Anaerobic treatment of coconut husk liquor for biogas production

Abstract

The market for coconut water causes environmental problems as it is one of the major agro-industrial solid wastes in some developing countries. With the aim of reusing the coconut husk, Embrapa developed a system for processing this raw material. During the dewatering stage Coconut Husk Liquor (CHL) is generated with chemical oxygen demand (COD) varying from 60 to 70 g/L due to high concentrations of sugars and tannins. The present study evaluated the feasibility of anaerobic treatment of CHL through Anaerobic Toxicity Assay and the operation of a lab-scale Upflow Anaerobic Sludge Blanket (UASB) reactor. Results showed that CHL can be treated through a UASB reactor operating with an OLR that reaches up to 10 kg/m3.d and that is maintained stable during the whole operation. With this operational condition, the removal efficiency was higher than 80% for COD and approximately 78% for total tannins, and biogas production was 20 m3 of biogas or 130 KWh per m3 of CHL. Seventy-five percent of the biogas composition was methane and toxicity tests demonstrated that CHL was not toxic to the methanogenic consortia. Conversely, increasing the concentration of CHL leads to increased methanogenic activity.

Anaerobic Processes

“…Using an Anaerobic Toxicity Assay (ATA), coconut husk liquor treatment was evaluated (Leitao et al, 2009). The researchers also investigated treatment using a laboratory-scale UASB reactor, which resulted in 80% removal efficiencies for COD and 78% for tannins.…”

Semi-industrial production of methane from textile wastewaters

“…Apart from the obvious wastes from domestic homes and especially economic plants such as corn, wheat, rice, and all kinds of vegetables and fruits, various industry-specific recycling strategies have been developed to generate an added value in the production chain and to minimize pollutions. This includes the biogas generation from wastewaters coming from, e.g., food, chemical, and pharmaceutical industries [11][12][13][14][15][16][17]. In the textile industry, and especially here in the cotton manufacturing, various scientific groups are investigating the biogas or bio-ethanol production starting from solid residuals such as willow dusts or fiber wastes with a subsequent enzymatic or chemical hydrolysis of the cellulosic material [18][19][20][21].…”

Hazardous Waste Treatment Technologies

“…CAOP removed 75 and 65.6 % formaldehyde and COD, respectively. The final effluent after SBR was free of formaldehyde and contained less than 60 mg/L COD.Leitao et al(Leitao, Araujo et al 2009) studied anaerobic degradation of coconut husk liquor (CHL) in UASB. CHL was effectively treated even at high OLR of 10 kg/m 3 -d generating biogas with methane concentration of 75%.…”