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Domestic wastewater is a potential medium for microbial cultivation because it contains abundant non-toxic inorganic salts and organic nutrients. However, studies of the feasibility of using wastewater as medium have focused on removal rates, while ignoring changes in biomass composition. Therefore, this study investigated the feasibility of growing Chlorella vulgaris in domestic wastewater, while focusing on its nutrient removal rates and biomass composition. Results showed that Chlorella vulgaris growth rate and biomass were significantly promoted by domestic wastewater compared with BG11 medium. The maximum biomass (17.94 × 10 6 cell L −1 ) was obtained when 100% domestic wastewater was used. The highest COD removal rate was 93.6% obtained by 75% of wastewater, while the highest NH 4 + –N and TP removal rates were 98.69% and 86.07% by 25% of wastewater. The harvested biomass was rich in protein (40.9–50.7%) and low in lipids (23.4–28.5%), and both the nutritional quality and quantity of protein and lipid were increased in dilutions. These results indicated that domestic wastewater is a feasible medium for mass-cultivation of Chlorella vulgaris , and 100% dilution is suggested. [ABSTRACT FROM AUTHOR]

This study characterizes the extracellular polymeric substances and bacterial community composition of aerobic granules exposed to cefalexin (CLX). The presence of CLX potentially decreases granular stabilities, resulting in a lowered granule diameter. Chemical oxygen demand and NH 4 + –N removal efficiencies were slightly decreased and the denitrification process was inhibited with CLX addition. Extracellular polymeric substance contents were significantly increased in aerobic granules exposed to CLX. The shifts of fluorescence intensities and peak locations in 3D-EEM fluorescence spectra indicated changes of EPS components. High-throughput sequencing analysis showed aerobic granules with CLX addition in synthetic wastewater had superior diversity of microbial species, and this was the reason that the level and components of EPS changed. The species richness for bacteria was increased from 341 to 352, which was revealed by Chao1. The Shannon index of diversity rose slightly from 3.59 to 3.73 with CLX addition. The abundance of Proteobacteria significantly decreased, while the abundance of Bacteroidetes and Chloroflexi underwent a highly significant increase in aerobic granules exposed to CLX. [ABSTRACT FROM AUTHOR]