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Zhang C, Li Y, Yu Z, Liu Y, Dong L. Effectiveness of biological drying for citric acid dewatered sludge: Evaluating the impact of energy-efficient ventilation strategies. WASTE MANAGEMENT (NEW YORK, N.Y.) 2024; 182:237-249. [PMID: 38677141 DOI: 10.1016/j.wasman.2024.04.038] [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: 09/14/2023] [Revised: 03/30/2024] [Accepted: 04/21/2024] [Indexed: 04/29/2024]
Abstract
The effectiveness of dehydration and utilization processes for citric acid dewatered sludge is hampered by its high concentrations of polysaccharides, proteins, and water-binding properties of microbial extracellular polymers (EPS). This research explores the efficacy and mechanisms involved in extracting water from this type of sludge using biological drying technology, with varying rates of ventilation. Especially pertinent was the use of low ventilation rates as control variables. Our results suggest that a scheduled intermittent ventilation at lower rates allows for the most efficient removal of water, achieving a rate of 41.71 % within eight days, according to the zero-order kinetic model. Remarkably, the peak temperature registered was 60 °C, reaching this threshold in just 0.1 days and maintaining high temperatures for approximately 5.9 days. Component analysis of organic matter illustrated a preferential degradation process for lipids under these ventilation conditions which is pivotal for releasing and transforming bound water for efficient extraction, as well as facilitating the breakdown of easily hydrolysable materials. Further, polysaccharide/protein (EPS) decomposition contributed to water removal, though less significantly. The periodic ventilation strategy allowed for the maximum cumulative temperature to be sustained, demonstrating superior efficiency in harnessing bio-generated heat (82.77 % for water evaporation), resulting in dry sludge suitable for self-sustained combustion at relatively low cost ($26.61/t). Highlighted by this study is the considerable potential of energy-efficient ventilation methods in the biological drying treatment of citric acid fermented sludge and similar industrial waste materials.
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Affiliation(s)
- Chen Zhang
- Department of Environmental Science and Engineering, Beijing Technology and Business University, Beijing, China; Key Laboratory of Cleaner Production and Integrated Resource Utilization of China National Light Industry, Beijing, China
| | - YangYang Li
- College of Environment and Ecology, Chongqing University, Chongqing, China
| | - ZhanQiu Yu
- Department of Environmental Science and Engineering, Beijing Technology and Business University, Beijing, China; Key Laboratory of Cleaner Production and Integrated Resource Utilization of China National Light Industry, Beijing, China
| | - YanFeng Liu
- Department of Environmental Science and Engineering, Beijing Technology and Business University, Beijing, China; Key Laboratory of Cleaner Production and Integrated Resource Utilization of China National Light Industry, Beijing, China
| | - LiMing Dong
- Department of Environmental Science and Engineering, Beijing Technology and Business University, Beijing, China; Key Laboratory of Cleaner Production and Integrated Resource Utilization of China National Light Industry, Beijing, China.
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Wang K, Chen Y, Cao MK, Zheng GD, Cai L. Influence of microbial community succession on biodegradation of municipal sludge during biodrying coupled with photocatalysis. CHEMOSPHERE 2024; 349:140901. [PMID: 38065267 DOI: 10.1016/j.chemosphere.2023.140901] [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: 03/15/2023] [Revised: 11/09/2023] [Accepted: 12/03/2023] [Indexed: 12/23/2023]
Abstract
A 20-day sludge biodrying process was coupled with photocatalysis to improve biodrying efficiency and investigate the effect of photocatalysis on biodegradation. After biodrying, the moisture content in the coupled photocatalytic group (TCA) and the control group (TUCA) decreased from 63.61% to 50.82% and 52.94%, respectively, and the volatile solids content decreased from 73.18% to 63.42% and 64.39%, respectively. Neutral proteinase activity decreased by 9.38% and 28.69%, and lipase activity decreased by 6.12% and 26.17%, respectively, indicating that photocatalysis helped maintain neutral proteinase and lipase activities. The Chao1 and Shannon indices showed that photocatalysis increased fungal diversity and reduced bacterial richness and diversity. The β diversity clustering analysis indicated that the bacterial community structure during the thermophilic phase in TCA differed from that in TUCA. The Kyoto Encyclopedia of Genes and Genomes annotation showed that photocatalysis has the potential to promote the synthesis and degradation of ketone bodies. Biodrying coupled with photocatalysis can improve the dewatering of sludge without negatively affecting biodegradation.
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Affiliation(s)
- Kan Wang
- School of Civil and Environmental Engineering, Ningbo University, Ningbo, 315211, China
| | - Ying Chen
- School of Civil and Environmental Engineering, Ningbo University, Ningbo, 315211, China
| | - Meng-Ke Cao
- School of Civil and Environmental Engineering, Ningbo University, Ningbo, 315211, China
| | - Guo-Di Zheng
- Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, 100101, China
| | - Lu Cai
- School of Civil and Environmental Engineering, Ningbo University, Ningbo, 315211, China.
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Cai L, Cao MK, Zheng GD, Wang XY, Guo HT, Jiang T. Sludge biodrying coupled with photocatalysis improves the degradation of extracellular polymeric substances. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2023; 345:118590. [PMID: 37499415 DOI: 10.1016/j.jenvman.2023.118590] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Revised: 06/08/2023] [Accepted: 07/03/2023] [Indexed: 07/29/2023]
Abstract
The efficiency of sludge dewatering is limited by extracellular polymeric substances (EPS) during biodrying. This study investigated the effect of photocatalysis-mediated EPS degradation on sludge dewatering performance during the sludge biodrying process. The photocatalysis of municipal sludge was first carried out to choose a cost-efficient catalyst. Then sludge biodrying tests were performed using TiO2-coated amendment (TCA) and uncoated amendment (TUCA) as the control. Municipal sludge photocatalysis results showed that using TiO2 could efficiently degrade carbohydrates and proteins in the EPS within 60 min. After 20-day biodrying, photocatalysis significantly promoted a reduction in the moisture content and EPS by 17.64% and 6.88%, respectively. The surface-enhanced Raman scattering (SERS) intensities of the C-C-O symmetric stretching vibration peak of D-lactose and the C-S stretching vibration peak of cysteine were significantly decreased by approximately 33.19% and 44.76%, respectively, indicating that photocatalysis indeed promoted the reduction of polysaccharides and cysteine in the EPS, especially after the thermophilic phase. The hydrophilic amino acid content decreased by 23.02%, verifying that photocatalysis could improve EPS hydrophobicity. Consequently, municipal sludge biodrying coupled with photocatalysis promotes sludge EPS degradation and enhances sludge dewaterability, improving the efficiency of sludge biodrying.
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Affiliation(s)
- Lu Cai
- School of Civil and Environmental Engineering, School of Physical Science and Technology, Ningbo University, Ningbo, 315211, China
| | - Meng-Ke Cao
- School of Civil and Environmental Engineering, School of Physical Science and Technology, Ningbo University, Ningbo, 315211, China
| | - Guo-Di Zheng
- Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, 100101, China
| | - Xin-Yu Wang
- School of Civil and Environmental Engineering, School of Physical Science and Technology, Ningbo University, Ningbo, 315211, China
| | - Han-Tong Guo
- Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, 100101, China
| | - Tao Jiang
- School of Civil and Environmental Engineering, School of Physical Science and Technology, Ningbo University, Ningbo, 315211, China.
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Yu B, Chen T, Wang X, Yang J, Zheng G, Fu L, Huang X, Wang Y. Insights into the effect mechanism of back-mixing inoculation on sewage sludge biodrying process: Biodrying characteristics and microbial community succession. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 857:159460. [PMID: 36257443 DOI: 10.1016/j.scitotenv.2022.159460] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Revised: 09/29/2022] [Accepted: 10/12/2022] [Indexed: 06/16/2023]
Abstract
Back mixing was frequently used to replace conventional bulking agenting, however, however, the internal effect mechanism was unclear. This study compared four bulking agents: mushroom residue (MR), MR + primary BM (BM-P), BM-P, and secondary BM (BM-S). The effect mechanism of back mixing (BM) inoculation was assessed based on biodrying performance and microbial community succession. Four trials (Trial A, Trial B, Trial C, and Trial D) reached maximum temperatures of 61.9, 68.8, 73.7, and 69.9 °C on days 6, 3, 2, and 2, respectively. Application of BM increased pile warming rate and resulted in higher temperatures. Temperature changes and microbial competition lead to decline in microbial diversity and richness during the biodrying process. Microbial diversity increased of four biodried products. The number of microorganisms shared by Trial A, Trial B, Trial C, and Trial D were 90, 119, 224, and 300, respectively. The addition of BM improved microbial community stability, and facilitating the initiation of biodrying process. Microbial genera that played an important role in the biodrying process included Ureibacillus, Bacillus, Sphaerobacter, and Tepidimicrobium. Based on these results, it was concluded that BM was efficient method to enhanced the microbial activity and reduced the usage of bulking agent.
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Affiliation(s)
- Bao Yu
- Center for Environmental Remediation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Tongbin Chen
- Center for Environmental Remediation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xiankai Wang
- Center for Environmental Remediation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China; Yangtze Eco-Environment Engineering Research Center, China Three Gorges Corporation, Beijing 100038, China
| | - Junxing Yang
- Center for Environmental Remediation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Guodi Zheng
- Center for Environmental Remediation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China.
| | - Lili Fu
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China; Beijing Greentech Technology Group Co.Ltd., Beijing 100080, China
| | - Xue Huang
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China; Beijing Greentech Technology Group Co.Ltd., Beijing 100080, China
| | - Yagen Wang
- Beijing Greentech Technology Group Co.Ltd., Beijing 100080, China
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Cai L, Guo HT, Zheng GD, Wang XY, Wang K. Metagenomic analysis reveals the microbial degradation mechanism during kitchen waste biodrying. CHEMOSPHERE 2022; 307:135862. [PMID: 35944670 DOI: 10.1016/j.chemosphere.2022.135862] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Revised: 06/14/2022] [Accepted: 07/24/2022] [Indexed: 06/15/2023]
Abstract
Biodrying is a treatment to remove moisture using bio-heat generated during organic degradation. Organic matter degradation and microbial metabolism were studied during the whole kitchen waste biodrying, using metagenomic analysis. After the 25-day biodrying process, carbohydrate, protein and lipid contents decreased by 83.7%, 27.8% and 79.3%, respectively, and their degradation efficiencies increased after the thermophilic phase. Lipase activity exceeded 10 mmol d-1 g-1 throughout biodrying. Cellulase and lipase activities recovered by 2.21% and 5.77%, respectively, after the thermophilic phase, while the protease activity had a maximum increment of 347%. Metabolic analysis revealed that carbohydrate, amino acid and lipid metabolism was possibly inhibited by the high temperature, but the relative abundances of related predicted functions recovered by more than 0.9%, 7% and 11%, respectively, by the end of biodrying. Protein function prediction suggests that β-oxidation, fatty acid biosynthesis, and the degradation of cellulose and chitin were possibly enhanced during the thermophilic phase. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis revealed that leucine, isoleucine and lysine could ultimately degraded to acetyl-CoA. Weissella, Aeribacillus and Bacillus were the genera with the most enriched functional genes during the whole biodrying process. These findings help elucidate the microbial degradation processes during biodrying, which provides further scientific support for improving the application of biodrying products.
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Affiliation(s)
- Lu Cai
- School of Civil and Environmental Engineering, Ningbo University, Ningbo, 315211, China
| | - Han-Tong Guo
- Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, 100101, China
| | - Guo-Di Zheng
- Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, 100101, China
| | - Xin-Yu Wang
- School of Civil and Environmental Engineering, Ningbo University, Ningbo, 315211, China
| | - Kan Wang
- School of Civil and Environmental Engineering, Ningbo University, Ningbo, 315211, China.
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Yu B, Chen T, Zheng G, Yang J, Huang X, Fu L, Cai L. Water-heat balance characteristics of the sewage sludge bio-drying process in a full-scale bio-drying plant with circulated air. WASTE MANAGEMENT (NEW YORK, N.Y.) 2022; 141:220-230. [PMID: 35149478 DOI: 10.1016/j.wasman.2022.01.041] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 01/23/2022] [Accepted: 01/31/2022] [Indexed: 06/14/2023]
Abstract
Sewage sludge bio-drying technology has attracted considerable attention in recent years. In this study, we explored the water-heat balance under two ventilation strategies for the first time in bio-drying plants with circulated air, and examined the influence of air circulation on water removal and heat recovery. We want to obtain the relationships of pile temperature, ventilation, and water removal. Then, it provides support for optimizing the bio-drying process conditions and improving the efficiency through analysis of the water-heat relationship. In the low-ventilation and high-ventilation trials, water removed was mainly on Days 9-12 and 1-4, respectively. Ventilation and pile temperature jointly determine the water removed during the bio-drying process. Water balance indicated that more than 30% of the water was removed under the nonventilated process. More organic matter was degraded to maintain a higher pile temperature under low-ventilation than under high-ventilation, which also led to more radiation heat being lost. High-ventilation trial input less energy (3.36 MJ/kg water removed) but obtained a higher bio-drying index I (7.04) and heat utilization efficiency Qeffic (94.1%). Heat balance showed that lower energy consumption by dry air (Qdryair) was obtained due to circulation air with high temperature. Circulation air also has a higher carried capacity of water vapor but carries more water into the pile due to higher humidity.
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Affiliation(s)
- Bao Yu
- Center for Environmental Remediation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Tongbin Chen
- Center for Environmental Remediation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Guodi Zheng
- Center for Environmental Remediation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China.
| | - Junxing Yang
- Center for Environmental Remediation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China
| | - Xue Huang
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China; Beijing Greentech Group Co. Ltd., Beijing 100080, China
| | - Lili Fu
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China; Beijing Greentech Group Co. Ltd., Beijing 100080, China
| | - Lu Cai
- School of Civil and Environmental Engineering, Ningbo University, Ningbo 315211, China
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Cai L, Cao MK, Chen TB, Guo HT, Zheng GD. Microbial degradation in the co-composting of pig manure and biogas residue using a recyclable cement-based synthetic amendment. WASTE MANAGEMENT (NEW YORK, N.Y.) 2021; 126:30-40. [PMID: 33740711 DOI: 10.1016/j.wasman.2021.02.036] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Revised: 02/18/2021] [Accepted: 02/18/2021] [Indexed: 06/12/2023]
Abstract
This research investigated a synthetic amendment to improve composting and resource recycling of pig manure and biogas residue. We further examined whether adding a synthetic amendment impacts the microbial ecosystem in the composted materials. Three mixing ratios were used to investigate composting performance: no synthetic amendment (T0), 5% synthetic amendment (T1), and 10% synthetic amendment (T2) (T1 and T2 were measured as a wet weight ratio). There were no significant differences in the fundamental characteristics between composting products in T0 and T1. The moisture content of composting material in T0, T1, and T2 significantly decreased from a baseline of approximately 65% to 35.5%, 37.3%, and 55.9%, respectively. Meanwhile, the germination index significantly increased to 111.6%, 155.6%, and 62.3%, respectively. When an optimal proportion of synthetic amendment was added, T1 showed high degree of humification, lignocellulase activities, and effective biodegradation. Firmicutes, Actinobacteria, Proteobacteria, and Bacteroidetes were the dominant bacteria, while Ascomycota and Basidiomycota were the dominant fungi in all treatment groups. Amino sugar and nucleotide sugar metabolism, glycolysis, starch, and sucrose metabolism were among the primary pathways in predicted functions. The synthetic amendment can generate a mature composting product and can be reused or recycled to conserve resources.
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Affiliation(s)
- Lu Cai
- School of Civil and Environmental Engineering, Ningbo University, Ningbo 315211, China
| | - Meng-Ke Cao
- School of Civil and Environmental Engineering, Ningbo University, Ningbo 315211, China
| | - Tong-Bin Chen
- Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China
| | - Han-Tong Guo
- School of Civil and Environmental Engineering, Ningbo University, Ningbo 315211, China
| | - Guo-Di Zheng
- Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China.
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Cao MK, Guo HT, Zheng GD, Chen TB, Cai L. Microbial succession and degradation during kitchen waste biodrying, highlighting the thermophilic phase. BIORESOURCE TECHNOLOGY 2021; 326:124762. [PMID: 33517049 DOI: 10.1016/j.biortech.2021.124762] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2020] [Revised: 01/17/2021] [Accepted: 01/18/2021] [Indexed: 06/12/2023]
Abstract
Biodrying in conjunction with compound stone amendment was used to treat kitchen waste, which improved biodrying. After 16 days, the pile moisture content decreased from 68.8% to 23.0%. Lignin, cellulose and hemicellulose concentrations decreased from 104.6 mg g-1 d.b., 322.9 mg g-1 d.b. and 155.9 mg g-1 d.b., respectively, to 74.0 mg g-1 d.b., 224.8 mg g-1 d.b. and 134.5 mg g-1 d.b., respectively. The Shannon index for bacteria increased from 2.5 to 3.1, while for fungi, it decreased from 4.6 to 0.6. The relative abundances of Amino Acid Metabolism and Carbohydrate Metabolism exceeded 7%. The thermophilic phase during the process inactivated the pathogenic microorganisms, increased the bacterial diversity, decreased the fungal diversity, and potentially improved the metabolism of nutrients, including amino acids, carbohydrates, lipids and vitamins. The biomarker analysis and predicated protein sequences provide genetic evidence to elucidate why the thermophilic phase is the peak time for nutrient metabolism.
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Affiliation(s)
- Meng-Ke Cao
- School of Civil and Environmental Engineering, Ningbo University, 818 Fenghua Road, Ningbo 315211, China
| | - Han-Tong Guo
- School of Civil and Environmental Engineering, Ningbo University, 818 Fenghua Road, Ningbo 315211, China
| | - Guo-Di Zheng
- Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China
| | - Tong-Bin Chen
- Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China
| | - Lu Cai
- School of Civil and Environmental Engineering, Ningbo University, 818 Fenghua Road, Ningbo 315211, China.
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