Tetra Tech, on behalf of its clients, manages the complex chemicals investigation programme (CIP) which investigates the occurrence, sources and removal of trace substances from wastewater works to achieve the objectives laid out by the UK Water Industry Research (UKWIR) and the Environment Agency.
The programme commenced with CIP1 in 2010 and continues with the 4th phase CIP4 completing in 2027.
These studies have established a definitive basis for the overall national assessment of the risks posed by chemicals in wastewater discharges, to meet the objectives of the “programmes of measures” required under the Water Framework Directive (WFD).
Tetra Tech working on behalf Anglian Water, Severn Trent Water, South West Water, Southern Water, Thames Water, United Utilities, Northumbrian Water and Welsh Water has managed these complex programmes providing tailored solutions to their specific catchment requirements to achieve the objectives laid out by UKWIR and the Environment Agency.
Tetra Tech are also supporting UKWIR under a CIP4 research driver with the comprehensive analysis of biosolids, return liquors and active sludge to further the understanding of the mobility and fate of PFAS and other emerging contaminants throughout the sewage cycle. Other work associated with CIP4 catchment studies including the TraC investigations are being supported by Tetra Tech’s analytical laboratories covering freshwater and saline water trace nutrients.
Challenge
Many of these substances had never been analysed to these extremely low levels in such challenging and diverse matrices. To put this into context, the levels at which these substances must be detected was much lower than the levels required for potable drinking water.
Drinking water is a clean matrix and is relatively easy to work with compared to raw sewage or trade effluent. These substances are made up of a very complex and variable mixture of substances containing high levels of fats, oils and greases, which pose a real challenge as they have to be removed prior to analysis or they will foul the instrument and mask the substance of interest.
On top of the technical challenges, we also managed the logistics of collecting samples across a vast geographical area, and from very different sources ranging from under roadways to open rivers and treatment works.
Solution
The samples were collected by Tetra Tech sampling teams. As the holding times for these substances is temperature and time critical, the samples were filtered/stabilised on site prior to being delivered each day to our laboratories. Our team of scientists successfully developed robust methods to detect and quantify these substances at levels in the sub parts per trillion range using state-of-the-art instrumentation.
As Tetra Tech was one of a very small group of laboratories capable of carrying out this complex work, a laboratory technical steering group was set up in collaboration with UKWIR, the Environment Agency and a German University which assisted with the provision of performance testing samples to benchmark the quality of the analysis generated across the programme. The analytical results provided have, and will be, used to influence water quality legislation and future monitoring schemes.
Benefits
- More than 100,000 samples
- More than 400 priority and emerging substances
- 11 separate utility networks
At a glance
Client
Multiple (Thames Water, Anglian Water, United Utilities, South West Water, Severn Trent Water)
Location
UK-Wide
Services
Chemical analysis, data management and reporting of regulatory outputs, clean water and wastewater sampling, logistics and sample transport, method development and scoping works, project management
The project featured in this article was undertaken by RPS, A Tetra Tech Company and originally published on RPSgroup.com. In March 2026 RPS rebranded to Tetra Tech.