Innovative Solution

groundwater quality, ‘drinking and cooking’

technical

In Sri Lanka owing to the geology, rainfall patterns, land use etc. there is considerable variance in the quality of groundwater. Water quality issues include salinity, hardness, certain minerals such as Fe, Mn, Fluoride, agricultural pollution etc. The required water treatment technology is too expensive for rural water supplies and as a result, often the groundwater source is rejected. The North Central Province, a predominant paddy cultivation area, is plagued with chronic kidney disease (CKD). CKD is present in areas where the groundwater is hard and contains high Fluoride.

A new strategy where treated water is provided exclusively for drinking and cooking purposes has been developed.  A supply of 5 – 6 lpcd is considered adequate. 1 to 2 litres is the norm for drinking and 4 litres for cooking. For all other uses such as bathing, washing, toilet flushing, groundwater sources such as dug wells, hand pumps will be continued to be used.

Under the proposed system, groundwater could be treated using the appropriate advanced treatment technologies such as reverse osmosis, ultra-filtration or adsorption techniques. Water tankers could be deployed to supply community tanks within a radius of approx. 10 km from the water treatment centre. In the country’s typical rural setting one could expect approx. 12 villages having a total population of approx. 7750. The water requirement for drinking and cooking would be 40 m³/d. Thus considering 20 hours operation a 50 m³/d treatment plant would suffice. The capacities of storage tanks are designed based on filling being carried out twice a month.  The number and capacities of community storage tanks would be decided depending on the spread of housing units. The capital cost for such a system would be approx. Rs.11,000 (US$ 100) per beneficiary household.  The monthly recurrent cost will be within Rs. 300 (US$ 2.7) per household.

In sparsely populated rural areas where groundwater is available but the water quality has deteriorated to an extent that the conventional water treatment processes are ineffective.

Project was initiated by National Water Supply & Drainage Board.

Projects will be implemented in consultation with the local authorities. In disease prone areas, the Department of Health will also be a strategic partner.

NWSDB under its decentralized setup have Rural Water Supply Units in the provinces (1^st tier) which would facilitate project implementation and address sustainability issues.

Local authorities (2^nd tier) would address asset ownership and also engage in / facilitate operations.

Community Based Organisations (CBO) (3^rd tier) will act as caretaker of the community tanks and facilitate revenue collection.

NWSDB, the national agency responsible for water supply has approved the new concept. 

This concept was tested in a CKD affected village named Billewa  in March 2011 as a World Water Day event. The village was provided with 50 nos. 1000 litres storage tanks, one tank to be shared by 3 houses. Filling using water tankers is carried out twice a month. Each house was given two 10 litre containers. They are expected to fill the two containers once a day and use exclusively for drinking and cooking. Two additional projects covering populations of 7500 and 15500 are being planned. Possibility of outsourcing the operation to the private sector will be looked into. 

In rural areas where the groundwater quality is such that conventional treatment processes are ineffective, what could be the cost effective solution to provide safe drinking water?

The proposed solution is technically feasible, cost effective and affordable both in terms of capital and recurrent costs. It is socially acceptable for rural communities. Required maintenance support for the treatment units could be provided by NWSDB /private sector.

If these communities are to be provided safe drinking applying advanced treatment as practiced in conventional water supplies, the capital cost per beneficiary household will be in the order of US$ 1200. The monthly recurrent cost US$ 10 per household. The corresponding costs as per this proposal are US$ 100 and US$ 2.7 respectively.  As the treatment units are small maintenance is relatively easy. It is a simple, cost effective and reliable system.

The pilot project in the village, Billewa is functioning very satisfactorily. Other villages are also demanding such a facility.

• Time taken for implementation: As the project involves some degree of community participation, it would be necessary to monitor the total implementation time.
• Operation of treatment units: Although these relatively small units are easy to maintain, operators’ training, availability of spares etc. are important for satisfactory operation. Downtime for maintenance, water quality should be monitored.
• Intended proper use by the community: The system is designed such that the water supplied is used for ‘dinking and cooking’ only. This needs to be monitored.
• If it is a disease prone area, medium and long term health indicators: it is expected that there would be medium term and long term health impacts. The baseline data regarding the applicable health indicators should be established. There should be periodical monitoring of these indicators.

Government, Health Authorities, Area Politicians, Community would all be interested.

The solution will work well as it is cost effective, simple and reliable. Also, it is socially acceptable by rural communities.

When there are complex water quality issues such as salinity, hardness, fluoride, agricultural pollution etc. there are no straightforward solutions. Rainwater harvesting could be a solution. However, initial costs are higher and the houses should have a fairly regular and acceptable roofing to effectively harvest rainwater.

The local conditions such as, groundwater quality, availability of alternative sources, the spread of housing in the villages, affordability aspects etc. should be carefully considered in drawing up the proposals.

The investments/costs are,

• Capital cost US$ 100 per beneficiary household.
• Monthly operation cost US$ 2.7 per household.
• In Anuradhapura District, to cover 60000 households, US$ 6 Mn is needed.

For the success of the solution, community awareness and political will are necessary. In the local situation, there is a high degree of political will. Politicians at both central government and local government are extremely supportive to the concept.

National Water Supply and Drainage Board has approved the concept. The Hon. Minister and the Ministry of Water Supply and Drainage is very much supportive and have instructed to implement this programme. The Ministry of Health has fully endorsed this programme. We are holding meetings with them. Ministry of Finance and Planning has also endorsed the program.

The two projects being planned will be implemented with local funding.

No major funding commitments as yet.

National Water Supply and Drainage Board, Sri Lanka.

Nihal Ferdinando, Additional General Manager (Policy & Planning)

Email:  nihalferdi@hotmail.com

Phone: +94 773 129434

The relevant documents will be  emailed.