The guidelines from the Environment agency for underground interceptors/separators PPG3 and specifically PPG13, which are the guidelines for silt, vehicle wash and petrol oil separators and interceptors. These guidelines require discharge from brush wash or pressure washers to discharge into a foul drain.Where there is no foul drainage available, the effluent must be contained within a sealed drainage system or catch pit (silt trap) for disposal by a licensed waste contractor.

 

For more information click here