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2차침전조 대체 활성탄 패치의 포기조 내 설치에 의한 기존 활성슬러지공정 개선

Title
2차침전조 대체 활성탄 패치의 포기조 내 설치에 의한 기존 활성슬러지공정 개선
Other Titles
Improvement of Existing Activated Sludge Process by Installing Activated Carbon Patch as an Alternative of Secondary Clarifier
Author
이선옥
Alternative Author(s)
Lee, Sun Ok
Advisor(s)
김문일
Issue Date
2008-08
Publisher
한양대학교
Degree
Master
Abstract
전분폐수는 일반적으로 활성슬러지법에 의해 처리되고 있으나 이들 폐 수에는 곰팡이류 및 사상균 등의 번식으로 벌킹현상이 일어날 뿐만 아니 라 잦은 부하변동으로 처리에 어려움이 있는 실정이다. 본 연구는 골판지 공장 전분폐수를 대상으로 기존의 부유성장 활성오 니공정과 기존 폭기조 방류지점에 활성탄 패치를 설치한 개선공정의 부 유고형물 분리 효과가 방류 유기물 및 고형물에 미치는 영향을 고찰하고 자 한다. 기존 부유성장 활성오니공정에서, 운전조건에 따른 유입.유출 유기물 과 고형물의 농도변화는 다음과 같다. 미생물 반응조의 운전조건은 MLSS와 F/M비, SRT, HRT, RAS, DO는 각각 3,041∼3,260 ㎎/ℓ, 0.042∼0.067 ㎏.BOD/㎏.MLSS.day, 5.58∼11.16 days, 5.0∼6.25 hr, 0.18 ∼0.25 Q, 0.7∼1.8 ㎎/ℓ로 유지 하였을 때, 유입되는 유량과 TBOD5는 각각 8.0∼11.0 ㎥/day, 900∼1200 ㎎/ℓ이며 방류 유기물 및 고형물의 농도는 각각 72∼115 ㎎/ℓ, 77∼132 ㎎/ℓ였다. 방류 고형물의 농도가 높은 경향이 있는데, 이는 미생물 반응조내 높 은 MLSS와 낮은 F/M비, 긴 SRT, 많은 내생호흡 단계의 미생물이 원인 인 것으로 사료되었다. 2차 침전조 대체 폭기조내 활성탄 패치를 설치한 개선 공정에서, 운전 조건에 따른 유입.유출 유기물과 고형물의 농도변화는 다음과 같다. 미 생물 반응조의 운전조건은 MLSS와 F/M비, SRT, HRT, RAS, DO는 각 각 3,460∼3,600 ㎎/ℓ, 0.041∼0.075 ㎏.BOD/㎏.MLSS.day, 14.33∼25.00 days, 4.54∼6.25 hr, 0, 0.796∼1.095 ㎎/ℓ로 유지 하였을때, 유입되는 유량과 TBOD5는 각각 8.0∼11.0 ㎥/day, 900∼1200 ㎎/ℓ이며 방류 유 기물 및 고형물의 농도는 각각 35∼62 ㎎/ℓ, 32∼58 ㎎/ℓ였다. 기존의 부유성장 활성오니공정과 비교해 볼 때 방류 유기물 및 고형물 의 제거율이 상당히 높게 나타났는데, 이는 반응조내 활성탄 패치에 의 한 미생물의 floc이 쉽게 분리되고 활성탄 표면의 -OH기, -COOH기와 같은 친수기와 정(+), 부(-) 전하가 동시에 작용하여 방류 유기물 및 고 형물이 동시에 제거되는 것으로 사료되었다. 이상의 연구 결과로 볼때 폭기조 내 활성탄 패치를 설치한 개선공정은 기존의 2차 침전조가 불필요 하므로 폐수처리장의 콤팩트화가 가능하였 다. 또한 침전조 설치에 따른 경제적인 토지 소요면적 비용, 설계시공 비 용, 유지관리 비용 등의 절감효과를 기대할 수 있어 향후 경제적인 기대 효과는 더욱 증가할 것으로 판단된다.
The aim of this study was improving existing activated sludge process by installing activated carbon patch (ACP) in order to elevate sludge settling properties. Generally, wastewater containing starch produced from a corrugated paperboard factory, have been treated by conventional activated sludge process. However, there are several difficult operational problems in the conventional process: sludge bulking due to the propagation of fungi and high organic loads fluctuation, and decrease of solids and liquid separation in secondary clarifier. Therefore, ACP was installed in existing aeration tank for improving sludge settling properties and effluent quality. The summary of this study was as follows. 1) The MLSS concentration and SRT of the conventional process were 3,041∼3,260㎎/ℓ and 5.6∼11.2days, respectively. DO concentration during this study was kept 0.7∼1.8㎎/ℓ. For maintaining MLSS concentration in the existing aeration tank, F/M ratio and RAS was kept 0.042∼0.067㎏?BOD/㎏?MLSS/day and 0.18∼0.25Q, respectively. According to high fluctuation of flow rate (8.0∼11.0㎥/day), HRT was changed from 4.54hr to 6.25hr. Influent TBOD5 was varied from 900 to 1,200㎎/ℓ, thus the effluent quality was not good and the range was big. Effluent quality of the conventional process could not satisfy and TBOD5 and TSS concentration was 72∼115㎎/ℓ and 77∼132㎎/ℓ, respectively. It was estimated that high organic loads variation and decreasing HRT was a main cause of poor sludge settling properties and TBOD5 removal efficiency. Also, low F/M ratio and long SRT condition was a cause of endogenous respiration stage of existing aeration tank. 2) With respect to identified the cause of existing activated sludge process, the conventional process was upgraded by installing ACP as an alternative of the existing secondary settling tank. The improved ACP process was operated with same operating conditions and the existing secondary clarifier was fully removed. After installing ACP, MLSS concentration and SRT was increased and was 3,460∼3,600㎎/ℓ and 14.3∼25.0days. The effluent quality was greatly improved by keeping stable and higher MLSS concentration and longer SRT and TBOD5 and TSS concentration was 35∼62㎎/ℓ and 32∼58㎎/ℓ. According to improving SVI, sludge settling properties was clearly improved and it was confirmed that ACP was a suitable alternative with removing existing secondary clarifier. 3) After retrofitting existing activated sludge process, there are several cost-effectiveness by introducing ACP process. First is that the site of old secondary clarifier might be reuse for constructing other facilities and buildings. Second, improved ACP process could be operated with easy way rather than those of conventional activated sludge process. According to improving sludge properties, sludge disposal cost might be saved due to small wasted sludge producing of ACP process.
URI
https://repository.hanyang.ac.kr/handle/20.500.11754/146127http://hanyang.dcollection.net/common/orgView/200000409420
Appears in Collections:
GRADUATE SCHOOL OF INDUSTRIAL ENGINEERING MANAGEMENT & DESIGN[E](산업경영디자인대학원) > DEPARTMENT OF CONSTRUCTION ENGINEERING(건설공학과) > Theses (Master)
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