BAGUIO SEWAGE TREATMENT PLANT

NORTH SANITARY CAMP, BAGUIO CITY

YEAR CONSTRUCTED: 1986

ESTIMATED PROJECT COST: Ranges from 1.576 Billion Yen-2.697 billion yen

DESCRIPTION OF THE SEWAGE TREATMENT FACILITIES

After removing the coarse material by screening in the GRIT CHAMBER, the sewage water flows into the PRIMARY SEDEMENTATION TANK.

In the PRIMARY SEDEMENTATION TANK, 30 % of bilogical oxygen demand (BOD) and 40% of suspended solids (SS) are expected to be removed. The clarifier is operated continously in this tank and the withrawal of sludge is accomplished by intermittent operation of pumps.

The outflow from this tank then flows into the OXIDATION DITCH which is equiped with rotors. The sewage is mixed, agitated and aerated in this ditch. The soluble organic matter is absorbed to be oxydized and assimalated by activated sludge.

The mixture of sewage and activated sludge is sent to the FINAL SEDIMENTATION TANK where it is separated into liquid and solid components.

Supernatant flows into the DISINFECTION TANK where it is chloronated by using calcium hypopchlorite and then discharge into the Balili River.

Part of the settled sludge in the FINAL SEDEMENTATION TANK is drawn off by pumps to be returned to the OXIDATION DITCH and the rest is also drawn off to be sent to the SLUDGE THICKENER as excess sludge. The sludge from the primary PRIMARY SEDIMENTATION TANK is mixed with the excess sludge before entering the SLUDGE THICKENER.

The thickened sludge flows into the SLUDGE STORAGE TANK where it is agitated by a pump to prevent settlement and aerated to keep its aerobic condition.

The sludge is then introduced into the SLUDGE FRYING BED which is covered with polycarbonate plate roof to accelerate and maintain evaporation evenm during the rainy season.

MAIN FACILITIES

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FACILITY NAME DIMENSIONS QUANTITY CAPACITYINFLOW PIPE Dia. 600 mm 1GRIT CHAMBER Parallel flow

W 2.20m x L 4.30

2(1-standby)

Overflow rate 1.818m3/m2/day

PRIMARY SEDIMENTATION TANK

Radial Flow Circular tank Dia.21.34 m x D 2.17 m

1(existing) Sedimentation time 2.17 hr.Overflow rate 24.1 m3/m2/dayWeir rate 128 m3/m day

OXIDATION DITCH Recirculation flow ditch W 10.00 m x L 56.00 m x D 3.00m

4 BOD-SS loading 0.053 kg/SS-kg/day BOD Volumetric Loading: 0.186 kg/m3/daySludge age: 18.8 daysAeration Time: 18.1 hrSludge Return ratio: 100%

FINAL SEDIMENTATION TANK Radial Flow Circular tank dia. 15.00 m x d 3.20 m

2 Sedimentation Time 3.16 hr. Overflow rate: 24.4 m3/m2.dayWeir rate: 91.3 m3/mday

DISINFECTION TANK Horizontally baffled flow Rectangular tank W 2.00 m x L 6.00 m x 4 channels x W2.00 m

1 Contact time 16.0 min

RETURN SLUDGE PUMP 6RAW SLUDGE PUMP 2EXCESS SLUDGE PUMP 2DRAINAGE PUMP 2SLUDGE THICKENER Radial flow

circular tankDia. 5.20 m x d

2 Thickening time: 27.0 hrOverflow rate

3.00 m

1213

SLUDGE STORAGE TANK Rectangular tank W 6.00 m x L 6.00 m x D 2.50

1 Storage time 2.2 days

SLUDGE DRYING BED Covered Air Drying Bed W 11.00 m x L 13.50

15 Thickness of sludge 0.30 m layerDrying time 16.3 days

ADDITIONAL INFORMATION

Tax ordinance covering sewerage fees; CSS coverage

# 2003-004 65 Barangays, fully or partially connected

Number of registered sewer concessionaires(1951-dec. 2007)

Residential: 5,119 or 59%Commercial: 3614 or 41%Total:8,723 (2009;9044)

Decentralized (onsite) systemsOutside of the sewer pipe network

(as of dec. ’10)

9 communal septic or imhoff tanks, serving 10 barangays (partially)

Individual septic tanks in 53 barangays found outside of BSTP coverage area and in partially

connected barangays within the BSTP coverage area

Total length of pipe installed and total Number of manholes as of dec 31, 2010

53.22 linear kilometers 2235 units

Baguio Sewage treatment plant Designed capacity: 8,60 cu.m/day2010: average inflow: 12, 434 cu.m per day

Designed influent BOD: 200mg/l2010 average influent BOD: 419 mg/l

ACTUAL PICTURES 0F THE SEWAGE TREATMENT PLANT