If you are an engineer or facilities manager maintaining cooling towers, you will no doubt have asked
Why does water treatment cost so much?
Here’s a quick breakdown of what you are paying for (and how to get more for your money)
COST No1 – CHEMICALS
Chemical dosing programmes for cooling towers usually consist of:
- Scale/corrosion inhibitor
- Primary biocide
- Secondary biocide
Let’s look at each of these to see what they do and how to check you are getting value for money:
As the name suggests, these chemicals are dosed to the system to reduce scale formation and corrosion. They are clever mixtures and really work – the manufacturers have laboratory test results to prove it. And for this, you pay a premium price – they are not cheap. Ok, so how do you know the right amount of this expensive stuff is going into your system? Your service provider will do a field test (usually once per month) which is ok, but the test is very approximate and – its only once per month. In the days and weeks between the tests, you could be using far too much, or maybe not enough.
One solution is to use a sensor called a fluorometer which measures the amount of chemical in the system and tells a controller to put more or less in the system – cost effective, reliable and simple.
The other question you might ask is – how do I know my expensive corrosion inhibitor chemical is even working – is my system corroding? The good news is – there are simple, cost effective ways to measure corrosion in water systems.
Biocides are chemicals that kill micro-organisms (bugs) like bacteria which can cause you serious problems in your water system. The primary biocide is normally an oxidiser such as bromine or chlorine. Like bleach, they kill all the bugs, all the time. But, as with any chemical they only work if applied properly. If not, you are throwing chemicals (and money) down the drain – literally.
You can test for the biocide level very easily using a kit like this www.droptestkits.com/test-kits/comparator-test-kits
Most cooling tower operators carry this testing out at least once per week
If you are adjusting the dosing manually based on these results you could be wasting a large amount of expensive biocide – accurate dosing to the minimum level saves chemical and money. Here’s a graph from a site doing just that. The hatched area where dosing is above the maximum shows how much is being wasted.
This chemical helps the primary biocide, often by breaking up biofilms. Dosed based on the volume of the system. This leads to 2 questions:
- What is the volume of the system? You might need to calculate this.
- Is the correct volume of chemical going into the system? You need to confirm this by calibrating the chemical dosing pump and/or measuring the amount of chemical being used. You could add a mark with the date onto the chemical container after each dose.
We always recommend that you review the water treatment chemicals you use and see if there are better alternatives.
Also – review the volumes of chemicals you use; are you using more than you should be? And check your £spend – are you getting everything you are paying for?
COST No2. SERVICE
This usually includes a service engineer coming to site and carrying out water tests with a kit – the results of these tests will guide your entire programme, so they are important. Make sure you get good, clear advice about what the results mean and what you need to do. Getting this wrong can result in major problems and serious costs.
You could save money on by opting for a cheaper service provider, but beware – this is usually false economy. Good water chemistry saves you water and energy, and avoids problems like downtime and repairs.
Good service providers will ‘go the extra mile’ by
- regularly reviewing your programme
- addressing problems before they escalate
- identifying improvements (including savings) and helping you implement them
You can also reduce your spend (and improve your water chemistry) by carrying out some tests in-house. By investing in training and a basic test kit, you could make significant improvements to your water treatment and benefit from reduced fuel, water and chemical usage.
Part of the cost of your programme is for your provider to produce reports showing test results, summary reports, recommendations etc, and for a system to keep the records in. This should be user-friendly – you need to be able to access this information to manage the system, and you may need to call upon it as evidence of your compliance.
If you are paying for a comprehensive record keeping system – make sure you understand it and can make use of it, otherwise consider a simpler more cost-effective system.
IN SUMMARY, OUR SUGGESTIONS Are
- Make sure you understand your costs – get a breakdown from your service provider
- Review your programme – do you need everything you are paying for?
- Track chemical usages and review often – are you using more than you need to?
- Congratulate yourself and enjoy the peace of mind!