| The processing of natural rubber produced large volume of high concentration organic wastewater, which quality is complex and causes serious pollution to the environment. Wastewater for natural rubber processing contained COD, NH3-N and BOD5. The treatment effects of common bio-treatments are limited and the follow-up processing cost is expensive. In this study, a treatment using anaerobic-contact oxidation process by bioaugmentation with cultured and domesticated MEM was applied to treat wastewater for natural rubber processing. The degradation effect and removal law of COD and NH3-N were investigated, the removal mechanism of pollutants in the system was discussed, and the optimum operation parameters of the process were studied as well.The sludge system through inoculation and culture of bacteria were promoted, the biofilms were cultivated with seed sludge was obtained from anaerobic pool and the oxidation ditch terminal. It took about 11d to complete the start-up under the condition of MEM adding proportion was 1/1000, temperature around 25～29℃, HRT was 192h, GWR was 50:1, and ADR was 2:1. At this condition, average COD and NH3-N removal efficiency was 88% and 84%.Running parameters of anaerobic-contact oxidation system were coordinated with wastewater for natural rubber processing. The optimum operating condition was obtained as MEM adding proportion of 1/700, HRT of 168h, GWR of 80:1, ADR of 2:1. At this condition, the removal rate of COD, NH3-N, BOD5 and SS reached to 97.9%,98.6%,99% and 93%, respectively. The effluent average concentrations of COD, NH3-N, BOD5 and SS could be 79.2mg/L,1.79mg/L,13mg/L and 42mg/L. And the effluent water quality came up to the First Grade Standard of Integrated Wastewater Discharge (GB 8978-1996) of China, the treatment effect of the pollutants was better than that without MEM bacteria. Pollutants of the wastewater were mainly removed in the anaerobic pond and the first order contact oxidation pond. Removal rate for pollutants in these rector accounted for a considerable proportion of the total rate, the remove quantity of the second order contact oxidation pond was relatively small. The number of the effective microorganism can be increased, after MEM bacteria were added to the anaerobic-contact oxidation system, the stable ecosystem micro-ecological environment and the reasonable microbial distribution structure can be formed, too. So, Great advantages, which include high contaminant removal ratio and strong impulsion load resistance, have been observed when MEM bacteria were used in treatment rubber wastewater. The paper preliminarily established the dynamic model of anaerobic pond and the contact oxidation pond, and the corresponding dynamic parameters were also determined, during the period of wastewater for natural rubber processing were treated. |
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