Anaerobic digestion of Olive Mill Wastewater: Anaerobic Filter vs. Hybrid

Transcription

1 Departamento de Energias Renováveis Anaerobic digestion of OMW: Department of Renewable Energy LNEG Laboratório Nacional de Energia e Geologia National Laboratory of Energy and Geology Anaerobic digestion of Olive Mill Wastewater: Anaerobic Filter vs. Hybrid Isabel Paula Marques isabel.paula@ineti.pt Marta Gonçalves and Paulo Freitas

2

3 IPaula Silvio Tanaka Olive tree olives (fruit) olive oil

4 Olive oil industry Anaerobic digestion of OMW: Great economic and social importance: Mediterranean area [Olives are also cultivated: USA, Argentina, Australia and South Africa] olives (fruit) olive oil 5 kg olives Olive Mill Wastewater (OMW) 5 L OMW 1 L olive oil

5 OMW [three-phase extraction system]

6 OMW generated in huge quantities during a short period of the year one of the most polluting agro-industrial effluents OMW holds a great energetic potential (Biogas)

7 Anaerobic digestion - OMW promising attempt to face the negative environmental impact high organic matter of these effluent (200 kg COD m-3) lower: sludge volumes, space requirement and capital cost - aerobic proc., easily restarting after several mouths of shutdown, low energy requirement for operation, recovering the valuable end-product --- methane

8 Olive Mill Wastewater - OMW inhibiting substances (phenolic lipidic-lcfa) unfavourable C/N ratio acid ph render OMW inappropriate direct biological treatment

9 Reduce concentration and toxicity Olive Mill Wastewater high dilutions physic chemicalbiological addition of alkalis pre-treatments

10 OBJECTIVE: treat and recover the energetic potential of the raw OMW anaerobic digestion Successful digesting stability is obtained complementary substrate concept Depart. of Renewable Energies - LNEG without any pre-treatment tap water dilution chemical correction of OMW

11 OMW: composition + seasonal effluent Another effluent: continuously produced - same region + able to complement OMW Piggery effluent to secure a stable operation year-around

12 CQO C/N NH4+ ph (kg/m3) (kg/m3) Olive oil OMW high low 4-5 Swine Piggery effluent < 30 low high 7-8

13 Olive Mill Wastewater dilute and to supplement (N, P) Piggery effluent + decrease - inhibiting capacity more favourable C/N ratio ph values

14 OBJECTIVE: Anaerobic Filter vs. Hybrid g as g as ef ef inf. inf inf. UASB Anaerobic filter Hybrid Fixe bed

15 Operational difficulties g a s ef inf. inf. UASB Anaerobic filter Washout overload concentrated effluents [concentrated effluents] Channelling - Column clogging Packing bed material Lab. AF classic problems

16 Packing bed material Lab. good progress several long-term experiments no troubles as a result of a clogging process

17 OBJECTIVE: Anaerobic Filter vs. Hybrid g as g as ef ef economic issue: inf inf. least of packing material required Anaerobic filter Hybrid Fixe bed

18 packing material = 30% reactor height

19 Operational conditions Anaerobic Filter vs. Hybrid 53 % v/v) OMW (% OMW.H OMW.AF Time (d)

20 Operational conditions La (kgcod m-3) La (kgcod m-3) Hybrid La (in) La (OMW) Time (d) La (in) La (OMW) AF Time (d)

21 Results Bioga as (m3 m-3 d-1) Gas Anaerobic digestion of OMW: Biog-FA Biog-H CH4-FA CH4-H Loading rate, La (kg m3 d-1) CH4 (%) Gradual increase of biogas production increment LA Good methane content

22 Results Influe ent (kg COD m-3) COD removal: 27-41% OMW v/v Anaerobic digestion of OMW: CODt Inf. FA CODt Inf. H CODtr FA CODtr H La in (kg m3 d-1) CODr (%) AF H = COD removal

23 Results. Solids removal: 27-41% OMW v/v AF H TS (%) VS (%) VSS (%) 66/ /55-69 Some comments are needed to better understand the finding

24 Operational conditions 60 Anaerobic Filter vs. Hybrid 40 % v/v) OMW (% 20 0 OMW.H OMW.AF H overload Time (d)

25 Sharp change in sludge bed The blanket of biologic solids went upwards and penetrated the fixed bed section Some biomass was lost - not cause the failure [18% OMW] La = kg COD m -3 d -1 (31-55 kg COD m -3 ) Gas m 3 m -3 d -1 COD removal /69%

26 ability of resisting H - overloading was tested - new influent previous plan of work (27% OMW v/v)

27 Operational conditions % v/v) OMW (% OMW.H OMW.AF Time (d)

28 COD removal: + 53% OMW v/v Infl luent (kg COD m-3) CODr (%) La (kg m3 d-1) Inf-FA Inf-H CODr-FA CODr-H 0 digesters behaviour = AF. H

29 RESULTS H digester: remaining packing material - 1/3 height Effective effects - accidental overload The maintenance of a sufficient amount of biomass inside the unit allowed preventing the process failure

30 10 VFA removal VFA inf. (kg m-3) VFAin FA VFAin H VFAr FA VFAr H La (kg m3 d-1) VFA rem (%) Hybrid: VFA = 4 times more concentrated

31 Conclusions Anaerobic filter and hybrid: can be used to treat the raw OMW (without any pre-treatment or chemical correction) AF H (27 and 41% OMW v/v) = COD and solids removal AF=69-83% vs. H=60-73% [overload (18% OMW v/v)] H recovery process packed bed material was effective in preventing the excessive loss of biomass Confirmation better performance of H than AF (53% OMW v/v) [COD removal: AF = 80 70%, H = 73-78%]

32 Conclusions Anaerobic Filter vs. Hybrid Important issue related to the applicability of the Hybrid Anaerobic digestion of Olive Mill Wastewater is the lower costs related to the amount of packing material

33 Acknowledgements financial support project PTDC/ENR/69755/2006 and the grant given to Marta Gonçalves SFRH/BD/40746/2007.

34 Departamento de Energias Renováveis Anaerobic digestion of OMW: Department of Renewable Energy LNEG Laboratório Nacional de Energia e Geologia National Laboratory of Energy and Geology Anaerobic digestion of Olive Mill Wastewater: Anaerobic Filter vs. Hybrid Isabel Paula Marques isabel.paula@ineti.pt Marta Gonçalves, Paulo Freitas Thanks for your attention