Hippuris vulgaris could replace Myriophyllum aquaticum for efficiently removing water phosphorus under low temperature conditions in China

Purification mechanism of emergent aquatic plants on polluted water: A review

Nitrogen and phosphorus inputs to surface water bodies lead to a decline in water quality and a disruption in the balance of aquatic ecosystems. Emergent aquatic plants were widely used for their high efficiency in removing nitrogen and phosphorus from surface waters. However, there was a lack of systematic analyses on the purification of surface waters by emergent aquatic plants, and the mechanism of differences in nitrogen and phosphorus removal by different plants needs to be further revealed. By preferentially selecting emergent aquatic plants, the removal effects of 15 selected aquatic plants on five pollutant indicators (total nitrogen, ammonia nitrogen, nitrate nitrogen, total phosphorus, and chemical oxygen demand) were analyzed at different concentrations, and the characteristics of the removal of pollutants by different aquatic plants were explored. At the same time, combined with the morphology and synergistic action of microorganisms, in-depth research on the purification mechanism of water bodies by emergent aquatic plants was conducted. Differences were found in the purification of different water-supporting aquatic plants for different concentrations of pollutants. The comprehensive evaluation results of the membership function showed that the combined purification ability of Acorus calamus, Cyperus involucratus, Iris pseudacorus and Typha orientalis was better for the conventional pollutants. This study provides an important reference for the preferential selection of emergent aquatic plants to enhance water pollution purification and further promote the progress of ecological water treatment technology.

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.