Water pollution is caused by point and non-point sources. Point sources include sewage treatment plants, manufacturing and agro-based industries and animal farms. Non-point sources are defined as diffused sources such as agricultural activities and surface runoffs.
BOD POLLUTION LOAD
Domestic sewage discharge, in the form of treated sewage and partially treated sewage, remained the largest contributor of organic pollution load with an estimated biochemical oxygen demand (BOD) load of 883,391.08 kg/day. The estimated BOD loading contributed by other major sectors were agro-based and manufacturing industries (76,790.77 kg/day) and pig farming (213,215.00 kg/day). Table 6.1 indicates the total BOD load in kg/day discharged from sewage treatment plants throughout Malaysia in 2006.
Table 6.1 Malaysia: Total BOD Load (kg/day) from Sewage Treatment Plants
| State | No. of STP | Total PE | Flow
(m3/day)
|
BOD Load (kg/day)
|
| Selangor | 2,563 | 5,908,450 | 1,329,401 | 332,350.31 |
| Perak | 1,343 | 1,300,430 | 292,597 | 73,149.19 |
| Johor | 1010 | 1,198,417 | 269,644 | 67,410.96 |
| Negeri Sembilan | 928 | 931,458 | 209,578 | 52,394.51 |
| Kedah | 755 | 556,637 | 125,243 | 31,310.83 |
| Melaka | 725 | 570,192 | 128,293 | 32,073.30 |
| Pulau Pinang | 650 | 2,149,001 | 483,525 | 120,881.31 |
| Pahang | 486 | 314,830 | 70,837 | 17,709.19 |
| WP Kuala Lumpur | 299 | 2,571,877 | 578,672 | 144,668.08 |
| Terengganu | 224 | 75,184 | 16,916 | 4,229.10 |
| Perlis | 36 | 16,156 | 3,635 | 908.78 |
| WP Labuan | 32 | 39,265 | 8,835 | 2,208.66 |
| WP Putrajaya | 9 | 72,833 | 16,387 | 4,096.86 |
| Total | 9,060 | 15,704,730 | 3,533,563 | 883,391.08 |
Source: IWK Sdn. Bhd.
Note :
STP = Sewage Treatment Plant
PE = Population Equivalent
Source : http://www.doe.gov.my (Department of Environment website)
