Study On Swine Wastewater Treatment By Membrane Bioreactor

With the development of animal production, more and more animal waste was discharged form concentrated aimal feeding operations (CAFOs). Now what concers most is the environmental pollution from CAFOs, especially from swine facility due to significant amount and high organic concentration. To minimize the influence of pollutions on animal production and to reduce the demand for fresh water, it makes great sense to conduct deep treatment of wastewater and improve the quality of treated water, so as to reuse.Considering the present problems and the tendency of the treatment technology development, this paper has carried out some experiments on swine wastewater treatment by membrane bioreactor (MBR). Using a U shape and L shape hollow fibre membrane, four operation conditions were investigated in different influent COD and ammonia nitrogen concentration, different DO level and SRT in the reactor. In this experiment, the feasibility of MBR as swine wastewater aerobic treatment stage, COD and ammonia nitrogen removal efficiency and operation parameter were probed. The results showed that the third operation condition was the most effective. Based on the experiment results and literature review, a program aimed to design MBR system and the whole treatment process had been completed. The main results are showed as below:1. In the first operation condition, average COD concentration in the influent was 1259mg/l, removal efficiency of U shape and L shape membrane were 86.4% and 77.3%, respectively. Average influent ammonia nitrogen was 87.6mg/l, U shape and L shape membrane had achieved removal efficiency as 55.8% and 53.4%, respectively.2. In the second operation condition, average COD concentration in the influent was 1597mg/l, removal efficiency of U shape and L shape membrane were 83% and 81%, respectively. Average influent ammonia nitrogen was 87.6mg/l, U shape and L shape membrane had achieved removal efficiency as 52% and 62%, respectively.3. In the third condition, pH of mixed liquor remained 7.6-8.4, DO 1-3 mg/1, HRT 24h, SRT 45d, MLSS 11000mg/l. When the influent COD was 1860 mg/1 in average, the removal rates of U shape and L shape membrane were respectively 84.1%, 81.2%.When the influent NH4+-N is 511mg/1 in average, the removal rates were 93.81% in U and 93.61% in L respectively.4. In the fourth operation condition, average COD concentration in the influentwas 1025mg/l, removal efficiency of U shape and L shape membrane were 65% and 63%, respectively. Average influent ammonia nitrogen was 634mg/l, U shape and L shape membrane had achieved removal efficiency as 87% and 88%, respectively.5. The experiment results showed that in relative low MLSS concentration, as 1440-5644mg/l, COD removal efficiency of U shape was better than L shape, other MLSS conditions, there was no distinct difference.6. Based on the experiment results and literature review, a program aimed to design MBR system and the whole treatment process had been completed. When such data as breeding scale, discharged pollutant concentration and the target effluent quality were inputted, this program could output investment and operation expenditure and the actually effluent quality. For the selected treatment process, this program could give the detailed information about related construction and mechanical equipment.7. A case study was carried through using this program.