Basic Research Of COD And Ammonia Nitrogen Removals In High Salinity Wastewater By MABR

High salinity wastewater with organics is a typical refractory wastewater withlarge quantity, poor biodegradability, hard to reutilization and toxicity. Currently,though there are a variety of high salinity wastewater treatment processes, all of themhave different shortcomings, such as low processing efficiency, serious secondarypollution, high operating energy consumption, complex process, difficult to reach thestandard and so on. Membrane aerated biofilm reactor (MABR) is a novel process totreat organic wastewater. Howerer, the feasibility of MABR for hypersaline organicwastewater has not been studied until now.This paper applies MABR process to the treatment of high salinity wastewaterfor the first time. The MABR reactor used for domestication of biofilm anddegradation of high salinity wastewater was made in our laboratory. The reactor caneffectively avoid the happening of water short flow, has the advantage of simpleoperation and easy to run a long time. Three domestication ways (sodium chlorideconcentration gradient of1g/L,10g/L,5g/L, respectively) were adopted on thecultivation of the microbe. Studies have shown that the third domestication way withsodium chloride concentration gradient of5g/L is the most feasible method, which hasthe advantages of short domestication period and low impact to the microbesimultaneously.Long running experiments show that when the salt content in the wastewater isless than or equal to45g/L, the effluent COD, ammonia nitrogen are relatively stableat about20mg/L and0mg/L. And when the salt content is less than or equal to40g/L,the effluent nitrate and nitrite are also relatively stable at0.5mg/L and0mg/L.Tracking experiments demonstrate: when the salt content is less than or equal to35g/L, the effect of salt concentration on COD remoal is very small; when the saltcontent is less than or equal to25g/L, the effect of salt concentration on ammonianitrogen and nitrate removals is also very small; on the other hand, when the saltcontent is less than or equal to10g/L, the effect of salt concentration on nitriteremoval is very small; but when the salt content is higher than10g/L, the effect of saltconcentration on nitrite removal is obvious, which demonstrates that the nitriteoxidizing bacteria has the worst salt tolerance. In addition, this study examines the effect of the peristaltic pump rotational speed,aeration pressure and C/N ratio on the COD, ammonia nitrogen, nitrate, and nitriteremovals when the salt concentration is40g/L. And the optimal operating conditionshave been ultimately determined with the peristaltic pump speed of130r/min, aerationpressure of0.10MPa, and C/N ratio of8.Experiments show that MABR process has a good performance in treating thesimulation high salinity wastewater, which laies a solid foundation for MABR to treatactual high salt wastewater.