Ensuring energy efficiency in wastewater infrastructures

Water and wastewater infrastructures are recognised as one of the biggest energy consumers within municipalities, making energy efficiency improvements critical to these operations.

“The indications are that on average water and wastewater accounts for some 17% of energy consumption in a South African metro. In terms of electricity consumption alone (i.e. excluding liquid fuel use for vehicles), the proportion is far higher – often representing as much as 25% of the entire municipality’s electricity bill,” states Sustainable Energy Africa in its 2017 guide ‘Sustainable energy solutions for South African local government: a practical guide’.

KSB Pumps and Valves, suppliers of pumps, valves and related services, note that the water treatment and pumping stages of a water service system are where energy consumption is highest. It adds that the implementation of energy efficient systems will help municipalities obtain, retain and improve Green Drop and Blue Drop certification and can also help to reduce rates and taxes for consumers.

“We have found that the aeration stage is one of the stages which consumes a lot of energy as it requires large pump systems and municipalities may not always pay attention to this aspect and may neglect to overhaul due to the expensive nature of more energy efficient systems. However, what is important to remember is that although the expense may be high at the start, the benefits of cost saving in the long run will be worth it,” explains KSB Pumps and Valves senior project engineer Hugo du Plessis. 

The company notes that load-shedding has a significant impact on municipalities’ ability to provide services and that inefficient pump systems are not able to keep up with the backlog of water provision when load-shedding occurs. KSB Pumps and Valves provide expertise to assist with site energy efficiency audits and provide a full suite of solutions to assist municipalities to make the transition to more energy efficient systems.

Products include:

• High-pressure pumps from the HG range, suited for handling feed water in power stations and industrial plants, offering high levels of efficiency and reliability.
• Horizontal or vertical single-stage submersible motor pumps from the Amarex KRT range, suited to wastewater management applications such as wastewater treatment plants or sludge disposal.

“Reliable, energy efficient pump systems will not only result in energy and cost saving, but there are also other benefits for the municipality which include: no spillages, a reliable uptime, decline in downtime as well as better water quality,” adds Hugo.