Study On Simultaneous Nitrification And Denitrification Processes Of FMBR In Livestock And Poultry Breeding Wastewater Treatment

With scale development and centralization of aquaculture industry, treatment for livestock and poultry breeding wastewater, which has large inflow and high concentration, is becoming one of the most important concerns of environmental pollution. Large scale farming has become the main source of rural non-point source pollution. As a newly developed technology, FMBR is simple in process, simultaneous denitrification, no sludge discharge, energy saving, efficiency, water recyclable. Combined with remote monitoring technology, FMBR is standing out in wastewater treatment technology. FMBR in livestock and poultry breeding wastewater treatment is diminishing.In this study, FMBR is dealing with High concentrations of livestock and poultry breeding wastewater after simple pretreatment. By analysis start-up condition, implication and affection of FMBR achieving SND is was systematically studied. Established dynamics model of SND process within FMBR using pilot experiment. Mechanism of N2 O emission is also studied. The main research conclusions are as follows:(1) FMBR worked efficiently in livestock and poultry breeding wastewater treatment, forming high concentration activated sludge to adapt wastewater, showing high COD removal rate. Still, FMBR shows imperfection in ammonia nitrogen removal and TP removal. Treatment efficiency is highly sensitive to temperature, low temperature during start-up period showed low treatment efficiency.(2) FMBR achieving SND when DO is within 0.3 mg/L to 1.0 mg/L, while COD removal rate stays around 93%. NH4+—N removal rate is about 75%. Concentration of NO2-—N is approximates to zero. Concentration of NO3-—N decreased significantly from 32.45mg/L to 1.28mg/L. TN removal rate increased to about 78%. To guarantee the economic efficiency while promise treatment effect, HRT better stays within 14 h.(3) Based on Nitrification and denitrification reaction kinetics equation and material balance equations, dynamic model of SND in FMBR is deducted. Parameters of SND dynamic model were solved, C1 equals to-1.58,C2 equals to-0.84,KM equals to 0.42.Dynamic equation was established through analysis.(4) N2 Oreleased from all kinds of microbial biochemistry during SND in FMBR, requiring a variety of enzyme. N2 O released by non-biochemical reaction can be ignored. Dominate pathway of N2 O emission is AOB, which take NO2-—N as substrate. N2 O released as intermediate of incomplete denitrification. Thus NO2-—N formation rate becomes essential to N2 O emission.