Studies On The Performance And Membrane Fouling Characteristics Of Anoxic MBR-MMR Treatment Of Mariculture Wastewater

Along with the growth of population,people growing demand for seafood,in the process of production of 95%of the water consumption into contaminated wastewater,mariculture wastewater with high salinity produces adverse effect characteristics of the feed water treatment process.In addition,due to the limitation of mud,phosphorus removal is a big problem of traditional activated sludge process.Microalgae can not only be used in the production of various types of biofuels,but also as bait for aquatic animals,human health food and other widely used in various industries,so microalgae can be widely used in wastewater treatment at the same time for resource utilization.Using common Chlorella vulgaris（Chlorella.vulgaris）as experimental algae species,the related characters of common chlorella vulgaris were explored firstly,and the membrane hanging of anoxic sludge was completed on the filler.Anoxic MBR-microalgae membrane reactor（anoxic MBR-MMR）coupling system was built to treat mariculture wastewater.Pre-anoxic MBR was used for organic matter,NO₃^--N and NO₂^--N degradation.the released NH₄⁺-N entered into the microalgae for microalgae growth and was removed.The synergistic treatment efficiency and microalgae harvesting were investigated to explore membrane fouling behavior.Based on anoxic MBR-MMR,the system was operated for 91 days and the initial concentration of Chlorella vulgaris was 4×10⁷cells·m L^-1.The removal rate of NO₃^--N and NH₄⁺-N reached 90.0%and 88.0%respectively in the later stage of operation,and the average removal rate of PO₄^3--P and TOC was 49.4%and 84.7%respectively.Under the condition of intermittent harvesting,Chlorella vulgaris can operate stably with an average concentration of 9×10⁷cells·m L^-1,and achieve better removal efficiency and resource utilization.Through continuous monitoring of the transmembrane pressure difference during operation,the trend of membrane fouling was examined intuitively,and obtained by infrared spectroscopy scanning and three-dimensional fluorescence spectrum analysis,the main components of the EPS that caused membrane fouling were protein substances,and mainly alanine.SMP in both reactors contained tryptophan,humic acid substances,and hypoxia was more serious MBR intimal component contamination.The effects of different HRT conditions on anoxic MBR-MMR system were explored.the results showed that under the condition of anoxic MBR HRT of 16 h,anoxic sludge had better degradation ability to NO₃^--N and TOC pollution.At the same time,from the optimized experiment,we can obtain the method of continuous harvesting which is beneficial to the growth of common Chlorella vulgaris,its biomass growth is faster,and the degradation effects of NH₄⁺-N、PO₄^3--P are better.