Acclimating activated sludge with co-metabolic substrates for enhancing treatment of low-concentration polyether wastewater

Polyether wastewater from chemical industries is difficult to be degraded directly by microorganisms even at low concentration. The feasibilities and differences of using complex and single carbon sources as co-metabolic substrates to acclimate activated sludge for enhancing treatment of low-concentration polyether wastewater (LCPW) were comparatively analyzed. The complex carbon source was produced from citric acid production wastewater (CAPW), and the sodium acetate (NaAc) was selected as single carbon source. Results indicated that the LCPW could be effectively treated with acclimated activated sludge, and satisfying the wastewater discharge standard (COD <= 50 mg/L, TN <= 15 mg/L, TP <= 0.5 mg/L). Importantly, the activated sludge acclimated with CAPW (AS-CAPW) presented larger biomass, better treatment performance, and higher extracellular polymeric substance content, dehydrogenase activity and bacterial diversity than that acclimated with NaAc (AS-NaAc). Moreover, high-throughput sequencing revealed that the relative abundance of dominant families associated with nutrient removal in AS-CAPW or AS-NaAc (e.g., Nitrosomonadaceae and Rhodocyclaceae) was similar. In contrast, the dominant families involved in macromolecular pollutions degradation had significant differences. Phycisphaeraceae (10.3%) and Lentimicrobiaceae (14.3%) were mainly enriched in AS-CAPW and AS-NaAc, respectively. This comprehensive work provides a feasible biological process for enhancing treatment of LCPW.