Digester Volume Research Articles

Upgrading the performance of high solids feeding anaerobic digestion of chicken manure under extremely high ammonia level

Biogas production using high solids feeding anaerobic digestion has several benefits, including higher treatment capacity, lower energy requirements, and reduced volume of digestate. However, when chicken manure is used as a substrate, the process is prone to reactor instability due to ammonia inhibition. This study investigated the performance of three laboratory-scale anaerobic systems fed by chicken manure with total solids (TS) up to 15%, giving rise to total ammonia nitrogen (TAN) concentration of 7.5 g/L. The tolerance of the anaerobic system to ammonia inhibition was evaluated by operating three organic loading rates (OLR) in the range of 1.5–4.5 g-volatile solids (VS)/(L·d). The results showed that methane yield reached 0.33 L/g·VS under an OLR of 1.5 g-VS/(L·d), comparable to conventional wet-type process performance. The total volatile fatty acids (VFAs) were below 0.5 g/L, indicating a highly acceptable performance. The digestive performance deteriorated when the OLR was increased to 4.5 g-VS/(L·d) and highlighted the importance of selecting an appropriate OLR. The result may support the adoption of high solids feeding anaerobic treatment for nitrogen-rich materials.

An underground anaerobic digester with permissible temperature fluctuations: A parametric study

Many digesters are now abandoned or idle due to high thermal control requirements. Providing a suitable temperature range as well as low temperature fluctuations is essential for the efficient operation of anaerobic digesters. The present study aims to design an un-heated un-insulated cylindrical underground cow manure digester so that it works under permissible thermal conditions during winter. The investigation is carried out by using an in-house code based on the finite difference method and is conducted for Tehran, Iran. The results show that a proper adjustment of design parameters (including burial depth, diameter-to-height ratio and substrate initial temperature) leads to permissible thermal conditions during the whole winter without the need for any external heat source (i.e., only through heat exchange with the surrounding soil). It is observed that for a digester volume of πm3, burial depths of shallower than 5 m and diameter-to-height ratios of lower than 1/2 can lead to undesirable thermal conditions (that is, local temperatures outside the psychrophilic range of 10 °C-20 °C, or temperature fluctuations above 1°C/day). The results also reveal that undesirable temperature fluctuations, which mostly occur during the first day of operation, can be efficiently eliminated through the proper setting of the substrate initial temperature.

Sustainable development of environment and energy aspects of methane fermentation on family farms in Poland

The goal of these study was to present results of investigation concerning possibilities of utilization of harmful wastes in countryside area to produce ecological energy. Biogas production can be important from the point of view of environment protection especially in case of overproduction of animal wastes. Production and utilization of energy from agriculture residues gives a great chance for diversification and grows of income for family farms. Besides energetic and environment gains, we can obtain very valuable fertilizer, which is easy absorbed by plants in field crop production. The experimental study was conducted to investigate the effect of mixing process on the parameters of methane fermentation process. Temperature inside fermentation chamber, pH of fermented material, redox potential and carbon to nitrogen ratio (C:N) were investigated. Utilize wastes from pig and poultry houses were used for the study. Digestion in a chamber was provided at constant temperature of 37 °C. After adding fresh substrate to the digester, the temperature of the raw material decreased by 1,0-1.5 °C depending on the location in the tank. Also, it was observed that biogas production decreased. The mixing process had a positive effect on the homogeneity of the material throughout the digester volume. The best results for biogas production were obtained when the pH value was 7.0. Research results obtained from tested biogas installation show, that from two bio reactors at total capacity of 410 m3 we can get electrical energy at cost of 34,52 € MWh-1 and thermal energy at cost of 62,54 €×MWh-1. While the cost of producing electricity in a professional power plant based on lignite was 76.23 €MWh-1. The energy produced was used for the operational activities of the farm.

Manure as a source of energy and heat-insulating material in the cold climate of Yakutia

Energy is essential for the development of human society. Biogas plants, as a part of an integrated product-to-energy system, are an alternative to the use of waste biomass as raw materials due to their energy production capacity and thermal insulation material. Animal waste is an important resource that is used to replenish organic matter and improve soil conditions. Depending on the weight, cattle produce approximately 4 to 6 tons of fresh manure per year. With the constantly increasing prices for fossil energy resources, as well as the depletion of oil and gas reserves, an increasing number of countries are developing alternative energy sources. One of these types is biogas. It is necessary to note that the main disadvantage of biogas energy is the significant weight of specific capital costs and low profitability of projects. Despite this, in Russia there is the increase in demand for biogas units (BGU), both for small consumers (with a digester volume of 3-20 m3) and for medium-sized consumers (with a digester volume of 30-100 m3). The point is that biogas technologies properly fit into the UN Doctrine of sustainable development of society. Many in Russia are committed to this idea. They are guided by the principle “Reason is a clumsy instrument of a scientist; intuition is the unmistakable leader of the seer” and try to solve this problem each in his own way. According to UN experts, this very integrated approach, when a scheme for the selection of enterprises and industries operating on one type of raw material is carried out, and waste and byproducts of one production act as raw materials or semi-finished products for another type, can completely solve the problem of sustainable development of society.

The Current Status and Future Potential of Biogas Production from Canada’s Organic Fraction Municipal Solid Waste

With the implementation of new policies supporting renewable natural gas production from organic wastes, Canada began replacing traditional disposal methods with highly integrated biogas production strategies. Herein, data from published papers, Canadian Biogas Association, Canada’s national statistical agency, and energy companies’ websites were gathered to gain insight into the current status of anaerobic digestion plants in recovering energy and resource from organic wastes. The availability of materials prepared for recycling by companies and local waste management organizations and existing infrastructures for municipal solid waste management were examined. Governmental incentives and discouragements in Canada and world anaerobic digestion leaders regarding organic fraction municipal solid waste management were comprehensively reviewed to identify the opportunities for developing large-scale anaerobic digestion in Canada. A range of anaerobic digestion facilities, including water resource recovery facilities, standalone digesters, and on-farm digesters throughout Ontario, were compared in terms of digestion type, digester volume, feedstock (s), and electricity capacity to better understand the current role of biogas plants in this province. Finally, technology perspectives, solutions, and roadmaps were discussed to shape the future in terms of organic fraction municipal solid waste management. The findings suggested that the biogas industry growth in Canada relies on provincial energy and waste management policies, advanced technologies for diverting organic waste from landfills, improving biogas yield using existing pretreatment methods, and educating farmers regarding digester operations.

A new method of microglia sorting and functional characteristics of spinal microglia in aged rats

Objective: To establish an improved method of separating microglia from aged rats and to observe the biological characteristics of spinal microglia of aged rats. Methods: Young SD rats (2 months) were used as control group. Single cell suspension of rat microglia were prepared by trypsin, trypsin substitutes or mechanical net rubbing method. Then, by assessing the purity and survival rate of cells, and observing the morphological characteristics and analyzing the inflammatory functional characteristics, we optimized the isolation and purification method of microglia from aged rats (20 months old) , and observed the functional characteristics of spinal microglia in aged rats. Results: The survival rate of cells digested by pancreatic enzyme was low(young rats 83%, aged rats 60%). Although the survival rate of mechanical net rubbing method was higher than that of pancreatic enzyme digest methods (95%), the cell acquisition rate was lower(young rats(0.207±0.020)×106, aged rats(0.243±0.023)×106). Trypsin substitute dissociation combining density gradient centrifugation method was the best way to get abundant, active and higher survival microglia, and the purity reached more than 85%. We used this method to separate microglia from spinal cord of rats. Compared with the young rats, the spinal cord tissue of old rats was larger, the digestive fluid volume was higher, but the digestion time was shorter. Compared with the young rats, the aged rat spinal microglia had larger and rounder cell body, fewer and shorter protrusions, it tended to be activated morphologically, the level of proinflammatory cytokine IL-1β of microglia in aged rats was lower, and the level of antiinflammatory factor IL-10 was higher. Conclusion: The method of trypsin substitute dissociation combined with density gradient centrifugation was successfully established to isolate and purify microglia from spinal cord of rats, the spinal microglia of old rats showed anti-inflammatory phenotype.

Assessment of Petroleum-Based Plastic and Bioplastics Degradation Using Anaerobic Digestion

Bioplastics have emerged as a viable alternative to traditional petroleum-based plastic (PET). Three of the most common bioplastic polymers are polyhydroxybutyrate-valerate (PHBV), polylactide (PLA), and cellulose-based bioplastic (CBB). This study assessed biodegradation through anaerobic digestion (AD) of these three bioplastics and PET digested with food waste (FW) at mesophilic (35 °C) and thermophilic (55 °C) temperatures. The four plastic types were digested with FW in triplicate batch reactors. Additionally, two blank treatments (inoculum-only) and two PHBV treatments (with FW + inoculum and inoculum-only) were digested at 35 and 55 °C. The PHBV treatment without FW at 35 °C (PHBV-35) produced the most methane (CH4) normalized by the volatile solids (VS) of the bioplastics over the 104-day experimental period (271 mL CH4/g VS). Most bioplastics had more CH4 production than PET when normalized by digester volume or gram substrate added, with the PLA-FW-55 (5.80 m3 CH4/m3), PHBV-FW-55 (2.29 m3 CH4/m3), and PHBV-55 (4.05 m3 CH4/m3) having 848,275 and 561%, respectively, more CH4 production than the PET treatment. The scanning electron microscopy (SEM) showed full degradation of PHBV pellets after AD. The results show that when PHBV is used as bioplastic, it can be degraded with energy production through AD.

Natural diatomite mediated continuous anaerobic sludge digestion: Performance, modelling and mechanisms

Anaerobic digestion is generally restricted by the low degradability of waste activated sludge (WAS) and slow hydrolysis rate. This work provided an innovative technique to promote continuous anaerobic digestion performance mediated by natural diatomite. In continuous tests over 125 days, 2 g/g-Total solids (TS) of natural diatomite addition increased daily methane production and volatile solids (VS) destruction by 23.3% and 23.5%, respectively, leading to a 5.6% decrease in digestate volume for disposal. Microbial community in the natural diatomite mediated digester changed toward a favorable direction for anaerobic sludge digestion. Process modelling indicated that the increased natural diatomite presence increased hydrolysis rate, biomethane potential and degradation extent of the rapidly biodegradable substrates in WAS, with the highest enhancement being approximately 78.9%, 44.5% and 45.0%, respectively, achieved at 2 g/g- TS diatomite. However, the slowly biodegradable substrates in WAS stayed relatively stable. The mechanism studies revealed that natural diatomite mitigated ammonia inhibition and enhanced electron transfer for WAS-to-methane conversion mediated by its strong adsorption capacity and conductivity. The versatility of the technology proposed is also verified by the diatomite mediated experiments using different natural diatomite from different sources. Compared to the most natural minerals, diatomite exhibited either a greater anaerobic digestion performance or a lower dosage, bringing strong benefits in economy, environment and technology.

Sosialisasi pemanfaatan limbah kotoran sapi menjadi biogas sebagai sumber energi alternatif di Desa Kemuning Lor, Jember

Kemuning Lor Village, Jember majority working as a farmer and animal breeders especially cattle. Recorded 15 people from a total number of cattle with a total of 32 cows. One cow usually produces 10-15 kg of manure per day. According to the survey we have conducted, 5 out of 10 residents of Kemuning Lor are not aware of the use of cow dung in biogas. Volunteer activities in Kemuning Lor aim to provide education to residents in overcoming the problem of cow dung to be processed into biogas to deal with environmental pollution problems. Desa Sadar Energi program was initiated in Kemuning Lor to raise awareness from cow dung into energy that is sustainable and environmentally friendly. The implementation method consisted of pre-socialization interviews, socialization, and post-socialization interviews. There is a 72% increase in public understanding regarding the definition and use of biogas. Biogas with a digester volume of 9 m3 is equivalent to LPG of 4.14 kg. The processing of cow dung waste into biogas can reduce the cost of expenditure for household LPG so that it is more economical and the raw material, cow dung, which is abundant and sustainable, is very easy to reach by the society.

Novel anaerobic digestion and carbon dioxide emissions efficiency analysis of food waste treatment based on SBM-DEA model

With the development of the world economy and society, the living standards of residents have been improved, along with a large amount of food waste and carbon dioxide (CO2) emissions. In the face of global warming and energy shortages, food waste can be used as high-value bio-energy raw materials which is also an effective way to reduce CO2 emissions. Therefore, this paper proposes a novel anaerobic digestion and CO2 emissions efficiency analysis based on a Slacks-Based Measure integrating Data Envelopment Analysis (SBM-DEA) model to evaluate and optimize the process structure of anaerobic treatment of food waste. The total feed volume and the discharge volume of liquid digestate are taken as inputs, and the total methane (CH4) production volume is taken as the desirable output and CO2 emissions are regarded as the undesirable output to build the biogas production and CO2 emissions evaluation model during the anaerobic digestion process. Finally, the proposed method is used in the actual anaerobic digestion process. The results show that the overall efficiency values in January, April, May, and June in 2020 are higher than those in other months. At the same time, due to the optimal allocation of slack variables of inputs and undesirable outputs, the efficiency values of other inefficient anaerobic digestion days can be improved.

A mini review on effect of nano particles of Fe in the anaerobic digestion of waste activated sludge

Anaerobic digestion is one of the most preferred methods for sludge treatment in wastewater treatment plants. Though it is widely used because of its potential to generate renewable energy (biogas), there are some limitations in its efficient operation. The solubilization of sludge is identified as a very slow rate reaction and because of that higher volume of sludge digester is required for sludge treatment and is been identified as one of the main problems. This problem has been addressed by various pre-treatment methods. Nano materials-based pre-treatment was also attempted to enhance the solubilization of sludge and ultimately to improve the bio-methanation efficiency of sludge digesters. Recent studies have shown that nano particles of metallic oxides have aided in enhancing the methane generation and nano particles of iron oxides and hydroxides have shown a positive effect on the methane generation rate. This mini-review aims to summarize the recent advancements in nano particles of iron oxides and hydroxides as an additive, elucidate the various effects of parameters affecting the sludge treatment and thereby enhance the bio-methanation. This article is also supported with a preliminary study to examine the effect of granulated nanoscale oxyhydroxides of Fe (GNOF) in the sludge solubilization rate and overall effect on the sludge digestibility of a lab scale anaerobic reactor fed with waste activated sludge. The study was conducted for hydraulic retention time (HRT) of 40 days and 20 days. The treated samples were analyzed for pH, volatile fatty acids (VFA), alkalinity, and SCOD. The results showed a positive impact of GNOF in the sludge solubilization and subsequent anaerobic digestion. The work presented in this review would help to advance the knowledge and ultimately helps in improving the bio-methanation efficiency of anaerobic digesters.

Anaerobic Digestion of Wastewater Sludge and Alkaline-Pretreated Wheat Straw at Semi-Continuous Pilot Scale: Performances and Energy Assessment

During the last decade, the application of pretreatment has been investigated to enhance methane production from lignocellulosic biomass such as wheat straw (WS). Nonetheless, most of these studies were conducted in laboratory batch tests, potentially hiding instability problems or inhibition, which may fail in truly predicting full-scale reactor performance. For this purpose, the effect of an alkaline pretreatment on process performance and methane yields from WS (0.10 g NaOH g−1 WS at 90 °C for 1 h) co-digested with fresh wastewater sludge was evaluated in a pilot-scale reactor (20 L). Results showed that alkaline pretreatment resulted in better delignification (44%) and hemicellulose solubilization (62%) compared to untreated WS. Pilot-scale study showed that the alkaline pretreatment improved the methane production (261 ± 3 Nm3 CH4 t−1 VS) compared to untreated WS (201 ± 6 Nm3 CH4 t−1 VS). Stable process without any inhibition was observed and a high alkalinity was maintained in the reactor due to the NaOH used for pretreatment. The study thus confirms that alkaline pretreatment is a promising technology for full-scale application and could improve the overall economic benefits for biogas plant at 24 EUR t−1 VS treated, improve the energy recovery per unit organic matter, reduce the digestate volume and its disposal costs.

Cost effective in-situ methane enrichment for chicken farm biogas system

This study aims to investigate an in-situ methane enrichment in an anaerobic digestion of chicken manure. The process was carried out by desorbing carbon dioxide (CO2) from the effluent and recirculating effluent back to the digester. Laboratory-scale experiments were conducted in a 1100-liter anaerobic channel digester equipped with an external bubble column for the CO2 desorption. The experimental results showed that the CO2 desorption was achieved in a range of 98 to 121 l/day. The efficiency of CO2 desorption depended on a ratio between liquid and gas flow rates (L/G ratio) which the flow rate of liquid ranged between 230% and 430% of the digester volume per day. A higher methane content (65.12–72.68% CH4 by volume) was obtained whereas the methane (CH4) loss was in a range of only 1.15–2.58% which was relatively low. Not only the CO2 can be desorbed, but hydrogen sulfide can also be removed.

Effects of a temporary increase in OLR and a simultaneous decrease in HRT on dry anaerobic digestion of OFMSW

ABSTRACT The effects of the temporary increase of organic loading rate (OLR) combined with the simultaneous decrease of hydraulic retention time (HRT) on the stability of a pilot scale dry anaerobic digester were investigated. The separately collected organic fraction of municipal solid waste in mesophilic conditions (T = 40°C) was treated. The objective of this study was to verify whether it is possible to feed the digester for short periods, about three consecutive weeks, with higher OLRs and lower HRTs than those considered optimal without generating process failure or long-term instability. Starting from stable operation at a daily OLR of 10.0 kg of total volatile solids (TVS) for digester volume and an HRT of 23 d, the reactor was fed with an OLR of 10.8, 11.7 and 12.5 kg TVS m−3 d−1 corresponding to an HRT of 21, 19 and 18 d, respectively. It was observed that after using an OLR of 10.8 and 11.7 kg TVS m−3 d−1 for 3 weeks with satisfying results, it was possible to restore stable operating conditions at an OLR of 10.0 kg TVS m−3 d−1 in a short time. Otherwise, after using an OLR of 12.5 kg TVS m−3 d−1 the anaerobic digestion was deeply unbalanced and quickly failed. In this latter case, however, it was possible to fully recover and restore the stable conditions of the process within two months.

Development of a Mathematical Model and Validation for Methane Production Using Cow Dung as Substrate in the Underground Biogas Digester

South Africa is highly dependent on conventional fuels from non-renewable energy sources such as coal and fossil fuels. The methane from biogas is a renewable energy source for generating electricity using a combined heat and power plant. Therefore, the aim of the study is to develop and validate a mathematical model for predicting methane production in an underground biogas digester. The developed model was able to predict the production of methane gas as separate entity differing from other models. A total of 286 datasets were used as a trained dataset for the model development, and 144 datasets served as test data for the validation of the model, making a total of 430 measured datasets of all the predictors. The determination coefficient (R2) and the p-value of the predicted and calculated methane yield were 0.962 and 0.920, respectively. The high R2 in the present study confirms a good correlation between the model and experimental value. Hence, the model is of significance because it is applicable in predicting the performance of methane production of systems of the same design used in different locations, thereby arriving at the same constant values. From the study, the ambient weather factors (ambient temperature, relative humidity, and global horizontal irradiance) affected the methane production. Additionally, the indoor parameters (pH, gas temperature, slurry bottom and slurry top temperature) impacted on the yield of the methane production because the scaling factors associated with these quantities are non-zero real numbers. Hence, the scope of the study did not consider the volume of the biogas digester as an input parameter to the response.

Effects of Liquid Digestate Treatment on Sustainable Microalgae Biomass Production

The aim of the study was to investigate the potential of microalgal cultivation on anaerobic liquid digestate as a growth medium. The two methods of liquid digestate treatment including centrifugation and distillation and the two algal strains (Chlorella vulgaris and Arthrospira platensis) were compared. Additionally, the volume of the liquid digestate used to prepare the culture medium constituted from 10 to 50% of the medium volume. The study demonstrated that the highest C. vulgaris and A. platensis biomass productions of 2490 mg TS/L and 2990 mg/L, respectively, were obtained by adding 50% of distilled digestate to a growth medium. Regarding centrifuged liquid digestate, only 10% dilution was required to obtain the maximum final biomass concentration. A. platensis removed 81.1% and 66.4% of the total nitrogen from medium prepared on distilled and centrifuged digestate, respectively, while C. vulgaris ensured 64.1% and 47.1% of removal, respectively. The phosphorus removal from both culture media was higher than 94.2% with A. platensis, while it was 70.4% from distilled and 87.4% from centrifuged media with C. vulgaris. The study confirmed a great potential of microalgal biomass production on anaerobic liquid digestate with a high treatment efficiency of digestate.

Development of a method for calculating a anaerobic digester with bubbling mixing

Currently, there is a development of biogas technologies designed to obtain an alternative source of biogas energy and utilize organic waste. When developing and designing biogas plants, an important task is to determine the design and technological parameters of the anaerobic digester in order to obtain the maximum biogas yield. For the research, an anaerobic digester equipped with a bubbling mixing system was used. The bubble tube is made in the form of a spiral and forms a cone with the base downward. A calculation method has been developed that makes it possible to determine the physical and chemical properties of the biomass, the geometric parameters of the digester, the specific and total volume of biogas produced, the design parameters of the digester heating system, the design and technological parameters of the bubbling-type mixing system. With the help of the developed methodology, the design and technological parameters of the anaerobic digester of the biogas station for the disposal of organic waste from a pig breeding enterprise and a meat processing plant were determined. As a result of calculations, it was established that the station contains 3 anaerobic digester tanks with a volume of 200 m3 each, utilizes 40 m3 of waste per day and produces 1600 m3 of biogas per day.

Comparative analysis of the thermal hydrolysis integration within WWTPs as a pre-, inter- or post-treatment for anaerobic digestion of sludge

Anaerobic digestion (AD) is the most widely applied technology for the treatment of sludge produced in WWTPs. At present, thermal hydrolysis (TH) is becoming the technology of choice to improve anaerobic digestion due to its techno-economic advantages. The drivers behind the decision to install this technology, however, differ widely as they depend on local legislation and prevailing pricing structure. Thermal hydrolysis can be applied with different objectives (increase biogas yield, reduce digestion volume, reduce digestate quantity, pathogens removal) that can result in different optimum configurations. In this context, the same TH process can be placed as pre-, inter- and post-treatment to AD, each with distinct advantages and drawbacks.For all cases analysed there is a solid business case, with attractive payback, and the site-specific conditions will be key to determine the optimum location of the TH technology within the WWTP. Pre-treatment of mixed sludge is the configuration showing the lowest capex and is attractive for grassroots designs, but presents a poor energy balance. Inter-treatment incurs in higher capex, but in return this energy self-sufficient configuration yields the best operating numbers. Post-treatment is to be considered only attractive at relatively high biosolid prices and demands careful consideration of odour issues.

Performance of 500 Liter Stainless Steel Portable Biogas Anaerobic Digester with Agitator Designed for the Tropical Developing Country

This document it is established that 2 types of biogas anaerobic digester that usually found in developing country. First type is fixed dome type of anaerobic digester and secondly is floating drum biogas anaerobic digester. Both of this type have draw back that the anaerobic process is not completed with agitation process that yield low rate of biogas production. Other serious problem is the release of slurry cannot optimal. Some of the slurry will still remain stay in the anaerobic digester especially scum. To drain and cleaning the fixed dome or floating drum biogas anaerobic digester is mandatory to be done regularly that consume time and cost. The fixed dome types as well as floating drum type are usually not portable which cause no possibility to relocate in the new site. It is the purpose of this work to introduce portable biogas anaerobic digester that suitable for developing country with volume of digester around 500 liter of slurry. The requirement of agitator is facilitated, and the anaerobic digester is possible to be operated in batch system or continuous system. The material that is used for anaerobic digester is stainless steel 304 with tungsten inert gas welding technology that is used for the manufacturing. With this design the anaerobic digester are easy to be maintenance. The batch system can keep producing biogas until 52 day with total production of biogas around 3320 liters. The continuous system was conducted by releasing for about 5 liters slurry from the outlet and after that filled with new slurry with stirring with agitator was conducted for about 10 minutes for 3 times in a day (morning, noon, and evening). The result for continuous system is a linear biogas production with rate biogas production is around 51.7 liter/day (1550 liter/30days).

Anaerobic Co-digestion of Cooked Food Waste, Paper Waste and Potato Peel Waste

Conventional anaerobic digestion technology of mono substrate has certain limitations such as it has low waste to energy conversion efficiency, low degradation rate, low buffering capacity which leads to large volume of digester and high cost of biogas production So, in order to improve conversion efficiency and to accelerate biogas production, the researchers co-digested new combinations of various substrates like cooked food waste (CFW), crushed paper waste (CPW), dry & crushed potato peel waste (DCPPW) in different proportion using cow dung inoculum in the present study. This study was carried out under mesophilic temperature condition of 33°C in lab scale digesters. The results of study showed that maximum methane gas was produced at ratios of 2:2:4 CFW: CPW: DCPPW and at pH value of 7.1 while no biogas was produced at the ratios of 2:4:4, 4:2:2, 2:2:2 CFW: CPW: DCPPW due to deviation of pH value from ideal (6.8-7.2) that is required for survival and growth of methanogenic bacteria. By analyzing the data, it has been found that factor A (Cooked Food waste) had significant 59.3 % impact on methane gas yield which was followed by interaction factor ABC (CFW*CPW*DCPPW) 20.5%, interaction factor AB (CFW*CPW) 12.26%, interaction factor BC (CPW* DCPPW) 3.37% and factor AC (CFW*DCPPW) 2.99%. The factor B (Crushed paper waste) as well as C (Dry & Crushed potato peel waste) alone had negligible impact on methane gas yield. Using formulated regression model, optimum volume of predicted methane gas was found out which was 398.5 Nml.