A Shortcut Nitrogen Removal Process Using An Algal-bacterial Consortium In A Photo-Sequencing Batch Reactor(PSBR)

In recent years,the issue of nitrogen pollution has received widespread attention.Many new biological nitrogen removal processes such as partial nitrification-anaerobic ammonia oxidation processes have emerged.Microalgae are also attracting researchers' attention in the field of wastewater treatment,partially because of their high capacity of nutrients uptake and oxygen production thus facilitating aeration in wastewater.This study use non-woven fabrics to immobilize Chlorella and nitrifying bacteria,with this algal-bacterial symbiotic system startup partial nitrification reactor.The results showed that:(1)Synthetic wastewater was employed for partial nitrification reactor activation.With influent ammonium concentration 100 mg/L,temperature 30 ? 0.5?,pH 7.5~8.5,hydraulic retention time 24 h,and by controlling DO concentration of wastewater,the partial nitrification reactor was activated in 35 days.Accumulation rate of nitrite and removal rate of ammonium exceeded 90%.(2)Immobilized chlorella reveals higher mechanical strength,and its oxygen production is lower than the one in free state,but it can remain active in wastewater and its maximum oxygen production is 12.62 mg/L.In wastewater containing N,with the increase of N concentration,immobilized chlorella performs lower removal rate.When the same amount of ammonium,nitrite and nitrate co-exist in wastewater,immobilized chlorella consume ammonium before nitrite and nitrate.(3)Synthetic wastewater was employed for algal-bacterial symbiotic partial nitrification reactor activation.With influent ammonium concentration 100 mg/L,temperature30 ? 0.5?,pH 7.5~8.5,hydraulic retention time 24 h,and by adjusting illumination intensity to 3000 lux and light/dark ratio to 9 h:15 h,the partial nitrification reactor was activated in 32 days.The removal rate of ammonium and the accumulation rate of nitrite reach 92.19% and92.81% respectively.