שאלה | Anaerobic digestion and disinfection are often applied in addition to the main activated sludge process. Onto which streams they are applied? (Chose the correct statement)

Anaerobic digestion and disinfection are often applied in addition to the main activated sludge process. Onto which streams they are applied? (Chose the correct statement)

		Anaerobic digestion is applied to the sludge and disinfection to the secondary effluent.
		Anaerobic digestion is applied to both the sludge and the secondary effluent.
		Disinfection is applied to both the sludge and the secondary effluent.
		Anaerobic digestion is applied to the secondary effluent and disinfection to the sludge.