| Title |
Comparison of Municipal Wastewater Treatments between the Biofilm Process Utilizing PVDC & PEPP and the Activated Sludge Process |
| Abstract |
Municipal wastewater was treated by the method of aerated submerged biofilm process using PVDC (polyvinylidene chloride) or PEPP (polyethylene polypropylene) as the attachment media. Comparing with the conventional activated sludge process, the aerated submerged biofilm processes showed a higher removal efficiency in COD_(cr), BOD, and SS. The PEPP was superior to the PVDC in removing organic matters. For T-N and T-P, while the aerated submerged biofilm process gave 52.4-54.0% and 56.9-63.2% removal, respectively, with insignificant difference between the PEPP and PVDC media, the activated sludge process resulted in 15.9-21.4% and 29.5-37.4% removal, respectively. In the biofilm process, the attached biomass was 40.7-42.4% and 49.3-50.3% of the total biomass for PVDC and PEPP media, respectively. The adequate loading rate of organics in municipal wastewater seemed to be 1.0 ㎏ COD/㎥ ·day and 0.5 ㎏ COD/㎥ ·day. The total oxygen uptake and endogenous respiration rates in the biofilm process were 7.3-11.1 ㎎ O₂/L, and 5.4-8.2 ㎎ O₂/L, respectively, which were much lower than those in the activated sludge method. At a similar organics loading rate condition, the biofilm process gave a higher SV_(30) value and lower sludge product than the activated sludge process. In comparing dewaterability, specific resistance coefficient (γ) was 5.28 X 10^(13)㎝/g in the activated sludge and 3.65-5.22 X 10^(13)㎝/g in the aerated submerged biofilm process. Dewatering was relatively easy in the aerated submerged biofilm process, especially in PEPP media. |