Increasing Anaerobic Digestion Performance of Wastewater With Co-Digestion Using Decanter Cake

Abstract

Low biogas production in the frozen seafood wastewater anaerobic digestion is observed due to the low organic and Total Solids (TS) contents in the wastewater. In this research the decanter cake will be used in the anaerobic co-digestion process to improve the biogas production rate. The effect of co-digestion and Hydraulic Retention Time (HRT) will be investigated using the continuously stirred tank reactors under anaerobic conditions. Moreover, the study determines the biogas production potential of different HRTs and that of wastewater digestion alone. The anaerobic co-digestion is operated in continuous with continuously stirred reactors at HRT of 10, 20 and 30 days. The mechanical stirring units of all reactors are operated automatically. The stirring action occurred continuously during the experiments. The anaerobic co-digestion results show that the anaerobic co-digestion provides higher biogas production rate and higher methane yield than that of the wastewater digestion alone. The optimum HRT of the anaerobic co-digestion is 20 days. This reactor produces 2.88 L day −1 , with 64.5% of methane and the maximum methane production rate of 1.87 L day −1 and the methane yield of 0.321 l CH 4 /g COD removed . The anaerobic co-digestion of wastewater with decanter cake provides the higher methane yield potential production than that provided by the wastewater digestion alone at the ambient temperature. The best HRT is 20 days for anaerobic codigestion between the wastewater and decanter cake. The experimental results reveal that HRT and codigestion are the parameters that can affect the biogas production and methane yield.

Biochemical methane potential (BMP) from anaerobic co-digestion of sewage sludge and decanter cake

“…It has been reported by Kaosol and Sohgrathok (2014) that the mixing ratio with frozen seafood wastewater (as inoculum) increased the methane gas production volume, and also co-digestion of wastewater and decanter cake at each different HRT produced larger amount of methane gas compared to single digestion, at ambient temperature (mesophilic). The methane yield obtained from this co-digestion of sewage sludge and decanter cake increased with decrease F/I ratio.…”

“…The co-digestion between decanter cake and seafood wastewater also has a stimulatory effect on methane gas productions in BMP test [7].…”

“…The biogas produced can be used for electricity generation, cooking, pipeline injection and heating. It is a valuable renewable energy source while it can reduce the greenhouse gas emissions from fossil fuel [7]. The benefits of anaerobic co-digestion include improving the nutrient balance, increasing digestion rate, increasing load of biodegradable organic matter and producing better biogas yield [8].…”

“…The anaerobic co-digestion also may improve the biogas production due to carbon, nitrogen and nutrient balance [9]. Recently, researches on decanter cake as a substrate in anaerobic co-digestion has been reported due to its high biodegradability [7]. Decanter cake is one type of waste produced from palm oil industry in the of oil purification [10].…”

“…It is also used to determine the quantity of methane that the waste can potentially produce in anaerobic condition [7]. BMP test is low cost and repeatable method for relative comparisons of the anaerobic digestibility and potential biogas production among various substrates.…”