Eco-trick - Fill media for bio-filters


Fill media for bio-filters

ECO-TRICK is a modern geometrical fill media purposely designed for high-medium trickling filter loads.

Crisscross parallelepiped hexagonal-duct module.

  • Module size: 1,200 x 0,600 x H = 0,500m
  • Duct size: hexagon 30 mm. side
  • Specific surface: minimum
  • Dry Weight: ca. 25,1 kg/mc
  • Void Index: minimum
  • Minimum Free-Flow: sphere diameter circa 20 mm.
  • Operational Weight: Max. 400kg/CM
  • Material: Thermoformed PVC

PVC, or Polyvinyl Chloride, has excellent thermal and chemical resistance features what makes them ideal in typical percolator environment. ECO-TRICK has deliberately less specific surface in favor of other important features:

  • High Free-flow. A 20 mm. sphere will freely pass through its hexagonal ducts.
  • Very high Void Index (minimum 98.5%). Air’s natural draft and the oxygenation of adherent biomass are guaranteed in case of heights above 8 meters.

ECO-TRICK is an advanced orderly fill media developed and tested to design modern medium-high trickling filters for biodegradable domestic and industrial sewage: Diary plants, meat processing facilities, fruit processing installation; breweries, intensive breeding etc.

ECO-TRICK is deployed in:

  • SINGLE-STAGE trickling filters (sewage with BOD lower than 400 mg/l after decantation).
  • DOUBLE-STAGE trickling filters (sewage with BOD higher than 400 mg/l after decantation).
  • DOUBLE-STAGE Systems (heavily loaded sewage treated by degreaser percolator and active sludge)
  • Enhancement of existing installations, as adjunct unit or as a substitute of a traditional system.

ECO-TRICK’s strength compared to lose fill media lies in its orderly geometry with wide and regular ducts which avoids clogging of the filter-bed and ensures:

  • Percolation of sewage subject to fine grilling (solid matter in grilled sewage shall be equal to or lower than 4 to 6 mm. Primary decantation is always advised in these cases
  • The direct recycling of the effluent from the percolator permits simple installation.
  • Other general advantages of ECOPLAST’s fill media are: High specific surface which delivers high BOD removal yield even in case of high organic loads.
  • Lower energetic costs compared to active sludge systems.
  • Simple management and high-load resistance over longer periods of inactivity.
  • Lightness which allows installation of more simple and less costly percolators compared to traditional ones.
(for urban sewage only)

Eco-TRICK’s removal efficiency is directly linked to the applied organic load. See Fig. 4

Efficiency diagram in Fig. 4 has been determined in the following experimental conditions.

  • Settled domestic sewage percolation with BOD5 between 100 and 400 mg/l
  • Sewage temperature of 15°C
  • Constant organic load
  • Efficiency is determined in absence of recycle.
    In order to determine the right volume of percolation the recycle influence has to be determined in introducing a corrective parameter. This correction can be done using the “dilution Method”

Sewage recycling after filtering via trickling filter is an advantageous practice which allows higher filtering performances. Moreover, recycling is necessary in order to obtain the correct hydraulic load.
With ECO-TRICK settling is NOT required when recycling because the wide passages avoid clogging of the trickling filter-bed. It is anyhow necessary that the effluent undergoes fine grilling or primary settling.

Only guidelines can be illustrated here since:
Nitrifying bacteria are very sensitive to environmental conditions and their variation, compared to those who demolish organic carbon.
Many factors influence the general picture, Sewage temperature and its variations.
Applied organic load and its variations
Absolute pH value and its variations
Nitrification is heavily influenced by these factors and the chemical event is only stable in the above mentioned conditions.
Experience confirms the following axioms as true:

  • In favorable conditions nitrification is almost complete, equal to or higher than 85%.
  • In adverse conditions nitrification is close to null, less than 15%.
  • In practice it almost impossible to determine the value of nitrification between the two above mentioned extremes.
  • Quick variations of environmental or operational conditions, block nitrification process which might resume after an adaptation period.

The complete nitrification of domestic sewage is obtained, theoretically, when the following conditions are met simultaneously:

  • Applied organic load: 2.0 BOD/SM per DAY
  • Sewage Percolation temperature: 15°C circa
  • Sewage BOD after settling equal or lower than 20 mg/l, as peak value.
  • Absence of inhibiting activity.

In all other conditions nitrification is not guaranteed and cannot be obtained in security and continuity.

When ECO-TRICK fill media for bio-filters are being used, the following rules should be observed:

  • The hydraulic load, referred to the horizontal section of the percolator, has to be comprised between 1.0 and 4.5 CM/H*SM (preferably between 1.5 and 3.5 CM/H*SM)
  • The sewage distribution on the bed has to be uniform and jets have to be soft.
    The best irrigation system is the classical rotary distributor with circa 0.8 ÷ 1.2 m/sec centrifugal speed.
  • Minimum ECO-TRICK bed-height: 3.0 meters ( 6 modules ) in any case, the higher the better.
  • Max filling height:
    With 1 bed support frame max 8.0 meters.
    With 2 bed support frames, each one with proper support frame and ventilation opening: 12 meters
  • Ventilation openings
    The natural ventilation of the bed is ensured when openings on the bed are at least 4% of the horizontal section of the bed.
    For double-bed percolaters the same rule applies for each bed.
    It is good practice that ventilation openings can be partially opened or closed and are free from obstruction.
  • In order to support the bed of fillers, a metallic girder warp needs to be set-up at the right distance from the bottom for ventilation and access.
  • The first layer of ECO-TRICK warp layout will have the short side parallel to the girders. The next layers’ layout will be orthogonal to the previous.
  • The first layer of ECO-TRICK will rest on 4/5/6 girders at the same distance for their respective heights of 4/6/8 meters.
  • Girder width shall not exceed 50 mm. (I NP 100 and/or NP 100).
  • The area surface of the supports has to be dimensioned to a specific load of the first layer of maximum 1.3kg/SCM, considering the weight of the bed at about 400 kg/CM.
  • At the same time the structure shall not occupy more than 25% of the horizontal surface area of the bed in order not to obstruct the natural ventilation of the percolator.
  • Metallic parts should be protected from rust.
    A double antirust galvanizing is recommended.
  • The correct release and uniformity of distribution of sewage is crucial to the functioning of the percolator. It is therefore good practice to use the classic rotator for equal sprinkling.
  • From a functional point of view, the best bed shape is a circle even if this means that modules will have to be shaped, with a large amount of waste product.
  • An acceptable compromise is a 6-sided or more shape.
  • The working area in this case will be the inner circle, hence the more sides the better.
  • The highest ECO-TRICK yield is obtained when the percolators have a square or rectangular base with sides 1.20 meter or its multiples. The biggest issue with these kinds of shapes is the spraying of the bed.
  • In case square or rectangular percolators are used, a cost/benefit balance
    must be drawn:
    Active factors: economies from absence of swarf from ECO-TRICK, higher building simplicity, higher area usage.
    Passive factors: higher cost due to complex spraying systems; higher energetic use due to loss of load from nozzles; reduction of the active surface of the percolator bed; higher maintenance costs of nozzle cleaning.
  • We will assist you in sizing the percolators in case you provide us with:
    1) Plant project data
    2) Plant work-diagram