Study On Slightly-polluted Water Treatment By New Carrier In MBR

The treatment of slightly-polluted water was studied by using columnar polypropylene carrier and corncob. In this article we mainly focus on biodegradable carrier—corncob and membrane bio-reactor combination process to discuss operating results.The test results indicated that both of the crafts had good removal efficiencies of suspended solids and turbidity. Moreover, it found that the removals both of COD and ammonia were enhanced by prelonging HRT from 2h to 4h, while there were different scopes in each sector. Furthermore, results indicated that the removal efficiencies of ammonia nitrogen and the COD could be increased by increasing dissolved oxygen concentration, while total nitrogen removal was reduced.Compared with the columnar polypropylene carrier, the corncob displayed the characteristic of hanging the membrane quickly duing to the big surface roughness and good adsorption capacity. When corncob was used as the biofilm carrier, the removal rate of slightly-polluted water was improved. The increase of COD, ammonia and total nitrogen removals rate were 7.76%, 3.54%~4.59% and11.03%, respectively. The COD, NH4+-N and total nitrogen removal rate were 59.78%, 87.80%, 55.87% respectively. Results indicated that there were a series of depolymerization, break reactions for transforming cellulose molecules into the monosaccharide by the help of cellulase producted by microorganism in the carrier, which enhanced the carbon /nitrogen ratio, improved microorganism activity and fastened denitrification rate. Moreover, the system had achieved steady elimination for UV254, whose effluent was 0.057~0.097 cm-1.During the experiment we have inspected biomass and biofilm activity in the bioreactor. It indicated that with the extension of time, the biomass on the carrier kept growing and finally tended to be stable. When the biofilm quantity was low, biofilm activity increased along with time. As the biomass increased, activity of biofilm adhered to the carrier decreased.The biofilm microscopic observed results indicated that biofacies were quite rich in the biofilm, including all kinds of bacteria, fungus rubber group, protozoa, metazoa and so on.