Wastewater Management
Process water filtration should not be as clear as mud
If an organisation can clean up process water and re-use it just one more time, it will effectively reduce its process water costs. Steve Cupples reports.
Wenn ein Unternehmen Prozesswasser reinigen kann und auch nur ein einziges Mal wiederverwenden kann, senkt es schon effektiv seine Prozesswasserkosten. Steve Cupples berichtet.
Si une organisation peut nettoyer l’eau de traitement et la réutiliser ne serait-ce qu’une fois, cela réduira effectivement ses frais de traitement de l’eau. Steve Cupples témoigne.
I
ndustry worldwide uses water in many different ways and in different amounts, therefore water- saving technology, in many cases, is used in multiple applications.
The commonalities however are that
highly efficient water-saving techniques are proven to not only reduce an organisation’s carbon footprint but also to make huge savings on energy bills and improve production and performance. In many operations within the
manufacturing, industrial and commercial sectors the use of water is often an accepted process cost. There is scant attention paid to reducing such a significant service cost, with fixing leaking taps often being the extent of energy saving in this area. With water, unlike with electricity
or gas, the consumer pays for both the supply of water to the plant and once used he pays again for its disposal. The simple fact is if an organisation
can clean up this process water and re-use it just one more time it will effectively reduce its process water costs by a staggering 50%. If, say, a food processing plant /hr (10,000
uses 10 m3
litres) and is a 24-hour operation, the water bill for this operation could well be in the region of six figures. Yet having the ability
Fig. 1. (Right) Process water users can save money by the installation of CrossFlow HEMF, and at the same time reduce operating costs.
to remove solids of 1.0 micron and less, plus any additional treatments, to enable process water re-use would cost just US$50,000 to US$80,000 giving a payback within six months. This is a fantastic ROI. Industry will also see a reduction in plant downtime, increase productivity and reduce
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wastage without affecting the quality of the finished product.
So how can savings be made? A medium sized building with computers may well have installed refrigeration chillers that have 200- 300kw of electrical energy. Larger buildings with high populations or personnel and or computers can be much bigger. Many buildings require heating in
winter and so use a combined system of chilled water and hot water. On the hot water systems this is connected to the hot water boiler, very often driven by oil or gas. On the cooling side, a cool water circuit is connected to refrigeration chillers to enable cooling to occur. The energy input by the boiler or the
chiller is significant whether using gas, oil or electricity to achieve the heating/ cooling. Ask any maintenance engineer what
colour the water is in this system and this will range from pale straw (usually found in a new system) to black (found in a typical system). This discolouration is not just ‘yucky’, it is actually having a major negative effect on the system.
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