Question

The waste sludge production form a trickling filter plant is 12.5 m³/d containing 620 kg of solids (70% volatile). The proposed anaerobic digester design to stabilize this waste consists of two floating-cover heated tanks, each with a volume of 480 m³ when the covers are fully raised and a volume of 310 m³ with the covers resting on the landing brackets. (A) Calculate the digester volume per equivalent population with the covers fully raised. Assume 100 g of solids production per capita. (B) Calculate the digest loading in terms of kg volatile solids fed/m³ of tank volume below the landing brackets/day. (C) Calculate the digested sludge storage time available between lowered and raised cover positions. Assume a volatile solids reduction of 60% during digestion and a digested sludge moisture content of 93%. Show all steps.

Answer 1