Study On The Treatment Of Dairy Industrial Wastewater With Acid Hydrolysis And Novel Netlike RBC

Biofilm technology is a kind of biological treatment methods, which provides filter material or carrier to let the microorganism grow on them in order to absorb and degrade the pollutants to purify the wastewater. It is widely used because of the advantages below: large amount of microorganism, highly adaptation to the change of quality and quantity, no sludge bulking, less quantity of surplus sludge and convenience for operation and management. As the biofilm technology, rotating biological contactor (RBC) and biological contact oxidation pond are becoming the main treatment process because of the features formed after the research and development based on their traditional advantages.This thesis uses the rotating biological contactor and biological contact oxidation pond as a biofilm group technology to cope with the diary industrial wastewater, this kind of wastewater has a high content of organics and a lot of volatility of quality and quantity, although the biochemical performance is good, it’s easy to cause the sludge bulking, it’s just right to utilize this kind of group technology.A novel netlike rotating biological contactor biofilm reactor system is designed and set up. After the start and domestication of the system, author of this paper studied the influence of hydraulic retention time (HRT), the RBC rotary speed and dissolved oxygen concentration (DO) on the system. A contrast research was conducted between three novel RBC systems at the same time.After the inoculation of RBC and biological contact oxidation pond with the inoculated sludge discharged quickly, add up the dairy industrial wastewater’s proportion of sewage to domesticate the biofilm on the carrier. After 32 days’ domestication, the thickness of biofilm is about 2～3 mm and the color is taupe. We can find dense zoogloea and a lot of protozoan, metazoan and algae by microscopy, it means that the biofilm has a good biological activity. The domesticated system shows a good treatment effect on the dairy industrial wastewater, the chemical oxygen demand (CODCr) removal efficiency can reach more than 93% and ammonia nitrogen (NH4 +-N) removal rate for more than 82%.For the RBC, the study is about the influence of HRT(4h、6h、8h、10h、12h) and rotary speed(6 r/min、8 r/min、10 r/mim、12 r/min、16 r/min、20r/min) on it. Combining the removal efficiency and the RBC energy consumption, we finally made the HRT 10h and the rotary speed lOr/min, under the condition that RBC average removal rate of dairy industry wastewater CODCr, NH4+-N, TP reached 85.83%,79.34% and 79.34% respectively, and the effluent CODCr、NH4+-N、TP concentration were 129mg/L、4.67 mg/L、2.81 mg/L. The RBC kept a good removal efficiency and maintained a suitable thickness of the biofilm and microbial activity in the process of wastewater treatment.Taking the HRT(2h、4h、6h、8h) and DO(0.5～1.0mg/L、2.5～30mg/L、4.5～5.0mg/L) as the research subject to study the biological contact oxidation pond. The experiment determined the HRT of 4h and the DO concentration of 2-3mg/L with taking both removal efficiency and energy consumption into consideration. The CODCr, NH4+-N, TP removal rates of biological contact oxidation pond reached 71.27%,71.27% and 65.8% on average and the effluent reached 55 mg/L,4.44 mg/L and 1.42 mg/L which met the primary standard B level of Discharge standard of pollutants for municipal wastewater treatment plant.At the end of this experiment, three novel RBCs consisted of netlike polythene material, quartz sand and BioMTM microorganism film were taken into comparison in domestication start capacity under the same condition. The results showed that the polythene netlike RBC was easy to form the biofilm whose amount of microorganism was large and stable, with less surplus sludge in the reactor. It presented a stable removal efficiency of CODCr、NH4+-N and TP which demonstrated a good feasibility and practicability.