Which of the following is the main component of the Type A dispersal bed?

• A. A treatment unit
• B. A gravel layer
• C. A sand layer
• D. A drainage pipe

Answer: (A)

In a Type A dispersal bed, the central element is the treatment unit because this design centers on providing initial wastewater treatment as the primary function before the effluent enters the soil. The treatment unit handles solids removal and begins breaking down organics and pathogens, reducing the load that reaches the soil. The gravel and sand layers, along with the drainage pipe, are important for distributing the effluent and filtering it as it moves through the bed, but they serve to support and convey the wastewater rather than serve as the main processing component. So the treatment unit is the best answer because it defines the bed’s primary treatment role within the system.