Bio-eco - Fill media for trickling filters


Fill media for trickling filters

BIO-ECO is a modern fill media specifically developed for medium and high–load trickling filters.

Shape spherical
Dimension ca.70 mm
Specific surface ca. 140 mq/mc
Void index ca 95%
Dry Weight 47 kg mc
Working Weight ca 350kg/mc
Matter Black isotactic PP

Black isotactic PP has excellent mechanical and chemical work –load properties. Furthermore it is not deteriorated by sunlight.

BIO-ECO is a fill media for medium/high-load trickling filters, for household and industrial water reflux treatment. The most common industrial wastewater treated via Bio-filtration are distilleries, agro-food, animal-rearing, plant, etc. BIO-ECO can be used in:

  • Single-stage trickling filters (BOD°5 equal or inferior 400mg/lt. sewage)
  • Double stage trickling filters (BOD°5 greater than 400mg/lt. sewage)
  • Double stage systems (thinning trickling filters, and active sludge in complex cases of heavy sewage depuration)
  • In order to enhance existing plants, as a substitution of “traditional” fill media as adjunct depuration unit.

With BIO-ECO it is possible to build modern medium/high load trickling filters.
These are the updated versions of the traditional percolating filters (rockbed filters) which were the first household-sewage depuration devices. With BIO-ECO we have two main advantages:

  • By percolation we use less energy compared to active sludge filters, simple maintenance over-load resistance, reduced dimension.
  • BIO-ECO’s usage guarantees high specific surface and high void index; lightness that allows larger and less expensive trickling filters.

in principle, the most efficient scheme is the following.

BOD5 removal yield (only for urban sewage)

BIO-ECO’s BOD5 removal yield depends on the organic load applied. Diagram in drawing 2.

Yields have been calculated in the following conditions:

  • Decanted household sewage percolation with BOD5 between 100 to 400 mg/l. (for other biodegradable wastewater liquids, these have to be determined experimentally).
  • Sewage temperature 15°C (for other temperature a correction factor will be used).
  • Steady organic load. If this is not the case an equalizer of the same is required.
  • Absence of recycle. In order to establish the correct volume of percolation influence of recycle must be considered (dilution method).
  • Nitrification: The almost complete nitrification of household sewage is obtained when to following conditions are met simultaneously.
  • Applied organic load equal or lower than circa 2Kg BOD5/CM/day; considering the recycle effect.
  • Post-percolation sewage temperature equal or higher than circa 15°C.
  • Post-decantation effluent BOD5 of the percolator equal or lower than circa 20mg/l. as peak index.
  • Absence of inhibition factors.
  • In different conditions of the above, the nitrification is close to null (lower than 15%) and is NOT advisable.

Sewage recycling is an advantageous practice, necessary in order to obtain the correct hydraulic load.
it is important that the stream of recycle is void of solids in suspension, therefore recycle has to be done clarified sewage.

when BIO-ECO trickling filters are built the following indications must be observed:

  • Filter-bed height between 3 and 6 meters.
  • Surface hydraulic load comprised between 0,75 and 4,5 CM/H.SM. better if between 1,5 and 3,5 CM/H.SM.
  • Sewage allotment on the surface of the bed has to be even by gentle jets. The best way is the classic rotary distributor with peripheral speed of circa 0,8-1,2 m/s.
  • natural ventilation is obtained when the aeration grid are equal to at least 4% of the horizontal section of the bed. To support the BIO-ECO fillers a 40x40mm. grid is recommended (ECO-GRID).

for further information refer to BIO-ECO monographed. ECOPLAST offers advice for sizing of the percolator.