The impact of pH variation on aerobic granular sludge stability and performance was investigated. A 9-day alkaline (pH=9) and acidic (pH=6) pH shocks were imposed on mature granules with simultaneous chemical oxygen demand (COD), nitrogen and phosphorus removal. The imposed alkaline pH shock (pH 9) reduced nitrogen and phosphorus removal efficiency from 88% and 98% to 66% and 50%, respectively, with no further recovery. However, acidic pH shock (pH 6) did not have a major impact on nutrient removal and the removal efficiencies recovered to their initial values after 3 days of operation under the new pH condition. Operating the reactors under alkaline pH induced granules breakage and resulted in an increased solids concentration in the effluent and a significant decrease in the size of the bio-particles, while acidic pH did not have significant impacts on granules stability. Changes in chemical structure and composition of extracellular polymeric substances (EPS) matrix were suggested as the main factors inducing granules instability under high pH.
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http://dx.doi.org/10.2166/wst.2015.460 | DOI Listing |
Membranes (Basel)
November 2024
Department of Chemical Engineering, Lakehead University, 955 Oliver Road, Thunder Bay, ON P7B 5E1, Canada.
This study presents a theoretical and mathematical analysis and modelling of the emerging microalgal membrane photobioreactors (M-MPBRs) for wastewater treatment. A set of mathematical models was developed to predict the biological performances of M-MPBRs. The model takes into account the effects of hydraulic retention time (HRT), solid retention time (SRT), and the N/P ratio of influent on the biological performance of M-MPBRs, such as microalgal biomass production and nutrient (N and P) removals.
View Article and Find Full Text PDFEnviron Res
December 2024
College of Chemistry, Fuzhou University, Fuzhou, Fujian, 350108, China; CAS Key Laboratory of Design and Assembly of Functional Nanostructures, and Fujian Provincial Key Laboratory of Nanomaterials, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian, 350002, China; Xiamen Key Laboratory of Rare Earth Photoelectric Functional Materials, Xiamen Institute of Rare Earth Materials, Haixi Institutes, Chinese Academy of Sciences, Xiamen, Fujian, 361021, China; Fujian College, University of Chinese Academy of Sciences, Fuzhou, Fujian, 350002, China. Electronic address:
Calcite is a promising material choice for adsorbing phosphates because of its abundance and environmentally benign nature. However, the slow adsorption kinetics and hence low adsorption capacity within a short time frame hinders its practical application. In this work, we solve these problems by presenting a low Mg-doped calcite adsorbent, Mg-10.
View Article and Find Full Text PDFInt J Hyg Environ Health
December 2024
Department of Chemistry, Institute of Exact and Biological Sciences, Federal University of Ouro Preto (UFOP), Ouro Preto, 35450-000, Minas Gerais, Brazil.
Trimethoprim (TMP) and sulfamethoxazole (SMX) are bacteriostatic agents, which are co-administered to patients during infection treatment due to their synergetic effects. Once consumed, TMP and SMX end up in wastewater and are directed to municipal wastewater treatment plants (WWTPs) which fail to remove these contaminants from municipal wastewater. The discharge of WWTP effluents containing antibiotics in the environment is a major concern for public health as it contributes to the spread of antimicrobial resistance.
View Article and Find Full Text PDFJ Environ Manage
December 2024
School of Environmental Science & Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China; Yazhou Bay Institute of Deepsea Science and Technology, Shanghai Jiao Tong University, Hainan, 572025, China. Electronic address:
Nutrient recovery from aquaculture sludge is vital for promoting hydroponic plant growth and achieving near-zero solid waste discharge in aquaponic systems. Modified biological aerated filters (MBAFs) are promising because of the dual capabilities of aquaculture sludge collection and aerobic mineralization. However, the bioconversion kinetics, which is indirectly related to the packed media, need to be improved.
View Article and Find Full Text PDFWater Res
December 2024
Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Xiao Ling Wei 200, Nanjing 210094, Jiangsu, China. Electronic address:
High temperature (HT) shock is one of environmental stressors suppressing microalgal activities in microalgal wastewater bioremediation system. However, its inhibition mechanism and how to alleviate such suppression remain inadequately understood. This study confirmed a transient ferroptosis as a novel form of programmed cell death in a wastewater-indigenous Chlorella sp.
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