Inoculum acclimation to oleate promotes the conversion of olive mill wastewater to methane

Abstract

a b s t r a c tThis work aims at selecting a suitable strategy to accelerate the start-up of the anaerobic treatment of olive mill wastewater (OMW) and to enhance the biogas production. Two anaerobic sludges were tested in toxicity and biodegradability batch experiments: biomass acclimated to oleate (BAO) and biomass non-acclimated (BNA). The results showed that the resistance to OMW toxicity was higher for the BAO than for the BNA. In the presence of OMW, the BNA was inhibited at all concentrations tested, whereas for the BAO no inhibition occurred at 5 and 10 g COD L À1 . In fact, even at 25 g COD L À1 both substrates (acetate þ OMW) were degraded. The biodegradation rate of OMW was higher in batch vials with the acclimated sludge.The results demonstrate that the use of an acclimated microbial consortium to LCFA compounds is a promising strategy to accelerate the start-up of the digestion process, and to improve the overall anaerobic treatment of a real oily wastewater such as OMW with simultaneous bioenergy production (biogas).

Posttreatment of Olive Mill Wastewater by Immobilized TiO2 Photocatalysis

“…Among those processes, biological methods, whether aerobic or anaerobic , have been recognized as viable options. Due to high contents of chemical oxygen demand (COD), up to 220 g L −1 , OMW can be an excellent substrate for renewable energy production, such as in anaerobic digestion (AD) processes, which produce biogas and biohydrogen.…”

Anaerobic biodegradability of Category 2 animal by-products: Methane potential and inoculum source

“…Palatsi et al (2011) also reported a slow hydrolysis rate for this type of waste. The use of an inoculum adapted to high lipid and protein concentrations may reveal a good performance and a reduced start-up time for biogas production from ABP, as found by Gonçalves et al (2011) that obtained higher biodegradation rate and accelerated anaerobic digestion start-up for olive mill wastewater, with biomass previously acclimatized to oleate. The inoculum source provides different microbial populations and adaptability to the substrate (Forster-Carneiro et al, 2007;Gonçalves et al, 2011;Moreno-Andrade and Buitrón, 2004).…”

“…The use of an inoculum adapted to high lipid and protein concentrations may reveal a good performance and a reduced start-up time for biogas production from ABP, as found by Gonçalves et al (2011) that obtained higher biodegradation rate and accelerated anaerobic digestion start-up for olive mill wastewater, with biomass previously acclimatized to oleate. The inoculum source provides different microbial populations and adaptability to the substrate (Forster-Carneiro et al, 2007;Gonçalves et al, 2011;Moreno-Andrade and Buitrón, 2004). Recently, it was concluded that the slow lipid degradation rates and the need for specific enrichment of syntrophic microorganisms in the microbial community can be considered the main limiting factors for a successful anaerobic treatment of slaughterhouse waste mixtures (Palatsi et al, 2011).…”

“…Typical inoculum sources for anaerobic digestion studies include: sludge from anaerobic digester for the treatment of pig manure (Lozano et al, 2009); swine excrement, corn silage, restaurant waste digested mixed with rice hulls, cattle excrement, swine excrement mixed with anaerobically digested sludge from municipal wastewater treatment plants (Forster-Carneiro et al, 2007), granular sludge from anaerobic reactor treating brewery effluent (Neves et al, 2004) and more frequently, digested sludge from anaerobic digesters of municipal wastewater treatment plants (Forster-Carneiro et al, 2007;Lee et al, 2009;Lozano et al, 2009). Nevertheless, the microorganisms in contact with the substrate will adapt or undergo a natural selection process and, with time, the remaining microorganisms in the reactor are already adapted to the substrate (Gonçalves et al, 2011). The selection of the inoculum -substrate ratio (ISR) as well as the assessment of anaerobic biodegradability of the solid waste is also crucial (Fernandez et al, 2001).…”

Olive Mill Waste Water Management Study by Using Principal Component Analysis

“…To avoid these environmental impacts, olive mills were forced to treat or eliminate this waste. Hence, a wide range of systems has been studied for the disposal [7,8] or use of OMWW, such as aerobic [9,10] and anaerobic [11,12] treatments composting [2,13,14] and direct watering on fields [15][16][17]. However, these methods present several drawbacks that make their implementation very difficult and very expensive [5,18,19].…”