Identification of treatment conditions which minimise DBP formation

Reference: 20/TX/05/3
ISBN: 978-1-84057-892-8
Published Date: 15/07/2020

Disinfection by-products (DBPs) are formed from the reaction between an oxidative disinfectant (such as chlorine or ozone), and organic and inorganic precursor compounds, usually natural organic matter or bromide ions. This research sought to determine the relative importance of different DBPs and the factors that influence their formation, with the objective of developing a practical guide to assist water companies in managing DBPs. This was achieved through a literature review of toxicity data to establish a ranked list of priority DBPs. Extensive laboratory investigations were undertaken to determine the influence of different treatment processes on precursor removal across five different chemical groups of DBPs (21 individual compounds) for different types of water source. Samples were also taken across drinking water treatment works to validate the laboratory results. The toxicity data was used to assess potential risk (the hazard index) and the relative importance of DBPs shown to change for different water sources and treatment processes. A limited number of DBPs were dominant in the overall assessment of hazard index. These were principally the haloacetic acids, specifically those that incorporated bromide into their structure. However, when present, the nitrogenous DBPs were also important. Guidance was developed on the operation of different treatment processes for minimisation of the priority DBPs.

Price: £300  

A sampling and analysis programme to determine the concentration of radon in water samples

Reference: 17/TX/01/38
ISBN: 1 84057 827 0
Published Date: 17/02/2017

The objective was to develop a sampling and analysis programme to determine the range of concentrations of radon in public water supplies. The study focussed on sampling groundwater sites that had previously been classified as being of medium and high Hazard potential of containing radon in water. Over 300 samples were analysed from 124 England and Wales public water groundwater supplies with the majority from sites classified as medium radon hazard. Most of the sites classified as High Hazard sites were also sampled. All samples were recorded as having radon concentrations below 100 Bq/L-1 with the vast majority below 50 Bq/L-1. The low concentrations of radon found in samples from public water supplies provide some reassurance for public health protection.

Price: £100  

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  

Assessment of the Performance of Wastewater Treatment Works in Removing Oestrogenic Substances

Reference: 10/TX/04/17
ISBN: 1 84057 562 X
Published Date: 24/06/2010

The National Demonstration Programme(NDP) has been established to further an understanding of how current and advanced treatment processes used at wastewater treatment works affect the concentration of certain endocrine disrupting chemicals (EDC). This project has undertaken the co-ordination of the NDP investigations, the establishment of quality control procedures for data collection and the interpretation and reporting of the results obtained. The study has shown that, where adequate receiving water dilution is available, EDC removal by conventional nitrifying treatment processes is sufficient to meet tentative predicted no-effect concentrations for the substances of concern. Where adequate dilution is not available, more advanced tratment may be required but this would result in significant additional cost and increased greenhouse gas emissions. Of the three advanced treatment processes investigated (oxidation using ozone or chlorine dioxide, or adsorption using granular activated carbon), the most cost effective was found to be ozone at a dose of 1 mg/l.

Price: £14