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Zhang K, Wang N. Machine learning modeling of thermally assisted biodrying process for municipal sludge. WASTE MANAGEMENT (NEW YORK, N.Y.) 2024; 188:95-106. [PMID: 39128323 DOI: 10.1016/j.wasman.2024.07.032] [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: 06/01/2024] [Revised: 07/12/2024] [Accepted: 07/29/2024] [Indexed: 08/13/2024]
Abstract
Preparation of activated carbons is an important way to utilize municipal sludge (MS) resources, while drying is a pretreatment method for making activated carbons from MS. In this study, machine learning techniques were used to develop moisture ratio (MR) and composting temperature (CT) prediction models for the thermally assisted biodrying process of MS. First, six machine learning (ML) models were used to construct the MR and CT prediction models, respectively. Then the hyperparameters of the ML models were optimized using the Bayesian optimization algorithm, and the prediction performances of these models after optimization were compared. Finally, the effect of each input feature on the model was also evaluated using SHapley Additive exPlanations (SHAP) analysis and Partial Dependence Plots (PDPs) analysis. The results showed that Gaussian process regression (GPR) was the best model for predicting MR and CT, with R2 of 0.9967 and 0.9958, respectively, and root mean square errors (RMSE) of 0.0059 and 0.354 ℃. In addition, graphical user interface software was developed to facilitate the use of the GPR model for predicting MR and CT by researchers and engineers. This study contributes to the rapid prediction, improvement, and optimization of MR and CT during thermally assisted biodrying of MS, and also provides valuable guidance for the dynamic regulation of the drying process.
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Affiliation(s)
- Kaiqiang Zhang
- College of Mechanical Engineering, Qinghai University, Xining, Qinghai 810016, China
| | - Ningfung Wang
- College of Chemical Engineering, Qinghai University, Xining, Qinghai 810016, China; Key Laboratory of Salt Lake Chemical Materials Qinghai Province, Xining, Qinghai 810016, China.
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Yang N, Ji Y, Shao Y, Shi J, Tang T, Liu L. Thermophilic bacterial agent inoculation enhances biodrying of kitchen waste: Insights into process properties, organic degradation, bacterial communities and metabolic pathways. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 951:175671. [PMID: 39168328 DOI: 10.1016/j.scitotenv.2024.175671] [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: 04/27/2024] [Revised: 08/18/2024] [Accepted: 08/18/2024] [Indexed: 08/23/2024]
Abstract
The high moisture content of kitchen waste (KW) restricts the future treatment and resource utilization. Biodrying is an effective approach to remove the water of KW. However, conventional biodrying only uses the heat generated by the indigenous microorganisms to remove water, which has long treatment cycle and low moisture removal rate. Microbial bioaugmentation is an emerging approach to improve the biodrying efficiency of KW. In this study, a thermophilic bacterial agent (TBA) composed of Bacillus, Geobacillus and Acinetobacter was used to promote water evaporation during the biodrying process. Based on the results, the moisture removal rate of experimental group inoculated with TBA was 82.20 %, which was notably higher than CK group without inoculation. Moreover, TBA significantly increased the amount of organic matter degradation. Microbial community analysis revealed that TBA could promote the proliferation of thermophilic bacteria and make bacterial community more tolerant to high temperature environment. Further analysis of metabolic pathways showed that quorum sensing and glyoxylate and dicarboxylate metabolism were enhanced by TBA inoculation, which can help microorganisms to better adapt to high temperature environment and release more energy to facilitate the water evaporation. This study offers a fresh approach to improve the water removal efficiency in biodrying process.
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Affiliation(s)
- Ning Yang
- Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201210, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yuji Ji
- Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201210, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yiheng Shao
- Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201210, China
| | - Jiping Shi
- Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201210, China
| | - Tao Tang
- Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201210, China.
| | - Li Liu
- Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201210, China; Shanghai Engineering Research Center of Biotransformation of Organic Solid Waste, Shanghai 200241, China.
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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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Teng F, Tan G, Liu T, Zhang T, Liu Y, Li S, Lei C, Peng X, Yin H, Meng D. Inoculation with thermophiles enhanced the food waste bio-drying and complicated interdomain ecological networks between bacterial and fungal communities. ENVIRONMENTAL RESEARCH 2023; 231:116299. [PMID: 37268211 DOI: 10.1016/j.envres.2023.116299] [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: 02/23/2023] [Revised: 04/23/2023] [Accepted: 05/31/2023] [Indexed: 06/04/2023]
Abstract
Bio-drying is a practical approach for treating food waste (FW). However, microbial ecological processes during treatment are essential for improving the dry efficiency, and have not been stressed enough. This study analyzed the microbial community succession and two critical periods of interdomain ecological networks (IDENs) during FW bio-drying inoculated with thermophiles (TB), to determine how TB affects FW bio-drying efficiency. The results showed that TB could rapidly colonize in the FW bio-drying, with the highest relative abundance of 5.13%. Inoculating TB increased the maximum temperature, temperature integrated index and moisture removal rate of FW bio-drying (55.7 °C, 219.5 °C, and 86.11% vs. 52.1 °C, 159.1 °C, and 56.02%), thereby accelerating the FW bio-drying efficiency by altering the succession of microbial communities. The structural equation model and IDEN analysis demonstrated that TB inoculation complicated the IDENs between bacterial and fungal communities by significantly and positively affecting bacterial communities (b = 0.39, p < 0.001) and fungal communities (b = 0.32, p < 0.01), thereby enhancing interdomain interactions between bacteria and fungi. Additionally, inoculation TB significantly increased the relative abundance of keystone taxa, including Clostridium sensu stricto, Ochrobactrum, Phenylobacterium, Microvirga and Candida. In conclusion, the inoculation of TB could effectively improve FW bio-drying, which is a promising technology for rapidly reducing FW with high moisture content and recovering resources from it.
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Affiliation(s)
- Fucheng Teng
- School of Minerals Processing and Bioengineering, Central South University, Changsha, 410083, China; Key Laboratory of Biometallurgy, Ministry of Education, Changsha, 410083, China
| | - Ge Tan
- School of Minerals Processing and Bioengineering, Central South University, Changsha, 410083, China; China Tobacco Hunan Industrial Co., Ltd., Changsha, 410014, China
| | - Tianbo Liu
- China Tobacco Research Institute of Hunan Province, Changsha, 410004, China
| | - Teng Zhang
- School of Minerals Processing and Bioengineering, Central South University, Changsha, 410083, China; Hunan Urban and Rural Environmental Construction Co., Ltd, Changsha, 410118, China
| | - Yongjun Liu
- China Tobacco Research Institute of Hunan Province, Changsha, 410004, China
| | - Sheng Li
- College of Resources & Environment, Hunan Agricultural University, Changsha, 410128, China
| | - Can Lei
- Changsha Leibang Environmental Protection Technology Co., Ltd, Changsha, 410199, China
| | - Xing Peng
- Hunan Renhe Environment Co., Ltd, Changsha, 410022, China
| | - Huaqun Yin
- School of Minerals Processing and Bioengineering, Central South University, Changsha, 410083, China; Key Laboratory of Biometallurgy, Ministry of Education, Changsha, 410083, China
| | - Delong Meng
- School of Minerals Processing and Bioengineering, Central South University, Changsha, 410083, China; Key Laboratory of Biometallurgy, Ministry of Education, Changsha, 410083, China.
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