Pre-filter from 800L to 5500L polyethylene

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, ...).
Quick 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 role of fuse, the suspended matter is trapped there, thus protecting the elements located downstream of the die (sand filter ...). It is operational after filling with pozzolan (independent supply).
The effluent arrives in the upper part of the filter bed, in order to facilitate maintenance operations in the event of clogging (this principle limits the actions of removal of the filter material at each inspection and emptying).
The decolloid must be filled with pozzolan, a mineral, heavy filter material (regular particle size between 20 and 40 mm).
Reminder: The pozzolan must be ordered separately and it is delivered in bags of 40kg (about 59 liters) reference PZ01.
The unit will be installed outside the building and placed perfectly level. He will be buried outside a vehicle crossing.
Its lid will reach the ground level and will remain easily accessible for maintenance. The bottom of the excavation will be perfectly flat and covered with 10 cm of sand. The embankment will be made with sand, and in no case with stone or gravel.
The apparatus will be filled with pozzolan or other filtering materials of regular granulation between 40 and 50 mm. This operation will be done before or at the same time as the backfilling.
In the case where the cover can not reach the ground level, the apparatus will have to receive a slab of concrete, being supported on the edges of the excavation; this slab will be calculated to withstand the imposed constraints.
In case of passing vehicles regardless of the device, it must receive a concrete slab.
All these models can be equipped with polyethylene extensions.
In case of presence of water table, consult our Design Office.
Annually, aspirate the supernatant.
Check the condition of the filter materials frequently. If they are clogged, remove them from the appliance, wash them with a jet and put them back in place. If clogging persists, check if the all-water pit or the digester settler should not be drained. Otherwise, you have to change the filter materials. In average, the filter material is to be changed every 2 years.