Study On Treatment Of Wastewater With Modified Polyurethane Foam

In this study, modified polyurethane foams were applied as microbial carrier to dealwith domestic sewage and garbage leachate and used as a carrier of the microbialadsorbent for adsorption of low concentration cadmium ion in water.Modified polyurethane foams were studied for domestic wastewater treatment at theconditions of pH=7, T=25℃. Results show thatthe unmodified and modified polyurethanefoams may be acted as better wastewater treatment microbial carriers in the equipment ofbiological aerated filter. The modification of polyurethane foams improves the removal ofCOD and ammonia nitrogen rate in domestic wastewater. The COD removal efficiency oftwo modified polyurethane foams were82.1%and78.2%, and the ammonia removalefficiency reached98.5%and92.8%as the stable microbial membrane formed on thecarriers.The modified polyurethane foams were used as the microbial carrier in BAF to dealwith landfill leachate possessing the characteristics of high concentrations COD andammonia nitrogen. The modified polyurethane were found to display larger specificsurface area and more suitable for microbial growth. When two-stage biological aeratedfilter process was adopted, ammonia nitrogen removal rate reached94.6%and CODremoval rate reached90.0%.The effects of the temperature and pH changing on treatmenteffect were studied. Experimental results showed that the optimal processing temperaturewas25℃and the optimum pH was8under the single factor influence.Modified polyurethane foams were used as a carrier of the adsorbent-for adsorptionof heavy metal cadmium ion. The microbial loading efficiency of modified group reached69.2%in comparison to53.8%of the unmodified group showing obvious enhancement. Interms of absolute adsorption quantity of heavy metal cadmium ion, the maximum amountof selective adsorption Cd2+for modified polyurethane foams loaded microorganism were112mg/g.The peeling problem in the absorption process was mostly solved usingpolyvinyl alcohol as adhesive between polyurethane foams and microorganism.Studies shows that the modified polyurethane foams are better microorganism-loadedcarriers. The polyurethane foams are promising materials for domestic wastewater andgarbage leachate treatment,and have prospecting application in the treatment of heavymetal ions wastewater as well.