Greater Colombo Waste Water Management Project:

Efficient sewerage system to enhance Colombo's image

By Ranil Wijayapala

With the ongoing Colombo city beautification programs, improving its infrastructure to meet the demands of the increasing population and development needs has become a challenging task.

It is not only the outward appearance but also having basic hygiene facilities in keeping with the increasing population and development requirements has become an essential part of the development drive if it is to be sustainable.

There is no use in keeping the city beautiful and clean if the sewerage lines in the city suddenly collapse putting the entire effort of developing the city in an embarrassing position.

However, Colombo city experienced such situations during the past few years as roads in the city suddenly collapsed creating huge craters in busy streets.

The reason for the sudden collapse in city streets was due to the collapse of sewer lines beneath the roads and the authorities concerned had to make a big effort to repair the damaged sewer lines, inconveniencing the public during the rush hour.

Therefore, focusing attention on the nearly 100-year-old sewerage system in Colombo city has become an important part in the process of developing Colombo city to be on par with the developed cities in the world.

The Local Government and Provincial Councils Ministry along with the Colombo Municipal Council has taken the responsibility of rehabilitating and repairing the sewerage system of Colombo city under a loan facility obtained from the Asian Development Bank. According to the Secretary to the Local Government and Provincial Councils Ministry, R.A.A.K. Ranawake, the Greater Colombo Waste Water Management Project has been designed to improve the urban environment and public health for the urban and suburban residents in Colombo through improvements to waste water management services.

“The project involves upgrading the sewerage infrastructures, strengthening institutional and operational capacity and project management and implementation,” he said.

As mentioned by Richard Eustace Tickell, a British Engineer in his paper on 'Colombo Drainage Works' in February 1923, in the Minute of Proceedings Vol.216, of the Institution of Civil Engineers, London, the planning of the sewerage system in the Colombo Municipal Council area commenced in 1896 and the construction work had started in 1906. The major part of the work had been completed by 1925 and it had been funded by the then government through a loan to the Colombo Municipal Council.

“Therefore, the sewerage system in Colombo city is more than 85-years-old now and during this period it has not undergone major repairs despite rapid changes and increase in population. The Greater Colombo Waste Water Management Project has become an urgent need to fulfil this task,” he said.

The Local Government and Provincial Council Ministry has undertaken a major part of the Greater Colombo Waste Water Management Project while a small component of the project in the Dehiwala-Mount Lavinia Municipal Council has been undertaken by the Ministry of Water Supply and Drainage.

According to the Project Manager of the Greater Colombo Waste Water Management Project in Colombo city, Kumudunee Samarasinghe, when the sewerage system was set up in 1920s they had laid the sewerage lines and also set up some pumping stations to pump sewage into the sea from two outfalls in Wellawatte and in Modera.

“These pipe lines are either damaged or corroded as they had not been repaired from the date they had been laid. The crater on the Galle road in Wellawatte was due to the collapsing of these sewerage lines during the rainy seasons due to a problem in the slope of the pipe lines,” she said.

“The sewerage system gets affected from time to time in many other areas too during the rainy season. This is because the system is not in a good condition,” she said. Therefore, this project aims at repairing and improving the two marine outfalls in Wellawatte and Modera and to repair a part of the damaged sewer lines and also to repair pumping stations in many parts of Colombo city. Nearly Rs. 13 billion has been allocated to improve the sewer lines in Colombo city under this project.

The sewerage systems in Dehiwala-Mt. Lavinia Municipal Council and Kolonnawa Urban Council areas were built between 1983-1987 based on the Sewerage Master Plan by Howard Humphrey in 1972.

Under the same development plan the sewerage system in Colombo Municipal Council area was partly rehabilitated and expanded. The sewage from Dehiwala-Mt. Lavinia Municipal Council and Kolonnawa Urban Council areas are discharged into the sea through the Colombo sewerage system.

“Therefore, the rehabilitation and repair of the two outfalls at Wellawatte and Modera are vital under this project,” she said.

This will be a five-year project and the project has been undertaken by the Provincial Councils and Local Government Ministry. Since the project comes under the Colombo Municipal Council area the CMC will be the implementing agency while the Ministry, the executing institute.

Under this project 11 pumping stations will developed and out of that one will be a new pumping station to facilitate the pumping of sewage from the Colombo harbour area. Out the ten existing pumping stations, four will be replaced with new ones as they are dilapidated, Kumudunee Samarasinghe said.

The balance pumping stations will be repaired either by replacing or repairing the civil structure or the civil-mechanical structure of these pumping stations,” she said.

The pumping stations in Bambalapitiya, Wanathamulla, Maligawatta, New Fort, St. John's Market, Colombo Harbour, Thimbirigasyaya, Borella, Slave Island, Polwatta and Vystwyke will be rehabilitated and improved under this project.

Rehabilitation of the sewerage system will be done in many parts of the Colombo city.

“We selected the sewerage lines that don’t have the capacity to cope up with the present population in the city. Therefore, 10 kilometers of sewer lines in a few places in Colombo city will be relaid,” she said.

Accordingly the sewerage lines at Marine Drive, Duplication Road, Mallikarama Place in Maligawatta, Thurstan road and Flower road will be relaid.

Apart from that a 125 kilometers of the sewer lines will be checked by using of CCTV cameras and other sophisticated equipment to find out the real situation of these sewer lines for future rehabilitation purposes.

“The project aims at developing the sewerage system in the city to cope up with the changes in the city in the next 40 years. We have planned this project according to the city zoning plan prepared by the Urban Development Authority and they have estimated the population in different areas in the city. We have planned our project according to that plan,” she said.

Under the project the capacity of the Colombo Municipal Council to maintain this sewerage system in a good condition will be improved. In this regard Greater Colombo Waste-Water Management project will help CMC build institutional skills, comprehensive technical, financial reforms and develop suitable operational system and processes, so that the CMC becomes an efficient and effective waste-water service provider.

Accordingly, the project has purchased four jetting and vacuum trucks, spare parts and accessories worth over Rs. 164 million for Colombo Municipal Council. These four jetting machines given to four Colombo Municipal Council District offices will be used to clean nearly 260 kilometres of sewer lines in the city including 7,000 manholes. The jetting machines help to clean and unclog sewer lines by removing silt, hard deposits and encrustations by using a high pressure water jet.

Apart from that there is another component of the project to conduct awareness programs to educate the public to make them aware of the coorperation they should extend to the CMC to maintain the sewerage system in the city,” she said.

She said that a survey is going on to implement the second stage of the project to cover the areas in the city that have not been covered by the sewerage system.

“We have identified 11 catchment areas that have not been covered by the sewerage system in the city. Mattakkuliya and Kirulapona are such areas. We requested ADB assistance to lay new sewer lines to cover those areas also but we were told since the sewerage lines already existing in the city were not in good condition they have to be rehabilitated first,” she said.

Once this survey is completed Kirulapona and Mattakkuliya will be provided with a sewerage system under the second phase of the project.

The project is being implemented in accordance with environmental safeguards, social safeguards, anti-corruption measures, procurement policy, financial management procedures and information education and communication strategy that have been agreed upon between Government and the Asian Development Bank.

“The project commenced in April 2010 and real construction work began in 2012 and we expected to complete the project by December 2014,” she said.