With the revamping of the sewer system under the ADB funded Greater Colombo Wastewater Management Project, it is likely that a sewerage tax will have to be introduced in the future, an official of the Colombo Municipal Council, Drainage and Water Supply Division said.
Colombo Municipal Council, Director Engineering (Drainage and Water Supply), MIM Salim said that it has now become inevitable to impose the tax. He said this in response to the laying of sewage pipes in Colombo.
“Seventy per cent of Colombo city is already under sewage,” said Salim. He added that under the ADB funded project the rest of Colombo will be provided with the facility.
The sewage from the Dehiwala-Mount Lavinia Municipal Council and Kolonnawa Urban Council areas are connected to the Colombo system for sea disposal. Additionally 11 institutions located outside Colombo Municipal limits discharge their sewage through the Colombo system. This sewage is dumped into the sea 1.5 kilometres offshore, untreated through two sea outfalls, in Wellawatta (1243 metres) and Modera (1834 metres), each disposing approximately 150 million litres of sewage per day, according to Salim.
The waste includes bathroom and toilet waste and liquid kitchen waste. The gravity sewer system is approximately 300 kilometres in length. The sewage collected is transported over 38 kilometres by 20 pumping stations. The pipes consist of clay, PVC and DI (Ductile iron).
Increasing pressure on sewer system
However, the increasing population in the city has reduced the capacity of the sewer system that is made up of nine to 12-inch pipes, which will be upgraded to 450 mm pipes under the ADB project.
The key problems in the up-keep of the sewer system are the high energy and operational costs involved in the operation and maintenance of a system that is now obsolete. This also results in frequent breakdowns. Lack of awareness is another issue that leads to increasing maintenance and repair costs, according to Salim.
“People flush everything from polythene to towels down the toilet. These clog the lines leading to huge repair costs”, he said.
An ADB loan worth US $343 million has been passed to revamp the sewer system that’s 91 years old. Major works of the existing sewer system was completed in 1925. Under the ADB loan, areas that are not provided sewage facility, such as Kirulapone and Mattakkuliya will be developed. Salim said that new treatment plants are also planned under the ADB project.
He revealed that similar projects are planned for both the North and South which will include waste treatment plants. He said that the ADB loan for the Northern catchment area will be signed in the near future.
Raising concerns about the effectiveness of such waste treatment, Sri Jayawardenepura University, Geography Department, Emeritus Professor Jinadasa Katupotha pointed out that Sri Lanka is located in the open sea. “There are no islets to shield us from the open ocean currents that will wash pollutants of our own making back ashore”, he said.
Although unrelated to the sewage problem, Prof Katupotha pointed out that with hospitals and restaurants thriving in Colombo, food waste and potentially dangerous waste such as blood and surgical waste added to the problem.
Prof Katupotha warned that dumping untreated sewage in the sea could have extreme detrimental effects on marine biology as well as human health. He pointed out that Sri Lankans consume fish caught from these seas and consumers often confide that fish caught off Wellawatte, near the sewage outfall, are comparatively ‘tastier’.
He said that the sewage has become a food source for the fish that have made the sea surrounding Sri Lanka their habitat. He also raised concerns about the chemicals that will invariably be discharged with any treated waste water after the treatment plants are put in place. These chemicals will in turn make way into the human food chain.
“The plant at Wellawatta will be completed in two years and the one in Mutwal (Modera) in four years approximately,” said Salim. He said that the cost of operating and maintenance of the plants will add to a host of other expenditure.
“As things stand, the government spends one billion a year for maintenance and operation of the existing sewer system,” said Salim. According to him, the monthly electricity bill for the two biggest pumping stations, that pump sewage to the two sea outfalls, is a staggering three million each.
All this may come at a price to the consumer in the future. Salim confided that although such a service was provided free of charge to the urban public for so long, when the project is completed and the treatment plants fall in place and in working order, it will add to the maintenance and operational cost of the sewer system.
“The public may have to pay a tax in the future”, Salim declared.
Salim explained that the sludge left over by the treatment process will be disposed with the solid waste. He said they have no hope of composting as there is little demand for it in Colombo.
Salim claimed that energy generation through biogas produced from waste is a viable option, but pointed out that the biggest obstacle for such a venture is space. “Colombo is already so congested and we barely have enough space to expand the existing sewer system”, said Salim.
He admitted that Sri Lankan city planning is flawed. “Even the existing sewer lines run below private lands, because they have been permitted to build over sewer lines,” Salim said.
He explained that this creates difficult maintenance and they are now in the process of relocating these sewer lines onto public roads.
“We are also planning to ban any building over sewer lines under new regulations,” said Salim.
To minimize road damage in the process, Salim said that they would use something referred to as micro tunnelling or pipe jacking to lay the new sewer lines. He claimed that this will result in minimum road breakage. It involves digging two holes, the jacking pit, through which the pipe is sent to the receiving pit.
“If not for micro-tunnelling, damage caused would be immense,” concurred Road Development Authority (RDA) Chairman Nihal Sooriyarachchi. Regarding the removal of sewage pipe lines out of private lands and relaying them in public roads, which will invariably entail road breakage, Sooriyarachchi said: “This will have to be corrected somewhere down the line, but will be done with minimum road breakages.”
Referring to the lack of coordination between government departments such as Telecom, Water Board and local authorities when repeatedly opening up roads to lay utility lines, Sooriyarachchi admitted that this is something they are working to streamline immediately.
“Such coordination is required at a national policy and planning level,” emphasized Sooriyarachchi. He said that utility providers such as Water Board, LECO, Irrigation Department and Urban Development Authority are working with the RDA to reduce damage to the road system during repairs and the laying of new utility lines.
“For example, when RDA took over the work of the 174 bus route, we came to an agreement that there would be no road breakage for another five years,” said Sooriyarachchi. He said that at a coordinating meeting held between the RDA and utility providers with regard to the road construction work of the 155 bus route from Ela Kanda, Ja Ela to Fort in Colombo, it was decided that all utility lines will be laid on the pavement instead of the road. “This way the road will not have to be broken every time a utility line has to be repaired”, he said.
Sooriyarachchi emphasized that the RDA will not approve any road breaking activity unless funds are passed for its repair. “No utility provider can take up any kind of construction on the road without the written approval of the RDA. But in emergency situations, the RDA consents to any road breakage based on mutual agreement and any road repair will be done immediately,” he assured.
(Pics by Chamila Karunarathne)