1
|
Le V, Thompson S, Roden E, Zahasky C. In Situ Measurements of Dynamic Bacteria Transport and Attachment in Heterogeneous Sand-Packed Columns. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:15588-15597. [PMID: 37782746 DOI: 10.1021/acs.est.3c02197] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/04/2023]
Abstract
Prevention, mitigation, and regulation of bacterial contaminants in groundwater require a fundamental understanding of the mechanisms of transport and attachment in complex geological materials. Discrepancies in bacterial transport behaviors observed between field studies and laboratory experiments indicate an incomplete understanding of dynamic bacterial transport and immobilization processes in realistic heterogeneous geologic systems. Here, we develop a new experimental approach for in situ quantification of dynamic bacterial transport and attachment distribution in geologic media that relies on radiolabelingEscherichia coliwith positron-emitting radioisotopes and quantifying transport with three-dimensional (3D) positron emission tomography (PET) imaging. Our results indicate that the highest bacterial attachment occurred at the interfaces between sand layers oriented orthogonal to the direction of flow. The predicted bacterial attachment from a 3D numerical model matched the experimental PET results, highlighting that the experimentally observed bacterial transport behavior can be accurately captured with a distribution of a first-order irreversible attachment model. This is the first demonstration of the direct measurement of attachment coefficient distributions from bacterial transport experiments in geologic media and provides a transformational approach to better understand bacterial transport mechanisms, improve model parametrization, and accurately predict how local geologic conditions can influence bacterial fate and transport in groundwater.
Collapse
Affiliation(s)
- Vy Le
- Department of Geoscience, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Sophia Thompson
- Department of Geoscience, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Eric Roden
- Department of Geoscience, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Christopher Zahasky
- Department of Geoscience, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| |
Collapse
|
2
|
Removal of Phosphorus from Hypolimnetic Lake Water by Reactive Filter Material in a Recirculating System—Laboratory Trial. WATER 2022. [DOI: 10.3390/w14050819] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
A toolbox of methods must be available for the remediation of lakes and water bodies suffering from eutrophication. One method suggested is hypolimnetic withdrawal based on a closed-circuit system. Prior to the start of a pilot-scale test at Lake Hönsan, Sweden, a laboratory trial with containers filled with water and bottom sediment from this lake was performed. A peristaltic pump distributed equal bottom water volume to four columns, two filled with glass beads and two with the filter material Polonite, and then back to the surface of the containers. The reactive filter medium (RFM) removed phosphate (PO4-P) efficiently (98.6%), despite the relatively low influent concentration (390 µg L−1). The control column filled with glass beads, removed 2.9% of the PO4-P. The anoxic sediment, containing 2.47 mg P g−1, released PO4-P, which was indicated by the increased concentration in near-bottom water. The redirected water after RFM filtration had high pH (x¯=11.1); however, an equalization took place in the water mass to a lower but still increased pH value (x¯=8.7) compared to the control (x¯=7.02). This article reports the pros and cons of a full-scale system using the proposed method.
Collapse
|
3
|
Removal of Pathogens in Onsite Wastewater Treatment Systems: A Review of Design Considerations and Influencing Factors. WATER 2021. [DOI: 10.3390/w13091190] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Conventional onsite wastewater treatment systems (OWTSs) could potentially contribute to the transmission of infectious diseases caused by waterborne pathogenic microorganisms and become an important human health concern, especially in the areas where OWTSs are used as the major wastewater treatment units. Although previous studies suggested the OWTSs could reduce chemical pollutants as well as effectively reducing microbial contaminants from onsite wastewater, the microbiological quality of effluents and the factors potentially affecting the removal are still understudied. Therefore, the design and optimization of pathogen removal performance necessitate a better mechanistic understanding of the hydrological, geochemical, and biological processes controlling the water quality in OWTSs. To fill the knowledge gaps, the sources of pathogens and common pathogenic indicators, along with their major removal mechanisms in OWTSs were discussed. This review evaluated the effectiveness of pathogen removal in state-of-art OWTSs and investigated the contributing factors for efficient pathogen removal (e.g., system configurations, filter materials, environmental and operational conditions), with the aim to guide the future design for optimized treatment performance.
Collapse
|
4
|
Feng C, Zhang S, Wang Y, Wang G, Pan X, Zhong Q, Xu X, Luo L, Long L, Yao P. Synchronous removal of ammonium and phosphate from swine wastewater by two agricultural waste based adsorbents: Performance and mechanisms. BIORESOURCE TECHNOLOGY 2020; 307:123231. [PMID: 32224425 DOI: 10.1016/j.biortech.2020.123231] [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: 02/06/2020] [Revised: 03/17/2020] [Accepted: 03/19/2020] [Indexed: 06/10/2023]
Abstract
Two agricultural wastes, Chinese medicinal herbal residue and spent Pleurotus ostreatus substrate, were developed to remove ammonium and phosphate from swine wastewater. These adsorbents were mesoporous materials with abundant smooth layered pores, and rough protuberances and grooves, respectively. Their adsorption capacities were 1131.65 and 1631.79 mg N g-1, and 63.41 and 62.58 mg P g-1 at pH 8.0, dosage of 0.2 g L-1 and contact time of 360 min. And kinetics data of ammonium and phosphate fitted best with the intra-particle diffusion and pseudo-second-order models, respectively. Based on the point of zero charge, FTIR and XPS analyses, ammonium was removed mainly by electrostatic attraction, ion exchange and surface precipitation, while phosphate was by ligand exchange, surface complexation and precipitation. Therefore, the two agricultural wastes have great potential to synchronously remove ammonium and phosphate from swine wastewater.
Collapse
Affiliation(s)
- Can Feng
- College of Environmental Sciences, Sichuan Agricultural University, Wenjiang 611130, PR China; Sichuan Provincial Key Laboratory of Soil Environmental Protection, Wenjiang 611130, PR China
| | - Shirong Zhang
- College of Environmental Sciences, Sichuan Agricultural University, Wenjiang 611130, PR China; Sichuan Provincial Key Laboratory of Soil Environmental Protection, Wenjiang 611130, PR China.
| | - Yating Wang
- Chengdu Academy of Environmental Sciences, Chengdu 610031, PR China
| | - Guiyin Wang
- College of Environmental Sciences, Sichuan Agricultural University, Wenjiang 611130, PR China; Sichuan Provincial Key Laboratory of Soil Environmental Protection, Wenjiang 611130, PR China
| | - Xiaomei Pan
- College of Environmental Sciences, Sichuan Agricultural University, Wenjiang 611130, PR China; Sichuan Provincial Key Laboratory of Soil Environmental Protection, Wenjiang 611130, PR China
| | - Qinmei Zhong
- College of Environmental Sciences, Sichuan Agricultural University, Wenjiang 611130, PR China; Sichuan Provincial Key Laboratory of Soil Environmental Protection, Wenjiang 611130, PR China
| | - Xiaoxun Xu
- College of Environmental Sciences, Sichuan Agricultural University, Wenjiang 611130, PR China
| | - Ling Luo
- College of Environmental Sciences, Sichuan Agricultural University, Wenjiang 611130, PR China
| | - Lulu Long
- College of Environmental Sciences, Sichuan Agricultural University, Wenjiang 611130, PR China
| | - Ping Yao
- Chengdu Academy of Environmental Sciences, Chengdu 610031, PR China
| |
Collapse
|
5
|
Crushed Autoclaved Aerated Concrete (CAAC), a Potential Reactive Filter Medium for Enhancing Phosphorus Removal in Nature-Based Solutions—Preliminary Batch Studies. WATER 2019. [DOI: 10.3390/w11071442] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Phosphorus (P) is a limited resource and can promote eutrophication of water streams and acidification of oceans when discharged. Crushed autoclaved aerated concrete (CAAC), a by-product from demolition, has shown great potential for recovering P. The potential of CAAC to be used in nature-based solutions as a P-reactive filter medium was evaluated by performing preliminary batch essays. Here, we evaluated the interactions and main effects of the initial concentration of P (Pi; 5, 10 or 20 mg L−1), particle size (PS; 4 or 5 mm) and contact time (CT; 60, 180, 360, 720 and 1440 min) upon the removal. We performed physical and chemical characterization to understand the removal processes. Data collected were fitted in adsorption kinetic models. The statistical analysis showed a significant interaction between CT and Pi, with the combination of its main effects stronger on P removal than each one separately. Intriguingly, we noticed that the higher the concentration of Pi, the faster and higher the removal of P. Contrary to expectations, PS 5 mm showed higher removal rates than PS 4 mm, indicating that besides adsorption, other unidentified chemical processes are in place. Further studies using columns/pilots with real wastewater are recommended for a future follow-up.
Collapse
|
6
|
Performance of an On-Site Wastewater Treatment System Using Reactive Filter Media and a Sequencing Batch Constructed Wetland. SUSTAINABILITY 2019. [DOI: 10.3390/su11113172] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Many on-site wastewater treatment systems, such as soil treatment systems, are not sustainable in terms of purification efficiency, nutrient recycling potential, and economics. In this case study, a sequencing batch constructed wetland (SBCW) was designed and added after a package treatment plant (PTP) using reactive filter media for phosphorus (P) removal and recycling. The treatment performance of the entire system in the start-up phase and its possible applicability in rural areas were investigated. Raw and treated effluents were sampled during a period of 25 weeks and analyzed for nitrogen, phosphorus, BOD7, and bacteria. Field measurements were made of wastewater flow, electrical conductivity, oxygen, and temperature. The entire system removed total-P and total inorganic nitrogen (TIN) by 83% and 22%, respectively. High salt concentration and very low wastewater temperature were possible reasons for these unexpectedly low P and TIN removal efficiencies. In contrast, removal rates of bacteria (Escherichia coli, enterococci) and organic matter (as BOD) were high, due to filtration in the alkaline medium Polonite® (Ecofiltration Nordic AB, Stockholm, Sweden) and the fine sand used as SBCW substrate. High pH in effluent from the PTP was efficiently reduced to below pH 9 in the SBCW, meeting recommendations by environmental authorities in Sweden. We concluded that treating cold on-site wastewater can impair treatment performance and that technical measures are needed to improve SBCW performance.
Collapse
|
7
|
Modelling Phosphorus Sorption Kinetics and the Longevity of Reactive Filter Materials Used for On-Site Wastewater Treatment. WATER 2019. [DOI: 10.3390/w11040811] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Use of reactive filter media (RFM) is an emerging technology in small-scale wastewater treatment to improve phosphorus (P) removal and filter material longevity for making this technology sustainable. In this study, long-term sorption kinetics and the spatial dynamics of sorbed P distribution were simulated in replaceable P-filter bags filled with 700 L of reactive material and used in real on-site treatment systems. The input data for model calibration were obtained in laboratory trials with Filtralite P®, Polonite® and Top16. The P concentration breakthrough threshold value was set at an effluent/influent (C/C0) ratio of 1 and simulations were performed with P concentrations varying from 1 to 25 mg L−1. The simulation results showed that influent P concentration was important for the breakthrough and longevity, and that Polonite performed best, followed by Top16 and Filtralite P. A 100-day break in simulated intermittent flow allowed the materials to recover, which for Polonite involved slight retardation of P saturation. The simulated spatial distribution of P accumulated in the filter bags showed large differences between the filter materials. The modelling insights from this study can be applied in design and operation of on-site treatment systems using reactive filter materials.
Collapse
|
8
|
Shen Z, Bai J, Zhang Y, Li J, Zhou T, Wang J, Xu Q, Zhou B. Efficient purification and chemical energy recovery from urine by using a denitrifying fuel cell. WATER RESEARCH 2019; 152:117-125. [PMID: 30665158 DOI: 10.1016/j.watres.2018.12.066] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2018] [Revised: 12/23/2018] [Accepted: 12/25/2018] [Indexed: 06/09/2023]
Abstract
Urine is a major biomass resource, and its excessive discharge would lead to severe aquatic nitrogen pollution and even eutrophication. In this study, we designed an innovative denitrifying fuel cell (DFC) under illumination to purify urine and convert its chemical energy into electricity. The central ideas include the following: 1) on the anode, chlorine radicals (Cl) and hydroxyl (HO) radicals were induced to react with amine or ammonia in urine into N2, and to mineralize organics into CO2, respectively; 2) on the cathode, NO2- or NO3- generated in the cell was selectively reduced to N2 and tiny NH4+ by Pd/Au/NF; 3) NH4+ was further oxidized to N2 by Cl according to process 1), then the total nitrogen (TN) was ultimately removed by a continuous redox loop between anode and cathode; 4) the separation and migration of charges were strengthened by a self-bias poly-Si/WO3 photoanode. Result indicated that the DFC showed an efficient yield of electricity and almost completely N-removing properties: power density of 2.24 mW cm-2, total nitrogen and total organic carbon (TOC) removal efficiency, respectively 99.02% and 50.76% for artificial urine; and power density of 2.51 mW cm-2, TN and TOC removal efficiency, respectively 98.60% and 54.55% for actual urine. The study proposes a potential and environment-friendly approach by using novel DFC to purify urine and generate electricity.
Collapse
Affiliation(s)
- Zhaoxi Shen
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, No. 800, Dongchuan Rd, Shanghai, 200240, PR China
| | - Jing Bai
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, No. 800, Dongchuan Rd, Shanghai, 200240, PR China
| | - Yan Zhang
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, No. 800, Dongchuan Rd, Shanghai, 200240, PR China
| | - Jinhua Li
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, No. 800, Dongchuan Rd, Shanghai, 200240, PR China.
| | - Tingsheng Zhou
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, No. 800, Dongchuan Rd, Shanghai, 200240, PR China
| | - Jiachen Wang
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, No. 800, Dongchuan Rd, Shanghai, 200240, PR China
| | - Qunjie Xu
- Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200092, PR China; College of Environmental and Chemical Engineering, Shanghai University of Electric Power, No.2588 Changyang Road, Shanghai, 200090, PR China
| | - Baoxue Zhou
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, No. 800, Dongchuan Rd, Shanghai, 200240, PR China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200092, PR China; Key Laboratory of Thin Film and Microfabrication Technology, Ministry of Education, Shanghai, 200240, PR China.
| |
Collapse
|
9
|
Bus A, Karczmarczyk A, Baryła A. Calcined Eggshell as a P Reactive Media Filter-Batch Tests and Column Sorption Experiment. WATER, AIR, AND SOIL POLLUTION 2019; 230:20. [PMID: 30686844 PMCID: PMC6327085 DOI: 10.1007/s11270-018-4068-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Accepted: 12/28/2018] [Indexed: 06/09/2023]
Abstract
The goal of the study was to assess the sorption properties of calcined eggshells (CEs) as a P reactive media filter. The CEs were calcined in a temperature of 900 °C. A double stage test was performed: batch studies (kinetic and equilibrium) and small-scale column experiment. The estimation of optimal mass ratio of CEs for perspective usage was the additional benefit of column experiment. The short kinetic tests showed that 5 min of contact time with solution of initial concentration of 6.020 mgP-PO4 L-1 is enough to reduce the P-PO4 in 100%. The equilibrium studies were conducted with P-PO4 solution of 6.020 to 977.7 mg L-1 with contact time of 30 min. The obtained data was compensated by non-linear regression using the Marquardt algorithm in the Statgraphics Centurion XVI. The eggshell calcined characterized by high sorption capacity (S max = 72.87 mg g-1) obtained from the Langmuir isotherm model with a good fit (96.77%). To choose the appropriate ratio of a sand filter to eggshells amendment, four small columns were constructed and fed with P-PO4 solution (C in ≈ 5 mg L-1). The percentage mass (m/m) of CEs in the columns was 0.0 (the reference one); 1.0; 2.5; and 5.0. The unit sorption obtained during 95 days of column experiment was 10.668, 4.277, and 2.286 mg P-PO4 g-1 for 1.0, 2.5, and 5.0%, respectively. For practical implementation, the most recommended addition seems to be 1% of CEs. It corresponds, e.g., to the mass of 49 kg CEs for septic tank system.
Collapse
Affiliation(s)
- Agnieszka Bus
- Faculty of Civil and Environmental Engineering, Department of Environmental Improvement, Warsaw University of Life Sciences WULS – SGGW, Nowoursynowska 166, 02-787 Warsaw, Poland
| | - Agnieszka Karczmarczyk
- Faculty of Civil and Environmental Engineering, Department of Environmental Improvement, Warsaw University of Life Sciences WULS – SGGW, Nowoursynowska 166, 02-787 Warsaw, Poland
| | - Anna Baryła
- Faculty of Civil and Environmental Engineering, Department of Environmental Improvement, Warsaw University of Life Sciences WULS – SGGW, Nowoursynowska 166, 02-787 Warsaw, Poland
| |
Collapse
|
10
|
Yin H, Yang C, Jia Y, Chen H, Gu X. Dual removal of phosphate and ammonium from high concentrations of aquaculture wastewaters using an efficient two-stage infiltration system. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 635:936-946. [PMID: 29710615 DOI: 10.1016/j.scitotenv.2018.04.218] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Revised: 03/31/2018] [Accepted: 04/16/2018] [Indexed: 05/03/2023]
Abstract
Nitrogen (N) and phosphorus (P) pollution from aquaculture has increased dramatically in recent years, and it is urgent to develop a cost-effective method to clean these polluted waters. The objective of this study is to investigate N and P removal using a two-stage infiltration system based on NaCl modified clinoptilolite (NCLP) and thermally-treated calcium-rich attapulgite (TCAP). Results from a batch study indicated that the maximum ammonium sorption capacity of NCLPs was in the range of 6.64 to 7.27 mg. N/g and decreased slightly among the three particle sizes studied (0.2-0.5 mm, 0.5 mm-1.0 mm and 1-2 mm). A 150-day column experiment indicated that the two-stage infiltration system achieved an average removal efficiency of 99.4% N and 99.0% P, and a removal rate of 50.3 g N/m3/d and 8.83 g P/m3/d for an influent concentration of 50 mg N/L and 10 mg P/L with a hydraulic retention time (HRT) of 16 h. When the influent concentration increased to 100 mg N/L and 20 mg P/L, the average ammonium removal efficiency decreased to 65.3%, while the system can still keep a high average P removal efficiency of 97.9% for 72 days of the experiment. Longer HRT favored N and P removal efficiency, but short HRTs can oxygenate ammonium sorbed in the NCLP filter and thereby refresh its sorption capacity. The results also indicated that longer wet and dry cycles can enhance the N removal efficiency of the system, but had minor influence on P removal. The sorbed clays contained high N and P content and might have use as a slow-release fertilizer. The results of this study indicate that a reactive clay-based treatment system can be used for dual removal of N and P from aquaculture wastewaters, making possible the development of a sustainable aquaculture model.
Collapse
Affiliation(s)
- Hongbin Yin
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, China.
| | - Chunhui Yang
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, China; University of Chinese Academy of Sciences, 19 Yuquan Road, Beijing 100049, China
| | - Yanxia Jia
- Nanjing University of Science and Technology, 200 Xiaolingwei Road, 210094 Nanjing, China
| | - Huiui Chen
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, China
| | - Xiaohong Gu
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, China.
| |
Collapse
|
11
|
Su JF, Liang DH, Wei L, Luo XX. Coupled Carbon, Mn(II), and Nitrogen Cycles in a Mixotrophic Biofilm Reactor and Microbial Community Structure. Chem Eng Technol 2018. [DOI: 10.1002/ceat.201700306] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Jun Feng Su
- Xi'an University of Architecture and Technology; School of Environmental and Municipal Engineering; No. 13 Yanta Street, Beilin District 710055 Xi'an China
- State Key Laboratory of Urban Water Resource and Environment; School of Municipal and Environmental Engineering; No. 73 Huanghe Road, Nangang District 150090 Harbin China
| | - Dong Hui Liang
- Xi'an University of Architecture and Technology; School of Environmental and Municipal Engineering; No. 13 Yanta Street, Beilin District 710055 Xi'an China
| | - Li Wei
- State Key Laboratory of Urban Water Resource and Environment; School of Municipal and Environmental Engineering; No. 73 Huanghe Road, Nangang District 150090 Harbin China
| | - Xian Xin Luo
- Xi'an University of Architecture and Technology; School of Environmental and Municipal Engineering; No. 13 Yanta Street, Beilin District 710055 Xi'an China
| |
Collapse
|
12
|
Bove P, Claveau-Mallet D, Boutet É, Lida F, Comeau Y. Development and modelling of a steel slag filter effluent neutralization process with CO 2-enriched air from an upstream bioprocess. WATER RESEARCH 2018; 129:11-19. [PMID: 29127830 DOI: 10.1016/j.watres.2017.11.005] [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: 08/16/2017] [Revised: 10/27/2017] [Accepted: 11/02/2017] [Indexed: 06/07/2023]
Abstract
The main objective of this project was to develop a steel slag filter effluent neutralization process by acidification with CO2-enriched air coming from a bioprocess. Sub-objectives were to evaluate the neutralization capacity of different configurations of neutralization units in lab-scale conditions and to propose a design model of steel slag effluent neutralization. Two lab-scale column neutralization units fed with two different types of influent were operated at hydraulic retention time of 10 h. Tested variables were mode of flow (saturated or percolating), type of media (none, gravel, Bionest and AnoxKaldnes K3), type of air (ambient or CO2-enriched) and airflow rate. One neutralization field test (saturated and no media, 2000-5000 ppm CO2, sequential feeding, hydraulic retention time of 7.8 h) was conducted for 7 days. Lab-scale and field-scale tests resulted in effluent pH of 7.5-9.5 when the aeration rate was sufficiently high. A model was implemented in the PHREEQC software and was based on the carbonate system, CO2 transfer and calcite precipitation; and was calibrated on ambient air lab tests. The model was validated with CO2-enriched air lab and field tests, providing satisfactory validation results over a wide range of CO2 concentrations. The flow mode had a major impact on CO2 transfer and hydraulic efficiency, while the type of media had little influence. The flow mode also had a major impact on the calcite surface concentration in the reactor: it was constant in saturated mode and was increasing in percolating mode. Predictions could be made for different steel slag effluent pH and different operation conditions (hydraulic retention time, CO2 concentration, media and mode of flow). The pH of the steel slag filter effluent and the CO2 concentration of the enriched air were factors that influenced most the effluent pH of the neutralization process. An increased concentration in CO2 in the enriched air reduced calcite precipitation and clogging risks. Stoichiometric calculations showed that a typical domestic septic tank effluent with 300 mg/L of biodegradable COD provides enough biological CO2 for neutralization of a steel slag effluent with pH of 10.5-11.5. A saturated neutralization reactor with no media operated at hydraulic retention time of 10 h and a concentration of 2000 ppm in CO2 enriched air is recommended for full-scale applications.
Collapse
Affiliation(s)
- Patricia Bove
- Department of Civil, Geological and Mining Engineering, Polytechnique Montreal, Montreal, H3C 3A7 Quebec, Canada
| | - Dominique Claveau-Mallet
- Department of Civil, Geological and Mining Engineering, Polytechnique Montreal, Montreal, H3C 3A7 Quebec, Canada.
| | - Étienne Boutet
- Bionest, 55, 12e Rue, C.P. 10070, Shawinigan, Quebec G9T 5K7, Canada
| | - Félix Lida
- Bionest, 55, 12e Rue, C.P. 10070, Shawinigan, Quebec G9T 5K7, Canada
| | - Yves Comeau
- Department of Civil, Geological and Mining Engineering, Polytechnique Montreal, Montreal, H3C 3A7 Quebec, Canada
| |
Collapse
|
13
|
Zhao C, Si B, Mirza ZA, Liu Y, He X, Li J, Wang Z, Zheng H. Activated carbon fiber (ACF) enhances the UV/EF system to remove nitrobenzene in water. Sep Purif Technol 2017. [DOI: 10.1016/j.seppur.2017.05.030] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
|
14
|
Rodríguez-Gómez R, Renman G. Phosphorus removal from UASB reactor effluent by reactive media filtration. ENVIRONMENTAL TECHNOLOGY 2017; 38:2024-2031. [PMID: 27750543 DOI: 10.1080/09593330.2016.1244570] [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: 06/23/2016] [Accepted: 09/28/2016] [Indexed: 06/06/2023]
Abstract
The phosphorus (P) and BOD7 removal performance of an upflow packed bed reactor (PBR) filled with two reactive filter media was studied over 50 weeks. The lower one-fifth of the reactor was filled with calcium-silicate-hydrate (Sorbulite®) and the upper four-fifth with calcium-silicate (Polonite®). A laboratory-scale upflow anaerobic sludge bed reactor (UASB) delivered wastewater to the PBR. A model was developed to describe the gradient in P concentration change in the reactor, based on reaction kinetics. The reaction terms were assumed to follow the Langmuir isotherm, based on the results obtained in a batch test. First, a comparison was made between experimental and simulated results. The capability of the model to forecast P removal capacity was then tested for three hypothetical cases: (i) reactor filled with Sorbulite and Polonite, (ii) reactor filled with only Sorbulite, and (iii) reactor filled with only Polonite. Finally, a sensitivity analysis was performed for the main parameters in the model. The average removal of P and BOD7 from the UASB effluent was 98% and 90%, respectively. The starting pH of the dual-medium effluent was 12.2 and decreased gradually over time to 11.1. The simulation both overestimated and underestimated mean measured P removal but was within the range of maximum and minimum measured values. The hypothetical cases revealed that most P was removed by Polonite due to calcium phosphate precipitation. The removal capacity of the two filter materials and their layer height in the reactor were the most sensitive parameters in the simulation.
Collapse
Affiliation(s)
- Raúl Rodríguez-Gómez
- a Department of Sustainable Development, Environmental Science and Engineering , KTH Royal Institute of Technology , Stockholm , Sweden
- b WSP Sverige , Stockholm , Sweden
| | - Gunno Renman
- a Department of Sustainable Development, Environmental Science and Engineering , KTH Royal Institute of Technology , Stockholm , Sweden
| |
Collapse
|
15
|
Yin H, Yan X, Gu X. Evaluation of thermally-modified calcium-rich attapulgite as a low-cost substrate for rapid phosphorus removal in constructed wetlands. WATER RESEARCH 2017; 115:329-338. [PMID: 28288312 DOI: 10.1016/j.watres.2017.03.014] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Revised: 02/24/2017] [Accepted: 03/05/2017] [Indexed: 06/06/2023]
Abstract
The cost-effective and geographically available substrates are vital for the design of constructed wetlands (CWs), especially the saturated subsurface flow CWs, which are deemed as an efficient way to remove the inlet-lake phosphorus concentrations. In this study, phosphorus removal of thermally-treated calcium-rich attapulgite (TCAP) with varied particle sizes (0.2-0.5 mm, 0.5-1 mm and 1-2 mm) was assessed using batch and long-term column experiments to evaluate its feasibility as a CWs substrate. The phosphorus-bound mechanism in TCAP was identified in various initial phosphorus concentrations. Batch studies indicated that more than 95% of P can be rapidly (<1 h) removed by TCAP from solution with a concentration of 20 mg P/L, and P sorption can be well fitted by a pseudo-second-order equation. The maximum P sorption capacity of TCAP was in the range of 4.46-5.99 mg P/g, and the availability of Ca2+ concentration might limit the P removal capacity of TCAP at high phosphorus concentrations. Both the P removal rate and capacities decreased with the increase of TCAP particle sizes. Column P removal experiments indicated that hydraulic retention time (HRT) exerts great influence on P removal performance and longer HRTs favor the dissolution of CaO in TCAP, consequently increasing the P removal rate. In a 150-day P removal experiment, TCAP removed an average of 93.1%-95.4% of the influent P with a HRT of eight hours. Both the batch and chemical extraction of the P fraction of TCAP showed that the P removed by TCAP was mainly through formation of Ca phosphate precipitation. However, the species of Ca-P precipitation formed might be varied in different phosphorus concentrations. All results indicated that TCAP can be a suitable substrate when used in CWs, and field experiments should be carried out to test its real P removal performance in the future.
Collapse
Affiliation(s)
- Hongbin Yin
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, 73 East Beijing Road, Nanjing 210008, China.
| | - Xiaowei Yan
- Nanjing University of Science and Technology, 200 Xiaolingwei Road, 210094 Nanjing, China
| | - Xiaohong Gu
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, 73 East Beijing Road, Nanjing 210008, China.
| |
Collapse
|
16
|
Rodríguez-Gómez R, Renman G. Sequential UASB and dual media packed-bed reactors for domestic wastewater treatment - experiment and simulation. WATER SCIENCE AND TECHNOLOGY : A JOURNAL OF THE INTERNATIONAL ASSOCIATION ON WATER POLLUTION RESEARCH 2016; 73:2959-2970. [PMID: 27332842 DOI: 10.2166/wst.2016.162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
A wastewater treatment system composed of an upflow anaerobic sludge blanket (UASB) reactor followed by a packed-bed reactor (PBR) filled with Sorbulite(®) and Polonite(®) filter material was tested in a laboratory bench-scale experiment. The system was operated for 50 weeks and achieved very efficient total phosphorus (P) removal (99%), 7-day biochemical oxygen demand removal (99%) and pathogenic bacteria reduction (99%). However, total nitrogen was only moderately reduced in the system (40%). A model focusing on simulation of organic material, solids and size of granules was then implemented and validated for the UASB reactor. Good agreement between the simulated and measured results demonstrated the capacity of the model to predict the behaviour of solids and chemical oxygen demand, which is critical for successful P removal and recovery in the PBR.
Collapse
Affiliation(s)
- Raúl Rodríguez-Gómez
- Division of Land and Water Resources Engineering, KTH Royal Institute of Technology, Teknikringen 76, Stockholm SE-100 44, Sweden E-mail:
| | - Gunno Renman
- Division of Land and Water Resources Engineering, KTH Royal Institute of Technology, Teknikringen 76, Stockholm SE-100 44, Sweden E-mail:
| |
Collapse
|