The Study Of Treatment Performance Of High-salinity Wastewater In Fluidized-bed Biofilm Reactor

The treatment of high-salt wastewater is difficult. Emissions of high-saltwastewater without properly handled would bring many environmental pollution. Inthis study, wastewater from a food plant for cleaning seafood and discharge ofkimchi water is handled by fluidized-bed biofilm reactor. The study scheme containsstart program, the best operating conditions and impact resis tance. It is all forimproving treatment system and optimize the design.The influent flux of plant wastewater ranges from500t/d to2000t/d. Theconcentration of COD ranged from50mg/L to800mg/L. The concentration ofammonia is between8mg/L and150mg/L. The salinity vary from0.5g/L to2.5g/L.Experiments of artificial sewage influx with COD300mg/L, ammonia15mg/L, salt2.5g/L are operated under20℃. This paper studied two ways of start-up biofilmreactor. One is start-up and domestication at the same time. The other isdomestication after start-up.The biofilm of simultaneous program was matured after12days. The CODremoval percentage could reach about90%eventually. The removal percentage ofammonia can reach70%. The removal percentage of activated sludge can reach87%in the end. The removal rate of ammonia stabilized at65%afer15days. The biofilmof two-step scheme was matured after19days. The COD removal percentage couldreach about74%eventually. The removal percentage of ammonia can reach60%.By orthogonal experiments without interaction, effect of various factorsaffecting the treatment system is: HRT>salinity>DO>filling proportion>pH>CODconcentrations. The best operating parameters is：HRT of10h, salinity of10g/L, DOof2.5mg/L, filling proportion of50%, pH of7, COD concentration of500mg/L.Considering the case of interaction, the effect of various fac tors is: HRT> pH>temperature; the optimal operating parameters is pH of7.0, temperature of25℃,HRT of24h. Salinity> filling proportion>nutrition ratio. Filling proportion of40%,salinity of10g/L, carbon: nitrogen:phosphorus ratio is100:5:1. Salin ity> residencetime, the optimal salinity is7.5mg/L, the optimal HRT is16h.When dissolved oxygen concentration rises from2mg/L to4mg/L, biofilm is15%higher than activated sludge in COD removal efficiency,10%higher inammonia removal effic iency. When temperature varys from10℃to30℃, CODremoval efficiency with biofilm is about20%higher at10℃, about15%at15℃,about5%at20℃. When residence time changes from2hour to24hour, CODremoval efficiency of biofilm is about20%higher than activated sludge; ammonia removal efficiency is15-20%higher. When influx of COD100mg/L, ammonia20mg/L rises to COD800mg/L, ammonia160mg/L, COD removal percentage is about15%higher than the activated sludge, ammonia removal efficiency is15-20%higher.When salinity impact varis from5g/L to30g/L, COD and ammonia removalpercentage of biofilm is5-10%, higher than the activated sludge.