Denitrification Experimental Study Based On Short-cut Nitrification And Denitrification Treatment For Landfill Leachate

Landfill leachate is a kind of complicated composition and high pollutantconcentration of pollutant of wastewater, its main feature is the highconcentration of organic matter and ammonia, poor biodegradability, many kindsof refractory organics, high salt, heavy metal ion, water instability. How toremoval of the ammonia in the leachate effectively has been the focus of research.In the study, the leachate from Xiaping solid waste landfill in Shenzhen city asthe research object, relying on existing fields under floor A/O-MBR landfillleachate treatment process, characterized by a high concentration of ammonia forlandfill leachate, conduct the realization of a feasibility study shortcutnitrification and denitrification landfill leachate treatment.This study investigated the A/O-MBR reactor to achieve nitrification anddenitrification via nitrite feasibility; inspect the A/O-MBR reactor deal withdifferent concentrations of ammonia leachate performance. Study achievingnitrous nitrification treatment effect of landfill leachate in SBR reactor; examineSBR reactor combined with A/O-MBR reactor treatment performance of landfillleachate. Finally beaker experiments investigated the initial ammoniaconcentration, pH and hydraulic retention time on the mechanism of nitrousnitrification, through the above work to be proposed for the leachate treatmentusing nitrification and denitrification processe to support the theory and data on.Through the study found that the A/O-MBR reactor is difficult to passcontrol of free ammonia, DO concentration, pH and other factors to achievenitrification and denitrification, and the A/O-MBR reactor ammonia shock loadresistance is poor, the influent ammonia concentration is not too high, theconcentration of ammonia water had better not be more than700mg/L for a longtime.Single-stage SBR reactor can realize nitrous nitrification, the effluentammonia concentration is stable. Influent ammonia concentration ofapproximately480mg/L or so, the average removal rate of ammonia up to90%;influent ammonia concentrations higher than850mg/L, the average removal rateof ammonia nitrogen is about68%. SBR reactor better resistance to shockloading of ammonia, phased single-stage SBR reactor influent ammoniaconcentration increased from400mg/L to2100mg/L in the process, the effluent ammonia concentration remained stable, small fluctuations in concentration.Single-stage SBR reactor with A/O-MBR reactor treating landfill leachate effectsassociated with stability, effluent ammonia, nitrogen and COD concentr ationswere approximately44mg/L,90mg/L and420mg/L, the effluent water qualitycan meet the A/O-MBR effluent requirements set.The beaker experiment research shows that the single-stage SBR systemmaintains pH between7.8-8.3, the system can maintain a high removal rate ofammonia and nitrite nitrogen accumulation rate. When the pH was6.0and6.8,ammonia removal efficiency in the system is low, and less accumulation ofnitrate nitrogen.The initial ammonia concentration of approximately200mg/L, the nitriteaccumulation rate is about40%; whereas when the initial ammonia concentrationof approximately300mg/L, when nitrite accumulation rate in more than50%,the system has complete nitrification into nitrite nitrification. And nitrousnitrification mainly by the FA and FNA alternately NOB activity inhibitionachieved accumulation of nitrite nitrogen.When the single stage SBR system maintains HRT about24h, the systemcan ensure that the system have higher removal rate of ammonia nitrogen andnitrite nitrogen accumulation rate. When HRT is12h, ammonia nitrogenremoval rate is about48%, nitrite nitrogen accumulation rate less than50%;When HRT is24h, removal rate of ammonia nitrogen and nitrite nitrogenaccumulation rate was the highest, and its value more than98%and98%respectively; HRT for48h, although the ammonia nitrogen removal rate canreach more than90%, but its nitrite nitrogen accumulation rate significantlydecreased, the accumulation rate of about70%.Through the study we found that when the system maintains the pH in7.8-8.1, initial ammonia concentration above300mg/L, HRT24h, the systemcan ensure a high removal rate of ammonia nitrogen and nitrite accumulationrate.