Cultivation and treatment characteristics of Chlorella-aerobic sludge coupled system

Abstract

Aerobic granular sludge was cultivated as a biological carrier under laboratory conditions, and Chlorella was inoculated to form algal-bacterial granular sludge(ABGS). The effects of different light intensities on pollutant removal efficiency of ABGS system were explored, and the enhancement of Chlorella on the treatment capacity of ABGS system under 5 klx light intensity was emphatically investigated. The results showed that the removal rates of COD, TN and TP by ABGS were 87.01%-95.32%, 53.14%-89.37% and 32.49%-99.40%, respectively, with the SND of 7.70%-83.66%. However, the removal rates of TP and TN in a single Chlorella system were only 20%-30%, while the removal effect of COD was not obvious. Chlorella could increase the concentration of dissolved oxygen in water within a certain light intensity range, and facilitate the degradation of pollutants by promoting the metabolic rate of bacteria in ABGS system. With the increase of light intensity, the removal rates of COD and TP in ABGS system increased, while the removal rates of TN and SND decreased. Too low or too high light intensity would inhibit the photosynthesis and even kill Chlorella, leading to the disintegration of ABGS, system collapse and poor pollutant removal effect. High throughput analysis showed that the addition of algae further expanded the relative abundance of bacteria related to nitrogen and phosphorus metabolism, and enhanced the nitrogen and phosphorus removal effect of the system.

Keywords

• abgs system
• aerobic granular sludge
• bacteria and algae symbiosis
• nitrogen and phosphorus removal