What type of waste does the activated sludge process primarily treat?

The activated sludge process primarily treats liquid wastewater. This technique involves aerating the sewage to promote the growth of microorganisms that consume organic matter found in the wastewater. As the microorganisms break down the organic pollutants, they form a mass known as activated sludge, which can then be separated from the treated water.

Liquid wastewater typically contains a variety of contaminants, including biodegradable organic materials, which are effectively broken down by the microorganisms in this process. The goal of the activated sludge method is to reduce the concentration of these contaminants in the effluent, ensuring that the water released into the environment meets regulatory standards for cleanliness.

The other types of waste listed do not accurately reflect the primary use of the activated sludge process. Solid waste is not treated by this method; instead, it typically involves different processes such as composting or incineration. Hazardous waste requires specialized treatment due to its potential risk to health and the environment, and biodegradable waste, while relevant in the context of the microorganisms used in the activated sludge process, is considered part of the overall liquid wastewater treatment rather than a standalone type of waste.