Co-digestion Of Vegetable Waste Research Articles

Enhancing biogas and methane production from leaf litter of neem by co-digestion with vegetable waste: Focus on the effect of tannin

Leaf litter of neem (LLN) represents a critical part of organic waste trashing our immediate environment. The current solution for its management is unsatisfactory. This paper presents a new approach to treat the waste. It examines the effect of LLN on biogas composition produced from vegetable waste (VW) and cattle dung (CD). Anaerobic co-digestion of LLN with VW (R1), mono-digestion of VW (R2), mono-digestion of LLN (R3), and co-digestion of VW with CD (R4) were conducted under mesophilic conditions. R1 and R4 produced higher biogas and methane than R2. The introduction of LLN to VW improved biogas and methane yields by 87.27 and 91.47% and reduced H2S by 146.73% compared to R2. The maximum methane content of R1 suffices for electricity and heat generation. It can help in comprehending another way of managing LLN and optimization of process conditions.

Dry mesophilic anaerobic co-digestion of vegetable wastes with animal manures using leach bed reactor

Anaerobic digestion is an environmentally sustainable technology for converting a variety of organic solid feedstocks to energy in the form of methane. To improve methane yield, the digestion of more than one waste is commonly applied. This study aimed to investigate the dry anaerobic co-digestion (TS of 20%) of vegetable wastes (VW) and animal manures (cow manure (CM) and poultry manure (PM)) through conducting biochemical methane potential (BMP) assays at different substrate to inoculum (S/I) ratio. Fractionation and fluorescence analyses showed that organic matter of VW was less accessible and less complex compared to that of CM and PM. The highest methane yields of mono-digestion experiments were registered with S/I 0.5. Best results of methane yield were observed by the co-digestion of VW and CM (284 mL/g VS), which was about 2.3-fold higher than that of VW mono-fermentation. This finding was confirmed at a laboratory-scale leach bed reactor. Result showed an increase of biogas yield from 220 to 445 mL/g VS, during mono and co-digestion, respectively. The co-digestion of VW and CM mixture led to the enhancement of both methane yield and digestate quality in comparison to mono-digestion.

Unification of Waste Management from Fish and Vegetable Markets Through Anaerobic Co-digestion

A considerable quantity of waste is being generated from fish markets and harbors of coastal regions in India. Presently, there is no systematic and sustainable ways of disposal which leads to unscientific handling and dumping in landfills. Upon considering the bottlenecks associated with the anaerobic digestion of fish waste (FW) as sole substrate, co-digestion with vegetable wastes (VW) could be an effective alternative to mitigate the problem along with simultaneous treatment of two different waste streams. In this study, an attempt has been made to examine the co-digestion efficiency of FW with VW for which three trials viz., T1 (mono-digestion of VW), T2 (mono-digestion of FW) and T3 (co-digestion of VW and FW) were conducted to analyze the biomethane production potential, degree of biodegradability and pH stability. From the obtained results co-digestion was found to yield 463 ± 6.73 L/kg VSfed of biomethane which is 24.13% and 22.32% higher as compared to VW (373 ± 4.94 L/kg VSfed) and FW (378 ± 4.55 L/kg VSfed) respectively. Maximum biodegradability based on organic carbon destruction was found to be 70% in co-digestion followed by mono-digestion of VW (58.8%) and FW (64%). Prevalence of acidification and ammonification in mono-digestion of VW and FW were reflected by physiological pH of 5.4 ± 0.41 and 8.3 ± 0.32 respectively. In co-digestion process pH was observed to be 7.3 ± 0.70 that indicated high stability and thus enhanced the biomethane yield. Co-digestion of these organic wastes could enhance the efficiency of methane production and therefore presents a unified waste management option.

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An Approach to Enhance Biomethanation by Thermophilic Aerobic Digestion of Combined Vegetable Waste.

In biogas volatile fatty acid are the principle source of energy for methanogens and an increase in their concentration can enhance the process performance of biogas digester. A two phase anaerobic digestion system was used to study the effect of various factors on the net production of volatile fatty acid (VFA). For this purpose thermophilic digester maintained at 55°c (i.e. digester I) and the main digester was kept at ambient temperature (i.e. digester II). Co-digestion of vegetable waste and cow dung was investigated in two phase anaerobic biodigester system. A comparative study was carried out between control and experimental system. The amendment was controlled air supply in predigester (digester I) designed to supply with precise control in the experimental system and no aeration was done in the predigester of control system. The conditions of start up and operation were same in both the systems except controlled supply of air. A conversion of an average of 75% of organic solids fed into digester at total of 15 days hydraulic retention time (HRT) was obtained for both the system. The organic loading rate in phase I digester was 4-4.5 kg VS/m 3 /d. This phase effluent portray a drop in the pH to 4.4-4.7 as high volatile fatty acid produced in the range of 2380-5464 mg/lt with a corresponding gas production of 0.401 m 3 /kg vs. fed in the experimental system, which showed increased biogas yield than the control system. Due to the auto thermal thermophilic aerobic digestion the VFA production was enhanced which ultimately increased the biogas production by 39.72%, as compared to the control system. The NPK value of the digested sludge obtained was having 0.55% of Nitrogen, 0.56% of Phosphorous and 0.61% of Potash. Thus, limited quantity of oxygen can even lead to improved performance of anaerobic digestion reactor, under certain operating conditions. This fact is also supported by the increase in the viable count of bacteria in the experimental system, It was seen that the aeration in predigester (in two phase anaerobic digestion), could assist anaerobic digestion and would prove much beneficial, for treatment strategy for simultaneous waste treatment and energy generation.

Effect of organic loading rate on the anaerobic co-digestion of vegetable wastes with activated sludge

Effect of organic loading rate on the anaerobic co-digestion of vegetable wastes with activated sludge