Thames Water has awarded an AMP7 framework contract for pollution investigation services with an estimated total value of up to £10.4 million.

The contract covers specialist investigation services by suppliers to resolve polluted surface water sewer outfalls by testing and tracing of the affected sewer network to determine where misconnections or other pollution sources exist. These range from widespread misconnections of household appliances (e.g. washing machines), raw sewage sources (toilets) to trade effluent from commercial premises.

Thames Water is usually alerted to the possibility of a polluted outfall by reports from the Environmental Agency, Local Councils, Thames’s own work force, stakeholder groups or the public.

The water company runs surface water outfall programme (SWOP) in conjunction with the Environment Agency to identify outfalls to watercourses suffering from wastewater pollution.

The outfalls have been diagnosed with widespread diffuse sources which are most likely from third-party misconnections.

The suppliers will trace the pollution and narrow down the areas in a catchment that require further investigation. Property surveys are then carried out in these areas which includes initial letters to notify properties of the survey requirement and letters to advise owners of any issues and/or misconnections that are identified by surveys of pipework using dye testing, caging, CCTV etc.

Water and Environmental Resource Management Ltd and RPS Environmental Management Ltd have both won a place on the framework contract, which will run for an initial 3 years with further extension options.