Self-Cleaning Networks

To assist water companies address customer complaints, particularly regarding brown water, KWR developed the Self-Cleaning Networks tool. Research into the origins and nature of discolouration problems shows that the major cause is the resuspension of accumulated sediments in pipes. Self-Cleaning Networks provides the user with the design instructions to make such networks self-cleaning. This entails maintaining a certain velocity in the network, which keeps the dynamic process of settlement and resuspension from leading to sediment accumulation. This prevents problems associated with discolouration and long residence times. Self-Cleaning Networks is part of the Watershare Suite of tools.

Drawing of one of the first self-cleaning distribution networks: 1 is the conventional secondary network, 2 and 3 show a typical self-cleaning branch as designed with Self-Cleaning Networks.

Step by step towards optimal network design

The Self-Cleaning Networks tool offers support in the application of new concepts in the drinking water distribution network. It provides the design rules to ensure that the self-cleaning velocity in the tertiary (‘last-mile’) network is attained at least once a day, on the basis of the pressure in the secondary and primary networks. The result is a 10 percent shorter network and a saving on fittings such as valves. And the network no longer needs cleaning, thus: no cleaning costs.

The tool involves a series of steps leading to an optimal network design. The first step consists of taking stock of the existing situation, particularly of the stakeholders, like fire departments or other special users. KWR can help you in harmonising and prioritising the needs of the stakeholders.

Implementation of the Self-Cleaning Networks concept implies a thorough understanding and application of the ‘particle-related processes’. This affects almost every component of the water company, and its success depends on effective change management. The process requires taking a systematic approach and giving careful consideration to each of the steps and stakeholders involved, both inside and outside the company. It concentrates on the detailed technical steps that are needed to enable the incorporation of the Self-Cleaning Networks concept into the network. Subsequently, these steps are translated into a communication process for the company, stakeholders and public.

Self-Cleaning Networks benefits:

• Optimal distribution network design, in terms of both quality and costs.
• About 20 percent saving on investments and commissioning of new and rehabilitated networks, compared to the traditional approach.
• Source-to-tap control, with the possibility of meeting the conditions to provide high-quality, chlorine-free drinking water.
• Satisfied customers relieved of brown-water or other aesthetic water quality problems.

Building a primary, secondary and tertiary distribution network. The Self-Cleaning Networks tool designs the branched tertiary network.

Top-quality, low-cost water supply

The Self-Cleaning Networks concept was developed together with the Dutch water companies, which are conscious of the importance of the distribution network for water quality. Several companies in the country apply the Self-Cleaning Networks design rules based on the particle-related processes model. As a result, the length of such networks exceeds 6,000 kilometres, including both new and rehabilitated networks.