BIOTREATMENT of WASTE GASES in BIO-TRICKLING FILTERS using adapted biomass, IMMOBILIZED on adsorbing , porous LEVAPOR – carrier material

The advanced biotreatment of complex, industrial waste gases, removing the volatile pollutants almost completely, requires more sophisticated technologies than classical biofilters, because of the
  • varying composition and concentration of the pollutants,
  • presence of acidifying pollutants (organohalogenes, amines, ammonia, etc.), which are converted biologically into mineralic acids (HCl, H2SO4, HNO3 ,etc.)
  • require easy operation (optimal filter humidity,good mass transfer, low pressure drop, easy regulation and maintenance,etc.).
For their biotreatment increased requirements must be fulfilled:
  • Adaptation of the applied biomass on complex organic molecules (halogenated, sulfonated, nitrated and/or sulfur containing organic compounds),
  • fast and complete neutralization of the biologically produced organic and/or mineralic acids,
  • optimal supply of the biomass with „food“ (substrate),
  • optimal mass transfer from the gaseous into the liquid phase and
  • maintenance of the required humidity in the filter bed containing the biomass.
All these targets can be achieved in optimized
  • BIO-TRICKLING FILTERS, BTF (figure 1 and 2), using
  • IMMOBILIZED on adsorbing, porous LEVAPOR carrier cubes.
The specialized biomass
  • will be adapted and prepared for every medium separately, resulting in
  • a comparably fast startup period and high pollutant removal efficiency.
The adsorbing, porous LEVAPOR- carrier
  • is very light (ca. 30 to 40 kg/m³ filterbed), but characterized by
  • a high water uptake of > 250 % b.w. of water (important for the bioactivity!),
  • comparably low pressure drop in the filter bed and
  • is colonized by microorganisms very fast (within 90 min).

Flow chart of a bio-trickling filter (BTF)

Fig.1 Flow chart of a bio-trickling filter (BTF)

How does the BTF work?

The polluted, previously humidified waste gas enters the reactor in the lower section and moves upwards through the bio-trickling filter bed, containing the highly adapted biomass, immobilized by the adsorbing, porous LEVAPOR-carrier cubes.
In the first step, the pollutants are adsorbed on the surface active carrier and oxidized biologically (mineralized) in the next step.

In order to maintain in the BTF the necessary conditions for a good activity of the microorganisms with humidity, the filter bed is from time to time sprayed with „wash water“, containing the necessary nutrients, micronutrients and pH-adjusting caustic (optionally).

BTF for storage gas treatment

Fig.2. BTF for storage gas treatment

Site   Target   Solution with BTF using LEVAPOR-C
Germany   Fish-meal processing
Q=200.000 o.u.à 1000-2000 o.u.
  Upgrading of existing plant by LEVAPOR-C (2001)
Germany   Indoor desodoration and filtration of 15.000 m³/h warehouse gases, loaded w. Aspergillus and sporogenic bacteria   BTF with 20 m³ filter bed,10 m² cross-section Aspergillus-elimination = 99% Desodoration > 80% (2001)
Germany   Biotreatm. of 285.000 m³/h waste gases of plastic recycling   2 BTF in operation, rest under construction (2001)
Germany   30.000 m³/h WWTP off- gases 300 mg/m³ VOC, 100 mg/m³ AOX   Pilot-BTF for Q = 1000 m³/h off-gas 98% AOX-elimination (1997-98)
Germany   Q = 10.000 m³/h from GFK-Production
styrene = 100-400 mg/m³
  styrene-elimination = 75 – 90% (2003)
Germany   Production of technical plastics 900 mg/m³ dichloromethane (DCM)   pilot plant for Q = 1000 m³/h DCM-elimination = 98-99%
Germany   Production of agrochemicals, CS2-containing waste-gases   Pilot plant for Q = 200 m³/h CS2- elimination = 97-99%
abroad   agrochemicals, Q= 30.000 m³/h, VOC~ 1,0 g/m³, toluene, MIBK, DCM, etc.   Pilot plant for Q= 1000 m³/h, elim. = 90-94% technical plant under construction
Germany   municipal composting plant 500 to 1800 mg/m³ VOC, NH3, etc.   BTF pilot plant for 500 to 1.500 m³/h.
explanation: (Q = gas flow , VOC = volatile organic carbon , O.U.= odor units, DCM-dichloromethane)

Table 1: Biotrickling-filters using LEVAPOR-C in technical and pilot scale


Fig. 3 and 4.: Pilot plant for the treatment of 1000 m³/h waste gas from the production of agrochemicals (left: reactor, right : Fittings,Instrumentation and Control)

This side is part one Framesets