1/8 inch Durable rigid polyethylene sheet for Sewage treatment plants . 25 04 2022 . Operation of Wastewater Treatment Plants: A Field Study Operation of Wastewater Treatment Plants, WPCF Manual of Practice No. 11, Water Pollution ntrol Federation, 3900 Wisconsin Avenue, WaHDPEngton, D.C. 20016. Price $2.00 to members; $4.00 to others. ...