Prefilter with floor for filter material in rotproof PEHD cells

A decolloid, also called prefilter or clogging indicator, retains suspended matter. Placed after a pit all waters or a settling digester, it avoids premature clogging downstream facilities (spreading, filter beds, ...).

Rapid sizing rules, according to local regulations:
- 5 to 10% of the volume of a pit all waters.
- 10 to 20% of the volume of a digester digester.
The decolloid has a fuse role, the suspended solids are trapped there, thus protecting the elements located downstream of the die (sand filter, etc.).

The horizontal tee-shaped inlet provides a jet breaker function. The effluent arrives at the upper part of the filtering mass, in order to facilitate maintenance operations in the event of clogging (this principle limits the actions of removal of the filtering material at each inspection and emptying).

All our PRV decolloid models are equipped with a raised floor, ETC200 filter material and a tilting cover allowing maximum accessibility inside the tank.

The ETC 200 cells made of HDPE, a rot-proof, non-corrosive synthetic material, have the advantage of an efficiency comparable to pozzolan for a much lower weight (specific surface area 300 m² / m³, porosity 90%, density 70 kg / m³).
These cells are delivered inside a net of a volume of about 500 liters and a weight of approximately 35 kg. They are simple and easy to handle during maintenance operations because they do not require any lifting gear.
The appliance will be installed outside the building and installed perfectly level. He will be buried outside a vehicle crossing. Its lid will reach ground level and remain easily accessible for maintenance. The bottom of the excavation will be perfectly flat and covered with 10 cm of sand. The fill will be made with sand or gravel. Apply the water before the backfill.
Annually, aspirate the supernatant.
Remove the nets containing the ETC200 cells to wash them with a jet of water and then put them back in place after emptying the decolloid.
If the "unclogging column" option has been ordered, it is possible to clean the filter material by backwashing with clean water.