Evaluation Of Aerobic Granules Formative Process And Its Thermogravimetric Characteristics Under Different Salinity

Aerobic granular is found in the past few years, it is granular microbial self-aggregate cultivated under aerobic conditions, and it is of a special form of biofilm growth. Compared with conventional activated sludge system, the aerobic granular has strong and compact microbial structure, improved stability, the process of effluent separating is simple, the occupied area is small, the system can withstand the unfavorable hydraulic effect and toxic substances. Compared with anaerobic granules, the aerobic granules are more stable when used to treat the organic wastewater of low concentration; the start-up period is much shorter than that of the anaerobic granules. At present the research of aerobic granular mainly concentrated in the process of particle mechanism and impact factors. Salinity wastewater has extensive sources and complex constituent, mainly exist in seawater alternative wastewater, industrial wastewater and wastewater from large ships, it is one of difficult treatment industrial wastewater. Such wastewater has greater buoyancy, this character often lead to sludge floating and wastage, and aerobic granular has good settlement, but has no report on aerobic granular sludge treatment of organic salinity wastewater. This study use aerobic granular sludge treatment to treat Salt of organic wastewater, mainly evaluation of aerobic granules formative process and its thermogravimetric characteristics under different sodium chloride concentrations.Experiments analyze aerobic granules under different sodium chloride concentrations, including particle shape, particle size distribution, SS and VSS, effluent SS and VSS, particle porosity and settling velocity, particle density, evaluation of granules using thermogravimetric analysis. The results show that, (1) Aerobic granules that developed under the sodium chloride concentrations of 1% (in Reactor R1), 2.5% (reactor R2) and 5% (reactor R3), the particles size of R1 and R3 concentrated in the 0.2-0.7 mm, and the particles size of R3is larger than R1. the formation particles size in R2 concentrated in the 0.2-0.5 mm. (2) The ripe particles' ratio of VSS and SS R1>R2>R3, and with the extension of time VSS/SS decreases, it was found that high sodium chloride resulted in particles of inert material increasing in internal,, that is particles formed under sodium chloride concentration more stable, and with the extension of sludge age, the increasing of sludge concentration, lack of nutrition in the reactor, resulting in emergence of non-organic components, particles become more and more stable. (3) It was found that high sodium chloride resulted in a low amount of strongly physically bound water in terms of the weight loss before 105℃. (4) The ratios of volatile suspended solids (VSS) to ash solids were 2.71, 1.15 and 1.05 in R1, R2 and R3, respectively, indicating that the activity of biomass decreased with the increase of salinity. The endothermic peaks shift to low temperature with the increase of salinity, and the DTA curves in R1 was the most complex with several peaks, suggesting the metabolite was rich in the low salinity conditions. This study shows that aerobic granular particles under high sodium chloride concentrations have strong and compact microbial structure, improved stability, is a promising approach.