Water Supply and Sanitation in Nelson Mandela Bay
Nelson Mandela Bay Metropolitan Municipality (NMBMM) provides water and sanitation services to one million people in the Despatch, Uitenhage and Port Elizabeth areas. Water comes from the nearby Kouga Mountain Range as well from the Orange River, which are both located more than 500 kilometers away. It takes a lot of energy to pump and transfer potable water to the city due to the large distances it must travel via large dams, tunnels, pipelines, secondary rivers and rugged undulating terrain.
The Alliance to Save Energy team has met with more than 10 municipal officials from both the water and sanitation units of the Technical Services Directorate, as well as operations and maintenance staff. Senior management officially endorsed the project, allowing implementation to proceed. The team is building relationships with officials in both water and waste water management, as well as third party goods and service providers who are contracted to provide related services to the municipality to acquire more data. During the course of these meetings, the Alliance team discussed the purpose and objectives of the project, planned approach and implementation strategy, data requirement needs, as well as how to overcome some potential challenges.
The Alliance team has made numerous trips to NMBMM to collect data on electric use, meter readings, system configuration, maintenance history, pump efficiency curves, suction and discharge pressures, layout drawings and locality for approximately 70 pump and motor sets located in 20 water pump stations. In addition, the team has inspected 20 water pump stations in the region and one large waste water pump station.
Flow rates, electrical consumption, pump curves and suction and discharge pressures will be used to establish the efficiency of each pump and motor set which will provide the basis for informing potential efficiency interventions.
Based on site visit inspections the Alliance team identified at least five pump stations showing the greatest potential for efficiency improvements. At one pump station there is an opportunity to improve time-of-use of electricity, which would avoid pumping during peak demand periods when costs are higher. Based on initial information provided by the municipality, at least eight waste water pump stations may also be good candidates for efficiency interventions.
Where Do We Get Our Data?
ESKOM, the national electrical utility supplier, released some electricity information on pump station energy use. Munilek, the internal Business Unit of NMBM responsible for supplying and distributing electricity across the city, supplies the remaining pump stations with electricity. The Alliance team is in the process of securing historical electrical usage data for the pump stations supplied by Munilek.
Measuring Water Flows
Measuring the flows at both the water and waste water pump stations is critical in order to establish the current efficiency level of the pumps. Some of the water pump stations are equipped with electro-magnetic meters, but no flow meters are installed at the waste water pump stations. With funds made available via the GlobalGiving Campaign, specialized metering equipment, including components for an ultra-sonic flow meter, pressure transducer and power monitor, will be purchased to measure flows emanating from individual pump and motor sets. Metering equipment is currently on order from Krohne Instrumentation.
Thank you for your support and we look forward to continuing this project so that 1 million South Africans are able to save water and energy!