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Anaerobic-Aerobic Treatment of Sulfite Pulp and Paper mill effluent using high Performance Levapor Carriers for the immobilization of micro-organism. A significant AOX reduction was observed and discharge limits for AOX emission were met successfully providing 80-85% COD reduction with useful bio gas generation for fuel.
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LEVAPOR
SAPPI- a case history
LEVAPOR GmbH, Leverkusen
www.levapor.com
SAPPI – Ehingen (Germany) - Biotreatment of toxic pulp mill effluents by LEVAPOR-fixed biomass.
SAPPI- a case history
SAPPI , Ehingen (Germany) : 90.000 t/yr pulp (1985) Sulfite pulp and paper mill, • bleaching with chlorine. • 10.000 m³/d pulp mill waste water, • 45 tons/day COD, • toxic effluents.
Lab tests for aerobic biotreatment had achieved only 40% COD removal (toxicity of bleaching effluents !).
Idea: anaerobic-aerobic treatment ? tests with LEVAPOR- fixed biomass.
Lab scale plants for anaerobic treatment of toxic pulp mill effluents
Effect of carrier types on COD-elimination under anaerobic biotreatment of toxic pulp mill effluents in lab scale plants
LEVAPOR
activated carbon
unmodified PUR-carrier
suspended anaerobic culture
COD effl.
1.500 susp. cells immob. cells 1 st. immob. cells 2 st.
1.000
500
0 0,65 2,35 3,57 g COD L x d
Effect of immobilization on COD effl. in the anaerobic treatment of pulp bleaching effluents
Vana =65.000 m³ Vana =20.000 m³ Vana =15.000 m³
SAPPI- case history
Solution: anaerobic pre-treatment using 1500 m³ LEVAPOR 66-70% COD-removal. Aerobic post-treatment removed further 50% of residual COD.Anaerobic reactors: only 15.000 m³ instead of 65.000 m³with suspended biomass !
Benefits for customer: 50.000 m³ less reactor volume Savings for customer: ~ ca. 12 to 15. mio € investition !
BUFFER +BIOCOND.
PULP MILLQ ~ 10.000 m³/dCOD ~ 45 t/dneutralised
ANAEROB-REACTOR
LEVAPOR
AEROBIC POST
TREATMENT
CLARIF.
BUFFERfor
AEROB-REACTOR
Excess sludge
4-5 t/d !
PAPER MILL Q~ 3.500 m³/dCOD ~ 2.45 t/d
BIOGAS
MIXED EFFLUENT
Q ~ 13.500 m³/d
OUTLETQ ~ 13.500 m³/d
SAPPI – basic process flow diagram
In order to confirm again the contribution of LEVAPOR
Biofilm Technology, for plant startup only two anaerobic
reactors had been filled each with 12 % carrier.
After four months after toxic shocks the minor stable
reactor with suspended biomass became inhibited and
not more able to recover prior bioactivity, proving the
importance of immobilisation (next graph).
0
0,5
1
1,5
2
2,5
3
3,5
1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41
susp.biomass
May 90 June 90
immob. biomasskgCOD/m³ x day
