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Baffoe EE, Otoo SL, Kareem S, Dankwah JR. Evaluation of initial pH and urea hydrogen peroxide (UHP) co-pretreatment on waste-activated sludge. ENVIRONMENTAL RESEARCH 2024; 246:118155. [PMID: 38211719 DOI: 10.1016/j.envres.2024.118155] [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: 06/27/2023] [Revised: 01/05/2024] [Accepted: 01/06/2024] [Indexed: 01/13/2024]
Abstract
Wastewater treatment and conversion into renewable energy sources have been of great interest in recent times due to growing environmental pollution concerns and need for sustainable energy sources. Sewage sludge treatment can convert sludge into renewable energy. In this study, the impact of initial pH and urea hydrogen peroxide (UHP) co-pretreatment on sludge hydrolysis and anaerobic digestion was investigated. The pH of sludge was initially adjusted to 7, 9, and 11 before the addition of 8 mmol/g VS UHP. Under 24 h pretreatment, alkaline medium and UHP effectively enhanced sludge solubilization and hydrolysis. The combination of chemical, sonication, and centrifugation improved the extraction of extracellular polymerase substances released in soluble state. Secondly, anaerobic digestion was performed for 11 days to determine the influence of a lower mesophilic temperature (20 °C) and retention time on the pretreated sludge. The highest NH4+-N concentration of 5.32 g/L was recorded in pH 7+UHP. The most significant total VFA concentration of 13.1 g COD/L was observed in pH 7+UHP on day 9. Acetic acid, isovaleric acid and propionic acid accounted for 80%-83% of the total VFA composition in all pretreated reactors. Lower mesophilic temperature efficiently optimized UHP and VFA production in the pretreated reactors. Microbial metabolism was stabilized under a longer retention time. Alkaline pH and longer retention time elevated NH4+-N and VFA concentration. The results showed that initial pH and UHP co-pretreatment of waste activated sludge offer an alternative pathway for enhancing sludge hydrolysis and VFA production applicable in sludge treatment.
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Affiliation(s)
- Estella Efiba Baffoe
- School of Resources & Environmental Engineering, Wuhan University of Technology, Wuhan, Hubei Province, 430070, China.
| | - Samuel Leumas Otoo
- School of Materials Science & Engineering, Wuhan University of Technology, Wuhan, Hubei Province, 430070, China
| | - Shefiu Kareem
- School of Materials Science & Engineering, Wuhan University of Technology, Wuhan, Hubei Province, 430070, China
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Yang Y, Yang X, Chen Y, Li X, Yang Q, Li Y, Ma P, Zhang H, Xu S. Response surface optimization of sludge dewatering process: synergistic enhancement by ultrasonic, chitosan and sludge-based biochar. WATER SCIENCE AND TECHNOLOGY : A JOURNAL OF THE INTERNATIONAL ASSOCIATION ON WATER POLLUTION RESEARCH 2024; 89:1630-1646. [PMID: 38619894 DOI: 10.2166/wst.2024.080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Accepted: 02/20/2024] [Indexed: 04/17/2024]
Abstract
Due to the colloidal stability, the high compressibility and the high hydration of extracellular polymeric substances (EPS), it is difficult to efficiently dehydrate sludge. In order to enhance sludge dewatering, the process of ultrasonic (US) cracking, chitosan (CTS) re-flocculation and sludge-based biochar (SBB) skeleton adsorption of water-holding substances to regulate sludge dewaterability was proposed. Based on the response surface method, the prediction model of the specific resistance to filtration (SRF) and sludge cake moisture content (MC) was established. The US cracking time and the dosage of CTS and SBB were optimized. The results showed that the optimal parameters of the three were 5.08 s, 10.1 mg/g dry solids (DS) and 0.477 g/g DS, respectively. Meantime, the SRF and MC were 5.4125 × 1011 m/kg and 76.8123%, which significantly improved the sludge dewaterability. According to the variance analysis, it is found that the fitting degree of SRF and MC model is good, which also confirms that there is significant interaction and synergy between US, CTS and SBB, and the contribution of CTS and SBB is greater. Moreover, the process significantly improves the sludge's calorific value and makes its combustion more durable.
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Affiliation(s)
- Yahong Yang
- School of Civil Engineering, Lanzhou University of Technology, Lanzhou, Gansu 730050, China; Wenzhou Engineering Institute of Pump & Value, Lanzhou University of Technology, Wenzhou, Zhejiang 325105, China E-mail:
| | - Xingfeng Yang
- School of Civil Engineering, Lanzhou University of Technology, Lanzhou, Gansu 730050, China; School of Environmental and Chemical Engineering, Organic Compound Pollution Control Engineering, Ministry of Education, Shanghai University, Shanghai 200444, China
| | - Yirong Chen
- School of Civil Engineering, Lanzhou University of Technology, Lanzhou, Gansu 730050, China; Wenzhou Engineering Institute of Pump & Value, Lanzhou University of Technology, Wenzhou, Zhejiang 325105, China
| | - Xiaowei Li
- School of Environmental and Chemical Engineering, Organic Compound Pollution Control Engineering, Ministry of Education, Shanghai University, Shanghai 200444, China
| | - Qiyong Yang
- College of Resources & Environment, Jiujiang University, Jiujiang, Jiangxi 332005, China
| | - Yangying Li
- School of Civil Engineering, Lanzhou University of Technology, Lanzhou, Gansu 730050, China; Wenzhou Engineering Institute of Pump & Value, Lanzhou University of Technology, Wenzhou, Zhejiang 325105, China
| | - Pengjing Ma
- School of Civil Engineering, Lanzhou University of Technology, Lanzhou, Gansu 730050, China; Wenzhou Engineering Institute of Pump & Value, Lanzhou University of Technology, Wenzhou, Zhejiang 325105, China
| | - Huining Zhang
- School of Civil Engineering, Lanzhou University of Technology, Lanzhou, Gansu 730050, China
| | - Shenghui Xu
- School of Civil Engineering, Lanzhou University of Technology, Lanzhou, Gansu 730050, China
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Li X, Zhao Q, Li L, Mei W, Wang Z, Gao Q, Wang K, Zhou H, Wei L, Jiang J. Enhanced dewaterability of food waste digestate by biochar/potassium ferrate treatments: Performance and mechanisms. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2024; 354:120268. [PMID: 38364546 DOI: 10.1016/j.jenvman.2024.120268] [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: 12/04/2023] [Revised: 01/21/2024] [Accepted: 01/31/2024] [Indexed: 02/18/2024]
Abstract
The combined process of biochar (BC) and potassium ferrate (PF) offers a fascinating technique for efficient dewatering of digestate. However, the effects of BC/PF treatment on the dewaterability and mechanisms of FWD are still unknown. This study aimed to reveal the impact mechanisms of BC/PF treatment on digestate dewatering performance. Experimental results indicated that BC/PF treatment significantly enhanced the dewaterability of digestate, with the minimum specific resistance to filtration of (1.05 ± 0.02) × 1015 m·kg-1 and water content of 57.52 ± 0.51% being obtained at the concentrations of 0.018 g·g-1 total solid (TS) BC300 and 0.20 g·g-1 TS PF, which were 8.60% and 13.59% lower than PF treatment, respectively. BC/PF treatment proficiently reduced the fractal dimension, bound water content, apparent viscosity, and gel-like network structure strength of digestate, as well as increased the floc size and zeta potential of digestate. BC/PF treatment promoted the conversion of extracellular polymeric substances (EPS) fractions from inner EPS to soluble EPS, increased the fluorescence intensity of the dissolved compounds, and enhanced the hydrophobicity of proteins. Mechanisms investigations showed that BC/PF enhanced dewatering through non-reactive oxygen species pathways, i.e., via strong oxidative intermediate irons species Fe(V)/Fe(IV). BC/PF treatment enhanced the solubilization of nutrients, the inactivation of fecal coliforms, and the mitigation of heavy metal toxicity. The results suggested that BC/PF treatment is an effective digestate dewatering technology which can provide technological supports to the closed-loop treatment of FWD.
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Affiliation(s)
- Xinwen Li
- Department of Environment Science and Engineering, School of Environment, Harbin Institute of Technology, Harbin, 150090, China
| | - Qingliang Zhao
- Department of Environment Science and Engineering, School of Environment, Harbin Institute of Technology, Harbin, 150090, China; State Key Laboratory of Urban Water Resources and Environment (SKLUWRE), School of Environment, Harbin Institute of Technology, Harbin, 150090, China
| | - Lili Li
- Department of Environment Science and Engineering, School of Environment, Harbin Institute of Technology, Harbin, 150090, China.
| | - Wangyang Mei
- Department of Environment Science and Engineering, School of Environment, Harbin Institute of Technology, Harbin, 150090, China
| | - Zhaoxia Wang
- Department of Environment Science and Engineering, School of Environment, Harbin Institute of Technology, Harbin, 150090, China
| | - Qingwei Gao
- Department of Environment Science and Engineering, School of Environment, Harbin Institute of Technology, Harbin, 150090, China
| | - Kun Wang
- Department of Environment Science and Engineering, School of Environment, Harbin Institute of Technology, Harbin, 150090, China
| | - Huimin Zhou
- Department of Environment Science and Engineering, School of Environment, Harbin Institute of Technology, Harbin, 150090, China
| | - Liangliang Wei
- Department of Environment Science and Engineering, School of Environment, Harbin Institute of Technology, Harbin, 150090, China
| | - Junqiu Jiang
- Department of Environment Science and Engineering, School of Environment, Harbin Institute of Technology, Harbin, 150090, China; State Key Laboratory of Urban Water Resources and Environment (SKLUWRE), School of Environment, Harbin Institute of Technology, Harbin, 150090, China.
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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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Zheng K, Wang Y, Guo H, Zhu T, Zhao Y, Liu Y. Potassium permanganate pretreatment effectively improves methane production from anaerobic digestion of waste activated sludge: Reaction kinetics and mechanisms. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 847:157402. [PMID: 35850326 DOI: 10.1016/j.scitotenv.2022.157402] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Revised: 07/08/2022] [Accepted: 07/12/2022] [Indexed: 05/21/2023]
Abstract
As a powerful oxidizing agent, potassium permanganate (KMnO4) has attracted widespread interest in sludge treatment and contaminant removal. However, its effect on the anaerobic digestion of waste activated sludge (WAS) is ambiguous. This investigation was designed to provide perspectives into this problem. In comparison with the control, 0.3 g KMnO4/g TSS pretreatment enhanced the methane production by 78.82 %. Model analysis demonstrated that the KMnO4 pretreatment enhanced the biochemical methane potential (B0) of WAS. Mechanistic studies elucidated that the KMnO4 pretreatment process generated reactive radicals such as ·OH, ·O2- and 1O2, which contributed to sludge disintegration and biodegradation process of dissolved substances, thus resulting in more substances available for subsequent methane generation. Enzyme activity analysis indicated that KMnO4 pretreatment facilitated the activities of key enzymes associated with anaerobic digestion to various degrees. Microbial analysis illustrated that the relative abundance of functional microorganisms was significantly elevated after KMnO4 pretreatment, which was conducive to methane production.
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Affiliation(s)
- Kaixin Zheng
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China
| | - Yufen Wang
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China
| | - Haixiao Guo
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China
| | - Tingting Zhu
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China
| | - Yingxin Zhao
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China
| | - Yiwen Liu
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China.
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Wang Y, Gu M, Ge D, Dong Y, Bai L, Han Y, Zhu N. Polyhexamethylene biguanidine used as a new type sewage sludge conditioning agent: Effect on sludge dewaterability and mechanism. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2022; 315:115146. [PMID: 35504185 DOI: 10.1016/j.jenvman.2022.115146] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 01/09/2022] [Accepted: 04/21/2022] [Indexed: 06/14/2023]
Abstract
Dewatering is the basic procedure of sludge treatment and disposal, and environmentally friendly and efficient sludge conditioning methods are urgently needed. Polyhexamethylene biguanide (PHMB), a broad-spectrum germicide used in daily life and medicine, was proposed as a sludge conditioning reagent in this paper, and its effect on waste activated sludge (WAS) dewaterability was studied for the first time. Results showed that PHMB can improve sludge dewatering performance, and capillary suction time (CST) and water content (Wc) of dewatered sludge cake was reduced by 78.11% and 13.37% with 100 mg PHMB/g dry sludge (DS). Further investigation revealed that the sludge properties changed pronouncedly after PHMB conditioning, the bound water content decreased from 1.58 g/g DS to 1.29 g/g DS, the particle size (D50) increased from 34.3 μm to 39.2 μm, the zeta potential increased from -20.96 mV to -3.36 mV, and the flowability increased whilst the viscosity decreased. When the dose of PHMB was lower than 50 mg/g DS, it mainly reacted with extracellular polymeric substance (EPS), resulting in a decrease in its content, which was also manifested by the decrease of molecular weights. However, when the dose reached 100 mg/g DS, PHMB would disrupt the cytomembranes of microorganisms and release cellular contents, reflected by a corresponding growth of EPS contents and the intensity of Fourier transform infrared (FTIR) spectrum. And the scanning electron microscope (SEM) images showed that PHMB conditioning made cracks and holes on sludge microstructures. The key mechanism of PHMB improving sludge dewaterability was inferred as "organic molecules disrupting" and "sludge particles flocculating". These findings demonstrate that PHMB is promising to be a novel, effective, and environmentally friendly sludge conditioning reagent.
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Affiliation(s)
- Yuhui Wang
- School of Environmental Science & Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - MinXue Gu
- School of Environmental Science & Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Dongdong Ge
- School of Environmental Science & Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Yanting Dong
- School of Environmental Science & Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Lu Bai
- School of Environmental Science & Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Ying Han
- Jiangsu Welle Environmental Technology Co., Ltd., Jiangsu, 213022, China
| | - Nanwen Zhu
- School of Environmental Science & Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China; Shanghai Engineering Research Center of Solid Waste Treatment and Resource Recovery, Shanghai, 200240, China.
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7
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Zhang X, Zhang H, Liu T, Yang J, Wang Z, Chen P. Insights into the respective role of oxidation and flocculation conditioning for enhancing paper sludge dewaterability. Chem Eng Res Des 2022. [DOI: 10.1016/j.cherd.2022.06.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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8
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Xiao X, Fang P, Huang JH, Tang ZJ, Chen XB, Wu HW, Cen CP, Tang ZX. Mechanistic study on NO reduction by sludge reburning in a pilot scale cement precalciner with different CO2 concentrations. RSC Adv 2019; 9:22863-22874. [PMID: 35514465 PMCID: PMC9067150 DOI: 10.1039/c9ra04065j] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Revised: 01/15/2020] [Accepted: 07/18/2019] [Indexed: 02/01/2023] Open
Abstract
The reducing gases of CO and NH3 produced by sludge reburning make a major contribution to NO reduction.
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Affiliation(s)
- Xiang Xiao
- South China Institute of Environmental Science
- Ministry of Ecological Environment of P. R. China
- Guangzhou 510655
- China
- The Key Laboratory of Water and Air Pollution Control of Guangdong Province
| | - Ping Fang
- South China Institute of Environmental Science
- Ministry of Ecological Environment of P. R. China
- Guangzhou 510655
- China
- The Key Laboratory of Water and Air Pollution Control of Guangdong Province
| | - Jian-Hang Huang
- South China Institute of Environmental Science
- Ministry of Ecological Environment of P. R. China
- Guangzhou 510655
- China
- The Key Laboratory of Water and Air Pollution Control of Guangdong Province
| | - Zi-Jun Tang
- South China Institute of Environmental Science
- Ministry of Ecological Environment of P. R. China
- Guangzhou 510655
- China
- The Key Laboratory of Water and Air Pollution Control of Guangdong Province
| | - Xiong-Bo Chen
- South China Institute of Environmental Science
- Ministry of Ecological Environment of P. R. China
- Guangzhou 510655
- China
- The Key Laboratory of Water and Air Pollution Control of Guangdong Province
| | - Hai-Wen Wu
- South China Institute of Environmental Science
- Ministry of Ecological Environment of P. R. China
- Guangzhou 510655
- China
- The Key Laboratory of Water and Air Pollution Control of Guangdong Province
| | - Chao-Ping Cen
- South China Institute of Environmental Science
- Ministry of Ecological Environment of P. R. China
- Guangzhou 510655
- China
- The Key Laboratory of Water and Air Pollution Control of Guangdong Province
| | - Zhi-Xiong Tang
- South China Institute of Environmental Science
- Ministry of Ecological Environment of P. R. China
- Guangzhou 510655
- China
- The Key Laboratory of Water and Air Pollution Control of Guangdong Province
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