Primary sludge, from different pulp and paper mills, was used as feedstock in simultaneous saccharification and fermentation (SSF) processes to produce ethanol. SSF was carried out with Saccharomyces cerevisiae ATCC 26602 yeast and NS 22192 enzymatic extract using 150gL(-1) of carbohydrates (CH) from primary sludge. The effect of sterilization, reduction of enzyme dosage and fed-batch vs. batch conditions were studied. The removal of sterilization can be considered since no contamination or atypical by-products were observed, although SSF efficiency slightly decreased. The reduction of the enzyme dosage from 35 to 15FPUgCH(-1) was successful. Despite of initial mixing difficulties, batch SSF enabled higher ethanol concentration (41.7gL(-1)), conversion yield (48.9%) and productivity (0.78gL(-1)h(-1)), compared to the fed-batch process at the same conditions of low enzyme dosage of 5FPUgCH(-1) and high solids content of 21.7%, rarely found in literature.
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http://dx.doi.org/10.1016/j.biortech.2016.07.140 | DOI Listing |
Water Res
December 2024
Department of Environmental Science and Engineering, University of Science and Technology of China, Hefei 230026, China. Electronic address:
Wastewater surveillance programs based at wastewater treatment plants (WWTPs) have been widely implemented, becoming a crucial measure for public health. Recently, the scope of monitoring has expanded from influent wastewater to include primary settled solids and activated sludge. The effectiveness of monitoring primary settled solids has been widely validated, but the suitability of activated sludge as a monitoring target remains unclear.
View Article and Find Full Text PDFJ Environ Manage
December 2024
College of Environmental and Municipal Engineering, Qingdao University of Technology, Qingdao, 266520, China.
The disposal of municipal solid waste (MSW) is a significant source of greenhouse gas (GHG) emissions. As incineration becomes the primary method of MSW disposal in China, MSW incineration (MSWI) plants are expected to play a crucial role in mitigating GHG emissions in the waste sector. This study estimated the quarterly GHG emissions from two representative MSWI plants in Qingdao using a life-cycle assessment (LCA) approach.
View Article and Find Full Text PDFHuan Jing Ke Xue
January 2025
College of Hydraulic and Civil Engineering, Xinjiang Agricultural University, Urumqi 830052, China.
To explore the changes in groundwater hydrochemistry and its source influence in the low water level period of the southern oasis area of Gaochang District, Turpan City before and after the management of groundwater overexploitation, based on 12 groups of water samples in 2016 (three groups of unconfined water, nine groups of confined water) and 18 groups of water samples in 2023 (five groups of unconfined water, thirteen groups of confined water), mathematical statistics, hydrochemical diagraph, hydrogen and oxygen isotope means, and an absolute principle component-multiple linear regression (APCS-MLR) model were used to analyze the changes and sources of groundwater hydrochemistry. The results showed that due to the dynamic conditions of groundwater, the dominant cation changed from Na to Ca, and the anion changed from HCO to SO. The dominant cation of confined water changed from Ca to Na, and the dominant anion remained unchanged as SO.
View Article and Find Full Text PDFHuan Jing Ke Xue
January 2025
School of Environmental Science and Engineering, Suzhou University of Science and Technology, Suzhou 215011, China.
Taking a sewage treatment plant in Suzhou City, Jiangsu Province, as an example, the greenhouse gas (GHG) emissions generated in the sewage treatment system were calculated using the carbon balance method and the emission factor method. The environmental impacts and economic aspects of different treatment units in wastewater treatment plants were analyzed using life cycle assessment, cost-benefit analysis, and data envelopment analysis models, and emission reduction pathways were proposed. The results indicated that the total GHG emissions (in terms of CO) from a certain municipal wastewater treatment plant in Suzhou were 6 653.
View Article and Find Full Text PDFJ Environ Manage
December 2024
Botanical Garden, Institute of Nature and Environmental Technology, Kanazawa University, Kakumamachi, Kanazawa, Ishikawa, 920-1192, Japan.
Quaternary ammonium compounds (QACs), ecotoxic organic chemicals linked to multidrug resistance, are being used increasingly, for example to prevent the transmission of infections such as covid-19, in households, hospitals, and industry. To understand the locations, fluctuations, and fractions of QACs entering sewers, we monitored 14 QACs (benzalkonium chloride [BAC]-C8, C10, C12, C14, C16, and C18; dialkyldimethylammonium chloride [DDAC]-C8, C10, and C12; alkyltrimethylammonium chloride [ATAC]-C12, C16, and C18; benzethonium chloride; and cetylpyridinium chloride), and a disinfectant (chlorhexidine) in influent at four Japanese sewage treatment plants (STPs) five times throughout a year. Mass inflows were relatively stable throughout the year, indicating that the recent seasonal covid-19 epidemic did not greatly influence them.
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