High strength nitrogen removal from nightsoil and piggery wastes

Abstract

Nightsoil and piggery wastes generally present high strength organics and nitrogen. This study evaluated the nitrogen removal characteristics with the existing and modified nightsoil and piggery waste treatment plants. The existing conventional plants showed 20 to 40% nitrogen removal, but the modification with SBR or MLE process could remove effectively both nitrogen and organics with the minimum COD/TN and alkalinity/TN ratios of 6 and 3.6, respectively. Nitrite nitrification and denitrification rates obtainable at higher nitrogen loads were faster than the rates of nitrate nitrification and denitrification resulting in less reactor volume requirement. However, the higher nitrogen loads increased the organic loads resulting in the reactor temperature inhibiting nitrification. Thus, a combined treatment with anaerobic digestion with the adjustment of influent bypass rates was proposed to reduce the reactor temperature and the external carbon requirement. The biological treatment could discharge about 1,100 mg/L soluble COD and 50 mg/L soluble nitrogen, respectively.

Estimating riverine discharge of nitrogen from the South Korea by the mass balance approach

“…A total amount of 329.5×10 3 tons N/yr was produced as animal wastes, of which 80% (263.5×10 3 tons) was applied to agricultural land and 20% (66×10 3 tons) was treated at the community plants in Korea (KMOE 2003). It was assumed that about 74% of the nitrogen removed by nitrification and denitrification, 20% by ammonia stripping, 3% by precipitation as struvite and 3% by effluent discharge (= 2×10 3 tons N/year) according to Choi et al (2003) proposed from nitrogen mass balance from several community animal waste treatment plants.…”

Progress in Slow Sand and Alternative Biofiltration Processes

“…Firstly, part of this missing nitrogen should be attributed to biomass assimilation, which is difficult to calculate in such systems. Choi et al (2004) stated that the COD/N ratio should be higher than 6 to achieve high nitrogen removal efficiency via nitrification and denitrification pathway. Known as the final product of complete denitrification, N 2 production measurement was impossible during this experiment because of its large presence in the system caused by aeration.…”

The effects of operation conditions of carbon/nitrogen ratio and pH on nitrogen removal in intermittently aerated membrane bioreactor (IAMBR)

“…Furthermore, a COD/ N ratio over 7 was required for nitrogen removal in the IAMBR system. Other important factors that are to be considered for nitrogen removal are alkalinity, temperature, and pH [26,27]. The purpose of this study is to show the effects of operation conditions of carbon/ nitrogen ratio and pH on nitrogen removal in simultaneous nitrification-denitrification process sustained in a lab scale membrane bioreactor.…”