Sustainable cleaning of cooling circuits

A new system-based approach to cooling water cleaning

Systems engineering specialist ONI has also repeatedly experienced problems with water quality in its customers’ systems. Maintenance staff from the companies concerned typically attempt to counter this problem by taking various measures and installing equipment – with varying degrees of success. In order to develop a sustainable method for cleaning cooling water, ONI has adopted a completely new system-based approach.

ONI-Wärmetrafo GmbH

ONI-Wärmetrafo GmbH, based in Lindlar in Germany’s Upper Bergisch region, has been specialising in energy-saving integrated systems solutions since the beginning of the eighties. ONI’s range of products and services ranges from consulting and planning to the turnkey construction of complex, energy-optimised systems. Today, the family business employs almost 500 people and works for more than 5900 customers in over 70 countries.

Improving water quality without biocides

Cooling water contamination via bacteria, viruses, algae and fungi is usually controlled by adding chemicals. As well as being difficult to handle, this process incurs substantial costs and rarely achieves sustainable success. In addition, the problem of contamination with solid particles remains; this applies to both coarse solids liable to settle quickly and dispersed fine solids. In cooperation with KSB, ONI has been exploring ways of improving water quality without biocides.

A filter flushing station with a high-pressure pump

ONI engineers designed a filter flushing station in which the membrane filters are regularly flushed by a high-pressure pump, eliminating the need for chemicals. Since the entire flushing mechanism had to be accommodated within a compact unit that could be easily transported to customers on other continents – not just in individual parts but as a whole – the installation space available for the high-pressure pump was extremely limited.

ONI and KSB have been working together in the field of industrial cooling systems for decades. Thanks to its high level of expertise in water pumps, KSB now supplies around 1000 Eta pumps a year to the systems engineering specialist. The strength of this partnership has always been the joint development of solutions. As KSB offers a wide range of high-pressure in-line pumps with various performance levels and designs, it proved possible for the company to equip ONI’s filter flushing station with the Movitec pump. In addition to its impressive performance, the vertically installed pump offered the further advantage of only requiring a small footprint, and thus meeting the limited space requirements within the flushing station.

The ONI-AquaClean filter flushing station flushes the membrane filters in defined cycles. This can dramatically improve water quality in relatively short periods of time. In some cases, as little as one week of operation can result in undetectably low levels of solid particles. Biological contamination levels in the cooling water can also be reduced by up to 99.9%.

Since 2018, 90 ONI-AquaClean filter flushing stations have been put into operation in Germany. As KSB – like ONI – works with customers in more than 70 countries, the company is able to offer its services across a geographical area which perfectly complements ONI’s activities. The use of ONI-AquaClean is proving to be a trend-setting solution, especially in terms of sustainability. A patent application for intended use and functionality has already been filed.

System: Cooling water systems

Client: ONI-Wärmetrafo GmbH

Products used:

1x Movitec V 004/08 per filter flushing station

(Status 05/2020: 90 units in total in Germany)