular at first (P < 0.01). Moreover, the P immobilization capability of DWTRs had little change after FA adsorption, while the capability of Phoslock® after FA adsorption decreased in solutions (P < 0.001) and sediments (P < 0.1); interestingly, from the view of engineering application, the performance of Phoslock® was not substantially affected. Overall, each P inactivating agent had its own particular responses of the physicochemical properties to environment factors, and detailed investigations on the applicability of each agent were essential before practical application.
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Affiliation(s)
- Changhui Wang
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, 210008, China
| | - He-Long Jiang
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, 210008, China.
| | - Huacheng Xu
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, 210008, China
| | - Hongbin Yin
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, 210008, China
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20
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Wang C, Yuan N, Pei Y, Jiang HL. Aging of aluminum/iron-based drinking water treatment residuals in lake water and their association with phosphorus immobilization capability. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2015; 159:178-185. [PMID: 26071931 DOI: 10.1016/j.jenvman.2015.04.047] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Revised: 04/27/2015] [Accepted: 04/28/2015] [Indexed: 06/04/2023]
Abstract
Aluminum and Fe-based drinking water treatment residuals (DWTRs) have shown a high potential for use by geoengineers in internal P loading control in lakes. In this study, aging of Al/Fe-based DWTRs in lake water under different pH and redox conditions associated with their P immobilization capability was investigated based on a 180-day incubation test. The results showed that the DWTRs before and after incubation under different conditions have similar structures, but their specific surface area and pore volume, especially mesopores with radius at 2.1-5.0 nm drastically decreased. The oxalate extractable Al contents changed little although a small amount of Al transformed from oxidizable to residual forms. The oxalate extractable Fe contents also decreased by a small amount, but the transformation from oxidizable to residual forms were remarkable, approximately by 14.6%. However, the DWTRs before and after incubation had similar P immobilization capabilities in solutions and lake sediments. Even the maximum P adsorption capacity estimated by the Langmuir model increased after incubation. Therefore, it was not necessary to give special attention to the impact of Al and Fe aging on the effectiveness of DWTRs for geoengineering in lakes.
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Affiliation(s)
- Changhui Wang
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China
| | - Nannan Yuan
- The Key Laboratory of Water and Sediment Sciences, Ministry of Education, School of Environment, Beijing Normal University, Beijing 100875, China
| | - Yuansheng Pei
- The Key Laboratory of Water and Sediment Sciences, Ministry of Education, School of Environment, Beijing Normal University, Beijing 100875, China
| | - He-Long Jiang
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China.
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21
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Dassanayake KB, Jayasinghe GY, Surapaneni A, Hetherington C. A review on alum sludge reuse with special reference to agricultural applications and future challenges. WASTE MANAGEMENT (NEW YORK, N.Y.) 2015; 38:321-335. [PMID: 25655353 DOI: 10.1016/j.wasman.2014.11.025] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2014] [Revised: 11/24/2014] [Accepted: 11/28/2014] [Indexed: 06/04/2023]
Abstract
Alum salts are commonly used in the water industry to promote coagulation in the production of clean drinking water, which results in the generation and accumulation of 'waste' by-product 'alum sludge' in large volumes. Effective and efficient management of alum sludge in an economically and environmentally sustainable manner remains a significant social and environmental concern with ever increasing demand for potable water as a result of rapidly escalating world population and urban expansion. Various intensive practices have been employed to reuse the alum sludge in an attempt to figure out how to fill the gap between successful drinking water treatment process and environmentally friendly alum sludge management for over the years. This paper primarily aimed at comprehensive review of the existing literature on alum sludge characteristics, its environmental concerns and their potential utilization, especially in agricultural and horticultural sectors leading to update our recent state of knowledge and formulate a compendium of present and past developments. Different types of alum sludge utilizations in various fields were recognized and examined. The strengths, weaknesses, opportunities and potential risks of alum sludge reuse options with particular reference to agriculture were highlighted and knowledge gaps were identified. Research priorities and future challenges that will support in the development of effective alumsludgemanagement practices in agriculture with multi-prong strategies were discussed.
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Affiliation(s)
- K B Dassanayake
- Melbourne School of Land and Environment, The University of Melbourne, 500 Yarra Boulevard, Richmond, Victoria 3121, Australia.
| | - G Y Jayasinghe
- Melbourne School of Land and Environment, The University of Melbourne, 500 Yarra Boulevard, Richmond, Victoria 3121, Australia; Department of Agric. Engineering, Faculty of Agriculture, University of Ruhuna, Sri Lanka.
| | - A Surapaneni
- South East Water, 20 Corporate Drive, Heatherton, Victoria 3202, Australia
| | - C Hetherington
- Transpacific Industries Group Ltd, 390 Princess Highway, Bomaderry 2541, Australia
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22
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Li C, Wu S, Dong R. Dynamics of organic matter, nitrogen and phosphorus removal and their interactions in a tidal operated constructed wetland. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2015; 151:310-316. [PMID: 25585144 DOI: 10.1016/j.jenvman.2015.01.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2014] [Revised: 09/26/2014] [Accepted: 01/07/2015] [Indexed: 06/04/2023]
Abstract
This paper demonstrates the potential of tidal flow operated constructed wetland application for the removal dynamics of organic matter, nitrogen and phosphorus. Near-complete removal of organic matter was achieved with a constant removal efficiency of 95%, irrespective of TOC influent loadings ranged from 10 g/m(2) · d to 700 g/m(2) · d. High NH4(+)-N removal at 95% efficiency under influent loading of 17 g/m(2) · d, was stably obtained and was not negatively influenced by increasing influent organic carbon loading rate. Increased influent TOC loading (350 g/m(2) · d to 700 g/m(2) · d) significantly enhanced denitrification capacity and increased TN removal from 30% to 95%. Under tidal flow operation, a higher carbon supply (C/N = 20) for complete TN removal was demonstrated as comparing to that observed in traditional CWs approaches. In addition, the removal of phosphorus was strongly influenced by organic loadings. However, further investigations are needed to elucidate the detailed mechanism that would explain the role of organic loading in phosphorus removal.
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Affiliation(s)
- Chunyan Li
- Key Laboratory of Clean Utilization Technology for Renewable Energy in Ministry of Agriculture, College of Engineering, China Agricultural University, 100083 Beijing, People's Republic of China
| | - Shubiao Wu
- Key Laboratory of Clean Utilization Technology for Renewable Energy in Ministry of Agriculture, College of Engineering, China Agricultural University, 100083 Beijing, People's Republic of China.
| | - Renjie Dong
- Key Laboratory of Clean Utilization Technology for Renewable Energy in Ministry of Agriculture, College of Engineering, China Agricultural University, 100083 Beijing, People's Republic of China
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23
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Kumar JLG, Zhao YQ, Hu YS, Babatunde AO, Zhao XH. Nitrogen dynamics model for a pilot field-scale novel dewatered alum sludge cake-based constructed wetland system. ENVIRONMENTAL TECHNOLOGY 2015; 36:732-741. [PMID: 25179044 DOI: 10.1080/09593330.2014.960476] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
A model simulating the effluent nitrogen (N) concentration of treated animal farm wastewater in a pilot on-site constructed wetland (CW) system, using dewatered alum sludge cake (DASC) as wetland substrate, is presented. The N-model was developed based on the Structural Thinking Experiential Learning Laboratory with Animation software and is considering organic nitrogen, ammonia nitrogen (NH3) and nitrate nitrogen (NO3-N) as the major forms of nitrogen involved in the transformation chains. Ammonification (AMM), ammonia volatilization, nitrification (NIT), denitrification, plant uptake, plant decaying and uptake of inorganic nitrogen by algae and bacteria were considered in this model. pH, dissolved oxygen, temperature, precipitation, solar radiation and nitrogen concentrations were considered as forcing functions in the model. The model was calibrated by observed data with a reasonable agreement prior to its applications. The simulated effluent detritus nitrogen, NH4-N, NO3-N and TN had a considerably good agreement with the observed results. The mass balance analysis shows that NIT accounts for 65.60%, adsorption (ad) (11.90%), AMM (8.90%) followed by NH4-N (Plants) (5.90%) and NO3-N (Plants) (4.40%). The TN removal was found 52% of the total influent TN in the CW. This study suggested an improved overall performance of a DASC-based CW and efficient N removal from wastewater.
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Affiliation(s)
- J L G Kumar
- a UCD Dooge Centre for Water Resources Research, School of Civil, Structural and Environmental Engineering , University College Dublin , Newstead, Belfield, Dublin 4 , Ireland
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24
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Zhao X, Zhao Y, Wang W, Yang Y, Babatunde A, Hu Y, Kumar L. Key issues to consider when using alum sludge as substrate in constructed wetland. WATER SCIENCE AND TECHNOLOGY : A JOURNAL OF THE INTERNATIONAL ASSOCIATION ON WATER POLLUTION RESEARCH 2015; 71:1775-1782. [PMID: 26067496 DOI: 10.2166/wst.2015.138] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Globally, alum sludge is an easily, locally and largely available by-product from water treatment plants where aluminium sulphate is used as the coagulant for raw water purification. Owing to the high content of Al ions (29.7±13.3% dry weight) in alum sludge and the strong affinity of Al ions to adsorb various pollutants especially phosphorus (P), alum sludge (in the form of dewatered cakes) has been investigated in recent years as a low-cost alternative substrate in constructed wetland (CW) systems to enhance the treatment efficiency especially for high strength P-containing wastewater. Long-term trials in different scales have demonstrated that the alum sludge-based CW is a promising technique with a two-pronged feature of using 'waste' for wastewater treatment. Alum sludge cakes in CW can serve as a medium for wetland plant growth, as a carrier for biofilm development and as a porous material for wastewater infiltration. After the intensive studies of the alum sludge-based CW system, this paper aims to address the key issues and concerns pertaining to this kind of CW system. These include: (1) Is alum sludge suitable for reuse in CWs? (2) Is Al released from the sludge a concern? (3) What is the lifespan of the alum sludge in CWs? (4) How can P be recovered from the used alum sludge? (5) Does clogging happen in alum sludge-based CW systems and what is the solution?
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Affiliation(s)
- Xiaohong Zhao
- The Key Laboratory of Water Supply and Drainage, Ministry of Housing and Urban-Rural Development, Chang'an University, Xi'an 710054, China E-mail: ; Dooge Centre for Water Resources Research, School of Civil, Structural and Environmental Engineering, University College Dublin, Newstead, Belfield, Dublin 4, Ireland
| | - Yaqian Zhao
- The Key Laboratory of Water Supply and Drainage, Ministry of Housing and Urban-Rural Development, Chang'an University, Xi'an 710054, China E-mail: ; Dooge Centre for Water Resources Research, School of Civil, Structural and Environmental Engineering, University College Dublin, Newstead, Belfield, Dublin 4, Ireland
| | - Wenke Wang
- The Key Laboratory of Water Supply and Drainage, Ministry of Housing and Urban-Rural Development, Chang'an University, Xi'an 710054, China E-mail:
| | - Yongzhe Yang
- Dooge Centre for Water Resources Research, School of Civil, Structural and Environmental Engineering, University College Dublin, Newstead, Belfield, Dublin 4, Ireland; School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Akintunde Babatunde
- Dooge Centre for Water Resources Research, School of Civil, Structural and Environmental Engineering, University College Dublin, Newstead, Belfield, Dublin 4, Ireland; Hydro-environmental Research Centre, Cardiff University School of Engineering, Queen's Buildings, The Parade, Cardiff, Wales CF24 3AA, UK
| | - Yuansheng Hu
- Dooge Centre for Water Resources Research, School of Civil, Structural and Environmental Engineering, University College Dublin, Newstead, Belfield, Dublin 4, Ireland; The R & D Centre of Sustainable Environmental Biotechnology, Beijing University of Civil Engineering and Architecture, 1 Zhan Lan Guan Road, Beijing 100044, China
| | - Lordwin Kumar
- Dooge Centre for Water Resources Research, School of Civil, Structural and Environmental Engineering, University College Dublin, Newstead, Belfield, Dublin 4, Ireland; Department of Soil Water Land Engineering and Management, Vaugh School of Agricultural Engineering and Technology, Sam Higginbottom Institute of Agriculture, Technology and Sciences, Allahabad, India
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25
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Keeley J, Jarvis P, Judd SJ. Coagulant Recovery from Water Treatment Residuals: A Review of Applicable Technologies. CRITICAL REVIEWS IN ENVIRONMENTAL SCIENCE AND TECHNOLOGY 2014; 44:2675-2719. [PMID: 26064036 PMCID: PMC4440624 DOI: 10.1080/10643389.2013.829766] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Conventional water treatment consumes large quantities of coagulant and produces even greater volumes of sludge. Coagulant recovery (CR) presents an opportunity to reduce both the sludge quantities and the costs they incur, by regenerating and purifying coagulant before reuse. Recovery and purification must satisfy stringent potable regulations for harmful contaminants, while remaining competitive with commercial coagulants. These challenges have restricted uptake and lead research towards lower-gain, lower-risk alternatives. This review documents the context in which CR must be considered, before comparing the relative efficacies and bottlenecks of potential technologies, expediting identification of the major knowledge gaps and future research requirements.
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Affiliation(s)
- J. Keeley
- Cranfield Water Science Institute, Cranfield University, Cranfield, Bedfordshire, UK
| | - P. Jarvis
- Cranfield Water Science Institute, Cranfield University, Cranfield, Bedfordshire, UK
- Address correspondence to P. Jarvis, Cranfield Water Science Institute, Cranfield University, Cranfield, BedfordshireMK43 0AL, UK. E-mail:
| | - S. J. Judd
- Cranfield Water Science Institute, Cranfield University, Cranfield, Bedfordshire, UK
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26
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Bai L, Wang C, He L, Pei Y. Influence of the inherent properties of drinking water treatment residuals on their phosphorus adsorption capacities. J Environ Sci (China) 2014; 26:2397-2405. [PMID: 25499487 DOI: 10.1016/j.jes.2014.04.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2014] [Revised: 04/17/2014] [Accepted: 04/22/2014] [Indexed: 06/04/2023]
Abstract
Batch experiments were conducted to investigate the phosphorus (P) adsorption and desorption on five drinking water treatment residuals (WTRs) collected from different regions in China. The physical and chemical characteristics of the five WTRs were determined. Combined with rotated principal component analysis, multiple regression analysis was used to analyze the relationship between the inherent properties of the WTRs and their P adsorption capacities. The results showed that the maximum P adsorption capacities of the five WTRs calculated using the Langmuir isotherm ranged from 4.17 to 8.20mg/g at a pH of 7 and further increased with a decrease in pH. The statistical analysis revealed that a factor related to Al and 200 mmol/L oxalate-extractable Al (Alox) accounted for 36.5% of the variations in the P adsorption. A similar portion (28.5%) was attributed to an integrated factor related to the pH, Fe, 200 mmol/L oxalate-extractable Fe (Feox), surface area and organic matter (OM) of the WTRs. However, factors related to other properties (Ca, P and 5 mmol/L oxalate-extractable Fe and Al) were rejected. In addition, the quantity of P desorption was limited and had a significant negative correlation with the (Feox+Alox) of the WTRs (p<0.05). Overall, WTRs with high contents of Alox, Feox and OM as well as large surface areas were proposed to be the best choice for P adsorption in practical applications.
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Affiliation(s)
- Leilei Bai
- The Key Laboratory of Water and Sediment Sciences, Ministry of Education, School of Environment, Beijing Normal University, Beijing 100875, China.
| | - Changhui Wang
- The Key Laboratory of Water and Sediment Sciences, Ministry of Education, School of Environment, Beijing Normal University, Beijing 100875, China
| | - Liansheng He
- Water Environment System Project Laboratory, Chinese Research Academy of Environmental Sciences, Beijing 100012, China
| | - Yuansheng Pei
- The Key Laboratory of Water and Sediment Sciences, Ministry of Education, School of Environment, Beijing Normal University, Beijing 100875, China.
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Wang C, Yuan N, Pei Y. Effect of pH on Metal Lability in Drinking Water Treatment Residuals. JOURNAL OF ENVIRONMENTAL QUALITY 2014; 43:389-397. [PMID: 25602573 DOI: 10.2134/jeq2013.06.0233] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Drinking water treatment residuals (WTRs), by-products generated during treatment of drinking water, can be reused as environmental amendments to remediate contamination. However, this beneficial reuse may be hampered by the potential release of toxic contaminants (e.g., metals) in the WTRs. In present study, batch tests and then fractionation, in vitro digestion, and the toxicity characteristic leaching procedure were used to investigate the release and extractability of metals in the Fe/Al hydroxides comprised WTRs under differing pH. The results demonstrated that significant release from WTRs for Ba, Be, Ca, Cd, Co, Cr, Fe, Mg, Mn, Pb, Sr, and Zn occurred under low pH (acid condition); for As, Mo, and V under high pH (alkaline condition); and for Al, Cu, and Ni under both conditions. In comparison, most metals in the WTRs were more easily released under low pH, but the release was stable at a relatively low level between pH 6 and 9, especially under alkaline conditions. Further analysis indicated that the chemical extractability and bioaccessibility of many metals was found to increase in the WTRs after being leached, even though the leached WTRs could still be considered nonhazardous. These results demonstrated that pH had a substantial effect on the lability of metals in WTRs. Overall, caution should be used when considering pH conditions during WTRs reuse to avoid potential metal pollution.
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Wang C, Pei Y. Effects of light, microbial activity, and sediment resuspension on the phosphorus immobilization capability of drinking water treatment residuals in lake sediment. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2013; 20:8900-8908. [PMID: 23749370 DOI: 10.1007/s11356-013-1865-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2013] [Accepted: 05/23/2013] [Indexed: 06/02/2023]
Abstract
Drinking water treatment residuals (WTRs), nonhazardous by-products generated in a drinking water treatment plant, can be reused to immobilize phosphorus (P) to control the internal P loading from lake sediments for eutrophication control. Reasonably, before practical application, it is essential to determine the P immobilization capability of WTRs in lake sediments under various conditions. In this work, laboratory scale experiments were conducted to investigate the effects of light, microbial activity, and sediment resuspension on the P immobilization capability of WTRs. The results suggested that absence of light, low microbial activity, and sediment resuspension can increase the internal P loading from lake sediments. WTRs can, however, reduce the internal P loading significantly. Further analysis demonstrated that WTRs can stabilize P, decreasing the P bioavailability in the sediments under varied conditions. WTRs also presented little undesirable effects on the dissolved oxygen levels and pH of overlying water. Therefore, light, microbial activity, and sediment resuspension have little effect on the P immobilization capability of WTRs in lake sediments.
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Affiliation(s)
- Changhui Wang
- The Key Laboratory of Water and Sediment Sciences, Ministry of Education, School of Environment, Beijing Normal University, Beijing, 100875, People's Republic of China
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Wang C, Pei Y. A comparison of the phosphorus immobilization capabilities of water treatment residuals before and after settling from lake water. Sep Purif Technol 2013. [DOI: 10.1016/j.seppur.2013.04.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Wang C, Bai L, Pei Y. Assessing the stability of phosphorus in lake sediments amended with water treatment residuals. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2013; 122:31-36. [PMID: 23542229 DOI: 10.1016/j.jenvman.2013.03.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2012] [Revised: 03/04/2013] [Accepted: 03/05/2013] [Indexed: 06/02/2023]
Abstract
The reuse of drinking water treatment residuals (WTRs) to immobilize phosphorus (P) in sediments is a novel application for lake restoration. The recycling of WTRs is beneficial from both environmental and economic standpoints. This work assessed the stability of P in sediments found in Lake Taihu and Lake Baiyangdian before and after being amended with WTRs. The results indicated that WTRs had similar effects on the stability of P in each of the lake's sediments. WTRs can significantly reduce the P desorption potential of the sediments at pH values less than 11. WTRs can also inhibit the competitive adsorption of SiO4(2-) with P. Compared with the raw sediments, the organic matter in the sediments, ion strength and anaerobic conditions presented minor undesirable effects on the stability of P in the WTRs-amended sediments. Moreover, WTRs can increase the P adsorption rate and capacity of the sediments. Overall, these results demonstrated that WTRs can make P more stable in lake sediments under various conditions.
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Affiliation(s)
- Changhui Wang
- The Key Laboratory of Water and Sediment Sciences, Ministry of Education, School of Environment, Beijing Normal University, Beijing 100875, PR China
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Hu YS, Zhao YQ, Zhao XH, Kumar JLG. Comprehensive analysis of step-feeding strategy to enhance biological nitrogen removal in alum sludge-based tidal flow constructed wetlands. BIORESOURCE TECHNOLOGY 2012; 111:27-35. [PMID: 22357288 DOI: 10.1016/j.biortech.2012.01.165] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2011] [Revised: 01/24/2012] [Accepted: 01/26/2012] [Indexed: 05/31/2023]
Abstract
Step-feeding strategies have been extensively studied and comprehensively analyzed in this study for a four-stage alum sludge-based tidal flow constructed wetlands (AlS-TFCWs) system. Enhanced total nitrogen removal of 83% is achieved under high nitrogen loading rate of 19.1 g N/m(2)d. The key issues towards the success of a significant nitrogen removal in step-feeding TFCWs are the bed resting time (which provides better aeration for nitrification) and up flow stage/delayed input of side stream(s) (which ensure favorable environment for better denitrification). Simultaneous nitrification and denitrification (SND) was found effective in the 1st stage of the system and SND via nitrite is the main nitrogen conversion mechanism. The optimal influent distribution fraction for step-feeding purpose can be estimated from a theoretical basis, which is a function of the influent BCOD/TKN ratio. Therefore the influent distribution fraction should be adjusted according to the variety of influent characteristics, rather than a fixed value.
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Affiliation(s)
- Y S Hu
- Centre for Water Resources Research, School of Civil, Structural and Environmental Engineering, University College Dublin, Newstead Building, Belfield, Dublin 4, Ireland
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Hu YS, Kumar JLG, Akintunde AO, Zhao XH, Zhao YQ. Effects of livestock wastewater variety and disinfectants on the performance of constructed wetlands in organic matters and nitrogen removal. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2011; 18:1414-1421. [PMID: 21487645 DOI: 10.1007/s11356-011-0507-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2011] [Accepted: 03/28/2011] [Indexed: 05/30/2023]
Abstract
BACKGROUND, AIM AND SCOPE Treatment performance of constructed wetlands (CWs) is largely dependent on the characteristics of the wastewater. Although livestock wastewater is readily biodegradable in general, its variety in biodegradability can still be significant in practice. In addition, it is a common practice to periodically use disinfectants in livestock activities for health concerns. Obviously, the residual of the disinfectants in livestock wastewater may have serious inhibitory effect on the microbial activities during wastewater treatment. Thus, the main objective of this study was to examine the variety of livestock wastewater in biodegradability and its effect on the performance of a pilot scale tidal flow CWs (TFCWs) in organic matter and nitrogen removal. Furthermore, investigation of the potential inhibition of the chosen disinfectants on organic matter biodegradation and nitrification was another aim of this study. MATERIALS AND METHODS The TFCWs system consisted of four-stage downflow reed beds with a hydraulic loading rate of 0.29 m(3)/m(2)·per day. Long-term stored livestock wastewater and fresh livestock wastewater were used, respectively, as feed to the system in different periods. Meanwhile, batch aeration tests were carried out to investigate the difference in biodegradation of the two types of wastewaters. Inhibitions of two types of disinfectants, namely UNIPRED and HYPROCLOR ED, on microbial activities were investigated in laboratory batch tests, with dosage of from 0.05% to 0.5%. RESULTS With fresh livestock wastewater, removal efficiencies of up to 93% and 94% could be achieved with average of 73% and 64% for chemical oxygen demand (COD) and TN, respectively. The performance deteriorated when the system was fed with long-term stored wastewater. In the batch tests, the long-time stored wastewater was characterized as non-biodegradable or at least very slowly biodegradable, while the fresh wastewater was readily biodegradable. UNIPRED showed very strong inhibition on both heterotrophic organisms and nitrifiers. Tested inhibition started from content of 0.05%, which is 1/10 of the recommended usage rate. Inhibitory effect of HYPROCLOR ED on COD degradation started from 0.1% and complete inhibition occurred from content of 0.3%, while significant inhibition on nitrification started from 0.1%. CONCLUSIONS Livestock wastewater could vary significantly in biodegradability and it may turn to be non-biodegradable after a long-term storage. The variety of the livestock wastewater has a decisive influence on the performance of the CWs system, especially in TN elimination. In addition, the application of disinfectants UNIPRED and HYPROCLOR ED may cause serious inhibition on microbial activities and subsequent system failure.
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Affiliation(s)
- Y S Hu
- Centre for Water Resources Research, School of Architecture, Landscape and Civil Engineering, Newstead Building, University College Dublin, Belfield, Dublin 4, Ireland.
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Babatunde AO, Kumar JLG, Zhao Y. Constructed wetlands using aluminium-based drinking water treatment sludge as P-removing substrate: should aluminium release be a concern? ACTA ACUST UNITED AC 2011; 13:1775-83. [PMID: 21547295 DOI: 10.1039/c1em00001b] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
This study investigated an important issue of aluminium (Al) release from a novel reuse of Al-based water treatment sludge (Al-WTS) in constructed wetland system (CWs) as alternative substrate for wastewater treatment. Al-WTS is an inevitable by-product of drinking water treatment plants that use Al-salt as coagulant for raw water purification. It has recently been demonstrated that Al-WTS can be reused as a low-cost phosphorus (P) adsorbent and biofilm carrier in CWs for wastewater treatment. However, to facilitate the large scale application of Al-WTS in CWs as wetland substrate, concerns about Al leaching during its reuse in CWs must be addressed as Al is a dominant constituent in Al-WTS. In this study, a desk review of literature on Al release during Al-WTS reuse was conducted. Furthermore, a 42-week Al monitoring was carried out on a pilot field-scale CWs employing Al-WTS as main substrate. Results show that 22 out of the 35 studies reviewed, reported Al release with levels of soluble Al reported ranging from 0.01 to about 20 mg L(-1). Monitoring of Al in the pilot field-scale CWs shows that there was Al leaching. However, except for the first three weeks of operation, effluents concentrations of both total- and soluble-Al were all below the general regulatory guideline limit of 0.2 mg L(-1). Overall, the study addresses a vital concern regarding the successful application of Al-WTS in CWs and shows that Al release during such novel reuse is quite low and should not preclude its use.
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Affiliation(s)
- Akintunde O Babatunde
- Centre for Water Resources Research, School of Architecture, Landscape and Civil Engineering, University College Dublin, Belfield, Dublin, 4, Ireland
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Babatunde AO, Zhao YQ, Doyle RJ, Rackard SM, Kumar JLG, Hu YS. Performance evaluation and prediction for a pilot two-stage on-site constructed wetland system employing dewatered alum sludge as main substrate. BIORESOURCE TECHNOLOGY 2011; 102:5645-5652. [PMID: 21382711 DOI: 10.1016/j.biortech.2011.02.065] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2010] [Revised: 02/14/2011] [Accepted: 02/15/2011] [Indexed: 05/30/2023]
Abstract
Dewatered alum sludge, a widely generated by-product of drinking water treatment plants using aluminium salts as coagulants was used as main substrate in a pilot on-site constructed wetland system treating agricultural wastewater for 11 months. Treatment performance was evaluated and spreadsheet analysis was used to establish correlations between water quality variables. Results showed that removal rates (in g/m(2)d) of 4.6-249.2 for 5 day biochemical oxygen demand (BOD(5)), 35.6-502.0 for chemical oxygen demand (COD), 2.5-14.3 for total phosphorus (TP) and 2.7-14.6 for phosphate (PO(4)P) were achieved. Multiple regression analysis showed that effluent BOD(5) and COD can be predicted to a reasonable accuracy (R(2)=0.665 and 0.588, respectively) by using input variables which can be easily monitored in real time as sole predictor variables. This could provide a rapid and cheap alternative to such laborious and time consuming analyses and also serve as management tools for day-to-day process control.
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Affiliation(s)
- A O Babatunde
- Centre for Water Resources Research, School of Architecture, Landscape and Civil Engineering, University College Dublin, Belfield, Dublin 4, Ireland
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Kumar JLG, Zhao YQ. A review on numerous modeling approaches for effective, economical and ecological treatment wetlands. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2011; 92:400-406. [PMID: 21134712 DOI: 10.1016/j.jenvman.2010.11.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2009] [Revised: 10/18/2010] [Accepted: 11/09/2010] [Indexed: 05/30/2023]
Abstract
Constructed wetlands (CWs) for wastewater treatment have evolved substantially over the last decades and have been recognized as an effective means of "green technology" for wastewater treatment. This paper reviews the numerous modeling approaches ranging from simple first-order models to more complex dynamic models of treatment behaviour in CWs. The main objective of the modeling work is to better understand the process in CWs and optimize design criteria. A brief study in this review discusses the efforts taken to describe the process-based model for the efficient removal of pollutants in CWs. Obtaining better insights is essential to understand the hydraulic and biochemical processes in CWs. Currently, employed modeling approaches can be seen in two categories, i.e. "black-box models" and "process-based models". It is evident that future development in wetland technology will depend on improved scientific knowledge of internal treatment mechanisms.
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Affiliation(s)
- J L G Kumar
- Centre for Water Resources Research, School of Architecture, Landscape and Civil Engineering, University College Dublin, Newstead, Belfield, Dublin 4, Ireland
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Wang C, Guo W, Tian B, Pei Y, Zhang K. Characteristics and kinetics of phosphate adsorption on dewatered ferric-alum residuals. JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH. PART A, TOXIC/HAZARDOUS SUBSTANCES & ENVIRONMENTAL ENGINEERING 2011; 46:1632-1639. [PMID: 22092260 DOI: 10.1080/10934529.2011.623643] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The characteristics and kinetics of phosphate (P) adsorption on dewatered ferric-alum water treatment residuals (Fe-Al-WTRs) have been investigated. The existence of both aluminum (Al) and iron (Fe) in the residuals can result in significantly high P adsorption capacities. The P adsorption kinetics of Fe-Al-WTRs exhibited an initial rapid phase, followed by a slower phase. This could be described by three models, including a pseudo-first-order equation, a pseudo-second-order equation, and a double-constant rate equation. The latter was especially good for those runs with initial P concentrations of 500 and 1000 mg L(-1). Both the Langmuir and Freundlich isotherms fit the experimental data well, particularly the Freundlich isotherm, which had a correlation coefficient of 0.9930. The maximum measured P adsorption capacity of Fe-Al-WTRs was 45.42 mg g(-1), which is high when compared to those of most WTRs, as well as other reported adsorbents. The results also show that the P adsorption is a spontaneous endothermic process. Highest P adsorption capacities of Fe-Al-WTRs were measured at low pHs and a particle size range of 0.6 to 0.9 mm.
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Affiliation(s)
- Changhui Wang
- The Key Laboratory of Water and Sediment Sciences, Ministry of Education, School of Environment, Beijing Normal University, Beijing, PR. China
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Saeed T, Sun G. The removal of nitrogen and organics in vertical flow wetland reactors: predictive models. BIORESOURCE TECHNOLOGY 2011; 102:1205-1213. [PMID: 20970997 DOI: 10.1016/j.biortech.2010.09.096] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2010] [Revised: 09/21/2010] [Accepted: 09/24/2010] [Indexed: 05/30/2023]
Abstract
Three kinetic models, for predicting the removal of nitrogen and organics in vertical flow wetlands, have been developed and evaluated. These models were established by combining first-order, Monod and multiple Monod kinetics with continuous stirred-tank reactor (CSTR) flow pattern. Critical evaluations of these models using three statistical parameters, coefficient of determination, relative root mean square error and model efficiency, indicated that when the Monod/multiple Monod kinetics was combined with CSTR flow pattern it allowed close match between theoretical prediction and experiment data of nitrogen and organics removal. The kinetic coefficients (derived from Monod/multiple Monod kinetics) was found to increase with pollutant loading, indicating that the coefficients may vary based on different factors, such as influent pollutant concentration, hydraulic loading, and water depth. Overall, this study demonstrated the validity of combining Monod and multiple Monod kinetics with CSTR flow pattern for the modelling and design of vertical flow wetland systems.
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Affiliation(s)
- Tanveer Saeed
- Department of Civil Engineering, Building 60, Monash University, Clayton, Victoria 3800, Australia.
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Yang Y, Zhang L, Zhao YQ, Wang SP, Guo XC, Guo Y, Wang L, Ren YX, Wang XC. Towards the development of a novel construction solid waste (CSW) based constructed wetland system for tertiary treatment of secondary sewage effluents. JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH. PART A, TOXIC/HAZARDOUS SUBSTANCES & ENVIRONMENTAL ENGINEERING 2011; 46:758-763. [PMID: 21644153 DOI: 10.1080/10934529.2011.571621] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
This study was conducted to examine the possibility of using construction solid waste (CSW), an inevitable by-product of the construction and demolition process, as the main substrate in a laboratory scale multi-stage constructed wetland system (CWs) to improve phosphorus (P) removal from secondary sewage effluent. A tidal-flow operation strategy was employed to enhance the wetland aeration. This will stimulate aerobic biological processes and benefit the organic pollutants decomposition and nitrification process for ammoniacal-nitrogen (NH(+)(4)-N) removal. The results showed that the average P concentration in the secondary sewage effluent was reduced from 1.90 mg-P/L to 0.04 mg-P/L. CSW presents excellent P removal performance. The average NH(+)(4)-N concentration was reduced from 9.94 mg-N/L to 1.0 mg-N/L through nitrification in the system. The concentration of resultant nitrite and nitrate in the effluent of the CSW based CWs ranged from 0.1 to 2.4 mg-N/L and 0.01 to 0.8 mg-N/L, respectively. The outcome of this study has shown that CSW can be successfully used to act as main substrate in CWs. The application of CSW based CWs on improving N and P removals from secondary sewage effluent presents a win-win scenario. Such the reuse of CSW will benefit both the CSW disposal and nutrient control from wastewater. More significantly, such the application can transfer the CSW from a 'waste' to 'useful' material and can ease the pressure of construction waste solid management. Meanwhile, the final effluent from the CSW-based CWs can be used as non-potable water source in landscape irrigation, agriculture and industrial process.
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Affiliation(s)
- Y Yang
- Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an, PR China.
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Zhao YQ, Babatunde AO. Special issue: Constructed wetland technology for water pollution control. Foreword. JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH. PART A, TOXIC/HAZARDOUS SUBSTANCES & ENVIRONMENTAL ENGINEERING 2011; 46:677-679. [PMID: 21644143 DOI: 10.1080/10934529.2011.571575] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Affiliation(s)
- Y Q Zhao
- Centre for Water Resources Research, School of Architecture, Landscape and Civil Engineering, University College Dublin, Dublin, Ireland
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40
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Zhao Y, Babatunde A, Hu Y, Kumar J, Zhao X. Pilot field-scale demonstration of a novel alum sludge-based constructed wetland system for enhanced wastewater treatment. Process Biochem 2011. [DOI: 10.1016/j.procbio.2010.08.023] [Citation(s) in RCA: 107] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Kumar JLG, Wang ZY, Zhao YQ, Babatunde AO, Zhao XH, Jørgensen SE. STELLA software as a tool for modelling phosphorus removal in a constructed wetland employing dewatered alum sludge as main substrate. JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH. PART A, TOXIC/HAZARDOUS SUBSTANCES & ENVIRONMENTAL ENGINEERING 2011; 46:751-757. [PMID: 21644152 DOI: 10.1080/10934529.2011.571600] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
A dynamic simulation model was developed for the removal of soluble reactive phosphorus (SRP) from the vertical flow constructed wetlands (VFCW) using a dynamic software program called STELLA (structural thinking, experiential learning laboratory with animation) 9.1.3 to aid in simulating the environmental nature and succession of relationship between interdependent components and processes in the VFCW system. In particular, the VFCW employed dewatered alum sludge as its main substrate to enhance phosphorus (P) immobilization. Although computer modelling of P in treatment wetland has been well studied especially in recent years, there is still a need to develop simple and realistic models that can be used for investigating the dynamics of SRP in VFCWs. The state variables included in the model are dissolved phosphorus (DISP), plant phosphorus (PLAP), detritus phosphorus (DETP), plant biomass (PLBI) and adsorbed phosphorus (ADSP). The major P transformation processes considered in this study were adsorption, plant and microbial uptake and decomposition. The forcing functions which were considered in the model are temperature, radiation, volume of wastewater, P concentration, contact time, flow rate and the adsorbent (i.e., alum sludge). The model results revealed that up to 72% of the SRP can be removed through adsorption process whereas the uptake by plants is about 20% and the remaining processes such as microbial P utilization and decomposition, accounted for 7% SRP removal based on the mass balance calculations. The results obtained indicate that the model can be used to simulate outflow SRP concentration, and it can also be used to estimate the amount of P removed by individual processes in the VFCW using alum-sludge as a substrate.
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Affiliation(s)
- J L G Kumar
- Centre for Water Resources Research, School of Architecture, Landscape and Civil Engineering, University College Dublin, Belfield, Dublin, Ireland.
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42
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Babatunde AO, Zhao YQ. Equilibrium and kinetic analysis of phosphorus adsorption from aqueous solution using waste alum sludge. JOURNAL OF HAZARDOUS MATERIALS 2010; 184:746-752. [PMID: 20846787 DOI: 10.1016/j.jhazmat.2010.08.102] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2010] [Revised: 08/13/2010] [Accepted: 08/25/2010] [Indexed: 05/29/2023]
Abstract
Excess phosphorus (P) in wastewaters promotes eutrophication in receiving waterways. A cost-effective method such as use of novel low-cost adsorbents for its adsorptive removal would significantly reduce such impacts. Using batch experiments, the intrinsic dynamics of P adsorption by waste alum sludge (an inevitable by-product of drinking water treatment plants) was examined. Different models of adsorption were used to describe equilibrium and kinetic data, calculate rate constants and determine the adsorption capacity. Results indicate that the intraparticle rate constant increased from 0.0075 mg g(-1)min(-1) at 5 mg L(-1) to 0.1795 mg g(-1)min(-1) at 60 mg L(-1) indicating that more phosphate is adsorbed per g min at higher P concentration. Further analyses indicate involvement of film and particle diffusion mechanisms as rate controlling steps at lower and higher concentrations, respectively. Mass transfer coefficient obtained ranged from 1.7 × 10(-6) to 1.8 × 10(-8) indicating a rapid transportation of phosphate molecules onto the alum sludge. These results further demonstrates that alum sludge-hitherto thought of as undesirable waste, can be used as novel adsorbent for P removal from wastewater through various applications, thus offsetting a portion of the disposal costs while at the same time improving water quality in sensitive watersheds.
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Affiliation(s)
- A O Babatunde
- Centre for Water Resources Research, School of Architecture, Landscape and Civil Engineering, Newstead Building, University College Dublin, Belfield, Dublin 4, Ireland.
| | - Y Q Zhao
- Centre for Water Resources Research, School of Architecture, Landscape and Civil Engineering, Newstead Building, University College Dublin, Belfield, Dublin 4, Ireland
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Babatunde AO, Zhao YQ. Two strategies for improving animal farm wastewater treatment in reed beds. ENVIRONMENTAL TECHNOLOGY 2010; 31:1343-1348. [PMID: 21121458 DOI: 10.1080/09593331003720623] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
In this study, dewatered alum sludge cakes were used as substrate in a laboratory scale tidal vertical flow reed bed system treating animal farm wastewater. Tidal flow operation was employed to enhance oxygen transfer into the system while dewatered alum sludge cake was used to enhance phosphorus (P) removal through ligand exchange. Except for the removal of P which was consistently high throughout the experiment, the removal of organics (BOD5, COD) exhibited a trend of gradual and increasing removal and this highlights the benefits of using dewatered alum sludge cake in the reed bed. For the removal of organics, a mean removal percentage of 82.3 +/- 3.5% was obtained for BOD5 at a mean loading rate of 84.6 g/m2.d. The first-order kinetics constant for BOD5 removal (K(BOD), m/d) obtained was about 9 times the rate constant commonly obtained in conventional horizontal flow systems. The mean level of dissolved aluminium (Al) monitored in the effluent was 0.04 +/- 0.01 mg/1 and this is well below the discharge limit of 0.2 mg/l for Al discharge into all waters.
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Affiliation(s)
- A O Babatunde
- Centre for Water Resources Research, School of Architecture, Landscape and Civil Engineering, Newstead Building, University College Dublin, Belfield, Dublin 4, Ireland.
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Babatunde AO, Zhao YQ. Leachability and leaching patterns from aluminium-based water treatment residual used as media in laboratory-scale engineered wetlands. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2010; 17:1314-1322. [PMID: 20232166 DOI: 10.1007/s11356-010-0311-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2009] [Accepted: 02/10/2010] [Indexed: 05/28/2023]
Abstract
UNLABELLED CONCEPT AND PURPOSE: Virtually all water treatment facilities worldwide generate an enormous amount of water treatment residual (WTR) solids for which environmentally friendly end-use options are continually being sought as opposed to their landfilling. Aluminium-based WTR (Al-WTR) can offer huge benefits particularly for phosphorus (P) removal and biofilm attachment when used as media in engineered wetlands. However, potential environmental risks that may arise from the leaching out of its constituents must be properly evaluated before such reuse can be assured. This paper presents results of an assessment carried out to monitor and examine the leachability and leaching patterns of the constituents of an Al-WTR used as media in laboratory-scale engineered wetland systems. MAIN FEATURES, MATERIALS AND METHODS Al-WTR was used as media in four different configurations of laboratory-scale engineered wetland systems treating agricultural wastewater. Selected metal levels were determined in the Al-WTR prior to being used while levels of total and dissolved concentration for the metals were monitored in the influent and effluent samples. The increase or decrease of these metals in the used Al-WTR and their potential for leaching were determined. Leached metal levels in the effluents were compared with relevant environmental quality standards to ascertain if they pose considerable risks. RESULTS Aluminium, arsenic, iron, lead and manganese were leached into the treated effluent, but aluminium exhibited the least leaching potential relative to its initial content in the fresh Al-WTR. Levels of P increased from 0.13 mg-P/g (fresh Al-WTR) to 33.9-40.6 mg-P/g (used Al-WTR). Dissolved levels of lead and arsenic (except on one instance) were below the prescribed limits for discharge. However, total and dissolved levels of aluminium were in most cases above the prescribed limits for discharge, especially at the beginning of the experiments. CONCLUSIONS, RECOMMENDATIONS AND PERSPECTIVES Overall, the study indicates that leaching is observed when Al-WTR is beneficially reused for enhanced P removal in engineered wetlands. In particular, levels of aluminium in the treated effluent beyond the prescribed limits of 0.2 mg/l were observed. However, since the results obtained indicate that aluminium leached is mostly associated with solids, a post-treatment unit which can further reduce the level of aluminium in the treated effluent by filtering out the solids could serve to mitigate this. In addition, plants used in such wetland systems can uptake metals and this can also be a potential solution to ameliorating such metal releases. Periodic monitoring is thus advised. Notwithstanding, the use of Al-WTR as a media in engineered wetlands can serve to greatly enhance the removal of P from wastewaters and also serve as support material for biofilm attachment.
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Affiliation(s)
- A O Babatunde
- Centre for Water Resources Research, School of Architecture, Landscape and Civil Engineering, Newstead Building, University College Dublin, Belfield, Dublin 4, Ireland.
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Moghaddam SS, Moghaddam MRA, Arami M. Coagulation/flocculation process for dye removal using sludge from water treatment plant: optimization through response surface methodology. JOURNAL OF HAZARDOUS MATERIALS 2010; 175:651-7. [PMID: 19944532 DOI: 10.1016/j.jhazmat.2009.10.058] [Citation(s) in RCA: 249] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2009] [Revised: 10/13/2009] [Accepted: 10/14/2009] [Indexed: 05/05/2023]
Abstract
In this study, performance of a waterworks sludge (FCS: ferric chloride sludge) for the removal of acid red 119 (AR119) dye from aqueous solutions were investigated. For this purpose, response surface methodology (RSM) was applied to optimize three operating variables of coagulation/flocculation process including initial pH, coagulant dosage and initial dye concentration. The results showed that the decrease of initial pH was always beneficial for enhancing dye removal and no re-stabilization phenomenon was occurred even at the used maximum FCS dosage. It seems that iron hydroxides of the FCS could neutralize the negative charges on dye molecules or cause to the trapping of the dye ones. Therefore, the sweep flocculation and/or the charge neutralization might play key roles in the enhancement of dye removal. The optimum initial pH, FCS dosage and initial dye concentration were found to be 3.5, 236.68 mg dried FCS/L and 65.91 mg/L, respectively. Dye removal of 96.53% is observed which confirms close to RSM results. Therefore, it can be concluded that reusing the FCS as a low-cost material into the coagulation/flocculation process in wastewater treatment plants can offer some advantages such as high efficiency for AR119 dye removal and economic savings on overall treatment plant operation costs.
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Affiliation(s)
- S Sadri Moghaddam
- Civil and Environmental Engineering Department, Amirkabir University of Technology (AUT), Hafez St., Tehran 15875-4413, Iran
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Zhao XH, Zhao YQ. Decolouration of H2SO4 leachate from phosphorus-saturated alum sludge using H2O2 and advanced oxidation processes in phosphorus recovery strategy. JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH. PART A, TOXIC/HAZARDOUS SUBSTANCES & ENVIRONMENTAL ENGINEERING 2009; 44:1557-1564. [PMID: 20183514 DOI: 10.1080/10934520903263504] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
As a part of attempt for phosphorus (P) recovery from P-saturated alum sludge, which was used as a low-cost P-adsorbent in treatment reed bed for wastewater treatment, decolouration of H(2)SO(4) leachate obtained from previous experiment, possessing a great deal of P, aluminum and red-brown coloured materials (RBCMs), by using H(2)O(2) and advanced oxidation processes (AOPs) was investigated. The use of H(2)O(2) and AOPs in the forms of Fenton (H(2)O(2)/Fe(2 +)) and photo-Fenton (UV/H(2)O(2)/Fe(2 +)) were tested. The changes in colour and total organic carbon (TOC) were taken place as a result of mineralization of RBCMs. The results revealed that all of these three processes examined were efficient. It was found that about 98% colour and 47% TOC can be removed under photo-Fenton treatment after 8 hours of UV irradiation.Correspondingly, the reaction rates of H(2)O(2) and Fenton systems were slow, but 100% colour and 59% TOC removal of H(2)O(2) process and 100% colour and 67% TOC reductions of Fenton process can be achieved after 72 hours of reaction. The changes of structure and molecular weight/size of RBCMs were also evaluated by HPLC and UV-vis spectroscopic analysis. From the results, some chromophores of RBCMs such as aromatic groups were appeared to be easily degraded to the smaller refractory components. Hence, based on the experimental results and considering the investment and expediency of operation, H(2)O(2) and Fenton oxidation could be suitable technologies for the treatment of the RBCMs derived from P-extraction stage by using H(2)SO(4) leaching.
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Affiliation(s)
- X H Zhao
- Centre for Water Resources Research, School of Architecture, Landscape and Civil Engineering, Newstead Building, University College Dublin, Belfield, Dublin, Ireland.
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Zhao YQ, Babatunde AO, Zhao XH, Li WC. Development of alum sludge-based constructed wetland: an innovative and cost effective system for wastewater treatment. JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH. PART A, TOXIC/HAZARDOUS SUBSTANCES & ENVIRONMENTAL ENGINEERING 2009; 44:827-832. [PMID: 19731840 DOI: 10.1080/10934520902928685] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
This article describes a research attempt to integrate the dewatered alum sludge, a residual by-product of drinking water treatment process, into a constructed wetland (CW) system for the purpose of enhancing the wastewater treatment performance, thus developing a so called alum sludge-based constructed wetland system. A multi-dimensional research project including the batch tests of phosphorus (P) adsorption onto alum sludge followed by the model CWs trials of single and multi-stage CWs, has been conducted since 2004. It has been successfully demonstrated that the alum sludge-based CW is capable of enhanced and simultaneous removal of P and organic matter (in terms of BOD5 and COD), particularly from medium and high strength wastewater. The sludge cakes act as the carrier for developing biofilm for organics removal and also serve as adsorbent to enhance P immobilization. Batch P-adsorption tests revealed that the alum sludge tested possesses excellent P-adsorption ability of 14.3 mg-P/g x sludge (in dry solids) at pH 7.0 with the adsorption favored at lower pH. The results obtained in a 4-stage treatment wetland system suggest that high removal efficiencies of 90.4% for COD, 88.0% for BOD5, 90.6% for SS, 76.5% for TN and 91.9% for PO4(3-)-P under hydraulic loading of 0.36 m3/m2 x d can be achieved. The field demonstration study of this pioneering development is now underway.
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Affiliation(s)
- Y Q Zhao
- Centre for Water Resources Research, School of Architecture, Landscape and Civil Engineering, University College Dublin, Belfield, Dublin, Ireland.
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Investigation of phosphorus desorption from P-saturated alum sludge used as a substrate in constructed wetland. Sep Purif Technol 2009. [DOI: 10.1016/j.seppur.2008.11.020] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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