Dealing with Trihalomethanes
Achieving 100% Compliance
Trihalomethanes (THMs) are easily the most daunting of all the Water Quality challenges that KWS Alpha is assessed against, due to the intense frequency of testing and the penalties that go with non-compliance.
The unique service provided to Northern Ireland Water, by KWS Alpha, presents a contractual compliance challenge, which is entirely different to the regulatory one facing the regulated water industy:
- KWS Alpha must achieve a final water THM concentration of less than 50 μg/l, which is half the PCV (Permitted Concentration or Value) target for all regulated UK Water Companies
- We are assessed post-works, and not at the customer's tap, so there is no margin for error; we can't blend our water and we can't utilise any distribution chlorine boost. If the water leaving a works exceeds our failure level, we deduct cost from our customers invoice to reflect it
- We have a commitment to NIW to dose chlorine, which contributes significantly to THM formation, for disinfection, and so we must balance chlorine and THM compliance 24 hours a day, 365 days a year.
In 2010/11, KWS Alpha introduced the 'THM Reduction Initiative', a long standing project that targeted 100% compliance with our contractual targets. We did this by:
- Understanding why each of our facilities may be susceptible to THM Exceedances
- Identifying what variables contributed most significantly to THM formation
- Creating bespoke solutions around a THM control philosophy, with clear strategic objectives
- Ensuring our Operations Team have the facilities and know-how they need to ensure 100% compliance, and empowering them to make the right calls to ensure consistently excellent Water Quality standards.
We devised solutions specific to our works based on, but not limited to, successful strategies employed elsewhere. Our approach to THM control is meticulous - we even went as far as to test some of our existing chemicals to see if improving the specification could enhance treatment.
The 'THM Reduction Strategy' results speak for themselves:
- In 2010/11, KWS Alpha experienced zero THM exceedances and, consequentially, incurred no performance deductions; an indisputable example of 100% Compliance
- An average decrease in THM concentration of 8.3% across all results
- The 2010/11 results show a remarkable example of operational excellence, resulting in 100% compliance for one of the UK Water Industry's most demanding Water Quality challenges
- Massive improvement in credibility and reputation with our client on what they consider to be one of, if not their single most, significant Water Quality parameters.
George Butler, Head of NI Water's Asset Strategy said; "The increase in compliance this year is largely due to the targeted capital investment to upgrade five major water treatment works under the £110 million Public Private Partnership (PPP) Project, called PPP Alpha. This has contributed to the significant improvement in Total Trihalomethanes (THMs) compliance from 86.43% in 2008 to 96.39% in 2009."