Enhanced methane yield through sludge two-phase anaerobic digestion process with the addition of calcium hypochlorite

2022 ◽  
pp. 126693
Author(s):  
Jiawei Hu ◽  
Jingsi Zhang ◽  
Zhuo Li ◽  
Wenquan Tao
2003 ◽  
Vol 48 (6) ◽  
pp. 255-262 ◽  
Author(s):  
E. Houbron ◽  
A. Larrinaga ◽  
E. Rustrian

This study attempted to investigate the feasibility of volatile fatty acid (VFA) production from coffee pulp hydrolyse, and further to determine the potential of methanization of both the pre-acidified effluent and the coffee wastewater. The experiments were carried out in 2 completely mixed reactors, each one with a working volume of 4 litres. Coffee pulp was used as substrate in the acidogenic reactor and different mixtures of pulper and wash-water and pre-acidified effluent in the methanogenic one. The acidogenic and methanogenic reactors were operated at an organic loading rate of 5 COD g.l-1.d-1 and 0.5 COD g.l-1.d-1. The total, soluble and VFA's effluent COD concentrations of the acidogenic reactor present average values of 57.75, 17.00 and 13.92 g.l-1 respectively. Under these experimental conditions, 23% (COD based) of coffee pulp was hydrolysed with a rate of 1.32 gCOD.l-1.d-1 and the soluble fraction was transformed to VFA's with an acidification efficiency of 82%. Total VFA's concentration reached a value of 13.9 gCOD.l-1, and acetate, propionate, butyrate and valerate represented 52%, 28%, 9% and 11% respectively of the liquid phase COD. In the methanogenic reactor, COD removal and methanization of fresh coffee wastewater, pre-acidified effluent and both combined occur with an efficiency of 85% to 95% respectively, with a characteristic biogas composition of 80% CH4 and 20% CO2. These results show that a humid coffee ‘Beneficio’ processing daily 23 tons of cherry coffee (fresh fruit), equipped with a two stage anaerobic digestion process could generate at least 1,886 CH4 m3.d-1. This represents an increase in methane production by a factor 3 to 5 compared to a ‘Beneficio’ using anaerobic digestion only for the treatment of its wastewater.


2000 ◽  
Vol 42 (9) ◽  
pp. 41-47 ◽  
Author(s):  
A. Huyard ◽  
B. Ferran ◽  
J.-M. Audic

Regulations for land application of wastewater sludges require the performing of treatment with a high efficiency on pathogens reduction. a reduction of 61% of the Volatile Solids content of the sludge, a reduction of fecal coliform, polio virus and Ascaris egg of 5.5, 4.0 and 2.6 respectively are achieved with a thermmophilic/mesophilic Two Phase Anaerobic Digestion process. According to the EPA 40 CFR 503 regulation, the process produces Class A biosolids and could be recommended as a Process to Further Reduce Pathogens.


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