Anaerobic digestion of spent coffee grounds

Anaerobic co-digestion of coffee waste and sewage sludge

“…The anaerobic digestion of coffee waste has been reported at mesophilic temperatures (Lane, 1983;Raetz, 1990) and also at thermophilic temperatures (Kida et al, 1992;Kostenberg and Marchain, 1993). Boopathy (1987) studied different inoculum sources and found that the biomass from a sewage digester appeared to acclimatise quickly to the coffee pulp.…”

Comprehensive monitoring and management of a long-term thermophilic CSTR treating coffee grounds, coffee liquid, milk waste, and municipal sludge

“…2 and the data presented in Table 4, it can be concluded that the digester worked with a good performance indicated by a long-term stability in biogas production, a high buffering capacity, low effluent's VFA when there was not an addition of nutrient. In contrast, previous studies on thermophilic system with coffee grounds as a sole substrate showed a process instability due to VFA accumulation and decreased bicarbonate alkalinity (Dinsdale et al, 1996) and accumulation of inhibitory components (Lane, 1983), thus indicating that co-digestion gives a better nutrient balance and increases stability. Similarly, Qiao et al (2013a,b) reported that nitrogen supplementation of 0.5 g-N/L-substrate was required to maintain a long-term stable co-digestion of coffee grounds and sludge under OLR 5.3 kg-COD/m 3 /d.…”

“…However, long-term continuous experiments showed process instability due to many factors. Lane (1983) reported a gradual decrease in biogas production in a mesophilic reactor after 80 days due to unknown inhibitory compounds. Dinsdale et al (1996) reported the failure of maintaining a stable biogas production in a thermophilic reactor treating coffee waste water due to the VFA accumulation.…”

On the Spent Coffee Grounds Biogas Production

“…When studying spent coffee grounds biogas production, biogas yields ranged from 0.500 -0.598 m 3 /kg dry organic matter with methane concentration in biogas 55 -61 %. Biogas production 0.54 m 3 /kg has been reported (Lane, 1983 …”

“…Another option is a spent coffee ground anaerobic fermentation. The coffee waste anaerobic fermentation has been reported at mesophilic temperatures (Lane, 1983;Raetz, 1990) and also at thermophilic temperatures (Kida et al, 1992;Kostenberg and Marchain, 1993). The review of the literature suggests that the anaerobic digestion of coffee grounds is possible but long term stability is a problem.…”