ACTIVE SLUDGE BIOLOGICAL SYSTEMS (PROLONGED AEREATION)

The water waste coming from built-up areas and the biological water coming from industrial activities can be treated with active sludge depuration systems.

In case of civil waste the depurating treatment foresees the following steps:

	PRIMARY DECANTATION. It takes place in an Imhoff tank in order to hold floating materials and likely sedimentable bodies to obtain a partially clarified effluent reducing the polluting load of approximately 30%. The soapy waters are pre-treated in a grease condensing tank.
	BIOLOGICAL OXIDATION. It takes place in an oxidation tank where the civil waste comes into contact with microorganisms that, with oxygen from blow side pipes, transform the organic substance into stable matter. The destruction of the polluting loads can get to 98% and it is closely correlated to the concentration of active sludge in the tank, to the applied organic load and to the retention time.
	FINAL DECANTATION. It takes place in the hopper-shaped chamber, where the sludge goes down to the base of the tank and the purified water comes out through a small baffle in the sample taking pit and then discharged to the receiving body. The decantated sludge is then taken and put into cycle in the oxidation tank.

 

In case of industrial biological waste that is treated in active sludge systems, proper pre-treatments are foreseen. They can change according to the sewage to be treated.

According to the user’s needs the following systems can be designed and manufactured:

	Monobloc systems, where the oxidation and decantation are made in only one tank (also monolithic-tank) separated by a divider
	Module systems in parallel that can be activated at two different moments. For this reason this type of system is suitable for those users who haven’t reached the full working capacity of the project but the system has to work immediately after the installation
	Industrial systems with pre-treatment activities and specific equipment according to the typology of sewage to be treated

Activating and management programs are elaborated according to the users’individual needs.