Disinfection By-Products

Disinfection By-Product Risk Assessment: DBPs of Concern

Reference: 14/TX/05/2
ISBN: 1 84057 704 5
Published Date: 27/01/2014

The disinfection by-product (DBP) rule requires water companies to keep DBPs in drinking water as low as possible without compromising the effectiveness of disinfection. In the UK, emphasis has been on the regulated DBPs, mainly the trihalomethanes (THMs), but other DBPs must not be present at concentrations that constitute a potential danger to human health. 

The large number of known DBPs makes measurement impractical, if not impossible. Accordingly, a pragmatic risk-based approach to identify potential DBPs has been developed, based on knowledge of factors which lead to their formation and mitigation. DBPs have been categorised according to their chemical structures and the potential risks for these categories, based on toxicity, likely occurrence and concentration.

This approach has been encapsulated in a spreadsheet-based risk assessment tool that enables the potential formation of DBPs at treatment works to be quickly assessed, and the works to be ranked according to the risk.

Price: £13  

Inorganic Disinfection By- Products

Reference: 98/TX/01/7
ISBN: 1 84057 136 5
Published Date: 17/04/2002

As part of the UKWIR toxicology programme, iodate and perchlorate were identified as having broad similarities to other oxyhalide ions such as bromate, chlorate and chorite. Discusses the formation, occurrence and analysis of iodate and perchlorate in groundwater, surface water and following chlorination in water treatment. Iodate showed persistance in the distribution system, but concentrations of perchlorate were found to be very low indeed.

Price: £10  

Trichloroacetaldehyde in Water Supplies

Reference: 95/DW/05/1
ISBN: 1 84057 044 X
Published Date: 17/04/2002

The objective of this work was to survey trichloroacetaldehyde (TCAL) concentrations in final waters from a selection of water treatment works acrtoss the UK. The selection covered a wide range of raw water types and treatment conditions. The results were compared to the provisional WHO guideline of 10 ug/ 1 in order to determine whether this value is likely to be exceeded in practice. The survey indicated that TCAL only exceeded the guideline value at a few works, one works exceeded this value by a considerable amount. One resampling at this works the concentration of TCAL was well below the provisional value. No clear explanation was obtained for these high concentrations of TCAL. In general concentrations were found to be low, with most having concentrations of less than 20% of the provisional guideline value. It was therefore considered that TCAL concentrations would not be aproblem for most treatment works. A few treatment works may experience concentrations close to or exceeding the guideline level.

Price: £10