ABSTRACT
Wastewater treatment facilities belonging to English and Welsh water companies are only obliged by law1 to treat wastes which will not prejudicially affect (eg, by being toxic or inhibitory) the treatment of the wastewater. They are designed, like any other industrial process, to accept certain qualities and quantities of input materials, energy etc.; delivering specified quantities of specified products. Measurement of the degree to which wastewater treatment may be affected by inhibitory wastes, and therefore its cost, has been difficult and contentious, especially since most wastes break down during treatment. Inhibition may have gone unnoticed because of oversized facilities. Biological waste treatment processes may acclimatize to inhibitory/toxic wastes and treat them but with variable consequences on performance.
