하·폐수 고도처리 및 핵심요소기술

Advanced Sewage And Wastewater Treatment And Development of Important Point Technologies

유체유동을 이용하여 오·폐수 분해 및 분리장치개발

(하수고도화 및 슬러지처리 중심으로)

Development Of Sewage/Wastewater Degradation And Separation Plant Using A Fluid Fluctuation

(Focused On The Sewage Advanced Treatment And Sludge Treatment)

(주)에코데이

환 경 부

071-031-060

- 1 -

제 출 문

환경부장관 귀하

본 보고서를 “유체유동을 이용하여 오·폐수 분해 및 분리장치 개발(하수고

도화 및 슬러지처리 중심으로)” 과제의 보고서로 제출합니다.

2006 년 7 월 31 일

주관연구기관명 : (주)에코데이

연구책임자 : 최 홍 복

연 구 원 : 이재기, 박주형

최은주, 김정래

- 2 -

보고서 초록

과제번호 071-051-060해당단계연구기간

2005.06.01 ～ 2006.05.31

구분 3차년 / 3차년

연구사업명 차세대 핵심환경기술개발사업

대분야명 하·폐수처리 고도화

중분야명 하·폐수 고도처리 및 핵심요소기술

연구개발과제명

국문명 유체유동을 이용하여 오·폐수 분해 및 분리장치개발 (하수고도화 및 슬러지처리 중심으로)

영문명Development of sewage/wastewater degradation and separation plant using a fluid fluctuation(focused on the sewage advanced treatment and sludge treatment)

연구책임자 최 홍 복

해당단계 참여연구원수

총 : 5 명내부 : 5 명외부 : - 명

해당단계 연구개발비

정부: 70,000 천원기업: 24,000 천원 계 : 94,000 천원

총연구기간참여연구원수

총 : 20 명내부 : 16 명외부 : 4 명

총연구개발비

정부: 394,000 천원기업: 146,000 천원 계 : 540,000 천원

연구기관명 및

소속부서명(주)에코데이 기술연구소 참여기업명 (주)에코데이

국제공동연구 상대국명 : 상대국연구기관명 :

위 탁 연 구 연구기관명 : 연구책임자 :

요약(연구개발결과를 중심으로 개조식 500자 이내)보고서면수

1. 유체유동을 이용한 생물반응기 개발

▸ 충분한 미생물 확보와 높은 산소전달효율을 갖는 고농도 페수처리용 생물반응기 개발 ▸ 일반반응조의 CSTR 형태에서 벗어나 처리효율이 높은 PFR 형태의 다단 반응기 구조 ▸ 고농도 미생물 유지 및 활성(MLSS 20,000mg/L 이상) ▸ 반응기 각단에 기체 체류공간을 확보하여 유체유동에 의한 혼합효과와 높은 산소전달효율 ▸ 고농도 음식물 폐수의 처리를 통해 BOD 99%의 제거효율(총 처리시간 4일)2. 슬러지의 호기성 소화

▸ 슬러지의 호기성 처리시간 4일 이내 TS 60%, 슬러지부피 70% 이상 감량화 ▸ 호기성 소화 후 유출수내 VS 함량 40～45%로 안정화 ▸ 반응기의 높은 산소전달율(25% 이상)로 인한 포기시 동력비 절감 ▸ 소화슬러지의 농축효율 및 탈수성 향상 ▸ 반류수 중의 질소 제거로 수처리 계통의 고도화 ▸ 슬러지 감량화 기술 적용 전과 비교시 슬러지 처리 비용의 46% 절감색 인 어

(각 5개 이상)

한 글 슬러지 감량화, 호기성 소화, 고형물 분리, 유체유동, 슬러지 전처리

영 어 Sludge reduction, Aerobic digestion, Solids separation, Fluids fluctuation, Sludge pre-treatment

- 3 -

요 약 문

Ⅰ. 제 목

유체유동을 이용하여 오·폐수 분해 및 분리장치개발

(하수고도화 및 슬러지처리 중심으로)

Ⅱ. 연구개발의 목적 및 필요성

생활수준 향상 및 환경문제에 대한 관심이 높아지면서 환경질 개선에 관한 요구의 증

가로 대도시 지역뿐만 아니라 중·소도시에서도 하수도 정비(하수처리시설 및 하수관거

정비)가 활발히 진행되고 있으며, 2006년 2월 현재 하수도 보급률이 선진국 수준인

83%로 금년내 85% 까지 증가시킬 계획이다. 이에 따라서 현재 우리나라 전체에서 발

생하는 슬러지는 2003년 연간 227만톤으로, 하수처리시설 정비 및 산업발전에 의하여

계속적으로 증가될 것으로 예측되고 있다.

하수슬러지의 처리는 매립에 의존하여 왔으나, 1993년도부터 슬러지의 해양배출이

시작되면서 직매립 금지조항이 설정된 초기인 2000년도부터 해양배출량이 급격히 증가

되어 최근에는 발생되는 슬러지의 70% 이상이 해양배출에 의존하고 있다. 육상에서의

처리·처분 및 자원화를 유도하기 위하여 시행된 직매립금지 조치가 해양배출로 집중되

는 현상이 관찰되고 있는 것이다. 그러나 하수슬러지의 해양배출은 런던덤핑협약과 관

련된 96의정서가 2006년 발효되었고, 이에 따라 해양배출 기준이 단계별로 강화되고

2012년부터 하수슬러지 등의 해양배출을 전면 금지하는 법안을 입법화 하고 있어, 이에

대한 근본적인 대책이 필요하다.

그러나 소각, 건조, 퇴비화, 고형화, 탄화 등의 슬러지 자원화 기술은 해양배출보다 많

은 운영비를 지출해야 하고 악취, 대기오염 등의 2차 오염 방지, 자원화 기술에 대한 신

뢰성, 자원화 산물의 질적 확보를 위해서는 탈수슬러지의 성상이 매우 중요하다. 그러

- 4 -

나 일반적으로 슬러지의 성상별 상관성을 검토해보면, 유기물의 함량이 높을수록 탈수

케이크의 함수율이 높아 재활용기술을 적용하기에 어려운 문제점들이 있다 따라서 슬

러지의 안정화와 감량화 기술의 적용을 통해 슬러지 재활용 산물의 경제성을 확보하고

자원화 산물의 질을 향상시켜야 할 것이다.

Ⅲ. 연구개발의 내용 및 범위

본 연구에서 개발할 슬러지 처리 공정은 1차 슬러지, 2차 슬러지의 농축을 유도하여

MLSS의 농도를 증가시키는 고액분리장치, 오존의 접촉효율을 높여 경제적 소독 및 슬

러지 전처리 용도의 오존 접촉조, 유체유동인 PFR 형태의 반응기 구조로 고농도 폐수

및 슬러지의 감량화를 효과적으로 하기 위한 호기성 생물 반응기를 통해서 통합 슬러지

처리 공정을 개발하여 슬러지 감량화를 통해 슬러지 처리의 경제성을 확보하고, 아울러

슬러지 처리계통에서 발생하는 반류수의 영향을 최소화 시켜 하수처리장 수처리 계통

의 효율을 높이는 것이다.

1. 유체유동을 이용한 생물반응기 개발

▸ 고농도 오·폐수의 고효율 처리가 가능한 생물반응기 개발 ▸ 처리효율이 높은 PFR 형태의 다단 반응기 구조 ▸ 고농도 미생물 및 활성 유지 ▸ 유체유동에 의한 혼합효과와 높은 산소전달효율

2. 슬러지 농축장치 개발

▸ 스컴, 플록을 배제하고 상등수 인출(상등수의 SS유출 최대한 억제) ▸ 저류조/농축조내 슬러지계면을 최대한 높게 하여 슬러지 농축 및 상등수 배출 ▸ 공기주입 및 배출에 의한 상등수를 유출시키는 부상 또는 고정식 장치 개발 ▸ 회분식 농축을 통해 활성슬러지 2배 이상 농축 ▸ 표면장력을 이용한 표면적 배출로 상승유속 최소화

- 5 -

3. 오존접촉장치 개발

▸ 오존 용해속도를 극대화시킬 수 있는 슬러지 전처리용 오존 접촉조 개발 ▸ 혼합효과 촉진에 의한 소량의 오존 주입에 의한 전처리 ▸ NaOH 등 화학적 전처리에 의한 경제성 비교 ▸ 오존체류시간 조정에 의한 짧은 시간에 오존 용해

4. 슬러지의 호기성 소화

▸ 슬러지의 호기성 처리시간 4～5일 이내 슬러지 조기안정화 유도 ▸ 슬러지의 최종 처분방식을 복토제 등 자연순환형으로 검토할 수 있을 정도의 슬러

지 안정화 지표에 맞추어 슬러지 처리

▸ 슬러지 농축 및 탈수성 향상 ▸ 반응기의 높은 산소전달율(25% 이상)로 인한 포기시 동력비 절감 ▸ 반류수 중의 질소 제거로 수처리 계통의 고도화

Ⅳ. 연구개발결과

슬러지의 호기성 소화 및 반류수 내 질소·인의 제거를 통한 하수고도화를 위한 단위

기술의 개발 및 ER-1 반응기를 이용한 슬러지 호기성소화 공정을 개발하였으며 이에

대한 연구결과는 다음과 같다.

1. 유체유동을 이용한 생물반응기 개발

▸ 충분한 미생물 확보와 높은 산소전달효율을 갖는 고농도 페수처리용 생물반응기 개발

▸ 일반반응조의 CSTR 형태에서 벗어나 처리효율이 높은 PFR 형태의 다단 반응기 구조

▸ 고농도 미생물 유지 및 활성(MLSS 20,000mg/L 이상) ▸ 반응기 각단에 기체 체류공간을 확보하여 유체유동에 의한 혼합효과와 높은 산소

전달효율(산소전달율 25～40% )

▸ 고농도 음식물 폐수 및 축산폐수의 처리를 통해 BOD 99%의 제거효율

- 6 -

2. 슬러지 농축장치 개발

▸ 스컴을 배제하고 상등수 인출할 수 있는 구조의 농축장치(디켄터) 개발 ▸ 농축조내 슬러지계면을 최대한 높게 하여 슬러지 농축 및 상등수 배출

(배출구와 슬러지계면 간의 거리 10～20cm)

▸ 회분식 농축(활성슬러지 2배 이상 농축, TS 20,000 mg/L 이상) ▸ 표면장력을 이용한 표면적 배출로 상승유속 최소화 ▸ 디켄터 적용시 침전조 또는 농축조를 30% 이상 활용 효과 증대

3. 오존접촉장치 개발

▸ 오존 용해속도를 극대화시킬 수 있는 슬러지 전처리용 오존 접촉조 개발 ▸ 혼합효과 촉진에 의한 소량의 오존 주입에 의한 전처리 ▸ 오존체류시간 조정에 의한 짧은 시간에 오존 용해(3분 이내) ▸ 하수소독에 적용시 기존 오존접촉장치에 비해 오존량 약 2.5배,

접촉조 용적은 4배 이상 감소

▸ 하수슬러지 전처리 장치로 활용시 오존주입량 0.3gO3/MLVSS일때 1,739% 가용화

4. 슬러지의 호기성 소화

▸ 슬러지의 호기성 처리시간 4일 이내 TS 60%, 슬러지부피 70% 이상 감량화 ▸ 호기성 소화 후 유출수내 VS 함량 40～45%로 안정화 ▸ 반응기의 높은 산소전달율(25% 이상)로 인한 포기시 동력비 절감

(산소전달율 이외에 통기저항이 1/2～1/3 수준 이하)

▸ 소화슬러지의 농축효율 및 탈수성 향상 ▸ 슬러지의 최종 처분방식을 복토제 등 자연순환형으로 검토할 수 있을 정도의 슬러

지 안정화 지표에 맞추어 슬러지 처리

▸ 반류수 중의 질소 제거로 수처리 계통의 고도화 ▸ 슬러지 감량화 기술 적용 전과 비교시 슬러지 처리 비용의 46% 절감

- 7 -

Ⅴ. 연구개발결과의 활용계획

ER-1 반응기를 이용한 호기성소화 기술의 핵심은 생물반응기를 프로그 흐름(PFR)으

로 구성하여 고농도 오폐수의 호기성 처리에서 부족되기 쉬운 산소공급충족, 빠른 물질

분해속도 유도, 고도처리 문제를 동시에 해결한 것이다. 본 연구에 의해 개발된 고효율

호기성 생물반응기 ER-1은 그 기술의 우수성을 인정받아 신기술인증(NET 제K055호,

과학기술부), 신제품인증(NEP-2004-21, 산업자원부), 및 조달청 우수제품인증(제

2005068호, 조달청)을 받은 바 있다. 또한 하수슬러지의 호기성소화 및 대표적인 고농도

오·폐수인 음식물 폐수와 축산폐수 분야에 적용하여 처리효율 및 경제성을 확보하였다.

이러한 연구 성과를 확대하여 보다 다양한 분야에 적용할 계획에 있으며, 적용 가능한

분야를 세분화하면 다음과 같다.

▸ 하수슬러지의 호기성소화에 의한 감량화 및 안정화 ▸ 하수슬러지 혐기성소화조 개선 ▸ 음식물 자원화 시설에서 발생하는 폐수 처리시설 ▸ 축산폐수처리시설 ▸ 식품폐수 등 기타 고농도 폐수처리시설

이 중 음식물폐수 처리기술은 아직까지 처리기술이 확립되지 않은 분야이며, ER-1

반응기를 이용한 효율분석을 통해 그 가능성을 확인한 바 있다.

2005년부터 음식물 직매립이 금지되면서 음식물의 재활용이 필수적인 화두로 대두되

었다. 그러나 지금까지 음식물의 재활용은 퇴비화, 사료화, 탄화, 소각, 감압증발, 혐기성

소화 등 고형물처리 위주의 공법이 주류를 이루고 각각의 처리공정의 부산물로 나타나

는 침출수, 탈리액 등의 폐수처리 부분에 대해서는 특별한 대안이 없이 대부분 해양배

출에 의존하고 있다. 따라서 현장화를 통해서 안정된 음식물 침출수처리를 입증하는 과

정은 매우 시급하고 중요한 사안이라고 할 수 있다. 따라서 음식물 폐수처리는 하수 슬

러지와 시기적으로 환경정책과 연계성이 매우 높은 과제라고 할 수 있다.

- 8 -

♦ 환경부, 해양수산부의 음식물 침출수 해양배출 억제 대책과 일치

♦ 축산분뇨, 하수슬러지 등 고농도 폐수 처리 해법의 제시

♦ 총량규제의 대응에 적합(높은 제거된 오염물질의 부하량/비용)

따라서 지금까지 3차년에 걸쳐 연구한 본 실용화 연구 결과와 연계하여 실증화 사업

으로 음식물 폐수에 대한 실증화 사업으로 활용 범위를 넓혀 보고자 한다. 그 필요성을

구체적으로 보면 아래와 같다.

▸ 본 장치가 대형화되었을 때 음식물 폐수와 같이 유입수에 높은 SS가 함유되는 경우, SS의 침전에 의한 MLSS 활성저하 효과 실험 및 확인이 필요함

▸ 유입수의 상태변화(하절기 지나친 pH 저하, 계절별 부하량의 변화 등)에 대응하는 고농도 전용 공정 개발이 필요함

▸ 고농도 유입수에서 견딜 수 있는 운전모드 확인이 필요함

▸ 하수슬러지의 경우 많은 실험을 통해서 더 이상의 실증화실험이 요구되지 않으며, 대형장치의 경우 음식물 침출수처리 자료를 활용할 수 있음

▸ 실증화사업의 취지인 “공정의 최적화”, “규모의 확장” “주변기술의 확보”를 동시에 충족시킬 수 있음

- 9 -

S U M M A R Y

Ⅰ. Title

Development of sewage/wastewater degradation and separation plant using a

fluid fluctuation(Focused on the sewage advanced treatment and sludge treatment)

Ⅱ. Purpose and Necessity

The purpose of this research is to develop an aerobic digestion process for sludge

reduction which minimize an side stream wastewater effect.

▸ Excess sludge resulting from municipal and industrial wastewater treatment is becoming a serious issue owing to prohibition disposal land and ocean dumping.

▸ But, there is no a suitable process to sludge treatment instead of incinerating, drying, composting and solidification process.

▸ A considerable part of the sludge from large scale wastewater plant is treated anaerobic digestion process. Aerobic digestion is to ask lower power

consumption for aeration. Because anaerobic digestion is to appear a low

treatment efficiency.

Ⅲ. Research Contents and Scope

1. Development of Bioreactor using Fluid fluctuation

▸ Development of high efficiency bioreactor for high concentration wastewater ▸ Multi stage and PFR structure ▸ High concentration biomass and activity

- 10 -

▸ Mixing effect and oxygen efficiency by fluid fluctuation

2. Sludge Separated and Concentration system

▸ Supernatant outflow without scum and floc ▸ Keep up maximum sludge level of sludge thickener and settling tank ▸ Floating and fixed type ▸ Batch thickening ▸ Minimum sludge rising velocity using surface tension

3. Development of Ozone Contactor

▸ Development of ozonecontactor for high ozone soluble rate ▸ High efficiency pretreatment for a small quantity of ozone by promote of

mixing

▸ Economic evaluation in comparison with chemical(NaOH) pretreatment ▸ Short time of ozonization by control of ozone retention time

4. Sludge Aerobic Digestion

▸ Short period sludge stabilization, aerobic digestion time within 4～5 day ▸ Improvement of thickening and dewaterability ▸ Reduce of power cost by high oxygen transfer rate ▸ Removing nitrogen and phosphorus in the side stream wastewater

Ⅳ. Results

1. Development of Bioreactor using Fluid fluctuation

▸ Development of high efficiency bioreactor(ER-1) with the enough biomass(more than MLVSS 20,000mg/L) and high oxygen transfer rate(more

than 25%).

▸ Bioreactor composed of multi-stage upflow PFR structure. ▸ Gas Holdup space each section in Bioreactor has mixture effect and high

oxygen transfer rate(more than 25～40%) due to Fluid fluctuation.

- 11 -

▸ Also food wastewater and livestock wastewater removal efficiency of BOD 99%.

2. Sludge Separated and Concentration system

▸ Effluent of supernatant exclusive of scum and keep up maximum sludge level(under 10～20cm from the effluent point).

▸ Batch concentration(Concentrating more than double of general thickened sludge).

▸ Minimization of sludge overflow velocity by surface tension. ▸ The Decanter will increase above 30% application volume for settling tank or

sludge thickener.

3. Development of Ozone Contactor

▸ Development of ozone contact for the sludge pretreatment which has the ozone solubility increase 1,739% at 0.3gO3/MLVSS.

▸ Minimum inject ozone for a pretreatment due to a promotion of mixture effective.

▸ Ozone solution time less than 3 minutes by the gas holdup. ▸ In sewage disinfecting, it compares in generation reactor, In comparison of

generation reactor, this reactor decreases to 2.5 times.

4. Sludge Aerobic Digestion

▸ Aerobic digestion time within 4day, reduce the sludge TS 60% and cake volume 70%.

▸ After aerobic digestion VS ratio less than 40～45%(stabilization). ▸ Other than oxygen transfer rate, ventilation resistance below 1/2～1/3 of

general diffuser.

▸ Improvement of Thickening Characteristics and Dewatering ability ▸ Nitrogen and phosphorus removal efficiency 60～70% in the side stream

wastewater

- 12 -

▸ 46% save in expenditures of sludge cake Disposal comparison with Before applying the sludge aerobic digestion.

Ⅴ. Application Plans

The aerobic digestion process using ER-1 is focused on PFR flow. Which

simultaneously solves oxygen supply for high concentration treatment, high speed

mass transfer velocity and nutrients removal.

ER-1 which developed in research of EcoDays Ltd. demonstrate the superiority of

technical power and receives New Excellent Product(NEP-2004-021, Ministry of

Commerce, Industry and Energy), New Excellent Technology(NET-K055, Ministry

of Science and Technology) and Excellent Product(2005068, Public Procurement

Service). Also it applied in the food wastewater and livestock wastewater where the

representative of high concentration wastewater.

This research result will apply in the field which is various and application as

follows.

▸ Reduction of solid and stabilization by aerobic digestion of sewage sludge

▸ Improvement of the existing sludge digestion facilities(usually anaerobic)

▸ Food wastewater, livestock wastewater and other high concentration wastewater treatment plant

- 13 -

- 14 -

C O N T E N T S

Chapter 1. Introduction

Section 1. Background and Necessity ·············································································· 31

Section 2. Objectives and Scopes ····················································································· 33

Chapter 2. Current State of Technology Development

Section 1. Status of Internal and External Technologies ·········································· 40

1. Statues of Domestic Technologies ··········································································· 40

2. Foreign Domestic Technologies ················································································ 45

Section 2. Sewage Sludge Digestion ················································································ 51

1. Classification of Sludge Treatment ·········································································· 51

2. Biological Digestion ······································································································ 54

3. Chemical Sludge Treatment ······················································································· 59

4. Mechanical Sludge Treatment ··················································································· 61

Section 3. Reuse of Sludge ································································································· 64

1. Composting ····················································································································· 64

2. Solidification and Alkaline Stabilization ·································································· 68

3. Vermicomposting ··········································································································· 70

Chapter 3. Research Contents and Results

Section 1. Development of Bioreactor using Fluid fluctuation ································· 72

1. Background ····················································································································· 72

2. Method and Results ····································································································· 91

- 15 -

Section 2. Sludge Separated and Concentration system ·················································· 149

1. Theory of Separation ································································································· 149

2. Development of Sludge Thickening Devices ······················································· 156

Section 3. Ozone Contactor ······························································································· 174

1. Theory of Ozonation ·································································································· 174

2. Development of Ozone Contactor ··········································································· 188

Section 4. Sludge Aerobic Digestion and Sewage Advanced ································· 202

1. Background ··················································································································· 202

2. Method and Results ··································································································· 219

3. Aerobic Digestion Efficiency and Economic evaluation using ER-1 ··········· 278

Section 5. Results ················································································································ 285

1. Development of Bioreactor using Fluid fluctuation ··········································· 285

2. Sludge Separated and Concentration system ····························································· 288

3. Development of Ozone Contactor ··········································································· 289

4. Sludge Aerobic Digestion ························································································· 290

Chapter 4. Goal Achievement and Contributions

Section 1. Achievement of Research Development ···················································· 295

Section 2. Extenrnal Contributions ················································································· 298

Chapter 5. Applicaion of Research Results ················································· 305

Chapter 6. Reference ····································································································· 309

- 16 -

目 次

제 1 장 서론

제 1 절 연구개발의 필요성 ··································································································· 31

제 2 절 연구개발 목표 및 내용 ··························································································· 33

1. 연구개발의 최종목표 ·········································································································· 33

가. 유체유동을 이용한 생물반응기 개발 ········································································ 33

나. 슬러지 농축장치 개발 ·································································································· 33

다. 오존접촉장치 개발 ········································································································ 34

라. 슬러지의 호기성 소화 ·································································································· 34

2. 연차별 연구개발목표 및 내용 ·························································································· 35

가. 단계별 연구개발 목표 및 범위 ·················································································· 35

나. 각 단계 연차별 연구개발 목표 ·················································································· 36

다. 각 단계 연차별 연구개발 내용 및 범위 ·································································· 37

제 2 장 국내외 기술개발 현황

제 1 절 국내외 하수슬러지 처리현황 ················································································ 40

1. 국내 하수슬러지 발생 및 처리현황 ················································································ 40

2. 국외 하수슬러지 발생 및 처리현황 ················································································ 45

- 17 -

제 2 절 하수슬러지 감량화기술 ··························································································· 51

1. 슬러지 처리 • 처분방법의 분류 ························································································ 51

2. 생물학적 처리에 의한 감량화 기술 ················································································ 54

3. 화학적 처리에 의한 감량화 기술 ···················································································· 59

4. 물리적 처리에 의한 감량화 기술 ···················································································· 61

제 3 절 하수슬러지 자원화기술 ··························································································· 64

1. 퇴비화 ···································································································································· 64

2. 고화 및 고형화 ···················································································································· 68

3. 지렁이 분변토 재활용기술 ································································································ 70

제 3 장 연구개발 수행 내용 및 결과

제 1 절 유체유동을 이용한 생물반응기 개발 ·································································· 72

1. 이론연구 ································································································································ 72

가. 생물학적 처리기술의 일반이론 ·················································································· 72

나. 반응기 흐름에 의한 특징 ···························································································· 76

다. 유체유동 적용 반응기 해석 ························································································ 82

2. 실험방법 및 결과 ················································································································ 91

가. 유체유동을 이용한 생물반응기의 개발 ···································································· 91

(1) 반응기의 구조 및 특성 ···························································································· 91

(2) 추적자(Tracer) Test를 통한 반응기의 유체 흐름 특성 실험 ························ 97

(3) 반응기 각단 추가에 따른 특성 실험 ·································································· 100

- 18 -

(4) 산소전달효율(KLa)의 측정 ··················································································· 105

(5) 반응기내 미세기포 측정 ························································································ 110

(6) OUR(Oxygen Uptake Rate) Test ······································································ 115

(7) ER-1의 운전시 진동측정 ······················································································ 120

(8) 전산모사를 통한 ER-1 반응기의 유체유동 해석 ············································ 127

나. ER-1 반응기의 고농도 오·폐수 분해효율 ······························································· 133

(1) ER-1을 이용한 축산폐수처리 ·············································································· 133

(2) ER-1을 이용한 음식물 폐수 처리 ······································································ 141

제 2 절 고형물 분리장치의 개발 ······················································································· 149

1. 여과이론 ······························································································································ 149

가. 분리막 여과 ·················································································································· 150

나. 분리막의 특성 비교 ···································································································· 155

2. 슬러지 농축장치 개발 ······································································································ 156

가. 분리막을 이용한 고형물 제거장치 개발 ································································ 156

(1) ES 반응기의 금속망을 이용한 고액분리 실험결과 ········································ 162

(2) 평막을 이용한 일반 MBR과 ES의 비교 실험결과 ········································· 164

나. 상등수 배출장치의 개발 ···························································································· 168

제 3 절 오존접촉장치의 개발 ····························································································· 174

1. 오존산화이론 ······················································································································ 174

가. 오존의 분해 메카니즘 ································································································ 177

나. 오존의 물에 대한 용해성 ·························································································· 180

- 19 -

다. 오존의 응용 ·················································································································· 184

2. 오존접촉반응장치 ·············································································································· 188

가. 실험 장치 개요 ············································································································ 190

나. 실증 pilot test를 통한 반응기 설계 ········································································ 191

다. 오존량에 따른 처리성능 최적화 실험 ···································································· 192

라. 실 험 결 과 ·················································································································· 194

(1) 오존주입률에 따른 처리성능 비교 결과 ···························································· 194

(2) ER-2 연속운전 결과 ······························································································ 196

(3) 초과유입수 및 초기강우의 오존처리공정의 적용성 실험 결과 ···················· 200

제 4 절 슬러지 호기성소화 및 하수고도화 기술 개발 ··············································· 202

1. 이론연구 ······························································································································ 202

가. 하수슬러지 물리화학적 성상 ···················································································· 204

나. 슬러지의 호기성 소화 ································································································ 213

2. 실험방법 및 결과 ·············································································································· 219

가. 슬러지의 전처리를 통한 가용화 ·············································································· 219

(1) 오존을 이용한 슬러지 전처리 실험 방법 ·························································· 219

(2) 알칼리 전처리 실험 ································································································ 226

(3) 전처리 효율 및 경제성 평가 ················································································ 229

나. ER-1 반응기를 이용한 호기성소화 ········································································ 231

(1) 1차슬러지(생슬러지)의 호기성 소화 실험 ······················································· 231

(2) 잉여슬러지와 생슬러지를 이용한 호기성소화 ·················································· 238

(3) 회분식 호기성 소화 실험 ······················································································ 240

- 20 -

(4) 연속 호기성 소화 실험 ·························································································· 253

(5) 혐기성 소화액 대상 호기성소화 ·········································································· 263

다. 슬러지 최종 처분 방법 ······························································································ 273

(1) ER-1을 이용한 소화 슬러지의 지렁이 퇴비화 가능성 검토 ························ 273

(2) 지렁이 퇴비화 적용을 위한 슬러지의 전처리 ················································ 274

(3) 지렁이 입식 및 조사 ······························································································ 274

3. ER-1을 이용한 호기성 소화 공정의 감량화 효율 및 경제성 검토 ······················ 278

가. 혐기성소화 기술 ·········································································································· 278

나. ER-1을 이용한 호기성소화 공정의 특징 ······························································ 278

다. ER-1 반응기를 이용한 슬러지 감량화 경제성 검토 ·········································· 279

제 5 절 결론 ···························································································································· 285

1. 유체유동을 이용한 생물반응기 개발 ············································································ 285

2. 슬러지 농축장치 개발 ······································································································ 288

3. 오존접촉장치 개발 ············································································································ 289

4. 슬러지의 호기성 소화 ······································································································ 290

5. 설계인자도출 ······················································································································ 292

제 4 장 목표 달성도 및 관련분야에의 기여도

제 1 절 연구개발목표의 달성도 ························································································· 295

제 2 절 대외기여도 ················································································································ 298

- 21 -

1. 신기술 및 신제품 인증 ···································································································· 298

2. 특허 및 실용신안등록 ······································································································ 299

3. 학회 및 세미나 발표 실적 ······························································································ 299

4. 기타사항 ······························································································································ 301

제 5 장 연구개발결과의 활용계획

연구개발결과의 활용계획 ··································································································· 305

제 6 장 참고문헌

참고문헌 ································································································································· 309

부록1. 연구관련 데이타

- 22 -

그 림 목 차

Fig. 1-1. 연도별 슬러지 발생량 추이 ·············································································· 31

Fig. 2-1 전국 하수슬러지 발생 및 처리 현황 ······························································· 42

Fig. 2-2. 표준활성슬러지법의 처리공정 ·········································································· 51

Fig. 2-3. 슬러지 감량화 기술의 종류 ·············································································· 52

Fig. 2-4. 혐기성소화에 의한 유기물의 분해단계 ·························································· 54

Fig. 2-5. 온도변화에 따른 가스생성량의 상대속도 ······················································ 55

Fig. 2-6. 초음파 처리를 이용한 슬러지 저감화 기술 ·················································· 62

Fig. 2-7. 볼밀파쇄기의 구조 ······························································································ 63

Fig. 2-8. 볼충진율이 가용화율에 미치는 영향 ······························································ 63

Fig. 3-1 활성 슬러지 공정의 예 ····················································································· 73

Fig. 3-2. CSTR 반응조 ······································································································· 76

Fig. 3-3. PFR 반응조 ·········································································································· 78

Fig. 3-4. 1차 반응에서 체류시간에 따른 CSTR/PFR의 비율 ··································· 82

Fig. 3-5 수중에서 기/액면 의 Two-film theory ························································ 84

Fig. 3-6. 수면에서 surface film형성의 모식도 ······························································ 86

Fig. 3-7. 실험에 사용된 고효율 호기성 생물반응기(ER-1) ······································· 92

Fig. 3-8. ER-1의 공기공급에 의한 유체이동 반응 ······················································ 92

Fig. 3-9. 일반반응기 GR와 ER-1 반응기에서 유체의 흐름 형태 비교 ·············· 94

Fig. 3-10. ER-1(Type A, B)의 체류시간에 따른 전기전도도의 변화 ····················· 99

Fig. 3-11. ER-1(Type C)의 체류시간에 따른 전기전도도의 변화 ··························· 99

Fig. 3-12 ER-1(Type C)의 각 단별 유기물, DO, MLVSS 분포도 ····················· 100

Fig. 3-13. 반응기 산소전달 효율측정을 위한 실험 장치 ·········································· 101

Fig. 3-14. 유체이동관수의 시간에 따른 DO 농도 변화 ·········································· 102

Fig. 3-15. 유체이동관 1단 설치시 용해속도 ································································ 103

Fig. 3-16. 유체이동관 1 • 2단 설치시 용해속도 ·························································· 103

Fig. 3-17. 유체이동관 1 • 2 • 3단 설치시 용해속도 ···················································· 104

Fig. 3-18. ER-1반응기 및 산소전달율 실험 ···························································· 106

- 23 -

Fig. 3-19. 공기 주입량에 따른 ER-1 용존산소 농도 변화 ······································ 109

Fig. 3-20. B구간에서의 총괄물질전달계수(KLa) ························································· 109

Fig. 3-21. 미세기포 측정 장치의 구성 ·········································································· 111

Fig. 3-22. 현미경에 의해 측정된 미세기포 사진 ························································ 112

Fig. 3-23. 현미경에 의해 측정된 미세기포 사진(5×7mm) ······································· 112

Fig. 3-24. 반응기내 미세기포의 크기별 분포도 ·························································· 114

Fig. 3-25. 반응기내 상/하단의 기포형태 사진 ···························································· 114

Fig. 3-26. 기질소모와 성장에 따른 호흡율의 관계 모식도 ······································ 116

Fig. 3-28. ER-1 반응기내 슬러지의 OUR 측정을 위한 장치도 ····························· 117

Fig. 3-28. F/M비에 따른 OUR값의 변화. ···································································· 119

Fig. 3-29. 진동 측정에 사용된 ER-1 실제 사진 ························································ 120

Fig. 3-30. ER-1의 측면(A,B,C,D)의 구조 ···································································· 121

Fig. 3-31. A면 높이에 따른 진동의 변화(36개 지점) ················································ 124

Fig. 3-32. C면 높이에 따른 진동의 변화(36개 지점) ················································ 124

Fig. 3-33. 반응기 전체 높이에 따른 평균 진동값의 변화(93개 지점) ··················· 125

Fig. 3-34. ER-1 반응기 원형 방향에 따른

진동 측정 지점 및 반응기 부착물 위치 ······················································ 126

Fig. 3-35. ER-1 반응기 원형 방향에 따른 진동 측정 ·············································· 126

Fig. 3-36. 유체유동 해석에 사용된 ER-1의 개략도 ·················································· 130

Fig. 3-37. Distribution of velocity contour. ································································ 130

Fig. 3-38. Distributions of velocity vectors. ······························································· 132

Fig. 3-39. 일반적인 분뇨 및 축산폐수 처리방법 ························································ 135

Fig. 3-40. ER-1을 이용한 축산폐수 처리공정 ···························································· 136

Fig. 3-41. ER-1을 이용한 축산폐수 Batch Test 결과 ············································· 137

Fig. 3-42. 공정별 축산폐수 처리 효율 ·········································································· 137

Fig. 3-43. 음식물 폐수 처리 공정도 ·············································································· 142

Fig. 3-44. 음식물 폐수 처리 Pilot Plant 전경 ···························································· 142

Fig. 3-45. 음식물 폐수의 BOD 제거효율 ····································································· 144

Fig. 3-46. 음식물 폐수의 T-N 제거효율 ····································································· 144

Fig. 3-47. 음식물 폐수의 T-P 제거효율 ······································································ 145

- 24 -

Fig. 3-48. 음식물 폐수 처리 결과 ·················································································· 145

Fig. 3-49. 음식물 폐수 처리 공정별 상태 사진 ·························································· 146

Fig. 3-50. Membrane Processes for liquid separation ············································· 150

Fig. 3-51. 일반적인 막의 구조 ························································································ 153

Fig. 3-52. ES의 유체 흐름 ······························································································· 157

Fig. 3-53. ES의 투과압력의 변화 ··················································································· 158

Fig. 3-54. ES의 내부 구조 변화 ····················································································· 161

Fig. 3-55. ES의 운전 후 내부 막오염 현상 ································································· 162

Fig. 3-56. 시간에 따른 Flux 변화 ·················································································· 153

Fig. 3-57. 막 지지대로 인한 표면적 감소 ···································································· 153

Fig. 3-58. 유체의 흐름 형태 ···························································································· 166

Fig. 3-59. 평막과 MBR system과 ES system의 사진 ············································· 166

Fig. 3-60. MBR system과 ES system 연속운전에 따른 차압의 변화 ················· 167

Fig. 3-61. G 하수 처리장 슬러지 처리 공정 ······························································· 170

Fig. 3-62. 표면장력을 이용한 상등수 배출장치 ·························································· 171

Fig. 3-63. 표면장력을 이용한 상등수 배출장치의 개략도 ········································ 171

Fig. 3-64. 디켄터를 이용한 2차 슬러지의 농축 ·························································· 173

Fig. 3-65. 디켄터로 배출되는 상등수의 TS 농도 ······················································ 173

Fig. 3-66. 오존분자의 구조 ······························································································ 174

Fig. 3-67. 오존 분해 메카니즘 ························································································ 177

Fig. 3-68. 오존 접촉 용해방식 ························································································ 189

Fig. 3-69. 오존유량에 따른 오존량 및 농도 변화 ······················································ 190

Fig. 3-70. ER-2 장치의 내부 구조 ················································································ 191

Fig. 3-71. ER-2 장치의 오존 주입률에 따른 대장균군의 처리효율 ······················ 195

Fig. 3-72. 오존처리 전 • 후 사진 ···················································································· 195

Fig. 3-73. ER-2 장치의 연속운전에 대장균군의 처리효율 ······································ 196

Fig. 3-74. ER-2 장치의 연속운전에 CODCr의 처리효율 ········································· 197

Fig. 3-75. ER-2 장치의 SS의 처리효율 ······································································· 197

Fig. 3-76. 오존주입률에 따른 1차 침전조 월류수의 CODMn 농도 변화 ············· 201

Fig. 3-77. 오존처리 후 활성탄 여과 처리효율 ···························································· 201

- 25 -

Fig. 3-78. Schematic representation of the activated sludge floc

on an arbitrary scale of size. ····································································· 211

Fig. 3-79. 세포소기관으로서의 기체물질이동경로에 대한 도식적 모형 ················ 216

Fig. 3-80. 오존을 이용한 슬러지 전처리에 실험 장치 구성도 ································ 220

Fig. 3-81. 슬러지 g당 오존주입량에 따른 가용화율 그래프 ···································· 222

Fig. 3-82. 오존주입량에 따른 BOD변화 ······································································· 222

Fig. 3-83. 오존주입량에 따른 TSS, VSS변화 ···························································· 223

Fig. 3-84. 오존주입량에 따른 T-N, T-P변화 ····························································· 223

Fig. 3-85. 오존주입량에 따른 pH, 전기전도도 경향 ·················································· 224

Fig. 3-86. 오존주입량에 따른 슬러지의 침강성과 탈수성 ········································ 224

Fig. 3-87. 오존주입량에 따른 슬러지 색도변화 ·························································· 225

Fig. 3-88. 오존접촉반응기 배오존가스 농도 측정 ······················································ 225

Fig. 3-89. 시간에 따른 pH와 용해율의 변화 ······························································· 226

Fig. 3-90. NaOH 주입량에 따른 용해율과 pH ··························································· 228

Fig. 3-91. 시간에 따른 NaOH 주입량 별 가용화율의 변화 ····································· 228

Fig. 3-92. 생슬러지의 TS와 VSS ·················································································· 233

Fig. 3-93. 생슬러지와 ER-1 내의 pH 변화 ································································· 233

Fig. 3-91. ER-1반응기 하단과 상단의 MLSS, MLVSS, MLFSS변화 ················ 234

Fig. 3-92. 유입 생슬러지 와 처리수의 CODcr ···························································· 234

Fig. 3-96. 원수(생슬러지)와 처리수의 NaOH처리 후의 SCODcr 변화 ················· 237

Fig. 3-97. ER-1을 이용한 슬러지 호기성 소화 실험 장치구성도 ·························· 239

Fig. 3-98. 잉여슬러지 회분식 호기성 소화 실험

(시간에 따른 유기물 농도 변화) ··································································· 241

Fig. 3-99. 잉여슬러지 회분식 호기성 소화 실험

(시간에 따른 고형물량의 변화) ····································································· 242

Fig. 3-100. 잉여슬러지 회분식 호기성 소화 실험

(시간에 따른 질소 계열 농도 변화) ····························································· 242

Fig. 3-101. ER-1 반응기 내 각단별 시간에 따른 OUR 비교 ································· 244

Fig. 3-102. ER-1 반응기 내 각단별 시간에 따른 OUR 평균 값 ··························· 244

- 26 -

Fig. 3-103. 1·2차 혼합 슬러지 회분식 호기성 소화 실험

(시간에 따른 고형물의 농도 변화) ······························································· 246

Fig. 3-104. 1·2차 혼합 슬러지 회분식 호기성 소화 실험

(시간에 따른 TCODcr 농도 변화) ································································ 247

Fig. 3-105. 1.2차 혼합 슬러지 회분식 호기성 소화 실험

(시간에 따른 SCODcr 농도 변화) ································································ 247

Fig. 3-106. 호기성 소화 시 분해 가능한 VS과 t와의 관계 ····································· 249

Fig. 3-107. 회분식 호기성 소화시 유입슬러지 조건에 따른 VS 감소율 ·············· 250

Fig. 3-108. 회분식 호기성 소화시 유입슬러지 조건에 따른 SCODcr 감소율 ····· 250

Fig. 3-109. 2차슬러지와 혼합슬러지를 이용한

호기성 소화 슬러지의 탈수성 실험 ······························································ 252

Fig. 3-110. 원심분리를 이용한 혼합슬러지 호기성소화의 침강성 실험 ·············· 252

Fig. 3-111. ER-1을 이용한 호기성소화 연속처리시간에 따른 TS의 변화 ·········· 255

Fig. 3-112. ER-1을 이용한 연속처리시간에 따른 TCODcr의 변화 ······················· 255

Fig. 3-113. ER-1을 이용한 연속처리시간에 따른 SCODcr의 변화 ······················· 256

Fig. 3-114. 호기성소화 유입, 유출수 중의 TCODcr과 TS 비교 ···························· 256

Fig. 3-115. 호기성소화 유입, 유출수 중의 SCODcr과 TS 비교 ···························· 257

Fig. 3-116. 호기성소화 유입, 유출수 중의 VS와 TS ················································ 257

Fig. 3-117. 2차슬러지 대상 ER-1 유입, 유출슬러지 중의 VS와 TS ···················· 258

Fig. 3-118. 혼합슬러지 대상 ER-1 유입, 유출슬러지 중의 VS와 TS ·················· 258

Fig. 3-119. 호기성소화 연속실험시 유입슬러지 조건에 따른

고형물의 제거량 비교 ······················································································ 259

Fig. 3-120. 혼합슬러지 대상 호기성소화 슬러지의 질소농도 그래프 ···················· 261

Fig. 3-121. 혼합슬러지 대상 호기성소화 슬러지의 질소농도 그래프 ···················· 261

Fig. 3-122. 내부순환에 의한 유입/유출 슬러지의 pH 변화 ····································· 262

Fig. 3-123. 내부순환 운전방법 시 시간에 따른 ORP와 DO 농도 그래프 ············ 262

Fig. 3-124. Pilot Plant 시설 사진 ·················································································· 263

Fig. 3-125. 혐기성소화액(원수)와 ER-1 유출수(처리수)의 TS, VS 비교 ············ 266

Fig. 3-126. 혐기성소화액의 호기성소화 중 BOD의 제거효율 ································· 266

Fig. 3-127. 혐기성소화액의 호기성소화 중 질소의 성상 ·········································· 267

- 27 -

Fig. 3-128. 혐기성소화액의 호기성소화 중 T-P의 제거효율 ·································· 268

Fig. 3-129. 농축효율 비교(농축시간 12시간) ······························································· 269

Fig. 3-130. ER 반응기를 이용한 혐기성 소화액의 고형물 감량화율 ···················· 270

Fig. 3-131. 호기성 소화 후 슬러지 형상(×640) ·························································· 270

Fig. 3-132. ER 반응기를 이용한 혐기성 소화액의 TS 감량화 ······························· 272

Fig. 3-133. CST를 이용한 탈수성 실험 ······································································· 273

Fig. 3-134. 지렁이 40g을 입식하여 40일 후의 생체량 변화 ···································· 277

Fig. 3-135. ER-1을 이용한 호기성소화 공정도 ·························································· 279

Fig. 3-136. ER-1 반응기를 이용한 슬러지 감량화 기술 적용 후

탈수케이크 발생량 비교 ·················································································· 281

Fig. 3-137. Removal efficiency according to MLSS and HRT ····························· 286

- 28 -

표 목 차

Table 2-1. 전국하수처리장 하수처리량, 슬러지 발생량 ·················································· 41

Table 2-2. 처리공법별 슬러지 발생 비교 ··········································································· 41

Table 2-3. 하수슬러지의 재활용 현황 ················································································· 43

Table 2-4. 폐기물의 해양배출 기준 ····················································································· 44

Table 2-5. 미국의 하수슬러지 처리율(%) 변화 ································································ 45

Table 2-6. 미국 주요 도시의 슬러지 처리 • 처분 현황 ··················································· 46

Table 2-7. 미국의 하수슬러지 처리 현황, 1998년 기준 ·················································· 46

Table 2-8. 유럽 주요국가의 하수슬러지 발생량 및 처리현황 ······································· 47

Table 2-9. 영국의 하수슬러지 처분현황 및 처분계획 ····················································· 48

Table 2-10. 일본의 하수슬러지 처리 현황 ········································································· 49

Table 2-11. 하수슬러지의 유효이용사례 ············································································· 50

Table 2-12. 슬러지 소화시설 운영에 따른 장·단점 비교 ··············································· 53

Table 2-13. 농림부의 부산물비료의 종류 및 규격 ··························································· 66

Table 2-14. 부숙토의 원료기준 및 제품기준 ····································································· 67

Table 3-1. 공기와 물에서 동점성계수 ················································································· 87

Table. 3-2 일반산기식 생물학적 처리장치와의 비교 ······················································· 96

Table 3-3. 추적자 Test에 사용된 생물 반응기 사양 ······················································ 97

Table 3-4. 산소전달 특성 실험에 사용된 ER-1반응기의 사양 ··································· 106

Table 3-5. 미세기포 측정에 사용된 ER-1 반응기의 구성 ··········································· 111

Table 3-6. OUR test에 사용된 미생물과 기질 ······························································· 117

Table 3-7. OUR test시 F/M비 변화 ················································································· 119

Table 3-8. ER-1의 진동 측정 결과 ··················································································· 123

Table 3-9. Distribution of velocity and volume fraction for air. ····························· 131

Table 3-10. 축종별 오염물질 발생농도 ············································································· 134

Table 3-11. 음식물 폐수의 성상 ························································································· 141

Table 3-12. 음식물폐수 처리 효율 ····················································································· 146

- 29 -

Table 3-13. 하수종말처리시설의 설계·운영 및 연계 음식물 처리수 농도 ··············· 148

Table 3-14. 음식물 처리수의 연계처리를 가정하였을 때 운영수질변화 ··················· 148

Table 3-15. 음식물 처리수를 10～30m3/d의 규모로 연계처리시 운영수질변화 ······ 148

Table 3-16. MF막 소재별 분류와 그 특성 ······································································ 151

Table. 3-17. RO 공정에 영향을 미치는 주요 인자들 ···················································· 154

Table 3-18. RO, UF와 MF막의 특성 비교 ······································································ 155

Table 3-19. 반응기 설계 과정 ····························································································· 160

Table 3-20. 슬러지 농축 실험 결과 ··················································································· 172

Table 3-21. 오존의 물리 정수 ····························································································· 175

Table 3-22. 수처리에서 오존이용 ······················································································ 176

Table. 3-23. 오존과 염소의 소독력에 대한 상대적 비교 ·············································· 185

Table. 3-24. 미생물을 99% 살균하는데 소요된 오존의 농도와 접촉시간 ················ 185

Table 3-25. 대상시료 유입수 성상 ····················································································· 193

Table 3-26. 수질분석 방법 ·································································································· 193

Table 3-27. 슬러지 종류에 따른 특성 및 고형물 ··························································· 203

Table 3-28. Definition of four categories of water in sludge. ·································· 210

Table 3-29. Property of sludge used in this study. ···················································· 220

Table 3-30. 산업용 전기 전력량 요금계(1,000kW 이상) ·············································· 229

Table 3-31. 슬러지 호기성 처리 실험에 사용된

ER-1 반응기의 구성 및 실험 조건 ···························································· 232

Table 3-32. 기질로 사용된 생슬러지의 특성 ··································································· 232

Table 3-33. 2차년도 호기성 소화실험 진행 내용 ··························································· 238

Table 3-34. 슬러지 호기성 처리 실험에 사용된 ER-1의 구성 및 실험 ··················· 238

Table 3-35. 호기성 소화에 사용된 잉여슬러지의 성상 ················································· 240

Table 3-36. 호기성 소화에 사용된 1,2차 혼합 슬러지의 성상 ···································· 245

Table 3-37. 연속 호기성 소화실험 초기 유입 슬러지 조건 ········································· 253

Table 3-38. 적용대상 G시의 혐기성 소화액의 성상 ······················································ 264

Table. 3-39. 농축슬러지와 상등수의 성상 ········································································ 271

Table 3-40. 농축슬러지와 상등수의 성상(TS, FS, VS) ··············································· 272

Table 3-41. 하수슬러지의 이화학적 성상 ········································································· 276

- 30 -

Table 3-42. 지렁이 40g을 입식하여 40일 동안 처리속도와 처리량 ·························· 276

Table 3-43. 하수종말처리장 슬러지 및 탈수케이크 발생현황 ····································· 280

Table 3-44. ER-1을 이용한 슬러지 감량화 기술 적용 후 경제성 비교 ··················· 282

Table 3-45. 소화조 운영시 경제성 세부내역 비교 ························································· 283

Table 3-46. 소화조 미운영시 경제성 세부내