1
|
Kotsia D, Sympikou T, Topi E, Pappa F, Matsoukas C, Fountoulakis MS. Use of recycled construction and demolition waste as substrate in constructed wetlands for the wastewater treatment of cheese production. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2024; 362:121324. [PMID: 38830284 DOI: 10.1016/j.jenvman.2024.121324] [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: 02/05/2024] [Revised: 04/26/2024] [Accepted: 05/30/2024] [Indexed: 06/05/2024]
Abstract
Recycled building debris has recently emerged as a suitable wetland infill substrate due to its low density, exceptional water absorption capabilities, and high porosity. This study investigated, for the first time, the use of construction demolition wastes (CDW), and rock processing residues (RPR) as substrate materials in vertical-horizontal flow hybrid constructed wetlands for the treatment of cheese production wastewater. Results showed that the use of both CDW as well as RPR, as substrate material, provided an equal or even better quality of treated wastewater compared to the conventional use of gravel as a substrate. High removal efficiencies were recorded for turbidity (CDW: 91-92%, RPR: 97%), solids (CDW: 85-88%, RPR: 96-97%), organic matter (CDW: 79-84%, RPR: 96-98%), and total phosphorus (CDW: 72-76%, RPR: 87%) for both examined recycled materials. During the experiment, different loadings rates (HLR) were tested: 25 mm d-1 and 37.5 mm d-1. Radiological measurements indicate that, their use did not cause toxic effects on the environment, as the amounts of radioactivity found in the effluent of the systems are not significant. Increasing the hydraulic loading rate appeared to have no negative effect on pollutant removal, as the systems and plants were fully acclimated and mature. This approach offers several advantages, including the use of readily available and abundant waste material, potential cost savings, and the environmental benefits of recycling CDW and RPR instead of disposing of them in landfills.
Collapse
Affiliation(s)
- Dimitra Kotsia
- Department of Environment, University of the Aegean, 81100, Mytilene, Greece.
| | - Theodora Sympikou
- Department of Environment, University of the Aegean, 81100, Mytilene, Greece
| | - Eleftheria Topi
- Department of Environment, University of the Aegean, 81100, Mytilene, Greece
| | - Filothei Pappa
- Department of Environment, University of the Aegean, 81100, Mytilene, Greece
| | - Christos Matsoukas
- Department of Environment, University of the Aegean, 81100, Mytilene, Greece
| | | |
Collapse
|
2
|
Jin F, Hu Z, Liu H, Su J, Zhang J, Wang S, Zhao Y. Impact of clogging on accumulation and stability of phosphorus in the subsurface flow constructed wetland. CHEMOSPHERE 2023; 313:137429. [PMID: 36462565 DOI: 10.1016/j.chemosphere.2022.137429] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Revised: 11/14/2022] [Accepted: 11/27/2022] [Indexed: 06/17/2023]
Abstract
Substrate clogging is one of the major operation challenges of subsurface flow constructed wetlands (SSF-CWs). And the phosphorus (P) removal performance and stability of P accumulation of SSF-CWs would be varied with the development of substrate clogging. In this study, three horizontal SSF-CWs microcosms with different clogging degrees were conducted to explore the mechanism of P accumulation behavior influenced by substrate clogging. Increase in clogging degree resulted in hydraulic retention time (HRT) diminution and adsorption sites increase, which jointly led to reduced P removal efficiency at low clogging degree (L-CW), however, higher P removal efficiency was obtained as adsorption sites increase offset HRT diminution at high clogging degree (H-CW). Substrate adsorption was the primary removal pathway in all SSF-CW systems. It accounted for 77.86 ± 2.63% of the P input in the H-CW, significantly higher than the control (60.08 ± 4.79%). This was attributed to a higher proportion of Fe/Al-P accumulated on the substrate of H-CW, since clogging aggravated the anaerobic condition and promoted the generation of Fe ions. The increase in clogging degree also elevated the release risk of the accrued P in SSF-CWs, since Fe/Al-P was considered bioavailable and readily released under environmental disturbance. The obtained results provide new insights into the P transport and transformation in SSF-CWs and would be helpful to optimize substrate clogging management.
Collapse
Affiliation(s)
- Fenglin Jin
- Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science & Engineering, Shandong University, Qingdao 266237, PR China
| | - Zhen Hu
- Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science & Engineering, Shandong University, Qingdao 266237, PR China.
| | - Huaqing Liu
- College of Safety and Environmental Engineering, Shandong University of Science and Technology, Qingdao 266590, China
| | - Jixin Su
- Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science & Engineering, Shandong University, Qingdao 266237, PR China
| | - Jian Zhang
- Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science & Engineering, Shandong University, Qingdao 266237, PR China; College of Safety and Environmental Engineering, Shandong University of Science and Technology, Qingdao 266590, China
| | - Shuo Wang
- Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science & Engineering, Shandong University, Qingdao 266237, PR China
| | - Yanhui Zhao
- Field Monitoring Station of the Ministry of Education for the East Route of the South-to-North Water Transfer Project, Shandong University, Jinan 250100, PR China
| |
Collapse
|
3
|
Lu H, Xiao L, Wang T, Lu S, Wang H, Guo X, Li J. The application of steel slag in a multistage pond constructed wetland to purify low-phosphorus polluted river water. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2021; 292:112578. [PMID: 33965685 DOI: 10.1016/j.jenvman.2021.112578] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Revised: 03/21/2021] [Accepted: 04/07/2021] [Indexed: 06/12/2023]
Abstract
To investigate the effect of a constructed wetland (CW) with steel slag as the filler on water contaminated by low phosphorus levels, a multistage pond CW system was designed in this study. Low-phosphorus polluted river water was used as the research object. This study explored the effects of using steel slag as a CW filler on phosphorus removal and the total phosphorus (TP) purification effect of the wetland system. The results showed that the TP removal rates in the ecological pond, oxidation pond, surface flow wetlands and submerged plant pond were 5.17%, 8.02%, 21.56%, and 16.31%, respectively. Intermittent increases in phosphorus concentration were observed in the reactors and were caused by the decay of plant tissues, which released pollutants. Because steel slag was added to the filler, the TP concentrations in the effluent of the first- and second-level horizontal subsurface CWs increased by 151.13% and 16.29%, respectively, compared to the influent concentration. The 20th to 40th days of the test run was a period of rapid phosphorus release of the system. The use of steel slag has a potential risk of phosphorus release when applied in CWs used to purify low-phosphorus contaminated water bodies.
Collapse
Affiliation(s)
- Hongbin Lu
- National Engineering Laboratory for Lake Pollution Control and Ecological Restoration, State Environmental Protection Scientific Observation and Research Station for Lake Dongtinghu(SEPSORSLD), State Environmental Protection Key Laboratory for Lake Pollution Control, State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, PR China; College of Water Sciences, Beijing Normal University, Beijing, 100875, PR, China
| | - Liping Xiao
- School of Environmental and Municipal Engineering, Qingdao University of Technology, Qingdao, 266033, China
| | - Tao Wang
- National Engineering Laboratory for Lake Pollution Control and Ecological Restoration, State Environmental Protection Scientific Observation and Research Station for Lake Dongtinghu(SEPSORSLD), State Environmental Protection Key Laboratory for Lake Pollution Control, State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, PR China; College of Environmental Science and Engineering, Liaoning Technical University, Fuxin, 123000, China
| | - Shaoyong Lu
- National Engineering Laboratory for Lake Pollution Control and Ecological Restoration, State Environmental Protection Scientific Observation and Research Station for Lake Dongtinghu(SEPSORSLD), State Environmental Protection Key Laboratory for Lake Pollution Control, State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, PR China.
| | - Huanhua Wang
- National Engineering Laboratory for Lake Pollution Control and Ecological Restoration, State Environmental Protection Scientific Observation and Research Station for Lake Dongtinghu(SEPSORSLD), State Environmental Protection Key Laboratory for Lake Pollution Control, State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, PR China
| | - Xiaochun Guo
- National Engineering Laboratory for Lake Pollution Control and Ecological Restoration, State Environmental Protection Scientific Observation and Research Station for Lake Dongtinghu(SEPSORSLD), State Environmental Protection Key Laboratory for Lake Pollution Control, State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, PR China
| | - Jiaxin Li
- National Engineering Laboratory for Lake Pollution Control and Ecological Restoration, State Environmental Protection Scientific Observation and Research Station for Lake Dongtinghu(SEPSORSLD), State Environmental Protection Key Laboratory for Lake Pollution Control, State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, PR China; School of Civil Engineering, Liaoning Technical University, Fuxin, 123000, China
| |
Collapse
|
4
|
Treatment of Combined Dairy and Domestic Wastewater with Constructed Wetland System in Sicily (Italy). Pollutant Removal Efficiency and Effect of Vegetation. WATER 2021. [DOI: 10.3390/w13081086] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Dairy wastewater (DWW) contains large amounts of mineral and organic compounds, which can accumulate in soil and water causing serious environmental pollution. A constructed wetland (CW) is a sustainable technology for the treatment of DWW in small-medium sized farms. This paper reports a two-year study on the performance of a pilot-scale horizontal subsurface flow system for DWW treatment in Sicily (Italy). The CW system covered a total surface area of 100 m2 and treated approximately 6 m3 per day of wastewater produced by a small dairy farm, subsequent to biological treatment. Removal efficiency (RE) of the system was calculated. The biomass production of two emergent macrophytes was determined and the effect of plant growth on organic pollutant RE was recorded. All DWW parameters showed significant differences between inlet and outlet. For BOD5 and COD, RE values were 76.00% and 62.00%, respectively. RE for total nitrogen (50.70%) was lower than that of organic compounds. RE levels of microbiological parameters were found to be higher than 80.00%. Giant reed produced greater biomass than umbrella sedge. A seasonal variation in RE of organic pollutants was recorded due to plant growth rate Our findings highlight the efficient use of a CW system for DWW treatment in dairy-cattle farms.
Collapse
|
5
|
Yuan Q, Wang S, Wang X, Li N. Biosynthesis of vivianite from microbial extracellular electron transfer and environmental application. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 762:143076. [PMID: 33129535 DOI: 10.1016/j.scitotenv.2020.143076] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 10/01/2020] [Accepted: 10/11/2020] [Indexed: 06/11/2023]
Abstract
Vivianite (Fe3(PO4)2·8H2O) is a common hydrous ferrous phosphate mineral which often occurs in reductive conditions, especially anoxic non-sulfide environment containing high concentrations of ferrous iron (Fe2+) and orthophosphate (PO43-). Vivianite is an important product of dissimilatory iron reduction and a promising route for phosphorus recovery from wastewater. Its formation is closely related to the extracellular electron transfer (EET), a key mechanism for microbial respiration and a crucial explanation for the reduction of metal oxides in soil and sediments. Despite of the natural ubiquity, easy accessibility and attractive economic value, the application value of vivianite has not received much attention. This review introduces the characteristics, occurrence and biosynthesis of vivianite from microbial EET, and systematically analyzes the application value of vivianite in the environmental field, including immobilization of heavy metals (HMs), dechlorination of carbon tetrachloride (CT), sedimentary phosphorus sequestration and eutrophication alleviation. Additionally, its potential functions as a slow-release fertilizer are discussed as well. In general, vivianite is expected to make more contributions to the future scientific research, especially the solution of environmental problems. Overcoming the lack of understanding and some technical limitations will be beneficial to the further application of vivianite in environmental field.
Collapse
Affiliation(s)
- Qing Yuan
- Tianjin Key Lab of Indoor Air Environmental Quality Control, School of Environmental Science and Engineering, Tianjin University, No. 92 Weijin Road, Nankai District, Tianjin 300072, China
| | - Shu Wang
- Tianjin Key Lab of Indoor Air Environmental Quality Control, School of Environmental Science and Engineering, Tianjin University, No. 92 Weijin Road, Nankai District, Tianjin 300072, China
| | - Xin Wang
- MOE Key Laboratory of Pollution Processes and Environmental Criteria, Tianjin Key Laboratory of Environmental Remediation and Pollution Control, Nankai University, No. 38 Tongyan Road, Jinnan District, Tianjin 300350, China
| | - Nan Li
- Tianjin Key Lab of Indoor Air Environmental Quality Control, School of Environmental Science and Engineering, Tianjin University, No. 92 Weijin Road, Nankai District, Tianjin 300072, China.
| |
Collapse
|
6
|
Saeed T, Hossain N. Organics and nutrients removal in vertical flow wetlands: loading fluctuation and alternative media. ENVIRONMENTAL TECHNOLOGY 2021; 42:1104-1118. [PMID: 31401944 DOI: 10.1080/09593330.2019.1655592] [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: 09/11/2018] [Accepted: 08/07/2019] [Indexed: 06/10/2023]
Abstract
Two wetland systems (conventional and structurally modified) were studied for the removal of organics and nutrients from municipal wastewater. Each system consisted of three vertical flow (VF) wetlands, which were filled with agricultural, construction waste materials and planted with Phragmites australis and Canna indica. The wetland units were operated under constant and consecutive shock hydraulic load (HL). Input nutrients and organics load across the wetland units ranged between 4.0-116.0 g N/m2d, 0.5-23.0 g P/m2d, 1.0-527.0 g biochemical oxygen demand (BOD)/m2d and 16.0-686.0 g chemical oxygen demand (COD)/m2d. Nitrification and organic carbon availability controlled nitrogen (N) removals in first and third stage VF wetlands, respectively, during constant load phase; organics removals were influenced by dissolved oxygen concentration of municipal wastewater. Second stage VF wetlands (of both systems) were inefficient in terms of COD removals during shock load periods, which were counter-balanced by first and third stages. First stage VF wetlands achieved higher N removal rates than following stages during shock load periods. Wetland maturation provided a buffer against substantial HL increment and sharp input load decrease in latter shock and recovery phases, respectively. Agricultural waste (sugarcane bagasse) provided carbon to support denitrification; construction materials (recycled brick and crushed mortar) removed phosphorus (P) from wastewater through adsorption. Coliform removal in VF wetlands was achieved through media filtration. Structurally modified system achieved higher removals than the conventional system. BOD, COD, total nitrogen and NH4-N removal percentage across two systems ranged between 76-79%, 59-63%, 73-77% and 90-95%, respectively. In general, this study enlightens potential application of appropriate waste materials for wastewater treatment.
Collapse
Affiliation(s)
- Tanveer Saeed
- Department of Civil Engineering, University of Asia Pacific, Dhaka, Bangladesh
| | - Nadim Hossain
- Department of Civil Engineering, University of Asia Pacific, Dhaka, Bangladesh
| |
Collapse
|
7
|
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.
Collapse
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.
| |
Collapse
|
8
|
Almeida A, Jóźwiakowski K, Kowalczyk-Juśko A, Bugajski P, Kurek K, Carvalho F, Durao A, Ribeiro C, Gajewska M. Nitrogen removal in vertical flow constructed wetlands: influence of bed depth and high nitrogen loadings. ENVIRONMENTAL TECHNOLOGY 2020; 41:2196-2209. [PMID: 30526391 DOI: 10.1080/09593330.2018.1557749] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2018] [Accepted: 12/03/2018] [Indexed: 06/09/2023]
Abstract
The aim of the study was to evaluate the nitrogen removal and its effects on the plant's growth and leaves morphology. using two subsurface vertical flow (VF bed), with different depths (0.24 m2 × 0.70 m; 0.24 m2 × 0.35 m) and nitrogen load increments. The VF bed were planted with Vetiveria zizanioides, filled with light expanded clay aggregates (Leca®NR 10/20) and fed in parallel mode with synthetic wastewater. High ammonium nitrogen concentration ([NH4 +-N] from 68 ± 3 to 290 ± 8 mg L-1) was used without toxicity symptoms in plants, although the effects of ammonium nitrogen load were stopped the growth of the plants. Significant differences between ammonium nitrogen removed in each VF bed obtained for total nitrogen (TNinfl.) ≥ 27 ± 0.8 g m-2 d-1. The nitrification was contributed to ammonium nitrogen removal because was found higher values of nitrate and nitrite in the effluent. These values were more higher in VF bed 1 than in the VF bed 2, since ammonium nitrogen removal were also more higher in VF bed 1 than in the VF bed 2. Total nitrogen mass balance was carried out and the results show that the nitrification/denitrification process occurred with nitrogen plants uptake. It was observed that the VF bed depth has an influence on all nitrogen removal processes. As higher the depth root system it is seemed to favour the creation of zones with different oxidations conditions that allow the nitrogen compounds to be removed intensively.
Collapse
Affiliation(s)
- Adelaide Almeida
- Department of Technologies and Applied Sciences, Polytechnic Institute of Beja, Beja, Portugal
- FibEnTech - Materiais Fibrosos e Tecnologias Ambientais, Covilhã, Portugal
| | - Krzysztof Jóźwiakowski
- Department of Environmental Engineering and Geodesy, University of Life Sciences in Lublin, Lublin, Poland
| | - Alina Kowalczyk-Juśko
- Department of Environmental Engineering and Geodesy, University of Life Sciences in Lublin, Lublin, Poland
| | - Piotr Bugajski
- Department of Sanitary Engineering and Water Management, University of Agriculture in Kraków, Kraków, Poland
| | - Karolina Kurek
- Department of Sanitary Engineering and Water Management, University of Agriculture in Kraków, Kraków, Poland
| | - Fátima Carvalho
- Department of Technologies and Applied Sciences, Polytechnic Institute of Beja, Beja, Portugal
- FibEnTech - Materiais Fibrosos e Tecnologias Ambientais, Covilhã, Portugal
| | - Anabela Durao
- Department of Engineering, Polytechnic Institute of Beja, Beja, Portugal
| | - Carlos Ribeiro
- Department of Technologies and Applied Sciences, Polytechnic Institute of Beja, Beja, Portugal
| | - Magdalena Gajewska
- Department of Water and Wastewater Technology, Gdańsk University of Technology, Gdańsk, Poland
| |
Collapse
|
9
|
Ironmaking and Steelmaking Slags as Sustainable Adsorbents for Industrial Effluents and Wastewater Treatment: A Critical Review of Properties, Performance, Challenges and Opportunities. SUSTAINABILITY 2020. [DOI: 10.3390/su12052118] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
This paper critically discusses the structure, properties and applications of ironmaking and steelmaking slags and their silicate-based variants as low-cost adsorbents for removing cations and anions from industrial effluents and wastewater. Undoubtedly, the performance of slag-based adsorbents depends on their physical, chemical and phase chemical properties. The presence of crystalline phases, for example, has a significant effect on the adsorption capacity. However, despite their low cost and ubiquity, their chemical and geometric heterogeneity significantly affects the performance and applications of slag-based adsorbents. These challenges notwithstanding, the efficacy of slag-based adsorbents can be significantly enhanced through purposeful activation to increase the specific surface area and density of adsorption sites on the surfaces of adsorbent particles. The synthesis of functionalised adsorbents such as geopolymers, zeolites and layered double hydroxides from silicate and aluminosilicate precursors can also significantly increase the performance of slag-based adsorbents. In addition, the ability to stabilise the dissolved and/or entrained toxic metal species in stable phases in slags, either through controlled post-process fluxing or crystallisation, can significantly enhance the environmental performance of slag-based adsorbents. Most critical in the design of future slag-based adsorbents is the integration of the engineered properties of molten and solidified slags to the recovery and stabilisation of dissolved and/or entrained metals.
Collapse
|
10
|
Liang Y, Wei D, Hu J, Zhang J, Liu Z, Li A, Li R. Glyphosate and nutrients removal from simulated agricultural runoff in a pilot pyrrhotite constructed wetland. WATER RESEARCH 2020; 168:115154. [PMID: 31630020 DOI: 10.1016/j.watres.2019.115154] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Revised: 08/20/2019] [Accepted: 10/01/2019] [Indexed: 06/10/2023]
Abstract
Pyrrhotite is often considered as a gangue mineral, and discarded in mine wastes and tailings. Glyphosate and fertilizer, often excessively used in agriculture, flow into water bodies with agriculture runoff, and cause pollution of water bodies. In this study, the pyrrhotite was used as a substrate in a pilot constructed wetland (CW) to remove the glyphosate and nutrients from simulated agriculture runoff. In nearly one year, the pilot pyrrhotite constructed wetland (Pyrr-CW) removed 90.3 ± 6.1% of glyphosate, 88.2 ± 5.1 of total phosphorus (TP) and 60.40 ± 5.60% of total nitrogen (TN) on average, much higher than the control CW. The abundances of sulfur-oxidizing bacteria, such as Sulfurifustis, Sulfuriferula and Thiobacillus, were much higher in the Pyrr-CW than those in the control CW. In the Pyrr-CW goethite was produced by pyrrhotite aerobic oxidation (PAO) and pyrrhotite autotrophic denitrification (PAD) continuously and spontaneously. Higher glyphosate and TP removals were resulted from adsorption on the goethite produced, and higher TN removal was attributed to the PAD. High glyphosate and nutrients removal could keep a long term until the pyrrhotite in the Pyrr-CW was used up. The phosphorus (P) sequestered in the Pyrr-CW existed mainly in organic P, (Fe + Al)P and (Ca + Mg)P, and their order was (Fe + Al)P > organic P > (Ca + Mg)P. No heavy metal ions released from the Pyrr-CW. With higher and lasting removal rate, and lower cost, the Pyrr-CW is a promising technology for simultaneous glyphosate and nutrients removal from agricultural runoff and wastewater.
Collapse
Affiliation(s)
- Ying Liang
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, 163# Xianlin Ave., Nanjing, 210023, China
| | - Dongyang Wei
- South China Institute of Environmental Sciences, MEE, Guangzhou, 510655, China
| | - Junsong Hu
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, 163# Xianlin Ave., Nanjing, 210023, China
| | - Jing Zhang
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, 163# Xianlin Ave., Nanjing, 210023, China
| | - Zhuo Liu
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, 163# Xianlin Ave., Nanjing, 210023, China
| | - Aimin Li
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, 163# Xianlin Ave., Nanjing, 210023, China
| | - Ruihua Li
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, 163# Xianlin Ave., Nanjing, 210023, China.
| |
Collapse
|
11
|
Wu J, Xu D, Zhou Q, Zhang L, He F, Wu Z. Effects of layered combined substrates on plant growth and treatment performance and its spatiotemporal variation of vertical-flow constructed wetlands. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2019; 26:23082-23094. [PMID: 31187376 DOI: 10.1007/s11356-019-05593-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2019] [Accepted: 05/27/2019] [Indexed: 06/09/2023]
Abstract
Layered combined bio-ceramic, zeolite, and anthracite were used as substrates in vertical-flow constructed wetlands (VFCWs) for enhancing contaminant removal from synthetic municipal wastewater. Plant growth and propagation and the removal of organic matter, nitrogen, and phosphorus as well as its spatiotemporal variation were evaluated systematically. The results demonstrated that three different substrates were adequate for the establishment of Canna indica L., especially for zeolite. All small-scale VFCW units were simultaneous efficient in removing CODCr (73.9-78.7%), NH4+-N (83.8-89.9%), TN (88.3-91.5%), SRP (93.8-98.6%), and TP (87.1-90.9%) with a little significant difference on treatment performance. Different pollution removal processes followed a different trend because of their different removal mechanisms driven by the synergy of substrate, plant, and microorganism. Purification space moved down due to the adsorption capacity consumption of upper layer substrate over time. It was concluded that VFCWs filled with layered combined bio-ceramic, zeolite, and anthracite had great potential for treating municipal wastewater.
Collapse
Affiliation(s)
- Junmei Wu
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, People's Republic of China.
| | - Dong Xu
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, People's Republic of China
| | - Qiaohong Zhou
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, People's Republic of China
| | - Liping Zhang
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, People's Republic of China
| | - Feng He
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, People's Republic of China
| | - Zhenbin Wu
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, People's Republic of China
| |
Collapse
|
12
|
Saeed T, Yasmin N, Sun G, Hasnat A. The use of biochar and crushed mortar in treatment wetlands to enhance the removal of nutrients from sewage. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2019; 26:586-599. [PMID: 30411289 DOI: 10.1007/s11356-018-3637-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Accepted: 10/30/2018] [Indexed: 06/08/2023]
Abstract
An experimental study was carried out using in pilot-scale constructed wetland systems, operated in parallel to treat raw sewage. Each system consisted of a vertical flow (VF) unit that was filled with biochar as the main media, followed by a horizontal flow (HF) unit filled with crushed cement mortar. Hydraulic loading (HL) ranged 340-680 mm/day was applied on the VF wetland units, where high total nitrogen (TN) mass removal rate (20-23 g N/m2 d) was obtained, demonstrating that biochar media had a beneficial effect on the degradation of nitrogenous pollutants. Total phosphorus (TP) removal percentage (concentration based) was ≥ 86% in HF wetlands packed with mortar materials. In one system, the flow direction of the sewage was directed by the deployment of downflow pipes and vertical baffles, aiming to facilitate the formation of aerobic and anaerobic zones in the wetland matrices. The effects of such arrangement were analyzed by comparing pollutant removal efficiencies in the two systems. On average, 99, 96, 93, and 86 percentage removals were obtained for ammonia (NH4-N), TN, biochemical oxygen demand (BOD), and TP, respectively, during the experiments. Biochar and crushed mortar proved to be a highly effective combination as media in subsurface flow constructed wetlands for wastewater treatment.
Collapse
Affiliation(s)
- Tanveer Saeed
- Department of Civil Engineering, University of Asia Pacific, Dhaka, Bangladesh.
| | - Nilufar Yasmin
- Department of Civil Engineering, University of Asia Pacific, Dhaka, Bangladesh
| | - Guangzhi Sun
- School of Engineering, Edith Cowan University, Joondalup, WA, 6027, Australia
| | - Ariful Hasnat
- Department of Civil Engineering, University of Asia Pacific, Dhaka, Bangladesh
| |
Collapse
|
13
|
Barca C, Roche N, Troesch S, Andrès Y, Chazarenc F. Modelling hydrodynamics of horizontal flow steel slag filters designed to upgrade phosphorus removal in small wastewater treatment plants. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2018; 206:349-356. [PMID: 29100147 DOI: 10.1016/j.jenvman.2017.10.040] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Revised: 09/26/2017] [Accepted: 10/19/2017] [Indexed: 06/07/2023]
Abstract
Steel slag filters, if well designed and operated, may upgrade phosphorus removal in small wastewater treatment plants such as stabilization ponds and constructed wetlands. The main objective of this study was to develop a systemic modelling approach to describe changes in the hydraulic performances and internal hydrodynamics of steel slag filters under real dynamic operating conditions. The experimental retention time distribution curves (RTD curves) determined from tracer experiments performed at different times during the first year of operation of two field-scale steel slag filters were analyzed through a three stage process. First, a statistical analysis of the RTD curves was performed to determine statistical parameters of the retention time distribution. Second, classical tanks in series (TIS) and plug flow with dispersion (PFD) models were used to obtain a first evaluation of the dispersion and mixing regime. Finally, a multi-flow path TIS model, based on the assumption of several flow paths with different hydraulic properties, is proposed to accurately describe the internal hydrodynamics. Overall, the results of this study indicate that higher CaO content, round shape, and larger grain size distribution of steel slag may promote plug-like flow rather than dispersion. The results of the multi-flow path TIS model suggest that the internal hydrodynamics of steel slag filters can be primarily described by two main flow paths: (i) a faster main flow path showing higher plug flow, followed by (ii) a slower secondary flow path showing higher dispersion. The results also showed that internal hydrodynamics may change over time as a consequence of physical-chemical phenomena occurring in the filter, including accumulation of precipitates, slag hydration and carbonation, and particle segregation.
Collapse
Affiliation(s)
- Cristian Barca
- Aix-Marseille Univ., CNRS, Centrale Marseille, M2P2 UMR 7340, 13451, Marseille, France.
| | - Nicolas Roche
- Aix-Marseille Univ., CNRS, Centrale Marseille, M2P2 UMR 7340, 13451, Marseille, France
| | - Stéphane Troesch
- Epur Nature SAS, ZAC des Balarucs, 84510, Caumont sur Durance, France
| | - Yves Andrès
- IMT Atlantique, GEPEA UMR CNRS 6144, Université Bretagne Loire, 4 rue Alfred Kastler, F-44307, Nantes, cedex 03, France
| | - Florent Chazarenc
- IMT Atlantique, GEPEA UMR CNRS 6144, Université Bretagne Loire, 4 rue Alfred Kastler, F-44307, Nantes, cedex 03, France
| |
Collapse
|
14
|
Tatoulis T, Akratos CS, Tekerlekopoulou AG, Vayenas DV, Stefanakis AI. A novel horizontal subsurface flow constructed wetland: Reducing area requirements and clogging risk. CHEMOSPHERE 2017; 186:257-268. [PMID: 28780453 DOI: 10.1016/j.chemosphere.2017.07.151] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Revised: 07/18/2017] [Accepted: 07/28/2017] [Indexed: 06/07/2023]
Abstract
The use of Constructed Wetlands (CWs) has been nowadays expanded from municipal to industrial and agro-industrial wastewaters. The main limitations of CWs remain the relatively high area requirements compared to mechanical treatment technologies and the potential occurrence of the clogging phenomenon. This study presents the findings of an innovative CW design where novel materials were used. Four pilot-scale CW units were designed, built and operated for two years. Each unit consisted of two compartments, the first of which (two thirds of the total unit length) contained either fine gravel (in two units) or random type high density polyethylene (HDPE) (in the other two units). This plastic media type was tested in a CW system for the first time. The second compartment of all four units contained natural zeolite. Two units (one with fine gravel and one with HDPE) were planted with common reeds, while the other two were kept unplanted. Second cheese whey was introduced into the units, which were operated under hydraulic residence times (HRT) of 2 and 4 days. After a two-year operation and monitoring period, pollutant removal rates were approximately 80%, 75% and 90% for COD, ammonium and ortho-phosphate, respectively, while temperature and HRT had no significant effect on pollutant removal. CWs containing the plastic media achieved the same removal rates as those containing gravel, despite receiving three times higher hydraulic surface loads (0.08 m/d) and four times higher organic surface loads (620 g/m2/d). This reveals that the use of HDPE plastic media could reduce CW surface area requirements by 75%.
Collapse
Affiliation(s)
- Triantafyllos Tatoulis
- Department of Environmental and Natural Resources Management, University of Patras, Agrinio, Greece
| | - Christos S Akratos
- Department of Environmental and Natural Resources Management, University of Patras, Agrinio, Greece.
| | | | - Dimitrios V Vayenas
- Department of Chemical Engineering, University of Patras, Patras, Greece; Institute of Chemical Engineering Sciences, Foundation of Research and Technology (FORTH), Patras, Greece
| | - Alexandros I Stefanakis
- Department of Environmental and Natural Resources Management, University of Patras, Agrinio, Greece
| |
Collapse
|
15
|
Queiroz RDCSD, Andrade RS, Dantas IR, Ribeiro VDS, Rodrigues LB, Almeida Neto JAD. Use of native aquatic macrophytes in the reduction of organic matter from dairy effluents. INTERNATIONAL JOURNAL OF PHYTOREMEDIATION 2017; 19:781-788. [PMID: 28448719 DOI: 10.1080/15226514.2017.1284750] [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: 06/07/2023]
Abstract
Considering the diversity and the unexplored potential of regional aquatic flora, this study aimed to identify and analyze the potential of native aquatic macrophytes to reduce the organic matter of dairy wastewater (DW) using experimental constructed wetlands. The dairy wastewater (DW) had an average chemical oxygen demand (COD) of 7414.63 mg/L and then was diluted to 3133.16 mg/L (D1) and to 2506.53 mg/L (D2). Total solids, COD, temperature, and pH analyses were performed, and the biochemical oxygen demand (BOD) was estimated from the COD values. The best performance in the reduction of the organic matter was observed for Polygonum sp. (87.5% COD and 79.6% BOD) and Eichhornia paniculata (90% COD and 83.7% BOD) at dilution D1, on the 8th day of the experiment. However, the highest total solids removal was observed for Polygonum sp. (32.2%), on the 4th day, at dilution D2. The total solid (TS) concentration has also increased starting from the 8th day of the experiment was observed which may have been due to the development of mosquito larvae and their mechanical removal by sieving, thus changing the steady state of the experimental systems. The macrophytes Polygonum sp. and E. paniculata were considered suitable for the reduction of organic matter of DW using constructed wetlands.
Collapse
Affiliation(s)
| | - Rodrigo Santos Andrade
- b Departmento de Ciências Agrárias e Ambientais , Universidade Estadual de Santa Cruz , Ilhéus , Brazil
| | - Isadora Rosário Dantas
- b Departmento de Ciências Agrárias e Ambientais , Universidade Estadual de Santa Cruz , Ilhéus , Brazil
| | - Vinícius de Souza Ribeiro
- b Departmento de Ciências Agrárias e Ambientais , Universidade Estadual de Santa Cruz , Ilhéus , Brazil
| | - Luciano Brito Rodrigues
- c Departmento de Tecnologia Rural e Animal , Universidade do Sudoeste da Bahia , Itapetinga , Brazil
| | | |
Collapse
|
16
|
Shi P, Jiang Y, Zhu H, Sun D. Impact of steel slag on the ammonium adsorption by zeolite and a new configuration of zeolite-steel slag substrate for constructed wetlands. WATER SCIENCE AND TECHNOLOGY : A JOURNAL OF THE INTERNATIONAL ASSOCIATION ON WATER POLLUTION RESEARCH 2017; 76:584-593. [PMID: 28759441 DOI: 10.2166/wst.2017.232] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The CaO dissolution from slag, as well as the effects of influencing parameters (i.e. pH and Ca2+ concentration) on the ammonium adsorption onto zeolite, was systematically studied in this paper. Modeling results of Ca2+ and OH- release from slag indicated that pseudo-second-order reaction had a better fitness than pseudo-first-order reaction. Changing pH value from 7 to 12 resulted in a drastic reduction of the ammonium adsorption capacity on zeolite, from the peak adsorption capacity at pH 7. High Ca2+ concentration in solution also inhibited the adsorption of ammonium onto zeolite. There are two proposed mechanisms for steel slag inhibiting the ammonium adsorption capacity of zeolite. On the one hand, OH- released from steel slag can react with ammonium ions to produce the molecular form of ammonia (NH3·H2O), which would cause the dissociation of NH4+ from zeolite. On the other hand, Ca2+ could replace the NH4+ ions to adhere onto the surface of zeolite. An innovative substrate filling configuration with zeolite placed upstream of the steel slag was then proposed to eliminate the disadvantageous effects of steel slag. Experimental results showed that this novel filling configuration was superior to two other filling configurations in terms of ammonium removal.
Collapse
Affiliation(s)
- Pengbo Shi
- College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China E-mail: ; State Grid Beijing Electric Power Research Institute, Beijing 100075, China
| | - Yingbo Jiang
- College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China E-mail:
| | - Hongtao Zhu
- College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China E-mail:
| | - Dezhi Sun
- College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China E-mail:
| |
Collapse
|
17
|
Constructed Wetlands for Agricultural Wastewater Treatment in Northeastern North America: A Review. WATER 2016. [DOI: 10.3390/w8050173] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
|
18
|
Ge Y, Wang XC, Dzakpasu M, Zheng Y, Zhao Y, Xiong J. Characterizing phosphorus removal from polluted urban river water by steel slags in a vertical flow constructed wetland. WATER SCIENCE AND TECHNOLOGY : A JOURNAL OF THE INTERNATIONAL ASSOCIATION ON WATER POLLUTION RESEARCH 2016; 73:2644-53. [PMID: 27232400 DOI: 10.2166/wst.2016.118] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Phosphorus (P) removal in constructed wetlands (CWs) is often low unless special substrates with high sorption capacities are used. However, the use of special substrates in vertical flow (VF) CWs has not been proved to enhance P sorption. Thus, two VF wetlands were designed to evaluate the potential for enhanced P removal from polluted urban river water, one with slag as substrate and the other as a control with gravel as substrate. Findings from batch experiments showed P sorption capacities of 3.15 gP/kg and 0.81 gP/kg, respectively, for steel slag and gravel. Different organic matter fractions played different roles in P sorption, the effects of which were significant only at high concentrations. Over a 220 days' operation, the VF-slag removed 76.0% of the influent total phosphorus (TP) at 0.159 g/m(2)·d and PO4-P of 70.9% at 0.063 g/m(2)·d, whereas the VF-gravel removed 65.0% at 0.136 g/m(2)·d and 48.6% at 0.040 g/m(2)·d, respectively. Therefore, the merit of using a steel slag substrate in VF wetlands can be significant for the removal of PO4-P.
Collapse
Affiliation(s)
- Yuan Ge
- Key Laboratory of Northwest Water Resources, Environment and Ecology, Ministry of Education, School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China E-mail:
| | - Xiaochang C Wang
- Key Laboratory of Northwest Water Resources, Environment and Ecology, Ministry of Education, School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China E-mail:
| | - Mawuli Dzakpasu
- Key Laboratory of Northwest Water Resources, Environment and Ecology, Ministry of Education, School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China E-mail: ; UCD Dooge Centre for Water Resources Research, School of Civil Engineering, Newstead Building, University College Dublin, Belfield, Dublin 4, Ireland
| | - Yucong Zheng
- Key Laboratory of Northwest Water Resources, Environment and Ecology, Ministry of Education, School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China E-mail:
| | - Yaqian Zhao
- UCD Dooge Centre for Water Resources Research, School of Civil Engineering, Newstead Building, University College Dublin, Belfield, Dublin 4, Ireland
| | - Jiaqing Xiong
- Key Laboratory of Northwest Water Resources, Environment and Ecology, Ministry of Education, School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China E-mail:
| |
Collapse
|
19
|
Han C, Wang Z, Wu Q, Yang W, Yang H, Xue X. Evaluation of the role of inherent Ca(2+) in phosphorus removal from wastewater system. WATER SCIENCE AND TECHNOLOGY : A JOURNAL OF THE INTERNATIONAL ASSOCIATION ON WATER POLLUTION RESEARCH 2016; 73:1644-1651. [PMID: 27054736 DOI: 10.2166/wst.2015.642] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The role of inherent Ca(2+) in phosphorus removal from wastewater was evaluated by batch tests. Precipitates were characterized by an X-ray diffractometer (XRD), Fourier transform infrared spectrophotometer (FT-IR) and scanning electron microscope with an energy dispersive spectrometer (EDS) system. Effects of inherent Ca(2+) on phosphorus removal through basic oxygen furnace slag (BOFS) were also analyzed. The results show that upon adjusting the pH to higher than 7.0, inherent Ca(2+) can remove phosphorus from wastewater and form Ca-P precipitates. Residual phosphorus exhibited a linear decreasing trend with increasing the pH from 7.0 to 10.0 and then remained unchanged at higher pH than 10.0. EDS determined that the precipitates contained the elements Ca, P and O. FT-IR spectra demonstrated that the functional groups of precipitates involved PO4(3-), OH(-) and CO3(2-). XRD indicated that the precipitates may consist of CaCO3 and some Ca-P phosphates such as CaHPO4, Ca4H(PO4)3, Ca3(PO4)2, and Ca5(PO4)3(OH). During the removal process of phosphorus by BOFS, due to the presence of inherent Ca(2+) in wastewater, the removal efficiency and rate of phosphorus increased by 15.5% and by a factor of about 3.0, respectively.
Collapse
Affiliation(s)
- Chong Han
- School of Metallurgy, Northeastern University, Shenyang 110819, China E-mail:
| | - Zhen Wang
- School of Metallurgy, Northeastern University, Shenyang 110819, China E-mail:
| | - Qianqian Wu
- School of Metallurgy, Northeastern University, Shenyang 110819, China E-mail:
| | - Wangjin Yang
- School of Metallurgy, Northeastern University, Shenyang 110819, China E-mail:
| | - He Yang
- School of Metallurgy, Northeastern University, Shenyang 110819, China E-mail:
| | - Xiangxin Xue
- School of Metallurgy, Northeastern University, Shenyang 110819, China E-mail:
| |
Collapse
|
20
|
Wang W, Zheng J, Wang Z, Zhang R, Chen Q, Yu X, Yin C. Performance of pond-wetland complexes as a preliminary processor of drinking water sources. J Environ Sci (China) 2016; 39:119-133. [PMID: 26899651 DOI: 10.1016/j.jes.2015.11.006] [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: 07/31/2015] [Revised: 11/13/2015] [Accepted: 11/16/2015] [Indexed: 06/05/2023]
Abstract
Shijiuyang Constructed Wetland (110 hm(2)) is a drinking water source treatment wetland with primary structural units of ponds and plant-bed/ditch systems. The wetland can process about 250,000 tonnes of source water in the Xincheng River every day and supplies raw water for Shijiuyang Drinking Water Plant. Daily data for 28 months indicated that the major water quality indexes of source water had been improved by one grade. The percentage increase for dissolved oxygen and the removal rates of ammonia nitrogen, iron and manganese were 73.63%, 38.86%, 35.64%, and 22.14% respectively. The treatment performance weight of ponds and plant-bed/ditch systems was roughly equal but they treated different pollutants preferentially. Most water quality indexes had better treatment efficacy with increasing temperature and inlet concentrations. These results revealed that the pond-wetland complexes exhibited strong buffering capacity for source water quality improvement. The treatment cost of Shijiuyang Drinking Water Plant was reduced by about 30.3%. Regional rainfall significantly determined the external river water levels and adversely deteriorated the inlet water quality, thus suggesting that the "hidden" diffuse pollution in the multitudinous stream branches as well as their catchments should be the controlling emphases for river source water protection in the future. The combination of pond and plant-bed/ditch systems provides a successful paradigm for drinking water source pretreatment. Three other drinking water source treatment wetlands with ponds and plant-bed/ditch systems are in operation or construction in the stream networks of the Yangtze River Delta and more people will be benefited.
Collapse
Affiliation(s)
- Weidong Wang
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
| | - Jun Zheng
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Zhongqiong Wang
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Rongbin Zhang
- Jiaxing Water Conservancy Investment Co. Ltd., Jiaxing 314033, China
| | - Qinghua Chen
- Jiaxing Water Conservancy Investment Co. Ltd., Jiaxing 314033, China
| | - Xinfeng Yu
- Jiaxing Jiayuan Water Supply and Drainage Co. Ltd., Jiaxing 314001, China
| | - Chengqing Yin
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| |
Collapse
|
21
|
Han C, Wang Z, Yang W, Wu Q, Yang H, Xue X. Investigation of the phosphorus removal capacities of basic oxygen furnace slag under variable conditions. ENVIRONMENTAL TECHNOLOGY 2015; 37:1257-1264. [PMID: 26507932 DOI: 10.1080/09593330.2015.1111425] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Effects of reaction time, initial phosphorus concentration, basic oxygen furnace slag (BOF-slag) dosage and size, and temperature on the phosphorus removal capacities (PRCs) of BOF-slag have been investigated in detail through batch tests. Weakly bound phosphorus, Fe- and Al-associated phosphorus, and Ca-associated phosphorus from fresh and reacted BOF-slag were analysed using sequential chemical extraction processes. It was determined that the PRCs of BOF-slag increased with the increase of initial phosphorus concentration and temperature while it decreased with the increase of BOF-slag dosage and size. The phosphorus removed by BOF-slag was primarily assigned to weakly bound phosphorus and Ca-associated phosphorus. Weakly bound phosphorus showed a significant decrease with the increase in all experimental parameter values. However, Ca-associated phosphorus exhibited a prominent increase with increasing reaction time, initial phosphorus concentration, and temperature. These demonstrate that experimental parameters can simultaneously affect the PRCs of BOF-slag and the ways of phosphorus removal by BOF-slag.
Collapse
Affiliation(s)
- Chong Han
- a School of Materials & Metallurgy , Northeastern University , Shenyang , People's Republic of China
| | - Zhen Wang
- a School of Materials & Metallurgy , Northeastern University , Shenyang , People's Republic of China
| | - Wangjin Yang
- a School of Materials & Metallurgy , Northeastern University , Shenyang , People's Republic of China
| | - Qianqian Wu
- a School of Materials & Metallurgy , Northeastern University , Shenyang , People's Republic of China
| | - He Yang
- a School of Materials & Metallurgy , Northeastern University , Shenyang , People's Republic of China
| | - Xiangxin Xue
- a School of Materials & Metallurgy , Northeastern University , Shenyang , People's Republic of China
| |
Collapse
|
22
|
Wood JD, Gordon RJ, Madani A, Stratton GW, Bromley HM. Performance of Seasonally and Continuously Loaded Constructed Wetlands Treating Dairy Farm Wastewater. JOURNAL OF ENVIRONMENTAL QUALITY 2015; 44:1965-1973. [PMID: 26641349 DOI: 10.2134/jeq2014.11.0488] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
A 2-yr study compared the performance of seasonally and continuously loaded constructed wetlands treating dairy farm wastewater. One wetland was loaded during the growing season (GS) periods only, while the other was continuously loaded. Weekly samples were analyzed for 5-d biochemical oxygen demand (BOD), total suspended solids (TSS), total Kjeldahl N (TKN), total ammoniacal N (TAN), total P (TP), and . Annual average daily mass removal rates (kg ha) were similar for both wetlands in both years; however, seasonal differences were observed. With the exception of BOD in Year 2, average daily GS areal mass removal rates were higher for the seasonal wetland. However, GS mass exports from the seasonal wetland were higher by 28 to 94%, with the exception of BOD in Year 1. Annual mass reductions (MRs; %) for nutrients were higher for the continuous wetland in both years. Annual MRs were similar for in both years and for TSS in Year 2. Annual mass exports from the seasonal wetland were higher for nutrients and by 14 to 77% in both years. Pollutant MRs generally decreased during the nongrowing season (NGS) for the continuous wetland; however, in Year 2 when lower loading rates were used, the wetland still removed 84 to 99% of the pollutant masses. The continuous wetland also performed better during periods of high flow that occurred during the GS. Although there were minimal differences in annual treatment performance, continuously loaded systems require less additional infrastructure and should require less maintenance and may, therefore, be more attractive for agricultural applications.
Collapse
|
23
|
Li X, Zhang M, Liu F, Li Y, He Y, Zhang S, Wu J. The Significance of Myriophyllum elatinoides for Swine Wastewater Treatment: Abundance and Community Structure of Ammonia-Oxidizing Microorganisms in Sediments. PLoS One 2015; 10:e0139778. [PMID: 26444015 PMCID: PMC4596523 DOI: 10.1371/journal.pone.0139778] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2015] [Accepted: 09/17/2015] [Indexed: 11/19/2022] Open
Abstract
Myriophyllum elatinoides was reported to effectively treat wastewater by removing nitrogen (N) and phosphorus (P). However, little is known about the abundance and community structure of ammonia-oxidizing microorganisms associated with M. elatinoides purification systems. The objective of this research was to characterize the abundance and community structure of ammonia-oxidizing microorganisms in swine wastewater and determine the main nitrogen removal pathways. In this study, five different waters were treated by M. elatinoides in microcosms for one month. The five waters included tap water (Control), swine wastewater (SW), 50% diluted swine wastewater (50% SW), and two synthetic wastewaters: 200 mg NH4+-N L−1 (200 NH4+-N) and 400 mg NH4+-N L−1 (400 NH4+-N). The most dramatic changes were in NH4+-N and total N (TN) concentrations, with average removal rates of 84% and 90%, respectively, in the treatments containing swine wastewater. On days 7, 14, and 28, the dissolved oxygen (DO) increased by 81.8%, 210.4% and 136.5%, respectively, compared with on day 0, in the swine wastewater. The results also showed that the bacterial amoA (AOB) copy numbers in the sediments of the treatments were significantly higher than those of archaeal amoA (AOA) copy numbers (p = 0.015). In addition, the high DO concentrations in swine wastewater responded well to the high abundance of AOB. The AOA and AOB community distributions were positively related with NO3-N and were negatively related with DO in swine wastewater treatments. In summary, our experimental results suggested that the M. elatinoides purification system could improve the activity of ammonia-oxidizing microorganisms and consequently might contribute to the significant N removal from the swine wastewater.
Collapse
Affiliation(s)
- Xi Li
- Key Laboratory of Agro-ecological Processes in Subtropical Regions, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Hunan, 410125, P. R. China
- Changsha Research Station for Agricultural & Environmental Monitoring, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Hunan, 410125, P. R. China
| | - Miaomiao Zhang
- Key Laboratory of Agro-ecological Processes in Subtropical Regions, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Hunan, 410125, P. R. China
- Changsha Research Station for Agricultural & Environmental Monitoring, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Hunan, 410125, P. R. China
| | - Feng Liu
- Key Laboratory of Agro-ecological Processes in Subtropical Regions, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Hunan, 410125, P. R. China
- Changsha Research Station for Agricultural & Environmental Monitoring, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Hunan, 410125, P. R. China
- * E-mail: (FL); (YL); (JW)
| | - Yong Li
- Key Laboratory of Agro-ecological Processes in Subtropical Regions, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Hunan, 410125, P. R. China
- Changsha Research Station for Agricultural & Environmental Monitoring, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Hunan, 410125, P. R. China
- * E-mail: (FL); (YL); (JW)
| | - Yang He
- Key Laboratory of Agro-ecological Processes in Subtropical Regions, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Hunan, 410125, P. R. China
- Changsha Research Station for Agricultural & Environmental Monitoring, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Hunan, 410125, P. R. China
- Graduate University of Chinese Academy of Sciences, Beijing, 100039, P. R. China
| | - Shunan Zhang
- Key Laboratory of Agro-ecological Processes in Subtropical Regions, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Hunan, 410125, P. R. China
- Changsha Research Station for Agricultural & Environmental Monitoring, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Hunan, 410125, P. R. China
- Graduate University of Chinese Academy of Sciences, Beijing, 100039, P. R. China
| | - Jinshui Wu
- Key Laboratory of Agro-ecological Processes in Subtropical Regions, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Hunan, 410125, P. R. China
- Changsha Research Station for Agricultural & Environmental Monitoring, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Hunan, 410125, P. R. China
- * E-mail: (FL); (YL); (JW)
| |
Collapse
|
24
|
Ge Y, Wang X, Zheng Y, Dzakpasu M, Zhao Y, Xiong J. Functions of slags and gravels as substrates in large-scale demonstration constructed wetland systems for polluted river water treatment. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2015; 22:12982-12991. [PMID: 25916476 DOI: 10.1007/s11356-015-4573-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Accepted: 04/19/2015] [Indexed: 06/04/2023]
Abstract
The choice of substrates with high adsorption capacity, yet readily available and economical is vital for sustainable pollutants removal in constructed wetlands (CWs). Two identical large-scale demonstration horizontal subsurface flow (HSSF) CWs (surface area, 340 m(2); depth, 0.6 m; HLR, 0.2 m/day) with gravel or slag substrates were evaluated for their potential use in remediating polluted urban river water in the prevailing climate of northwest China. Batch experiments to elucidate phosphorus adsorption mechanisms indicated a higher adsorption capacity of slag (3.15 g/kg) than gravel (0.81 g/kg), whereby circa 20 % more total phosphorus (TP) removal was recorded in HSSF-slag than HSSF-gravel. TP removal occurred predominantly via CaO-slag dissolution followed by Ca phosphate precipitation. Moreover, average removals of chemical oxygen demand and biochemical oxygen demand were approximately 10 % higher in HSSF-slag than HSSF-gravel. Nevertheless, TP adsorption by slag seemed to get quickly saturated over the monitoring period, and the removal efficiency of the HSSF-slag approached that of the HSSF-gravel after 1-year continuous operation. In contrast, the two CWs achieved similar nitrogen removal during the 2-year monitoring period. Findings also indicated that gravel provided better support for the development of other wetland components such as biomass, whereby the biomass production and the amount of total nitrogen (TN; 43.1-59.0 g/m(2)) and TP (4.15-5.75 g/m(2)) assimilated by local Phragmites australis in HSSF-gravel were higher than that in HSSF-slag (41.2-52.0 g/m(2) and 3.96-4.07 g/m(2), respectively). Overall, comparable pollutant removal rates could be achieved in large-scale HSSF CWs with either gravel or slag as substrate and provide a possible solution for polluted urban river remediation in northern China.
Collapse
Affiliation(s)
- Yuan Ge
- Key Laboratory of Northwest Water Resources, Environment and Ecology, Ministry of Education, School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an, 710055, China
| | | | | | | | | | | |
Collapse
|
25
|
Dunets CS, Zheng Y, Dixon M. Use of phosphorus-sorbing materials to remove phosphate from greenhouse wastewater. ENVIRONMENTAL TECHNOLOGY 2015; 36:1759-1770. [PMID: 25608464 DOI: 10.1080/09593330.2015.1009497] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
High phosphate content in wastewater is currently a major issue faced by the North American greenhouse industry. Phosphate-sorbing material filters could provide a means of removing phosphate from wastewater prior to discharge to the environment, but the characterization of economically viable materials and specific recommendations for greenhouse wastewater are not available. Batch and column experiments were used to examine the capacity of two calcium-based waste materials, basic oxygen furnace slag and a concrete waste material, to remove phosphate from greenhouse nutrient solution at varied operating conditions. Material columns operating at a hydraulic retention time (HRT) of 3 h consistently removed >99% of influent phosphate at a concentration of 60 mg/L over repeated applications and demonstrated high phosphate retention capacity (PRC) of 8.8 and 5.1 g P/kg for slag and concrete waste, respectively. Both materials also provided some removal of the micronutrients Fe, Mn and Zn. Increasing HRT to 24 h increased P retention capacity of slag to >10.5 g P/kg but did not improve retention by concrete waste. Decreasing influent phosphate concentration to 20 mg/L decreased PRC to 1.64 g P/kg in concrete waste columns, suggesting fluctuations in greenhouse wastewater composition will affect filter performance. The pH of filter effluent was closely correlated to final P concentration and can likely be used to monitor treatment effectiveness. This study demonstrated that calcium-based materials are promising for the removal of phosphate from greenhouse wastewater, and worthy of further research on scaling up the application to a full-sized system.
Collapse
Affiliation(s)
- C Siobhan Dunets
- a School of Environmental Sciences , University of Guelph , Guelph , Ontario , Canada
| | | | | |
Collapse
|
26
|
Han C, Wang Z, Yang H, Xue X. Removal kinetics of phosphorus from synthetic wastewater using basic oxygen furnace slag. J Environ Sci (China) 2015; 30:21-29. [PMID: 25872706 DOI: 10.1016/j.jes.2014.11.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2014] [Revised: 11/04/2014] [Accepted: 11/13/2014] [Indexed: 06/04/2023]
Abstract
Removal kinetics of phosphorus through use of basic oxygen furnace slag (BOF-slag) was investigated through batch experiments. Effects of several parameters such as initial phosphorus concentration, temperature, BOF-slag size, initial pH, and BOF-slag dosage on phosphorus removal kinetics were measured in detail. It was demonstrated that the removal process of phosphorus through BOF-slag followed pseudo-first-order reaction kinetics. The apparent rate constant (kobs) significantly decreased with increasing initial phosphorus concentration, BOF-slag size, and initial pH, whereas it exhibited an opposite trend with increasing reaction temperature and BOF-slag dosage. A linear dependence of kobs on total removed phosphorus (TRP) was established with kobs=(3.51±0.11)×10(-4)×TRP. Finally, it was suggested that the Langmuir-Rideal (L-R) or Langmuir-Hinshelwood (L-H) mechanism may be used to describe the removal process of phosphorus using BOF-slag.
Collapse
Affiliation(s)
- Chong Han
- School of Materials & Metallurgy, Northeastern University, Shenyang 110819, China.
| | - Zhen Wang
- School of Materials & Metallurgy, Northeastern University, Shenyang 110819, China
| | - He Yang
- School of Materials & Metallurgy, Northeastern University, Shenyang 110819, China
| | - Xiangxin Xue
- School of Materials & Metallurgy, Northeastern University, Shenyang 110819, China
| |
Collapse
|
27
|
Barca C, Troesch S, Meyer D, Drissen P, Andrès Y, Chazarenc F. Steel slag filters to upgrade phosphorus removal in constructed wetlands: two years of field experiments. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2013; 47:549-556. [PMID: 23198779 DOI: 10.1021/es303778t] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Electric arc furnace steel slag (EAF-slag) and basic oxygen furnace steel slag (BOF-slag) were used as filter substrates in two horizontal subsurface flow filters (6 m(3) each) designed to remove phosphorus (P) from the effluent of a constructed wetland. The influences of slag composition, void hydraulic retention time (HRTv), temperature, and wastewater quality on treatment performances were studied. Over a period of almost two years of operation, the filter filled with EAF-slag removed 37% of the inlet total P, whereas the filter filled with BOF-slag removed 62% of the inlet total P. P removal occurred predominantly via CaO-slag dissolution followed by Ca phosphate precipitation. P removal efficiencies improved with increasing temperature and HRTv, most probably because this affected the rates of CaO-slag dissolution and Ca phosphate precipitation. It was observed that long HRTv (>3 days) can cause high pH in the effluents (>9) as a result of excessive CaO-slag dissolution. However, at shorter HRTv (1-2 days), pH values were elevated only during the first five weeks and then stabilized below a pH of 9. The kinetics of P removal were investigated employing a first-order equation, and a model for filter design was proposed.
Collapse
Affiliation(s)
- Cristian Barca
- L'UNAM Université, Ecole des Mines de Nantes, CNRS, GEPEA, UMR 6144, 4 rue Alfred Kastler, 44307 Nantes, France.
| | | | | | | | | | | |
Collapse
|
28
|
Pratt C, Parsons SA, Soares A, Martin BD. Biologically and chemically mediated adsorption and precipitation of phosphorus from wastewater. Curr Opin Biotechnol 2012; 23:890-6. [DOI: 10.1016/j.copbio.2012.07.003] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2012] [Revised: 07/20/2012] [Accepted: 07/22/2012] [Indexed: 10/28/2022]
|
29
|
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.
Collapse
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.
| | | | | | | | | |
Collapse
|
30
|
Pratt C, Shilton A, Haverkamp RG, Pratt S. Chemical techniques for pretreating and regenerating active slag filters for improved phosphorus removal. ENVIRONMENTAL TECHNOLOGY 2011; 32:1053-1062. [PMID: 21882558 DOI: 10.1080/09593330.2010.525749] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Active slag filters are an emerging technology for removing phosphorus (P) from wastewaters. Recent research revealed that adsorption onto Fe oxides/oxyhydroxides at near-neutral pH and oxidizing Eh is the key mechanism of P removal by melter slag filters. Currently, filter lifespan is limited by available adsorption sites. This study examined whether the performance and longevity of active filters could be improved via chemical treatment to create additional reactive sites as well as regenerate exhausted ones. Fresh original melter slag as well as slag from an exhausted full-scale filter was tested. Chemical reagents that could manipulate the pH/Eh of the slag granule surfaces and potentially activate them for further P removal were used, namely hydrochloric acid (HCI), sodium hydroxide (NaOH) and sodium dithionite (Na2S2O4). Waste stabilization pond effluent was then applied to the treated slag to assess the effectiveness of the treatments at improving P removal. Fresh slag treated with Na2S204 and HCl, respectively, retained 1.9 and 1.4 times more P from the effluent than the untreated fresh slag. These reagents were even more effective at regenerating the exhausted slag, increasing total retained P by a factor of 13 and six, respectively, compared with untreated slag. Sodium hydroxide was ineffective at increasing P removal. The higher P retention by the 'treated exhausted slag' compared with the 'treated fresh media' indicates that adsorption sites on melter slag filters become increasingly reactive with time. This research is the first study to provide evidence that P retention by active slag filters can be increased by both (1) chemical pre treatment and (2) chemical post-treatment once their P removal is exhausted, thereby potentially transforming them from a single use system to a more viable, reusable treatment technology.
Collapse
Affiliation(s)
- C Pratt
- Landcare Research-Manaaki Whenua, Palmerston North, New Zealand.
| | | | | | | |
Collapse
|