To ask the Secretary of State for Environment, Food and Rural Affairs if she will make it compulsory for fast food outlets and commercial kitchens to install (a) fat traps and (b) grease interceptors in their waste water discharge systems. 
Sewerage undertakers have powers to control and reduce discharges of fat and oil into sewers. If they consider the discharge constitutes trade effluent, their consent is required in accordance with the provisions of the Water Industry Act 1991. The consent may set conditions and require the elimination or diminution of any specified constituent of the trade effluent before it enters the sewer. Such a discharge without the undertaker's agreement is a criminal offence.If the sewerage undertaker does not classify the discharge as trade effluent, it is still an offence under section 111 of the 1991 Act, for a person to empty into a public sewer, or any drain or sewer connecting with a public sewer, any matter which is likely to injure the sewer or drain, to interfere with the free flow of its contents or to affect prejudicially the treatment and disposal of its contents. Any person who is found guilty of an offence is liable to a fine or imprisonment. I consider these statutory controls to be sufficient. We would expect sewerage undertakers to take action where a problem arose and to encourage appropriate preventative measures to stop problems arising from fat and oil entering the sewers.