Automatic backwash wastewater treatment sand filter for irrigation

INTECH Media Filters - AEF

Each 48" AEF unit contains a certain volume of fine gravel that functions as the filtration media. The inlet of source water to the filter is built at the top of the filter. The water flows through the gravel media, leaving the solid impurities in it. After filtration the water flows through the nozzles at the bottom of the filter, where it is collected to the outlet manifold.

The three way valve on each filter's inlet, has 2 positions:

Filtration position - Inlet to the filter open - allows flow of the source water from the inlet manifold into the filter and through the gravel media to the outlet manifold and then to customer.
Backflush position - Inlet to the filter closes, and drain is opened clean water from the outlet manifold flows in the opposite direction into the filter, causing suspension of the gravel particles, and flushing the solid impurities from the gravel through the drain manifold.
The cleaning process of the media is at the full flow rate (of the filter) in the opposite direction.

The automatic backwash process is run by a controller. When the filters are loaded (with solid impurities) the difference of pressure between the inlet and the outlet of the filter system rises. In response to a programmed signal according to pressure difference or time interval, the control unit which starts and runs the backwash process of the filters in the battery one after the other. Only one filter at a time is cleaned while other filters in the battery continue to supply clean water to the downstream, and for the backwash process.