The 1000mm invert, 12 population gravity outlet shallow dig Delta sewage treatment plant is supplied with a low visibility locked pedestrian cover with internal blower housing located directly below for easy maintenance. The sewage treatment process takes place within the main body of the tank: first, coarse solids are filtered and retained for gradual breakdown. Then the resulting liquid is processed in the biozone treatment chamber. Finally, the solids are allowed to settle and the treated effluent is discharged by means of gravity. Manufactured by Clearwater from glass reinforced plastic (GRP) and certified to EN 12566 - building regulation compliant. The Overall dimensions are 2720mm diameter x 3244mm long.