News
Western Province drinking water heavily polluted by effluents and domestic waste
The Kelani River, which supplies drinking water to 80 percent of the Western Province’s population, is now a stew of pollutants including sewage and chemicals, causing the cost of purification to skyrocket.
There are 10,511 factories near the river. Pollution has spiked as a result of effluents and domestic waste, an environmental audit shows. The Seethawaka export processing zone (EPZ) has had no environmental protection licence (EPL) for eight years.
The river is dammed in two places upstream and the Ambatale and Pattivila pump houses treat and discharge water to around 2.4mn people in the Colombo District. It also supplies to water for beverages, textiles, steel, petroleum products, tires and fertilizer industries, among others. The water is also used for agriculture. The factories are located right up to the estuary. The Seethawaka EPZ has 37 industries, including garments, foods and plastics. The zone had an Environment Protection Licence (EPL) till December 2010 but the Central Environmental Authority (CEA) refused to renew it as certain mandatory conditions were not met. The status quo prevailed till last year, when the audit was completed.
The wastewater of 15 of the zone’s factories is first treated in-house and piped to its central treatment plant. Later, the National Water Supply and Drainage Board (NWSDB) purifies it before discharging into the Kelani River through a canal.
The 20-year old zone’s central treatment plant has a monthly capacity of 9,950 cubic metres of wastewater. But from January to June last year, it exceeded this by between 14,176 and 28,102 cubic metres a month. Consequently, wastewater was sometimes released into inland water bodies without sufficient purification. The plant has not been upgraded.
Some factories produced more wastewater than their in-house purification plants could handle. They took no steps to remedy this. As a result, the water in the retention pond is below prescribed standards. The NWSDB warned in June last year that surplus, untreated wastewater was going directly into the pond and thereafter into the Kelani River (particularly during rains) through canals.
Separately, around 15 tractor-loads of residual sludge are dumped everyday into a clay-bottomed open pit, leading to groundwater contamination.
The Biyagama EPZ has 60 factories. Here, treated wastewater goes into a retention pond, then into the Kelani River through a canal.
Water samples from the Biyagama EPZ when tested by the NWSDB revealed that total coliform content was 890,000 more than the prescribed limit of 10,000. The total coliform content in treated water from the retention pond was also more than 100,000 the standard limit.
The E-coli content in rainwater discharge from the EPZ was more than 546,000 the prescribed limit of 4000 and E-coli content in the retention pond was more than 106,000 the limit.
In the five kilometres from Modera to Ambatale, there are six major bridges. Pollution has risen because of rampant encroachment and unauthorised construction along the two banks. A legal provision that requires building to be done 198 metres from the river bank and at locations where the river’s width is more than 15m is widely abused.
The audit report lists several cases of pollution. For instance, the wall of Kohilawatte cemetery has collapsed towards the river raising the risk of bodies and polythene entering it. The Ragahawatta canal in the middle of the river is dirty with rubbish from construction and encroachment. The river bank near Kaduwela Bridge is damaged by large-scale constructions.
Solid waste is going into the river on a massive scale in Modera, Mattakkuliya, Wellampitiya, Peliyagoda, Kolonnawa and Angoda. This includes plastics, empty bottles, polythene, papers and rubble from demolished buildings. All rubbish from encroached houses at Mattakkuliya, Modera, Wattala, Wellampitiya, Peliyagoda and Grandpass areas also enter the river.
“Purified” water from factories in the Biyagama EPZ flows into the river through the Ragahawatte canal. The Pattivila canal starts near the Ceylon Petroleum Corporation. Factories and houses on either side of it send their waste into the canal which is brown with impurities. It joins with the Kelani River near the intake to the Pattivila water treatment plant.
Impure water is removed from the Pattivila pump house via three pipelines but this is again discharged into the river. Toilet impurities from houses near the Batakiththa canal and tourist hotels in Yatiyantota and Kitulgala areas also go into the river.
In most service stations, water from washing vehicles is not treated and sludge is not disposed of in an eco-friendly manner. This has a direct effect on the Kelani River.
The second phase of the Kelani River south bank water scheme uses a chemical mix of calcium oxide, cement chemical, gypsum, and hexavalent chromium to break up a huge rock. This waste goes into the Pattivila paddy field without treatment. The chemicals mixed with water could end up in the Kelani River via the Pattivila canal, the report warns.
From Modera to Ambatale, the audit found disposal of garbage without proper management, unauthorised constructions and disposal of sewage.
The Kelani River water was not suitable for drinking, bathing or entertainment with just minor purification, the audit states. During the past five years, the expenditure incurred on purification had risen. The reason is that significantly more chemicals are used. The total purification cost of the Ambathale reservoir was Rs 879 million in 2015. It rose to Rs 929 million in 2017. The quantity of chemicals used in the Pattivila Reservoir increased by 17 percent of alum, 37 percent of lime and 74 percent of chlorine. As the water impurity goes up, there is corresponding jump in chemical use. This cost will be borne by the consumer.