Microbial community response of the full‐scale MBR system for mixed leachates treatment

Abstract

In practice, mature landfill leachate and incineration (young) leachate are mixed to improve the biodegradability and enhance biological treatment performance. However, the ratio of mature‐to‐young leachates greatly influences MBR treatment efficiency and microbial community structure. This study investigated the treatment efficiency and microbial community structure of full‐scale MBR systems operated under two mix ratios, mature leachate: young leachate = 7:3 (v/v, denoted as LL) and 3:7 (v/v, denoted as IL). LL group showed lower Cl− and COD concentrations but a higher aromatic organic content comparing to IL group, and the COD and UV254 removals for LL were significantly lower than those for IL by MBR treatment. Microbial community structures were similar in both groups at phylum level, with dominant phyla being Proteobacteria (23.8%–32.3%), Bacteroidetes (15.25%–20.7%), Chloroflexi (10.5%–23.1%), and Patescibacteria (9.9%–13.2%). However, the richness and diversity of LL group were lower, and differences were observed at lower taxonomy levels. Results indicated that salinity mainly changed the structure of microbial community, resulting in greater abundance of salt‐tolerant microbials, while refractory organics affected microbial community structure, and also led to decreased diversity and metabolic activity. Therefore, in mixed leachates biological treatment, a higher young leachate ratio is recommended for better organics removal performance. Practitioner Points The trade‐off between refractory organics and salinity in mixed leachate treatment should be paid attention. Refractory organics reduced alpha and functional diversities of microorganisms. Mixed leachate with a higher young leachate ratio reached a better organic removal.

The study on the changing pattern of microbial community function and phenotypes in anaerobic–anoxic–oxic (A2O) process under the influence of temperatures in plateau habitats

“…The minimum was 6.117% at 10 °C, and the relative abundance was significantly affected by temperature ( P ≤ 0.05) for the trend of increasing to decreasing, then increasing again with the increase in temperature. According to Li et al , 48 chemoheterotrophy mainly comprises Rhodocyclaceae , Enterococcaceae , Sphingomonadaceae , Hyphomicrobiaceae and Peptostreptococcaceae . The Aerobic_chemoheterotrophy mainly comprises the families Rhodocyclaceae , Sphingomonadaceae , Hyphomicrobiaceae and Pseudonocardiaceae , while fermentation mainly comprises Peptostreptococcaceae , Burkholderiaceae , Eubacteriaceae , Spirochaetaceae and Leuconostocaceae .…”

“…The Aerobic_chemoheterotrophy mainly comprises the families Rhodocyclaceae , Sphingomonadaceae , Hyphomicrobiaceae and Pseudonocardiaceae , while fermentation mainly comprises Peptostreptococcaceae , Burkholderiaceae , Eubacteriaceae , Spirochaetaceae and Leuconostocaceae . 48…”

“…The minimum was 6.117% at 10 °C, and the relative abundance was significantly affected by temperature (P ≤ 0.05) for the trend of increasing to decreasing, then increasing again with the increase in temperature. According to Li et al, 48 Environmental Science: Water Research & Technology Paper aromatic_compound_degradation, animal_parasites_or_symbionts and human_pathogens_all were higher, which were mainly organic degradation and Parasites. Additionally, nitrate_reduction, nitrogen_respiration, nitrate_respiration, nitrite_respiration, intracellular_parasites, nitrogen_fixation and dark_oxidation_of_sulfur_compounds were higher when the temperature was 20 °C, and they were mainly associated with N and S cycles.…”