Reuse of Water and Biosolids in Sakai City Kumi Koyama Sewerage Management Division Sewerage Department Waterworks and Sewerage Bureau Sakai City 1. Water Environment Restoration Plan of Nintoku-ryo Tumulus and Uchikawa River (Revival of the Historic Water Landscape) Sakai City faces the sea and developed as a fishing port during the 12th and 13th centuries. After that time, Sakai City became a hub base of the marine transport in the western Japan and had a golden age during the 15th and 16th centuries. At that time through the overseas trading with China, Asian and European countries, Sakai City flourished as an autonomous city surrounded by the moats which served as barriers against enemies. To revive the landscape of the autonomous city that was at the zenith of its prosperity, Sakai City launched “Water Environment Restoration Plan of Nintoku-ryo Tumulus and Uchikawa River” and “Basic Revival Plan of Channel between Sayama Pond and Nintoku-ryo Tumulus”. These Plans were drawn up to restore the historic water landscape and the cultural heritage, highlighting the values of moats such as ecosystem, recreation, flood control and water purification. Another purpose of these two plans is the establishment of “Cool Lines” to develop “Cool City Sakai”. The Planned waterway will originate from the Sayama Pond located in the east of Sakai City and reaches the historic Old Sakai Port via the Nintoku-ryo Tumulus which is currently in the process of applying for World Heritage Site. 2. Reuse Treated Wastewater in Sakai City About 20 years ago, a member of operation and maintenance staff in Sambo Sewage Treatment Plant began to plant hydrangeas voluntarily for the children who came to watch the plant. Currently, about 50 kinds of hydrangeas 1,000 stocks creates a splendid “space of moisture” in full glory along the road of its 500 meter total length surrounding the sections. About 22,000 people visited to appreciate the flower garden in 2008. Since hydrangeas cultivation demands a large quantity of water, we use about 400m3/day of treated wastewater. The sprinkler pipe of about 800 meter in total extension which supply water for hydrangeas was installed by the staff.

-1-

On the basis of our 20 years’ experience of water reuse in the treatment plant, Sakai City initiated a treated wastewater supply project in 2007. This project, which is called “Sakaihama Treated Wastewater Supply Project”, supplies the effluent from the advanced treatment facilities in Sambo Sewage Treatment Plant to “Sakaihama” located at seaside. This project is seen as contributing to the sound water circulation as well as to ensuring the sustainability of water resource. The operation of applying treated wastewater will be started in August, 2009. In Sakaihama, the constructions of the large-scale public facilities and factories are currently in progress, such as a national center of soccer training, an area-wide disaster evacuation center and the factories of liquid crystal panel for the large-sized television and solar panel. This project comprises a pump facility, a sewage pipe network and two ozonation facilities. The treated wastewater is used mainly for toilet flushing, landscape irrigation and industrial uses. But the treated wastewater could be used for fire extinguishing in emergency. Treated wastewater use is roughly divided into two categories, depending on whether people are supposed to touch the water directly or not. Pursuant to the “technical standard for reuse of treated wastewater (Ministry of Land, Infrastructure, Transport and Tourism, 2005.4)”, ozonation process is applied for the former use and fiber filtration is applied for the latter, The reactor of Sambo Sewage Treatment Plant is now being remodeled to advanced treatment (step-feed biological nitrogen removal process with chemical addition plus fiber filtration) for the eutrophication control in the Gulf of Osaka. Regarding the supply of treated wastewater, a fraction of the effluent from Sambo Sewage Treatment Plant is supplied to the advanced treatment for reuse in the compact satellite facilities. 3. Reuse of Sludge in Sakai City In Ishizu Sewage Treatment Plant, 63,000m3/day of wastewater is treated by conventional activated sludge treatment method. The sewage sludge was incinerated for the purpose of its volume reduction previously. However, since 2004 the sludge recycling system has been in operation in "Sakai City Bio-Solid Composting Enterprise" to attain less environmental impact, energy-saving and low-cost. The composting process is unique in that extreme thermophile bacteria are applied in order to downsize the facility as well as to secure the public health and easy handling of the product. Thickened sludge (density 1%, about 1,000m3/day) is dehydrated under high pressure and aerobically fermented. In several days the temperature of sludge reaches to 85℃ or more, and it takes only 45 days to get smooth powder of compost. The product is so dry (water content is equal to or less than 30%) that it is use-friendly without odor. Plant growth test with this compost resulted in more favorable data, even compared with popular manure. The net cost of producing the compost from dehydrated sludge whit the subtraction of the gain from selling it 9,000yen/ton, which is smaller than the average unit cost for disposal (17,500 yen/ton - dehydrated sludge) in Japan. Nowadays, the product is shipped as organic fertilizer or fermentation promotion materials

-2-

premeditatedly. Furthermore, the research is conducted toward higher quality compost by the mixture with the cow dung. 4. Conclusions The composting of sludge has already reached practical use, and the reuse of treated

wastewater develops from the usage in sewage treatment plant to the usage in the city. However, these actions are quite primitive. We think that these actions have still more possibilities of development for a sustainable society in the future.

We are going to push forward investigation about various use of treated wastewater and sludge. And we would like to build a sustainable recycling society system which security and effectiveness were secured.

-3-

Reuse of Water and Biosolids in Sakai City

Sen-no-RikyuNintoku-ryo Tumulus

Japan

Sakai City

Kumi KoyamaSewerage Management Division Sewerage DepartmentWaterworks and Sewerage BureauSakai City

Hokubu processing ward

Semboku processing ward

Ishizu processing ward Ｉshizu Sewage

Treatment Plant

Semboku Sewage Treatment Plant

Imaike processing ward

Sambo processing ward

Sambo Sewage Treatment Plant

Plan Current

Sambo 1963.8 138,500 123,150

conventionalactivatedsludgeprocess

Ishizu 1972.2 102,400 76,400

conventionalactivatedsludgeprocess

Semboku 1969.3 204,700 90,100

conventionalactivatedsludgeProcess/A2O

Ccapacity (m3/day)Name Operation Method

2

Sewage Works of Sakai City

-4-

Irrigation ponds Cluster

A network to connect the history

Water and green network

Reuse of treated wastewaterYamato River

Supply of seawater

Nintoku-ryoTumulus

Sayama Pond

Gulf of Osaka

Uchikawa River

Doigawa River

Old Port of Sakai

Supply of Treated wastewater

Improvement of water environment

Water Environment Restoration Plan of Nintoku-ryo Tumulus and Uchikawa River

Daisen Channel

Sambo T／P

3

Uchikawa River Doigawa RiverUchikawa River Doigawa River

Nintoku-ryo Tumulus

Nintoku-ryo Tumulus

Sayama pond

Sayama pond

■ The protection of the cultural heritage ■ The improvement of the scene ■ Maintenance of the ecosystem ■ The security of the hydrophilic function ■ The improvement of the disaster prevention function ■ The improvement of the river improvement function ■ Water purification

■ The protection of the cultural heritage ■ The improvement of the scene ■ Maintenance of the ecosystem ■ The security of the hydrophilic function ■ The improvement of the disaster prevention function ■ The improvement of the river improvement function ■ Water purification

4

Basic Revival Plan of Channel between Sayama PondAnd Nintoku-ryo TumulusOld

Sakai Port

Old Sakai Port

-5-

The accumulation of the clean energy creation

institution

Restraint of passage traffic

LRT(low carbon type mobility)

Large-scale solar power station（Mega solar）

Energy Renaissance

parkForest of the

symbiosis（Cool Dam）

Mt. village （Cool Dam）

Environment advanced

model complex

Cool Line

Bicycle road

Anti-heat island measure

Tumulus Cluster / irrigation ponds

（Cool Spot）

Urban Channel(Cool Line)

Transit mall

““Cool City Sakai"Cool City Sakai"（（conceptual imageconceptual image））

Low carbon type residential quarter

Solar power generation

5

Treatment plant where hydrangeas Blooms

Sprinkling Pipe

6Ground plan of Sambo Sewage Treatment Plant

-6-

0

5,000

10,000

15,000

20,000

25,000

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

2005

2006

2007

2008

Year

Num

ber

of

vis

itors

Number of the visitors

7

Aria Sakai Hama district (about300ha)

PurposeReturning to health of water circulation system by reusing treated wastewater

Ensuring the sustainability by acquiring water resourceFacilities A water supply pumping station

Two satellite treatment plant (Ozonation)

Pipe (About12km)

Sakai Hama

Sakai city

Sakai stationSambo t／pSakai Hama

Sakai city hall

8

Sakaihama Treated Wastewater Supply Project

-7-

NTCWide area disaster prevention foothold

Large companies

Refuse disposal plant

Satellite t/p

Satellite t/p

Local industry business cluster

Sambo t/p

Pipeline network

Treated wastewater supply

User Quantity (m3/d) Use

NTC 400 Sprinklings

Disaster prevention foothold 500 Sprinkling

Refuse disposal plant 20 Sprinklings

Local industry business cluster 80 Restroom water, sprinkling

Large companies 33,000 Coolants

Total 34,000

9

Fiber filtration water Ozonation waterE.coli - Do not be detected

Hydrogen ion concentration Less than 8.6More than 5.8

Less than 8.6More than 5.8

Oder Do not be unpleasant Do not be unpleasantResidual chlorine - What is maintainedAppearance Do not be unpleasant Do not be unpleasant

10

Quality of Supplied Water

-8-

1% concentration

sluge

1% concentration

slugeConcentration

Concentration DryingDrying

Fermentation and

Cutback

Fermentation and

CutbackProduct

processingProduct

processing ShipmentShipment

Super-high temperature aerobic fermentation flowSuper-high temperature aerobic fermentation flow

Ventilation BloisTrack scale

A mixed tub

Fermentation tub

Product stuffing

equipmentShipment

Product stuffing

equipment

11

Composting Process at Ishizu Plant

Pressurization dehydrator

Pressurization dehydrator Fermentation tubFermentation tub

cutbackcutbackFermentation

situationFermentation

situation

Pressurization dehydrator

Pressurization dehydrator

Full ripeness manure

Full ripeness manure 12

Manufacturing process at Ishizu compost

-9-

13

Fermentation temperature , outside temperature, and moisture change at Ishizu compost

Capacity Change and PH Change

14

Volume and pH change of Ishizu compost

-10-

An examination item A unit A test result

The maximum of the harmful ingredient

Arsenic or the compound mg/kg <1 50cadmium mg/kg <2 5mercury mg/kg <0.5 2nickel mg/kg 53 300chromium mg/kg 50 500lead mg/kg 16 100copper mg/kg 300zinc mg/kg 460calcium % 18.7nitrogen % 1.5phosphoric acid gross

quantity % 3.01Potassium % 0.08The C / N ratio - 6.3PH - 7.8Water % 28.5

About the heavy metal such as arsenic, cadmium, mercurial nickel, chrome, the lead, there is it within the standard value of the national law.

15

Contents of Ishizu compost

16

ConclusionsConclusions

The composting of sludge has already reached practical use.

The reuse of treated wastewater develops to the usage in the city.

We are going to push forward investigation.

We would like to build a sustainable recycling society system.

-11-