Upper Kerayong, Ampang


The Upper Kerayong catchment located in Mukim Ampang is bounded by the Bunus catchment on the North, Cheras Mile 11 on the South, forest reserve on the East and Lower Kerayong on the west. Sungai Ampang tributaries flowing through the study area and merges with Sungai Gombak and eventually and eventually flows to Sungai Kelang which is Standard B catchment. Upper Kerayong sub-catchment covers an area of 23.0 km2. . The Bunus catchment is located just north and north east of Kuala Lumpur territory and falls under the jusrisdiction of Majlis Perbandaran Ampang Jaya (MPAJ).

Upper Kerayong sewerage catchment area is identified as a critical sewerage catchment area. The rapid growth in the Upper Kerayong catchment consists of 85% developed area while 15% are undeveloped area located towards eastern part of the catchment. The residential areas are connected to the IST while most of petrol stations, fast food restaurants or buildings are using their private STP. Government premises utilizes communal septic tank (CST). The entire Upper Kerayong catchment is served by 61 public sewage treatment plants (STP) serving 458,800 PE, 2 private plans about 9,100 PE, approximately 7,250 PE individual septic tanks (IST) and 100 pour flush systems in Upper Kerayong.

There are 36 public STP which are mostly T01 and T02 category STP located in the Upper Kerayong catchment. These STP’s have been taken over by IWK circa 1995 and are considered old plants. The treatment process here does not meet DOE effluent standards where none of these plants has been designed to remove ammonia from the sewage. Previously high ammonia had been detected in water treatment plants and has been associated the sewage treatment plants in discharging ammonia. Reducing or stripping ammonia will greatly reduce the impact but a more realistic approach is required as other sources of pollution resulting in the output of ammonia needs to be addressed and resolved. 

Odour and overloaded issues are also issues from the plants and the condition of the private plants in this catchment also contribute to effluent non-compliances. The issues faced within this catchment can be summarized as per below

  • Old plants not designed to meet current standards
  • Frequent complaints from the odour and buffer
  • Overloaded plants issues causing non compliance
  • Existing private plants contributing to non-compliance
  • Many old CTS’s located within this catchment not maintained accordingly relating to public nuisance complaints and highlighted by media


Due to this arising situation, these types of plants are selected for rationalization and upgrading programme in the Upper Kerayong Catchment.          

Based on the sewerage catchment strategy, it has been identified as a multipoint catchment as The studies shows due to current topography and geopgraphy it is not feasible to bring the entire catchment to Lower Kerayong. Taking into consideration of these issues, it is proposed that the entire flow will be channeled to 3 different sub regional STP sites to be implemented in 3 zones as follows;



Ultimate Catchment PE

Zone 1 (KLR 099)

243,000 PE

Zone 2 (AMA 034)

242,000 PE

Zone 3 (AMA 091)

74,000 PE


559,000 PE




The works for this Design and Build project encompasses of sewerage rationalizing works at Upper Kerayong sewerage catchment area for Phase 1 (Zone 1- 162,000 PE & Zone 3 – 37,000 PE). The works include the rationalizing of 15 numbers of public sewage treatment plants, 1 private sewage treatment plants, 7 private sewage treatment plants located within the government owned premises, build new trunk sewers, rationalize and extend sewers where required, decommission the rationalized sewage treatment plants including the last manhole serving the plants.

The rationalization project is aimed to achieve several but not limited to the benefits listed below;

  • To comply to latest Standard A effluent of Environmental Quality (sewage) Regulations 2009
  • Reduce pollution loading into receiving water courses
  • Reduce number of multi points STPs thus reducing the number of public complaints in relation to odour, buffer and aesthetic issues

Gravity designed sewers are mostly proposed along public road and are to be constructed using both open trenching (with sheet pile or temporary shoring) and pipe jacking method. Pipe Jacking has been proposed for all sewers deeper than 4 meters and for major road and river crossing.

All existing sewers and manholes which are to be decommissioned after diversion and connected to the new trunk sewers will be safely abandoned. The abandoned sewers have to be filled with sand and sealed permanently at the top. Manhole within road pavement should have the top section removed and the road paved over the abandoned manhole.

Total length of sewer line construction;

i) Zone 1 – 6552 m

ii) Zone 3 – 4541m

Two (2) numbers of Network Pump Stations(NPS) are to be constructed under this package. One (1) number of pump station will be in Zone 1 catchment and second one will be in Zone 3 catchment area. The 2 NPS are as follows;

i) NPS 1 at existing STP AMA 021, Taman Maluri C – 8350 PE

ii) NPS 2 at existing STP AMA 120, Taman Lembah Maju- 90314 PE



Zone 1

  • Taman Angsana Hilir
  • Kampung Pandan Luar
  • Kampung Pandan Dalam
  • Taman Maluri
  • Pandan Jaya
  • Pandan Indah

Total length of new sewer pipes for Zone 1:

Open Cut’: 166.23 meter

VCP Pipe Size: 225mm VCP & 375mm 

‘Pipe Jacking’: 4998.61 meter.

VCJP Pipe Size: 375mm

RCJP Pipe Size: 450mm, 525mm, 600mm, 750mm,900mm, 1200mm & 1350mm

Zone 3

  • Taman Pandan Indah
  • Taman Muda
  • Taman Lembah Maju
  • Taman Bukit Permai
  • Taman Mega Jaya

Total length of new sewer pipes for Zone 3:

Open Cut’: 2,604.54 meter

VCP Pipe Size: 225mm & 375mm

RCP Pipe Size: 525mm

‘Pipe Jacking’:1,882.54 meter

VCJP Pipe Size: 375mm

RCJP Pipe Size: 450mm & 525mm