Impact of nitrogen loading rates on nitrogen transformation for anaerobic effluent from latex processing industry

Abstract

This study evaluated the influence of nitrogen loading rates on fate of nitrogen treating anaerobic effluent from latex processing industry using a novel acryl-fibre biomass carrier-bio-fringe (BF) in a swim-bed reactor. At NLR of 0.5 kg N/m3.day, 60% to 70% TKN was converted and the nitrogen ratio N–NO2/ (N–NO2 + N–NO3) reached 80% to 90%. At NLR of 1 kg N/m3.day, conversion efficiency of TKN increases by 80% to 95% and the ratio reached 80% to 95%. However, this ratio decreased by 40% to 60% due to the influent alkalinity reduction. At increased NLR of 1.5–2 kg N/m3.day, nitrite and nitrate reduced less than 20 mg N/L. This is due to an increase in NLR and amount of alkalinity available. Reactor pH as high as 8.2–8.6 produced high free ammonia (FA) concentration restricting nitrite production. The COD removal efficiencies were 80–90% and 85–95% at NLR of 0.5–1 kg N/m3.day, respectively. This reduced 75– 88% at an increased NLR of 1.5–2 kg N/m3.day.