Quality of Raw Water

LWB abstracts its raw water from Lilongwe River. The raw water is of low quality mainly during the rainy season due to the nature of the environment along the river course. The river passes through a rural agricultural area and it is heavily degraded. The raw water is very turbid and has high microbial content during the wet months due to excessive run off water which carries with it soil particles, nutrients and other wastes that are deposited into the water bodies. This is because people have encroached the protected areas along the river banks for cultivation and settlement.

Raw Water Abstraction

The water abstraction points are located at Water Works and the water is abstracted by low-lift pumps into the treatment plants where it undergoes the treatment process. The treatment process is a six stage process and begins right at the abstraction point.

Stage1: Raw Water screening

At the intake points, the raw water is screened before it is conveyed into the raw water reservoir. At this stage big particles that come together with the raw water from the river are removed.

Stage 2: Natural Sedimentation

Screened water pumped into the raw water reservoir, undergoes a natural sedimentation process where settlement of heavier particles than water takes place.

Stage 3: Coagulation and Flocculation

The water undergoes a chemical dosage process. Suspended particles in water stick together when a chemical of opposite charge is added and neutralizes the negative charges on non-settleable suspended particles such as clay and colour producing organic substances.

Stage 4: Sedimentation

After the chemical dosage process, the water goes into sedimentation tanks where flocs formed through coagulation process settle down thereby separated from the water.

Stage 5: Filtration

During this process, all flocs that did not settle in the sedimentation tanks are removed through the use of three different layers of sand; pebbles, coarse and fine sand.

Stage 6: Disinfection

After filtration, a chemical process of disinfecting the water from all harmful bacteria is conducted to make the water safe for consumption. All these processes are monitored in the laboratory through process control tests that are carried out every 3 hours. Process Control Tests ensures optimization for chemical dosages and compliance with World Health Organization guidelines for drinking water quality.

Treated Water Quality

LWB makes sure that its treated water is of acceptable quality. LWB strives to ensure that its water is colourless, clear, odour free and has a pleasant taste. Of the few complaints that the Board receive, most are related to the aesthetic properties of the water as these are easily evaluated by the customer. The Board is committed to ensuring that customers receive water of acceptable quality and if there are problems to do with quality, the Board ensures that such problems are sorted out promptly when reported. To ensure that there is always supply of acceptable quality water, customers are encouraged to report any water quality problems they may notice.

Water Testing Equipment

LWB’s laboratory is equipped with a number of water analyzers for analyzing heavy metals. There are also other pieces of equipment used for routine water analysis such as pH meter, turbidity meters, filtration unit for culture, flocculator etc. The laboratory also provides services to private clients who bring their water samples for analysis at a minimal fee. Distilled water is also available for sell. For more information and enquiries can be made with the Laboratory personnel.

Sterilization of New Mains

All new mains and reservoirs undergo sterilization before they are used to transport and store water for consumption. This is done to ensure that they are free from harmful microorganisms and are clean for storage of water for human consumption. Periodic flushing of water mains is carried out to remove accumulated debris that emanate from pipe bursts. Water storage tanks are also cleaned once every two years.

Water Storage Facilities

Treated water is pumped from treatment plants into service reservoirs that are strategically located within the supply area. The Board ensures that water storage is adequate in the reservoirs enough to last for a number of hours when there is a water supply outage.

Catchment Management

LWB manages the catchment area around the two dams in Malingunde. The Board facilitated the formation of a local Community Based Organization (MECDO) to help in catchment protection. The Board supports the group in carrying out catchment management activities outside the buffer zone of the dams with such initiatives as training of the communities in management of natural resources, fruit grafting, financial management of funds generated from income generating activities, provision of tools and seeds for tree nurseries.

The Board also works with technical experts from Malawi Government, Lilongwe University of Agriculture and Natural Resources (LUANAR) and Non- Governmental organizations who offer their expertise in implementing environmental projects within Malingunde area.

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