Evaluation of the low technology tubular digesters in the production of biogas from slaughterhouse wastewater treatment
ELSEVIER, Journal of Cleaner Production, vol. 199, pag. 633-642, October 2018
Authors: J.Martí-Herrero a,b ; R.Alvarez c ; T.Flores d
a Centre Internacional de Mètodes Numèrics en Enginyeria (CIMNE), Building Energy and Environment Group, Edifici GAIA (TR14), C/Rambla Sant Nebridi 22, 08222, Terrassa, Barcelona, Spain
b PROMETEO Researcher, Instituto Nacional de Eficiencia Energética y Energías Renovables (INER), 6 de Diciembre N33-32, Quito, Ecuador
c IIDEPROQ, UMSA, Plaza del Obelisco, 1175, La Paz, Bolivia
c Ingenieria de petroleo, gas y energías, Universidad del Valle, C∖ Guillermina Martínez s/n, Tiquipaya, Bolivia
Abstract:
The aim of this research is to identify the operational conditions and performance of low cost tubular digesters producing biogas from the slaughterhouse wastewater treatment. Three full scale sequenced tubular digesters (of more than 8 m3 each), operating in a slaughterhouse in Cochabamba (Bolivia), have been monitored during one year. The Organic Load Rate (OLR) varied from 0.04 to 1.13 kgSV/m3d (0.04–1.07 kgCOD/m3d), and the Hydraulic Retention Time (HRT) from 3.2 to 87.4 days. The passive solar heating design considered drove the slurry temperature to 27 °C, 8 °C more than mean ambient temperature. The first digester has been filled with soda bottle plastic rings in order to increase the internal effective surface and evaluate, obtaining that an increment in 67% of the internal effective surface, more than doubles the biogas production and enables higher OLRs. A Biogas Production Rate (BPR) peak of 0.2 m3/m3d was observed for OLR = 0.37 kgSV/m3d, HRT = 9.7d and Specific Biogas Production (SBP) = 0.55 m3/kgSV. COD removal achieves values above 70% from HRT>19 d. A comparison with other anaerobic digestion technologies demonstrates that low cost tubular digesters with biofilm carriers, are competitive for OLR<0.5 kg COD/m3d of biogas production, and for 0.25 kgCOD/m3d, when the focus is on COD removal.
Highligths:
- Full scale tubular digesters treating slaughterhouse wastewater were monitored for one year.
- Appropriate design methodology, passive solar heating and biofilm carrier were considered.
- A Biogas production rate peak of 0.2 m3/m3d is found for 0.37 kgSV/m3d and HRT = 9.7d.
- Chemical Oxygen Demand removal achieves values above 70% for HRT>19 d.
- Biogas production is competitive for loads <0.5 kgCOD/m3d, and COD removal is for <0.25 kgCOD/m3d.
