SPOTLIGHT PROJECTS
Pelende Village Water Supply Rehabilitation
Pelende Village is located on a high plateau in Kwango Province, near the Angolan border, approximately 560 kilometres to the south and east of Kinshasa.
The original village water supply was constructed in 1956 which continued in operation until approximately twenty years ago when it finally stopped working due to age-related degradation and lack of maintenance. Discussions regarding refurbishment have taken place over the years, but funding has only recently become available.
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A 20-kilowatt PV system was installed in 2010 and upgraded in 2018. The system provides electrical power to the sisters’ community, hospital, and primary and secondary schools.
Pelende presents a difficult challenge as is blessed with an excellent source of clear water in the form of a natural spring. The issue, however, is that the spring is located at the base of a ravine at an elevation nearly 185 meters below the level of the village and at a distance along the ground of 850 meters from source to the village water storage tanks.
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The original technology utilized a hydraulic ram (bélier) type pump that utilizes the power of the flowing stream to drive the pump. The advantages are that the pump requires no electrical power or external controls, and can develop the very high pressures required to lift the water to the tanks located in the center of the village.
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The refurbishment of this system utilizes an updated version of the same technology with new piping, valves, accessories, and with distribution of water to the village at several points using buried piping. The goal is to provide the village with 72,000 litres per day of clean water. Purification will be performed as a secondary process at limited points of distribution.
Ngidinga PV and Water Systems
Sisters of Notre Dame de Namur Community, Ngidinga, is located approximately 350 kilometers to the southwest of Kinshasa, the capital city of the DRC. The village has several thousand inhabitants and potable water supplies are quite limited.
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A 45-kilowatt PV system was originally installed as one system, but due to the size and complexity of the site was later modified to be two separate systems. One serves the Sisters’ community and primary and secondary schools. The second serves the water plant, hospital, residences, and a health center. The combined systems feature 60 kilowatts of lithium-ion battery storage.
The Off Grid Systems project refurbished the original site headworks and source receiver tank for a small below ground natural spring whilst improving village access to the public discharge point. The spring supplies approximately 50,000 litres of clear water each day. The source receiver had to allow the source tank to fill whilst not disturbing the flow of water to the public sump.
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Water that fills the source tank is then pumped over a distance of 800 metres through 42 metres of elevation and discharged into one of two 6,000 litre above ground storage tanks which are fabricated with 60 degree cone bottoms. This configuration allows any sediments entrained in the raw water to settle into a trap and be readily flushed before the water is used. A centrifugal pump, powered by the site photovoltaic system, can fill one of the tanks in approximately two hours.
To supply electrical power to the pump and carry the water from the source, a trench at a depth of one metre had to be dug by hand from the site across open fields down to the location of the source.
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A second stage pump moves water from the ground storage tanks to a pressure tank located atop an eight-meter tower that allows for distribution of water to the site through buried piping.
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In addition to the SND community of sisters and support staff, the system also provides water for a primary and secondary school and the Ngidinga hospital, all of which are operated by the sisters.
