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