Until 2 January, the Wilton site had consent to discharge 150,000m3 of effluent per day into the Tees. It is the largest discharge of its kind in Britain and one of the largest in Europe.
The consent was "deemed", and as such imposed few specific limits on the effluent. Deemed consents were issued in 1984 as a transitional measure to legalise uncontrolled discharges before they were brought under full control.
Until now, t