Improval of bioprocesses via immobilization of biomass, particularly on adsorbing, porous LEVAPOR-carrier material

The biotreatment of complex effluents, containing poorly degradable pollutants is often problematical, because
  • their biodegradation is a result of a “microbial-teamwork”, while
  • such “specialists” mainly don´t tend to build fast settling flocs,
  • leading to their wash-out from the reactor and thus
  • resulting in a less efficient biotreatment process.
However, achieving an efficient retention of “specialists” in the bioreactor, renders the process stable.
One of the most effective methods for improval of bioprocesses represents
the immobilization of biomass
  • meaning the fixation of the microbial cells on solid surfaces by building biofilms
  • resulting in a higher
  • biomass concentration in the bioreactor
  • degradation efficiency and process stability, by
  • resistance to temperature-, pH- and toxic/loading peaks and
  • a lower excess sludge production.
The IMMOBILIZATION of biomass shows remarkable advantages, if the waste water
  • contains toxic and/or
  • slowly degradable pollutants and/or
  • high amounts of salts ( > 20 g/L)
  • shows considerable qualitative fluctuations in fluctuation or/and

the biomass shows

  • poor flocculation properties
  • low settling velocities (0,1 to 0,5 m/h) and
  • disintegration of the initial structure (flocs , pellets)
The physico-chemical properties of the carrier are influencing remarkablyvtheir efficancy as shown below:
„ideal“ carrier properties responsible for
1. fast wetting - homogene fluidized medium
2. proper water-binding - maintenance of bioactivity
3. fast colonisation - immediate performance
4. internal porosity - preventive protection of biofilm
5. buffering of toxic effects - better protection of biomass
6. good mass transfer - higher reaction velocity
7. good fluidisation properties - lower energy consumption, better mass transfer

Fig. 1. LEVAPOR-C, porous, adsorbing carrier material (electron microscop photo)

All these requirements can be met by LEVAPOR-carrier materials, an
  • adsorbing (comprising up to 50-100% of surface active pigments) and
  • porous, (figure 1.) polymeric matrix, impregnated up to 100 wt.% with adsorbing, inorganic or/and organic pigments, like activated carbon.
The activation of the surface, i.e. the remarkably increased adsorbing properties results in a faster and better colonization by microorganisms and in a temporary adsorptive binding of pollutants (figure 2), reducing the toxic effects of pollutants in the bioreactor and improving the biodegradation.

Figure 2. The influence of LEVAPOR-carrier () on the biodegradation of 2-chlorobenzoic acid under anaerobic conditions

(explanation: the carrier type with the highest content of 35% activated carbon achieved the fastest and highest methane production, however, reactors using suspended biomass immobilized on non modified carrier did not produce any methane)
Fields of application
Biological treatment of
  • municipal effluents
  • industrial effluents
  • contaminated groundwater
  • contaminated soils and
  • waste gases

with immobilized specialized microorganisms.

LEVAPOR can be applied in following effluent treatment processes and cases:

  • nitrification
  • removal of slowly degradable pollutants and of
  • inhibitory pollutants
  • suboptimal biomass flocculation and settling behavior

Fig. 3. Flow-chart of a fluidized bed reactor for the waste water treatment using immobilized organisms

•The activated surface results in faster and better

  • wetting and fluidization of the carrier material
  • binding of toxic pollutants via adsorption,
  • colonization with microorganisms

•The higher content of biomass in the reactor achieves

  • higher process stability
  • higher volume-time-yields
  • higher sludge age

•Protection of organisms inside of the carrier, against

  • high shear forces and
  • inhibitors
  • Retention of slowly settling biomass
  • Low degree of filling of the reactor (10 to 15%) sufficient
  • Existing plants can be upgraded
  • Very good colonization of the inner surface
  • Optimal mass transfer into the carrier/ microbial cell
  • Simple retention of the carrier
  • Special efforts for excess sludge removal are not required

Technical data LEVAPOR-C
Form: cuboids cubes
Dimension (mm): 14 x 14 x 7 14 x 14 x 14
to 20 x 20 x 8 40 x 40 x 40
Block density (kg/m³): ca. 50 75 - 100
Bulk weight (kg/m³): ca. 20 40 - 50
Material density (g/cm³): 1,04 - 1,1 -
Degree of reactor filling: 10 - 15 Vol. % > 50 %
Preferred types of reactors: fluidized bed fixed bed
    trickling filters
Excess sludge removal: via aeration via aeration
Settling velocities:
a.) without biomass colonization, W50 (m/h)
ca. 50 -
b.) with biomass colonization, W50 (m/h) ca. 70 -

Dr. Imre Pascik: List of designed plants for the biotreatment of effluents using microorganisms immobilised on LEVAPOR-carrier (April 2005)

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Dreistufige Kläranlage

Fig.4. Three step plant for anaerobic-aerobic treatment of toxic pulp mill effluents with immobilized adapted microorganisms


Fig.5. Bio-trickling filter for the treatment of 15000 m³/h of waste gases of a warehouse for plastic wastes

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