The water industry has embarked on a major programme of capital expenditure in order to comply with increasingly stringent environmental protection legislation. For wastewater, this expenditure is aimed at improving the general standard of treatment at wastewater plants and reducing the possibility of breaches of discharge consents. It is questionable, however, whether or not this almost total concentration on end of pipe facilities is the most beneficial approach for the protection of the environment. Much of the UK's sewerage system is aged and in need of repair. Earlier estimates of the condition of the pipeline network are now thought to have overestimated the amount of work required to maintain the network in sound structural condition, but other problems still exist. The effect of leakage into these pipelines through groundwater infiltration, or out of the pipelines and into the surrounding ground as exfiltration, has not yet been properly addressed. This Paper examines the economic, legal and environmental aspects associated with these extraneous hows by considering the effect they have on each stage of wastewater collection and treatment. Options for controlling pipeline leakage are considered and a more positive attitude to abatement of these flows is proposed.
