A Type B dispersal bed receives effluent from which treatment unit?

• A. Level I treatment unit
• B. Level II treatment unit
• C. Level III treatment unit
• D. Level IV treatment unit

Answer: (D)

Type B dispersal beds are designed to accept effluent that has been highly treated, with very low solids and a low organic load. The most advanced treatment unit (Level IV) produces this cleaner effluent, reducing suspended solids, BOD, and pathogens enough that the bed’s finer media and loading characteristics won’t clog or clog as quickly. If effluent from lower-level treatment units were used, the higher solids and organics could overwhelm the bed, leading to reduced infiltration and system failure. So, the Type B bed is matched with effluent from the highest level of treatment to ensure reliable performance and protect the soil absorption area.