It is known that an increase of COD/N ratio can result in an enhanced removal of nutrients in membrane bioreactors (MBRs); however, impacts of doing so on membrane filtration performance remain unclear. In this work, comparison of membrane filtration performance, microbial community, and microbial products under low temperature was carried out in anoxic/oxic (A/O) MBRs with COD/N ratios of 9.9 and 5.5 g COD/g N in influent. There was no doubt that an improvement of nitrogen removal under high COD/N ratio was observed; however, severer membrane fouling was found compared to the MBR fed with low COD/N ratio wastewater. The increase of COD/N ratio resulted in an elevated production of humic acids in soluble microbial product (SMP) and carbohydrates, proteins, and humic acids in loosely bound extracellular polymeric substance (LB-EPS). Quartz crystal microbalance with dissipation monitoring (QCM-D) analysis showed that the adsorption capability of SMP and LB-EPS was higher in the MBR with higher COD/N ratio. Four hundred fifty four high-throughput pyrosequencing revealed that the higher COD/N ratio led to the enrichment of Bacteroidetes at phylum level and Azospira, Thauera, Zoogloea, etc. at genus level. Bacteroidetes are considered to potentially release EPS, and Azospira, Thauera, and Zoogloea, etc. have denitrification activity. The change in microbial communities is consistent with MBR performance.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1007/s11356-015-4376-z | DOI Listing |
Horizontal subsurface flow constructed wetlands (HFCWs) are capable of eliminating organic matter and nitrogen while emitting less methane (CH) and nitrous oxide (NO) than free water surface flow wetlands. However, the simultaneous removal of pollutants and reduction of greenhouse gases (GHG) emissions from high-strength wastewater containing high levels of organic matter and ammonium nitrogen (NH-N) has not get been investigated. The influent COD concentration affected the efficiency of nitrogen removal, GHG emissions and the presence of iron from iron ore, but the COD and TP removal efficiencies remained unaffected.
View Article and Find Full Text PDFBioresour Technol
December 2024
Key Laboratory of Microbial Technology for Industrial Pollution Control of Zhejiang Province, College of Environment, Zhejiang University of Technology, Hangzhou 310014, China. Electronic address:
Municipal wastewater treatment plants in China face significant challenges in effectively removing pollutants from low-strength wastewater with a low carbon-to-nitrogen (COD/N) ratio. This study proposes a novel approach incorporating porous polymers embedded with iron-carbon (PP-IC) into an activated sludge system to enhance treatment. The PP-IC accelerated the formation of densified activated sludge (DAS), characterized by small particle sizes (<200 μm), excellent settleability (sludge volume index: 61 mL/g), and improved pollutant removal efficiency, with total nitrogen and total phosphorus removal rates increasing by 14.
View Article and Find Full Text PDFSci Total Environ
December 2024
International Science & Technology Cooperation Center for Urban Alternative Water Resources Development, Key Lab of Northwest Water Resource, Environment and Ecology, MOE, Engineering Technology Research Center for Wastewater Treatment and Reuse, Shaanxi Province, Key Lab of Environmental Engineering, Shaanxi Province, Xi'an University of Architecture and Technology, No. 13, Yanta Road, Xi'an 710055, China.
Understanding the relationship between recharge water quality and algal metabolism is critical for managing eutrophication in urban landscape water bodies. This study investigates six landscape water bodies in Xi'an City, utilizing natural and reclaimed water recharge sources to cultivate and evaluate the growth and biomass composition of Chlorella vulgaris. The findings revealed that the growth and metabolic rate of C.
View Article and Find Full Text PDFBioresour Technol
January 2025
Department of Hydraulics and Sanitation, São Carlos School of Engineering, University of São Paulo (USP), 1100 João Dagnone Avenue, São Carlos, SP, 13563120, Brazil. Electronic address:
J Environ Manage
November 2024
College of Marine Technology and Environment, Dalian Ocean University, Dalian, 116023, PR China; Key Laboratory of Nearshore Marine Environmental Science and Technology in Liaoning Province, Dalian Ocean University, Dalian, 116023, PR China. Electronic address:
Simultaneous nitritation and denitritation have the potential to significantly improve nitrogen removal in sewage treatment processes. However, their application in low-strength sewage treatment systems presents challenges. This study explored the impact of four solid carbon sources (SCSs) on N-removal via nitrite in a multi-cycle SBR with biocarriers.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!