National Project Leading to the Recycling Society with Sewage Sludge in Japan - LOTUS Project - Yoshihiro MORISHIMA* Japan Institute of Wastewater Engineering Technology(JIWET) 1. Background The lack of sludge dumping sites, increasing cost for sludge recycling and the social demand for the reduction in the emission of green house effect gas have been getting challenging issues for each municipality. “Biomass Nippon Strategy” and the commitment to attain the goal of the Kyoto Protocol urge national government to encourage local governments to internalize the concept of recycling and the measures against global warming in their sewerage works in Japan. The Ministry of Land, Infrastructure and Transport (MLIT) decided to start a new research and development project named “LOTUS Project” (Lead to Outstanding Technology for Utilization of Sludge Project) in 2005. LOTUS project focuses on sludge processing technologies for practical and economical recycling and fuel use. 2. Outline of the Development Technology The development target of LOTUS project is placed on the cost, which has been the biggest barrier against the recycling of sewage sludge. Two numerical targets were presented. One target is called “Sludge Zero-Discharge (ZD)” and another is called “Green Sludge Energy (GE)”. ZD target is 16,000 (yen/t-dewatered sludge) or 8,000 (yen/t-incineration ash) for enabling to recycle all sewage sludge at a lower cost than its disposal. This numerical target was determined so that sludge recycling ratio may be lifted up to 80% on the basis of the comparison with the sludge dumping cost. GE target is 9.32 (yen/kWh) for enabling to generate power from sewage sludge

*Suido-cho Bldg. 7F. Suido-cho 3-1,Sinjuku-ku,Tokyo 162-0811 Japan

E-mail:h-hayashi@jiwet.or.jp

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and other biomass such as garbage at a lower cost than purchase power. This target was determined taking into account the average power prices for the sewage treatment plants in Japan. 7 groups of private companies participated in LOTUS project: 3 groups for each of ZD and GE targets and 1 group for both targets. Every group started the demonstration with pilot-scale test plant in 2005 and evaluation committee was established in Japan Institute of Wastewater Engineering Technologies, entrusted by the government. All technologies have accomplished their development targets, and this project finished in fiscal 2007.

Table 1 Outline of the ZD technology development

No Technological proposer Development technology name The technological outline

1 Hitachi Zosen Corporation Production of biosolid fuel from sewage sludge

The technology which produces fuel from the dehydration Sludge which occurs at a sewage-treatment plant and uses it as alternate fuel of coal. Produced fuel is the granular one of several millimeters of diameter by less than 10 % of water content.

2 METAWATER Co., Ltd. Gifu City

The technology for recovery of phosphorus from sewage sludge incineration ash

The technology which collects the phosphoric acid by adding alkaline solution to incineration ash and makes it a value-added fertilizer raw material as a liquefied fertilizer or calcium salt phosphate

3 Kawasaki Plant Systems, Ltd. Kimura Manufacturing Co., Ltd.

Composition of activated carbon from sewage sludge and reduction of the cost for sludge treatment by effective utilization

The technology which produces an activated carbon from the dehydration Sludge and uses it as a sludge dehydration auxiliary agent, a sludge reforming agent, an adsorbent for dioxin of a garbage incinerator

Table 2 Outline of the GE technology development

No Technological proposer Development technology name The technological outline

4 Tsukisima Kikai Co., Ltd.

Energy recovery from sewage sludge and biomass with synchronous digestion

The technology which accepts the biomass of the garbage from sewage-treatment plant outside, digests by a digestive tank as well as the sewage Sludge which became more soluble by ultrasonic treatment, makes the digestion gas emission rate increased and uses it for generation of electricity

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JFE Engineering Corporation. Daiki Ataka Engineering Co., Ltd. Kajima Corporation Dainen Co., Ltd.

The Development of the Anaerobic Co-digestion System for Power Generation with Low Running-cost

The technology which accepts the biomass of the garbage from sewage-treatment plant outside, digests by a digestive tank as well as sewage Sludge, makes the digestion gas emission rate increased and uses it for generation of electricity after the biological desulphurization.

6 Hitachi Plant Technologies, Ltd. Kurita Water Industries, Ltd.

Sludge reduction through accelerating digestion and electrical generating system using digestion gas

The technology which makes sludge volume reduction and the digestion gas amount increased by reforming refractory organics by ozone and uses digestion gas for generation of electricity.

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Table 3 Outline of the technology development for both ZD and GE

No Technological proposer Development technology name The technological outline

7 Kawasaki Plant Systems, Ltd.

Methan fermantation system of sewage sludge and raw garbage, and carbonization-activation for utilization

The technology which mixes organism waste of garbage and sewage sludge, makes methane fermented and uses collected methane gas for generation of electricity also produces activated carbon from the dehydration sludge which is a fermented residual and promotes recycling.

Tables 1, 2 and 3 show the outline of each development technology conducted in LOTUS project.

3. The way of development Figure 1 shows the way of development in LOTUS Project.

Start

Setting of the equipment performance value to achieve the target cost

Demonstration experiment and collection of exsistence data

Inspection of the equipment performance value

Calculation of the cost and confirmation of the target cost achievement

Inspection of the equipment performance value

development complition

Fig. 1 The way of development 4. Conclusion LOTUS Project had been finished. However everything is not solved on the sludge recycling problems by means of LOTUS Project. For instance, issues of marketing the products made from sludge, stable supplier of bio-solid, municipal procurement of the facilities and/or O&M services may be the crucial point for the sustainable recycling of sewage sludge.

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1

National Project Leading to the RecyclingSociety with Sewage Sludge in Japan

LOTUS Project

Japan Institute of Wastewater Engineering Technology (JIWET)

Ｙoshihiro Morishima

2

Biomass Nippon StrategyKyoto Protocol Problem in the sewage

Background of LOTUS Project.

- Lack of sludge dumping site- Increasing cost for sludge recycling

Cost reduction for various productions and energy utilizations from sewage sludge

Chief purpose of technology development

MLIT started a new R&D Project in 2005LOTUS Project

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1.Sludge Zero-Discharge technology

Dewatered sludge : 16,000 yen/t or lessIncineration ash : 8,000 yen/t or less

enabling to recycle all sewage sludge at a lower cost than its disposal.

2.Green Energy Source technology

enabling to generate power from sewage sludge and other biomass such as garbage at a lower cost than commercial electric power cost in Japan.

9.32 yen/kWh or less

Development target (cost)

4

The calculation method of the cost

new equipment recycling product(P*Q) value of produced

energy

(f) sell income for products from sewage sludge and others

(g) recycling cost

(a) building cost

(c) running cost

(b) remodeling cost(d) increment of the running

cost(e) decrease of the fuel cost

by the energy recoveries

disposal cost(Z) before introduction

(z) after introduction

others(h) income for the disposal of

the other biomass

(i) others

existing equipment

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Development technology

All technologies have accomplished their developmenttargets, and this project finished in fiscal 2007.

3 technologies for Zero-Discharge target 3 technologies for Energy Source target1 technology for both targets

7 technologies in LOTUS Project

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Ｖerification test plant

Sludge mixer

Deodori-zationfurnace

Treatment capacity:1.7ｔ-cake/day

Heat medium heater

Dewatered sludge hopper chamber

Dewatered sludge piping

Dried sludge circulation elevator

Sludge dryer

1. Production of biosolid fuel from sewage sludge (Zero-Discharge)

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Equipment flow

BiosolidsFuel

Dehydration sludge

Extractor

DigestionTank

Treat water

Sending back water

Thickened sludge

(Digestion gas)

Exhaust

oil

Exhaust gas

Air

SludgeDryer-PelletizerUnit

Fuelscruber

heatexchanger Heat

mediumHeatingDevice

熱媒油

熱媒油

スクレーパ

伝熱盤

Scraper

Heat transfer oil

Heat ransfer

oil

Heat-transfer

plate

Heat transfer oil

Gas

Sludge

Water

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Ｖerification test plant

Phosphat

washing tank

Control panel

Treatment capacity :100 kg of incineration ash/day Dehydrator

Phosphat

atoragetank

2. The technology for recovery of phosphorus from sewage sludge incineration ash (Zero-Discharge)

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Equipment flow

Incineration ash

Na+ OH -

OH -

OH -

PO43-

OH-

OH- PO43-

Phosphate extraction

PO43-

OH -

P

OH-

OH-

Incineration ash recycling as a reactive liquid.

PO43-

K+

【 Case of recovery of calcium phosphate】

【 Case of recovery of liquid fertilizer raw

material】 Ca(OH)2⇒Ca3(PO4)2

De-P ash Recoverededphosphate

Raw material for liquid fertilizer

NaOHSolution Ca(OH)

2

Na+

Na+Na+ Na+

Na+

Na+

Na+

alkaline solution

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Ｖerification test plantStack

Carbonization furnace unit

Heat recovery device (heat exchanger)

Dryer unit

Drying sludge hopper

Treatment capacity :7.2 to 9.6 tons/day

3. Composition of activated carbon from sewage sludge and reduction of the cost for sludge treatment by effective utilization (Zero-Discharge)

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Dryer unitCarburization

furnace unit

Heat recovery device (heat exchanger)

Dewatered sludge

Dried sludge

Excess

gas

Dried exhaust gas

Combustion

exhaust gas

Activated carbon

product

Equipment flowSludge

Gas

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Ｖerification test plant

Control digestion tank (without receiving biomass)

Treatment capacity : 50kg/day

Heat exchanger

Digestion tank

4. Energy recovery from sewage sludge and biomass with synchronous digestion (Energy Source)

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Equipment flow

Existing digestion

Tank

Concentrated excess sludge

Concentrated raw sludge

BiomassBiomass

Preprocessing equipment

Digestion gas power generating unit

GasHolder

Collection heat

Electric power

Digestion gas

New establishment

Increase

Dehydration

Digested sludge

Outside

Hall

Supersonic wave solubilizationequipment Desulfurization tower

Sludge

Digestion gas

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Ｖerification test plant

Weighting measure

Mixing tank

Sludge circulation pump

Digestion tank (1 m3)

Treatment capacity : 50kg/day

Mixed digestion facility

Bio desulfurization tower

pH adjusting facility

Treatment capacity :20Nm3/hr

Heat exchanger

5. The Development of the Anaerobic Co-digestion System for Power Generation with Low Running-cost (Energy Source)

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Equipment flow

DigestionTank

(To the dehydration equipment. )

Electric power collection

Power generating unit

GasHolder

Surplus gasCombustion

Digestion gas

Warm

water

SiloxaneremoverGarbage

Hot water boiler

Warm water heat collection

DesulfurizationEquipment

FoodResidue

Desulfurizationequipment *1

*a

*b

*a *b

(To the existing processing place. )

Thickened sludge

Digested sludge

Preprocessing

equipment

Warm

water

Electric pow

er

Range of proposal equipment

*1 ① Increase only of increase's worth② replace with biological desulfurizer

(the whole quantity)

(receipt outside faction)

Warm water

Warm water

Digestion gas

Sludge

16Ozone reaction tank

Ozone generator (max. 2kg O3/hr)

Centrifugal thickener

Anaerobic digestion tank（1,800 m3）

Ｖerification test plant Treatment capacity : 30m3/day

6. Sludge reduction through accelerating digestion and electrical generating system using digestion gas (Energy Source)

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Equipment flow

GasHolder

Digestion gas

Concentrated machine

Warm water

Heater

Power generating

unit

Heat exchanger

Supplying Electric power

Coagulant

Oxygen gas

Atmospheric discharge

Exhaust gas

Thickened sludge

OzoneProcessor

To the water treatment

Thickened sludge

Recycle flow

Ozonation sludge

Warm water

Digestion Tank

Digested sludge(organic richness)

Digested sludge

Digested sludge(inorganic richness)

Proposal technology

Desulfurizationtower

Surplus gasCombustion

Concentrated machine

Digestion gasPreprocessing

deviceAtmospheric discharge

Waste heat recovery

Heat exchanger

Digestion gasSludge

Water

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Ｖerification test plant

Crusher/separator (raw garbage, etc.)

Current dryer

Activated carbon furnace

Vertical methane fermentation tank

Gas refining equipment

Treatment capacity : 1.0ton/day

Horizontalmethane fermentation tank

7. Methane fermentation system of sewage sludge and raw garbage, and carbonization-activation for utilization (Both Zero-Discharge and Energy Source)

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Equipment flow

Dehydrationsludge

FermentationResidue

SolubilizationAcid fermentationtank

Crusher

Dynamo

Garbage etc.Biomass Digestion tank

Thickened sludge

Activated

carbon

Electric power

Digestion gas

Range of evaluation of Energy Source technology

Range of evaluation of Zero-Discharge technology

Dehydration DryerCarbonization-Activation unit

Sludge and garbage

Digestion gas

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Private companies which developed each technology

1. Hitachi Zosen Corporation http://www.hitachizosen.co.jp/english/index-e.html

2.

3.

4.

5.

6.KURITA Water Industries Ltd. http://www.kurita.co.jp/english/index.html

7.

METAWATER Co., Ltd. http://www.metawater.co.jp/eng/index.html

Kawasaki Plant Systems. Ltd. http://www.khi.co.jp/kplant/english/index.html

Tsukishima Kikai Co.,LTD. http://www.tsk-g.co.jp/en/index.html

JFE Engineering Corporation http://www.jfe-eng.co.jp/en/index.html

Daiki Ataka Engineering Co．，Ltd． http://www.atk-dk.co.jp/english/index.html

Kajima Corporation http://www.kajima.co.jp/welcome.html

DAINEN Co., Ltd. http://www.dainen.jp/e/index.html

Hitachi Plant Technologies, Ltd. http://www.hitachi-pt.com/

Kawasaki Plant Systems. Ltd. http://www.khi.co.jp/kplant/english/index.html

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Japan Institute of Wastewater

Engineering Technology

Thank you for your kind attention.

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