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Hou J, Hong C, Ling W, Hu J, Feng W, Xing Y, Wang Y, Zhao C, Feng L. Research progress in improving sludge dewaterability: sludge characteristics, chemical conditioning and influencing factors. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2024; 351:119863. [PMID: 38141343 DOI: 10.1016/j.jenvman.2023.119863] [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: 09/11/2023] [Revised: 11/29/2023] [Accepted: 12/12/2023] [Indexed: 12/25/2023]
Abstract
Sludge from wastewater treatment processes with high water content and large volume has become an inevitable issue in environmental management. Due to the challenging dewatering properties of sludge, current mechanical dewatering methods are no longer sufficient to meet the escalating water content standards of sludge. This paper summarizes the characteristics of various sludge and raises reasons for the their dewaterability differences. Affected by extracellular polymeric substances, biological sludge is hydrophilic and negatively charged, which limits the dewatering degree. The rheological properties, flocs, ionic composition, and solid phase concentration of the sludge also influence the dewatering to some extent. For these factors, the chemical conditioning measures with simple operation and excellent effect improve its dewaterability, which mainly include flocculation/coagulation, acid/alkali treatment, advanced oxidation, surfactant treatment and combined treatment. There is a growing necessity to explore the development of new chemical conditioning agents, even though traditional agents continue to remain widely used. However, the development of these new agents should prioritize finding a balance between various factors such as efficiency, effectiveness, ease of operation, environmental safety, and cost-effectiveness. Electrochemical dewatering enhances solid-liquid separation, and its coupling with chemical conditioning is also an excellent means to further reduce water content. In addition, the improvement of press filter is an effective way, which is influenced by pressure, processing time, sludge cake thickness and pore structure, filter media etc. In general, it is essential to develop new conditioning agents and enhance mechanical filtration press technology based on a thorough understanding of various sludge properties. Concurrently, an in-depth study of the principles of mechanical pressure filtration will contribute to establishing a theoretical foundation for effective deep sludge dewatering and propel further advancements in this field.
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Affiliation(s)
- Jiachen Hou
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing, 100083, China
| | - Chen Hong
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing, 100083, China; Beijing Key Laboratory of Resource-oriented Treatment of Industrial Pollutants, University of Science and Technology Beijing, Beijing, 100083, China.
| | - Wei Ling
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing, 100083, China
| | - Jiashuo Hu
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing, 100083, China
| | - Weibo Feng
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing, 100083, China
| | - Yi Xing
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing, 100083, China; Beijing Key Laboratory of Resource-oriented Treatment of Industrial Pollutants, University of Science and Technology Beijing, Beijing, 100083, China
| | - Yijie Wang
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing, 100083, China
| | - Chengwang Zhao
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing, 100083, China
| | - Lihui Feng
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing, 100083, China
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Xia J, Ji J, Hu Z, Rao T, Liu A, Ma J, Sun Y. Application of Advanced Oxidation Technology in Sludge Conditioning and Dewatering: A Critical Review. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:ijerph19159287. [PMID: 35954642 PMCID: PMC9368043 DOI: 10.3390/ijerph19159287] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Revised: 07/22/2022] [Accepted: 07/26/2022] [Indexed: 02/04/2023]
Abstract
Sludge dewatering is an important link in sludge treatment. In practical engineering, the dewatering effect of unconditioned sludge is very poor. The use of advanced oxidation technology can improve sludge dewatering performance, reduce sludge capacity, and remove micro-pollutants, which is beneficial for sludge post-treatment and disposal. Based on the current status of sludge conditioning and dehydration, the characteristics of the advanced oxidation method for sludge dehydration were systematically explained using various free radical reaction mechanisms and dehydration conditions. The effects of various advanced oxidation technologies on sludge conditioning and dewatering has been extensively discussed. Finally, the application prospects of the advanced oxidation technology in sludge conditioning and dewatering are presented.
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Affiliation(s)
- Jiahua Xia
- Nanjing Jiangbei New Area Public Utilities Holding Group Co., Ltd., Nanjing 210044, China; (J.X.); (J.J.); (Z.H.); (T.R.)
| | - Juan Ji
- Nanjing Jiangbei New Area Public Utilities Holding Group Co., Ltd., Nanjing 210044, China; (J.X.); (J.J.); (Z.H.); (T.R.)
| | - Zhiqiang Hu
- Nanjing Jiangbei New Area Public Utilities Holding Group Co., Ltd., Nanjing 210044, China; (J.X.); (J.J.); (Z.H.); (T.R.)
| | - Ting Rao
- Nanjing Jiangbei New Area Public Utilities Holding Group Co., Ltd., Nanjing 210044, China; (J.X.); (J.J.); (Z.H.); (T.R.)
| | - Ankang Liu
- Nanjing Water Purification Environmental Research Institute Co., Ltd., Nanjing 211100, China;
| | - Jingqian Ma
- College of Urban Construction, Nanjing Tech University, Nanjing 211800, China;
| | - Yongjun Sun
- College of Urban Construction, Nanjing Tech University, Nanjing 211800, China;
- Correspondence:
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Navab-Daneshmand T, Guo B, Gehr R, Frigon D. Impact of pH and removed filtrate on E. coli regrowth and microbial community during storage of electro-dewatered biosolids. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 814:152544. [PMID: 34952058 DOI: 10.1016/j.scitotenv.2021.152544] [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: 09/10/2021] [Revised: 12/15/2021] [Accepted: 12/15/2021] [Indexed: 06/14/2023]
Abstract
Residual biosolids can be land applied if they meet microbiological requirements at the time of application. Electro-dewatering technology is shown to reduce biosolids bacterial counts to detection limits with little potential for bacterial regrowth during incubations. Here, we investigated the impacts on Escherichia coli regrowth and microbial communities of biosolids pH, removed nutrients via the filtrate, and inhibitory compounds produced in electro-dewatered biosolids. Findings suggest pH as the primary mechanism impacting E. coli regrowth in electro-dewatered biosolids. Propidium monoazide treatments were effective at removing DNA from dead cells, based on the removal of obligate anaerobes observed after anaerobic incubation. Analyses of high throughput sequenced data showed lower alpha-diversities associated with electro-dewatering treatment and incubation time. Moreover, biosolids pH and incubation period were the main factors contributing to the variations in microbial community compositions after incubation. Results highlight the role of electro-dewatered biosolids' low pH on inhibiting the regrowth of culturable bacteria as well as reducing the microbial community variance.
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Affiliation(s)
- Tala Navab-Daneshmand
- School of Chemical, Biological, and Environmental Engineering, Oregon State University, 105 SW 26th St., Corvallis, OR 97331, USA; Department of Civil Engineering and Applied Mechanics, McGill University, 817 Sherbrooke St. West, Montreal, Quebec H3A 0C3, Canada
| | - Bing Guo
- Department of Civil Engineering and Applied Mechanics, McGill University, 817 Sherbrooke St. West, Montreal, Quebec H3A 0C3, Canada; Centre for Environmental Health and Engineering, Department of Civil and Environmental Engineering, University of Surrey, Guildford, Surrey GU2 7XH, United Kingdom
| | - Ronald Gehr
- Department of Civil Engineering and Applied Mechanics, McGill University, 817 Sherbrooke St. West, Montreal, Quebec H3A 0C3, Canada
| | - Dominic Frigon
- Department of Civil Engineering and Applied Mechanics, McGill University, 817 Sherbrooke St. West, Montreal, Quebec H3A 0C3, Canada.
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Hui K, Song L, Yin Z, Song H, Wang Z, Gao W, Xuan L. Freeze-thaw combined with activated carbon improves electrochemical dewaterability of sludge: analysis of sludge floc structure and dewatering mechanism. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2022; 29:20333-20346. [PMID: 34731422 DOI: 10.1007/s11356-021-16837-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Accepted: 09/27/2021] [Indexed: 06/13/2023]
Abstract
Freeze-thaw (F/T) and electrochemistry both are environment-friendly and efficient sludge treatment technologies. In this study, the sludge samples were frozen at - 15 °C, and 20% g/gTss activated carbon (AC) was added to the dissolved sludge. Finally, the uniformly mixed sludge was treated at a voltage of 15 V for 25 min. During the experiment, the effect of F/T on the floc structure was analyzed by a laser particle analyzer and scanning electron microscope. F/T treatment improved the dewatering performance of the sludge and promoted the aggregation of sludge flocs into larger particles either. At the same time, the median diameter (D50) increased from 45.27 to 128.94 μm. AC was added to the thawed sludge solution before electrochemical treatment (EP). The conductivity of AC enhanced the effect of EP, thereby cracking the sludge flocs. Therefore, the three-dimensional excitation-emission matrix (3D-EEM) intensity of tightly bound extracellular polymeric substances (TB-EPS) decreased significantly. The protein in TB-EPS decreased from 54 to 33%, and the D50 was also reduced to 105.3 μm. The final specific resistance of filtration and water content were reduced by 96.39% and 32.17%, respectively. The dehydrated cake elemental analysis showed that increased AC improved the sludge cake's combustion efficiency significantly. Moreover, the preliminary economic analysis indicated that the cost of this research was low, which implied the potential application value of combined treatment.
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Affiliation(s)
- Kai Hui
- School of Civil Engineering, Inner Mongolia University of Technology, Hohhot, 010051, China
| | - Lei Song
- School of Civil Engineering, Inner Mongolia University of Technology, Hohhot, 010051, China.
| | - Zhenzhou Yin
- School of Civil Engineering, Inner Mongolia University of Technology, Hohhot, 010051, China
| | - Hongwei Song
- School of Civil Engineering, Inner Mongolia University of Technology, Hohhot, 010051, China
| | - Zehao Wang
- School of Civil Engineering, Inner Mongolia University of Technology, Hohhot, 010051, China
| | - Wenjian Gao
- School of Civil Engineering, Inner Mongolia University of Technology, Hohhot, 010051, China
| | - Lili Xuan
- School of Civil Engineering, Inner Mongolia University of Technology, Hohhot, 010051, China
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