Abstract
This study assessed the feasibility of odor removal by the application of Bacillus sp. that has many advantages in sewage treatment to sewage sludge. The NH3 removal rates in the treatment of primary sludge using only aeration were measured at 24, 48, and 72 hours of treatment and the results were 12.5 %, 12 %, and 42.1 %, respectively. The NH3 removal rates of a reactor injected with BIO-CLOD made by solidifying Bacillus sp. concentrated 10 % together with other substances were measured after 24, 48, and 72 hours of treatment and the results were 43 %, 70 %, and 81 % respectively. In the cases where the Bacillus sp. cultured in NB medium was injected into the primary sludge reactor to reach injection rates of 0 %, 1.7 %, 3.3 %, and 6.7(v/v%), the TVOC removal rates measured when 72 hours had passed after the injection were 59 %, 71 %, 88 %, and 98 % respectively, which were higher than the NH3 removal rates as the NH3 removal rates measured at the same time were shown to be 29 %, 25 %, 31 %, and 48 %, respectively. In the sludge dewaterability conducted with various Bacillus sp. injection concentrations, a Bacillus sp. concentration of 4(v/v%) was considered to be suitable. The Bacillus sp. concentrations and reduction in the bad odor substances were correlated with each other. The results showed that aeration and Bacillus sp. injection will assist biological oxidation so that the bad odor substances can be removed. Based on the SRF values of the primary sludge and digested sludge, in which Alum and PAC were used, the appropriate amount of Alum aggregate reagent was judged to be 500 mg/L, and when PAC was used, 6 mg/L was judged to be appropriate.
본 연구에서는 하수 처리에 많은 장점이 있는 Bacillus sp.를 하수 슬러지에 적용함으로써 악취 제거에 대한 타당성을 검토하였다. 1차 슬러지를 공기공급 만으로 24시간, 48시간, 72시간 경과 후의 $NH_3$제거율은 12.5 %, 12 %, 42.1 %를 나타내었고, Bacillus sp.농축액 10%와 기타 물질을 넣어 고형화시킨 BIO-CLOD를 주입한 반응기에서는 $NH_3$제거율이 43 %, 70 %, 81 %의 제거율을 보였다. NB배지에서 배양된 Bacillus sp.를 1차 슬러지 반응기에 주입율 0 %, 1.7 %, 3.3 %, 6.7(v/v%)에서 72시간 경과 후의 TVOC제거율은 59 %, 71 %, 88 %, 98 %를 나타내었고, $NH_3$제거율은 29 %, 25 %, 31 %, 48 %로서 TVOC 제거율이 더 높았으며, Bacillus sp.주입 농도에 따른 탈수 실험에서는 Bacillus sp.농도를 4(v/v%)로 하는 것이 적합한 것으로 판단되었다. Bacillus sp.농도와 악취물질 감소간에 상관관계가 성립되며, 공기공급과 바실러스의 주입은 생물학적 산화를 도와 악취물질의 제거가능성을 확인하였다. Alum과 PAC을 사용한 1차 슬러지와 소화슬러지의 SRF값으로 적정한 Alum응집제량은 500 mg/L이였고 PAC을 사용할 때는 적정량이 6 mg/L주입하는 것이 타당하다고 판단되었다.