NORTHERN REGION OF THE DISTRICT WATER SUPPLY
III (2) / 00 PROJECT

Location
The project consisted of a variety of Pressure type Filters for various locations throughout the northern region of Malawi, as listed below:

Mchinji Site
Four off W 4000 Pressure type Filters – having a total capacity of 72 m³/hr

Rumphi Site
Three off W 4000 Pressure type Filters – having a total capacity of 54 m³/hr

Chilumba Site
Two off W 5000 Pressure type Filters – having a total capacity of 45 m³/hr

Chintheche Site
Two off W 4000 Pressure type Filter – having a total capacity of 36 m³/hr

Nkhata Bay Site
Three off W 5000 Pressure type Filters – having a total capacity of 67,5 m³/hr

The W4000 and W 5000 Filter vessels were fabricated from mild steel plate throughout, and epoxy lined internally, and zinc chromate primed externally, and transported from South Africa to Malawi by road.
Loss of Head Measurement
Pressure gauges have been installed on each Pressure Filter to determine the head loss over the filter media.

Chemical Dosing
Two different types of chemicals dosing facilities have been provided for each location, consisting of Calcium Hypochlorite (HTH), for pre-filtration and post-filtration, and Aluminium Sulphate, for flocculation.

Backwashing Equipment
Water stored in elevated storage ranks is utilised for backwashing the Pressure Filters these storage tanks were filled by Booster pumps on the Mchinji and Rumphi sites.

Air Scouring
Roots type URAI Blowers are used to air scour the Pressure Filters.