Enhanced purification of kitchen-oil wastewater driven synergistically by surface microelectric fields and microorganisms

Advanced treatment of antibiotic-polluted wastewater by a consortium composed of bacteria and mixed cyanobacteria

This study constructed a cyanobacteria-bacteria consortium using a mixture of non-toxic cyanobacteria (Synechococcus sp. and Chroococcus sp.) immobilized in calcium alginate and native bacteria in wastewater. The consortium was used for the advanced treatment of sulfamethoxazole-polluted wastewater and the production of cyanobacterial lipid. Mixed cyanobacteria increased the abundances of denitrifying bacteria and phosphorus-accumulating bacteria as well as stimulated various functional enzymes in the wastewater bacterial community, which efficiently removed 70.01-71.86% of TN, 91.45-97.04% of TP and 70.72-76.85% of COD from the wastewater. The removal efficiency of 55.29-69.90% for sulfamethoxazole was mainly attributed to the upregulation of genes encoding oxidases, reductases, oxidoreductases and transferases in two cyanobacterial species as well as the increased abundances of Stenotrophomonas, Sediminibacterium, Arenimonas, Novosphingobium, Flavobacterium and Hydrogenophaga in wastewater bacterial community. Transcriptomic responses proved that mixed cyanobacteria presented an elevated lipid productivity of 33.90 mg/L/day as an adaptive stress response to sulfamethoxazole. Sediminibacterium, Flavobacterium and Exiguobacterium in the wastewater bacterial community may also promote cyanobacterial lipid synthesis through symbiosis. Results of this study proved that the mixed cyanobacteria-bacteria consortium was a promising approach for advanced wastewater treatment coupled to cyanobacterial lipid production.

Purification mechanism of microbial metabolism in kitchen-oil wastewater enhanced by cationic vacancies on γ-Al2O3

The use of catalyst materials to mediate the enhancement of microbial degradation in wastewater is a new economic and energy saving breakthrough in water treatment technology. In this study, γ-Al2O3, which is commonly used as catalyst/carrier, is used as biological filler to treat kitchen-oil wastewater with low biodegradability, and the COD removal rate is about 50 %. It is found that the complexation of cationic vacancies on Al2O3 surface with extracellular polymeric substance (EPS) secreted by microorganisms in wastewater lead to the polarization of electron distribution on biofilm. The efficient degrading bacteria are enriched on reaction interface and obtain electrons to maintain electron dynamic balance by enhancing the transmembrane metabolism of pollutants. The aluminum vacancies on Al2O3 surface accelerate the microbial degradation of pollutants. The cationic vacancies in the structure of catalyst accelerate the acquisition of exogenous electrons by microorganisms without the addition of external energy, which provides a new idea for catalytic fillers to enhance wastewater degradation.

Salinity-mediated water self-purification via bond network distorting of H2O molecules on DRC-surface

High salinity has plagued wastewater treatment for a long time by hindering pollutant removal, thereby becoming a global challenge for water pollution control that is difficult to overcome even with massive energy consumption. Herein, we propose a novel process for rapid salinity-mediated water self-purification in a dual-reaction-centers (DRC) system with cation-π structures. In this process, local hydrogen bond networks of H2O molecules can be distorted through the mediation of salinity, thereby opening the channels for the preferential contact of pollutants on the DRC interface. As the result, the elimination rate of pollutants increased approximately 32-fold at high salinity (100 mM) without any external energy consumption. Our findings provide a novel technology for high-efficiency and low-consumption water self-purification, which is of great significance in environmental remediation and even fine chemical industry.