| Due to its great environmental impact and large amount of drainage, the wastewater from natural rubber processing industry has been recognized as the most important pollution-control project in Yunnan Province. Due to the constant change of raw materials in the process of natural rubber, the effluent water quality and water quantity changed frequently and were unstable. There was some high concentration of organic matter, ammonia nitrogen and pollutants in the wastewater which could inhibited microbial growth. The effluent concentration of organic matter and ammonia nitrogen in the wastewater could not meet the standard because of slow microbial growth. In addition, the wastewater treatment facilities could not dispose the increasing quantity in time as the continuous expansion of the natural rubber production. Therefore, it is important to seek an effective and economical treatment technique and technology to improve the wastewater treatment efficiency.In this paper, A/O1/O2 process has been improved to promote wastewater treatment and microbial community structure stability. It turned out that the treatment effect was improved through bioaugmentation of functional bacteria compared to the traditional AO process. Moreover, the removal rate of COD and NH3-N were increased by 20.05% and 29.78% respectively. The start-up time of the system was shorten and the resistence shock loading of the system was enhanced.In order to make full use of the degrading bacteria as well as increase the biomass and bioactivity per unit volume, a new bioaugmented A/O1/O2 process was proposed by adding filler in every tank. The removal rate of COD and NH3-N was improved 6.87% and 7.21% due to immobilized microbial biofilms system. The activity of microorganisms was enhanced and pollutant removal efficiency was maintained at a higher level in immobilized microbial biofilms system. The attached biofilm on the carrier was observed by the scanning electron microscope and then the process of biofilm formation was analyzed. The morphological characteristics of the biofilm and microscopy microbes in different reaction chambers were acquired by optical microscope showed complete system of microbial food chain.To acquire further designing and operational parameters when adopting bioaugmentation in the disposal of the wastewater from natural rubber processing, influencing factor of bio augment A/O1/O2 biofilm system was studied. The single factor experiments were performed to analysis of the degradation of COD and NH3-N and examine along with the effect of microorganisms dosing proportion, HRT(Hydraulic Retention Time),DO(Dissolved Oxygen),the ratio of the optimal aeration rate in O1 and O2,temperature.Results indicated that the COD and NH3-N of effluent were removed 96.80% and 97.42% respectively with the COD and NH3-N concentration in raw waste water were 2983 mg/L and 307 mg/L when the microorganisms dosing proportion, HRT, DO, the ratio of the optimal aeration rate in O1 and O2,temperature was 1:700,7 d,3 mg/L and 25℃～30 ℃ respectively.In order to attain the accurate optimum reaction condition, a central composite design was used as an experimental design and optimum conditions were obtained by regression analysis based on the single factor experiments and response surface methodology. Study and analysis the linear relationship between two response indicators which were COD removal rate and NH3-N removal rate and four factors which were microorganisms dosing proportion, HRT,DO and the ratio of the optimal aeration rate in bio augment A/O1/O2 biofilm system. The paper established two models of treatment efficiency of wastewater from natural rubber processing. Based on the variance analysis for multifactor, the microorganisms dosing proportion and HRT of system had significant effect on COD removal rate and NH3-N removal rate. The optimum conditions were microorganisms dosing proportion 1:900, HRT 7days, DO 2.8 mg/L and the ratio of the optimal aeration rate 2:1.The removal rates of COD and NH3-N were 97.69% and 99.10%.Based on the precious research results, this A/O1/O2 bioaugmentation process technology was applied in the wastewater treatment of rubber factory in Jinghong city, the actual effect of the technique and application prospects were evaluated. The technology of wastewater treatment of rubber factory was designed. The results showed that the average removal rate of COD, BODs were 98.13%,98.87%, which the effluent concentration kept in range of 33 mg/L-55 mg/L and 11 mg/L～24 mg/L, and the total removal rate of NH3-N reached 98.93% which the effluent concentration kept in range of 0.21 mg/L～7.8 mg/L when the inlet water quality of A/O1/O2 biological membrane reaction pool was unstable. The results of acceptance monitoring of this project showed that the five indicators of rubber wastewater effluent met the requirement of related standards. Through the analysis of the economic and environmental benefits of the technology, bioaugmentation technology will not cause secondary pollution and reduces the cost with good environmental and economic benefit and broad prospects for promotion.Combined the culture-independent technology of PCR-DGGE and culturing technique, the spatial structure of microbial populations on biofilm and the superiority strains in bioaugmentation system was mainly analyzed. There were five functional superiority strains isolated from the bioaugmentation system. The amount and type of aerobic bacteria, facultative bacteria and anaerobic bacteria were increased due to the addition of microbial inoculum in this system. The removal efficiency of organic matter and ammonia nitrogen was enhanced which achieve the goal of bioaugmentation due to the synergistic effect between different microorganisms. The ammonia nitrogen degradation mechanism in the process of wastewater from natural rubber processing was discussed preliminarily based on the theory of simultaneous nitrification and denitrification environment and changed concentrations of NO3-N in the process of ammonia nitrogen degradation in the system.
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