Abdul Razaque Sahito

Modeling and simulation of landfill gas production from pretreated MSW landfill simulator

The cumulative landfill gas (LFG) production and its rate were simulated for pretreated municipal solid waste (MSW) landfill using four models namely first order exponential model, modified Gompertz model, single component combined growth and decay model and Gaussian function. Considering the behavior of the pretreated MSW landfill, a new multi component model was based on biochemical processes that occurring in landfilled pretreated MSW. The model was developed on the basis of single component combined growth and decay model using an anaerobic landfill simulator reactor which treats the pretreated MSW. It includes three components of the degradation i.e. quickly degradable, moderately degradable and slowly degradable. Moreover, the developed model was statistically analyzed for its goodness of fit. The results show that the multi components LFG production model is more suitable in comparison to the simulated models and can efficiently be used as a modeling tool for pretreated MSW landfills. The proposed model is likely to give assistance in sizing of LFG collection system, generates speedy results at lower cost, improves cost-benefit analysis and decreases LFG project risk. It also indicates the stabilization of the landfill and helps the managers in the reuse of the landfill space. The proposed model is limited to aerobically pretreated MSW landfill and also requires the values of delay times in LFG productions from moderately and slowly degradable fractions of pretreated MSW.

Appraisal of Biogas Potential of Biogas from Animal Dung in Saeedabad, Pakistan

Pakistan is facing energy scarcity. The biogas is one of the renewable substitutes. It does not only overcome the energy scarcity but also harness the energy from animal dung which causes the CO 2 emissions. The present study was done on the appraisal of potential of biogas from the dung of animals (Buffaloes, Cows, Goats and Sheep) within the villages surrounded by Taluka Saeedabad. The purpose of the study was the energy potential of the biogas and the selection of the most suitable design and size of the biogas plant for the villagers. The present study also includes the domestic biogas plant economics. As per the estimation, total quantity of animal dung generated was about 129 tons/day, which can produce 3859 m of biogas per day. On the contrary, for cooking villagers require only 2748 m of biogas per day. Moreover, the surplus biogas of 1111 m per day can be used to produce electricity of 6666 kWh per day, which can fulfill the demand of about half of the population of villages under study. People are using firewood, cotton stalks, kerosene oil and LPG (Liquefied Petroleum Gas) for cooking. Converting animal dung into the biogas not only reduces the consumption of the traditional fuels used (Firewood, Cotton Stalks, Kerosene Oil and LPG), but also prevents about 900 thousand tons of CO 2 emissions into the environment. Additionally, a fixed dome biogas plant of 8-10 m size was recommended for each of the houses under study.

Improving Methane Production through Co-Digestion of Canola Straw and Buffalo Dung by H2O2 Pretreatment

In this study an effect of acidic pretreatment on the CS (Canola Straw) and BD (Buffalo Dung) by anaerobic co-digestion was investigated. H2O2 (Hydrogen Peroxide) is a mainly accustomed reagent, used as a bleaching agent in the different industries such as paper and wood. In the present study, it was used as a pretreatment chemical at varying concentrations in batch reactors. The co-digestion of CS and BD was carried out in SAMPTS (Semi-Automatic Methane Potential Test System) at mesophilic (37±1oC) conditions. The CS was pretreated in glass bottles with different concentrations of the H2O2 for seven days. The inoculum used in the present study was an effluent of the CSTR (Continuous Stirred Tank Reactor), which was treating BD at mesophilic conditions. The specific methane production from the codigestion of canola straw and BD, by the pretreatment of H2O2 at concentrations of 0.5, 1.0, and 1.5% were 530.8, 544.5, and 510.3 NmL CH4 g/VS, respectively. The significant reduction in the volatile solids of CS was observed at the optimum pretreatment of 1.0% H2O2.