Application of highly adsorbent, highly porous PU carriers for nitrification of high ammonia containing industrial effluents

1. Biological nutrient removal
from industrial effluents
by
LEVAPOR BIOFILM TECHNOLOGIES
Complex industrial effluents are mainly polluted by molecules with different
• chemical structure, biodegradability, toxicity and contain often up to
• 15 to 50 g/L salts, characterized further by temporary fluctuations.
Due to their higher pollution with organic and inorganic N-compounds, fish-
toxicity of free ammonia, NH3 and carcinogenicity of nitrite (NO2
-
) ion ,
biological nutrient removal via nitrification and de nitrification becomes
very important also for industrial effluents.
Due to the
 slow growth rate and low cell yield of nitrifying microorganisms
(resulting their wash-out of the bioreactor), respectively 
 their remarkable sensitivity to changes of pH, temperature and salinity 
 organic and inorganic inhibitors, the key reaction of nutrient removal
process, NITRIFICATION becomes often unstable. 
Because of their high adsorbing capacity and porosity, especially
LEVAPOR carrier do support nitrification, by :
 Fast microbial colonisation and generation of active bio films result in 
- higher resistance against inhibiting effects and
- higher process performance, while their
 High adsorbing capacity reduces inhibiting effects and enables a
fast biodegradation of inhibitors. 
LEVAPOR supported biofilm reactors
Most practicable are fluidised bed reactors, containing 12 to 15 vol. % LEVAPOR .
Due to the low density of the cubes, even oxidation devices of existing plants are
sufficient for the fluidisation of the filter bed, enabling easier upgrading of existing
plants. Retention of carrier with 20x20x7 mm within preferably bottom-aerated
reactors occurs via adequate screens and/or grids.

2. Fig. 1 : Fluidised LEVAPOR carrier
Aerated reactor
Clarifierwith carrier
Fig. 2 Basic flow-sheet of a fluidised bed reactor
Nitrification of industrial effluents
Depending on waste water matrix, i.e. structure and concentration of organic
and inorganic pollutants, nitrifying microorganisms are able to oxidize
ammonical nitrogen in the practice from
 20 to 25 g N / kg biomass(MLSS) per day (inhibiting conditions) up to 
 160 to 220 g N / kg biomass (MLSS) per day (non inhibited process) . 
Increasing salinity results in decreased uptake of organic pollutants and
especially nitrogen, meaning lower degrees of COD- and N-elimination(Fig.3).
Presence of even low concentrations of special inhibitors results often in a
crash of nitrification process even under continued non inhibited COD-removal.

3. Due to this extremely wide range of possible biokinetic parameters, their
experimental determination using representative effluents is a must !
Elimination ( % )
100
80
COD
60
40
NH4-N
20
0
NaCl (g/L)
33 35,3 39,6 42,9 46,1 49,4 52,7 56
Fig. 3 Effect of increased salinity on non-inhibited nitrification by suspended
microorganisms
By immobilizing nitrifying biomass, negative effects of inhibitors can be
reduced remarkably (Fig. 4, right: 94,5 % nitrification, versus only 28% achieved
by suspended biomass, left). Both, higher resistance and higher number of
microbial cells fixed on carrier do contribute to stability of the process.
220
207
NH4N
195200
[mg/L ] 28 %
180
inlet
160 149
94,9 %
outlet
140
120
100
80
60
40
20 10
0
suspended biomass immobilised biomass
Fig.4 : Effect of biomass immobilisation on nitrification of saline and inhibiting
chemical effluents (salinity:20-25 g/L,COD~1600mg/L) at Lv~ 0,25gN/Lxd.

4. Nitrification of industrial effluents by biofilms fixed on LEVAPOR
in the practice
Project 1: Production of organic intermediates, complex, concentrated effluents:
 COD ~ 3100 mg/L, 
 TKN ~ 820 mg/L 
 Salinity ~ 20 to 34 g/L . 
Existing effluent treatment plant (WWTP), designed for COD-removal.
Key question: is a plant upgrading sufficient for a required nitrification and
denitrification ? is it cheaper than plant extension ?
Calculations showed, that provided a stable nitrification at volumetric loading
rates of Lv > 0,6 kgN/m³x day, upgrading would be feasible.
Results of continuous tests in a pilot scale fluidised bed reactor showed that
a) Process using suspended biomass achieved stable nitrification until
Food:Mass-ratio ~ 70 g N / kg biomass x day, corresponding with
loading rates of Lv ~ 0,3 – 0,35 kgN/m³ x day , which is not enough.
b) The same biomass, fixed on LEVAPOR carrier achieved a full nitrification of
these effluents at required loading rate(Fig. 5) .
c) Estimated cost savings of plant upgrading: ca. 50% of plant extension costs.
700
NH4N (mg/L)
600
500
400
NH4N-in
Lv (gN/m³xd)
300
200
100
NH4N-out days
0
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30
Fig. 5 : Nitrification pilot test confirming feasibility of the process at
Lv ~ 0,6 kgN/m³xday

5. Advantages of plant upgrading
Converting bioreactors with suspended biomass, into biofilm technologies by
filling them with 12 to 15% of adsorbing LEVAPOR carrier, biomass performance
and process stability can be improved, meaning
 Faster - upgrading can be realised within days 
 better - because of higher performance and stability of biofilms, and also 
 more economical – because of lower costs of plant upgrading, meaning 
80 to 110 Euro/ m³ for plant upgrading versus
280 to 400 Euro/m³ for a plant extension, further
 regarding to savings, via lower sludge production of biofilm systems. 
Fig.6 1000 m³ aerated basin converted into a fluidised bed
reactor for LEVAPOR supported nitrification.
Project 2 : Production of toxic agrochemicals (new plant)
COD : 8000 to 11000 mg/L
TKN : 600 to 750 mg/L
Salinity: 10 to 22 g/L
Active agents: up to 150 mg/L, inhibiting both, COD-removal and nitrification.

6. Tests in lab and pilot scale biofilm reactors showed, that by proper biological
pre-treatment steps, where toxic inhibitors would be converted into non inhi-
biting metabolites, also nitrification of generated ammonia becomes feasible.
Fig. 7 Multi-step plant for biotreatment of toxic agrochemical effluents,
including nitrification/denitrification.
450,0
N (mg/L) TKNinfl
400,0
350,0
300,0
250,0
200,0
150,0
100,0
50,0 NO
3
N
effl
NH
4
N
effl
0,0
5 5
.05 .05 .05
5
.05 .05
5 5
.05 .05 .05 .050 0
.0 0 0
. . . .
1 1
.11 .11 .11 .11 .11 .11
2 2
.12 .12 .12 .121 1 1 1
. . . .
6 8
13 15 20 22 27 29
4 6 1 3
18 201 1
Fig. 8 Nitrification of toxic agrochemical effluents in a pilot scale biofilm
plant using LEVAPOR carrier

7. Additional removal of hazardous micropollutants in
LEVAPOR-supported nitrification process:
Due to high adsorbing capacity of LEVAPOR, hazardous micropollutants
become fixed and more bioavailable for biofilms, resulting in their higher
degree of biodegradation, than by suspended microorganisms:
 PAH (EPA-method) = + 85 % higher removal
 Bisphenol-A = + 85 to 92 %
 Aniline = + 90 to 93 %
 Nitrobenzene = + 85 to 98
Our experiences with nitrification of complex industrial effluents
 Petrochemical 
 Chemistry and pharmaceuticals 
 Landfill leachates 
 Steel works 
 Coal conversion 
 Textile and leather industry 
 Sludge processing effluents 
Our services for you
we do offer also our services in designing tailor made problem solutions,
based on 40 years experiences on biofilm technologies and nutrient removal,
both in the field of science and in the practice. Our tools are:
 Analysis of the problem 
 Elaboration of alternatives for problem solution , supported by 
 Practice oriented biotests (especially for nitrification), 
 Process Design and/or Engineering 
 Production and delivery of the required LEVAPOR type and 
 Plant startup using optimized mixed biomass, enriched with microbes
essential for degradation. 
Presented information are based on experiences with application LEVAPOR carrier. Testimonies on expected
effects can be made in individual case only on basis of investigations of given emissions and in some cases on
basis of practice relevant experiments.
LEVAPOR GmbH
Kölner Str. 38 Tel.: + 49- 2173-938715
D- 51379-Leverkusen
www.levapor.com
Mobile: + 49- 177-786 5533
Germany E-mail: levapor@web.de