Conversion of Agricultural Waste (Maize) Into Energy Using Biogas Technology

The aim of the study was to examine the biogas and methane yield of maize silage, wastes in agricultural point of view and compare it to the biogas productivity of commonly used mixture of maize silage and mixed fodder with water. The experimental study was carried out into 2 parts. Firstly, the batch experiment was conducted in Mesophilic conditions (35°C), at five different hydraulic retention times (HRT): 6 Days, 11 Days, 20 Days, 29 Days and 41 Days. The results revealed that maize silage was generated the highest biogas yield of 537 mL /241 mL at the HRT of 6 days /41 days. Mixed fodder produced the highest biogas yield of 421 mL at the HRT of 6th days and the lowest one was 252 mL at the HRT of 20th days. Finally, the methane, carbon dioxide and hydrogen sulphide of biogas produced from maize silage and mixed fodder were analyzed using a gas chromatography. The results showed that biogas from maize silage precede the gas less than the mixed fodder. In the field level experiment proved that from mixed fodder produced gas which would be enough for 7 member’s family used 3 months for the purpose of their cooking.


INTRODUCTION
of the anaerobic digestion process, on type and chemical Bangladesh is in the midst of a severe and operational parameters [3]. Various types of worsening energy crisis, with a population of about biodegradable organic waste from agriculture and 160 million living in an area of 147, 570 km . In industry may be used as a substrate for biogas formation 2 Bangladesh, only 3% of the population enjoys the [4]. Maize (Zea mays L.) is one of the agricultural plants facility of natural gas coming to their homes through that is suitable substrate for biogas production. pipelines. Despite her large population, Bangladesh Fresh as well as ensiled maize can be used as biogas is one of the less energy consuming countries with substrate [5]. Maize silage is a substrate free of harmful 257 KwH per capita [1]. An agriculture based country like organic substances and heavy metals, which are Bangladesh has huge potentials for utilizing biogas responsible for the inhibition of the methane fermentation technologies. If each family of Bangladesh can be [6]. In recent decades, along with the development of associated with a biogas plant, then only human excreta renewable energy, both grain (Bioethanol) and silage will give about 10 billion cubic m biogas [2]. Biogas is (Methane fermentation) have been used for bio-energetic 3 produced from anaerobic digestion and is considered a purposes [7]. The goal of the combined cultivation is to clean energy source for those who want an alternative improve the silage through the combined harvest of energy pathway. Anaerobic digesters convert organic both crops and simultaneously complement the nutrient waste (Waste water sludge, agricultural and food waste, inputs, which in turn generate higher specific methane animal and human manure) into energy (Biogas). The yields and methane hectare yields. The aim of the study composition of biogas varies depending upon the origin is to sustain agriculture by using waste into energy. production. The digestion system was mixed for Location of the site is 24°75' N latitude and 90°5' E maintaining a contact between microorganisms and the longitude which fall under the AEZ 18 i.e. Young Meghna substrate (Fig. 2). It was finally sealed by a paraffin film. Estuarine Flood plain. The experimental site is indicated The anaerobic digestion system consists of 200 L digester on the map of AEZ of Bangladesh. The weather is tank and 150 L of storage tank. A quantity of biogas controlled by monsoon season and the soil is sandy production was daily recorded until no biogas produced. loamy. The laboratory experiment was done at Green Each experimental HRT was repeated 3 times to minimize energy knowledge hub (Biogas) laboratory, Bangladesh an experimental uncertainty. Agicultural University, Mymensingh, Bangladesh (Fig. 1).

Substrates:
The research material was maize and mixed used for determination of Ash content. Biogas 5000 gas fodder (Maize silage and grass fodder). The soil for the analyser is used for the Biogas analysis. To know the raw proposed maize crops was ploughed in the late winter in and processed agricultural wastes studied in this work the 2018. The soil was tilted by a power tractor in February biogas composition was analyzed using a mobile gas 2018. One maize hybrids "Hybrid Corn-984 Gold' and chromatography. 'Hybrid Suit Jambu grass were sown in sandy loam soil on day 75 kg maize substrate was added. Then after 5 days After oven dry it was weighted and then put into the (At the 6 days) the digester were filled with maize silage Ash container for Ash calculation. th and grass fodder together at 1425 kg (750kg +575 kg, respectively) and 1325 kg at the 9 day. Estimation of the Volatile Solids: The amount of residues th Methods Used for Producing Biogas: In this research we To determine volatile solid and Ash analysis, oven dried used anaerobic digestion methods to produced biogas in moisture free sample were weighed and place at the muffle China fixed dome plant. The biogas plant of daily gas furnaces at 575°C for minimum 4hrs. The dried samples production capacity of 150 cft (4.25 m ) has been used for were placed in smaller porcelain cup and the same 3 the studies procedure was followed. The porcelain cups were first Experimental Procedure: In this work the production of Afterwards they were put in the oven at 550oC and then biogas from raw and digested agricultural wastes were weighed again. The volatile solids were calculated using used through semi batch and continuous digestion the following equation: processes. Mixed fodder and maize silage chemical analysis was done in the biogas laboratory in Bangladesh Agriculture University, Mymensingh, Bangladesh. The maize silage was stored 14 days for decomposition.
where, In the laboratory experiment of the biogas production Wc is the Cup and the dried sample weight and Wi is the from the maize silage and mixed fodder done through the cup and incinerated sample weight.  Statistical Analysis: The collected data were subjected to was less in mixed fodder as same as the data showed in Analysis of Variance (ANOVA) with CRD method to Fig. 7, which represented the 11 days production. determine the significance of the effect of mixed fodder According to the Table 4 at the 20 days the percentage (silage and grass fodder) on the yield of biogas from maize of Methane of mixed substrates was less than the silage at 95% confidence level.
in individual but the amount of Hydrogen Sulphide was

RESULTS
composition of the substrates at 29 days where the

Composition of Substrates:
The findings and their the silage in individual. The compound of carbon dioxide implications should be discussed in the broadest context was less as compared to the mixed one except the amount possible. Future research directions may also be of the Hydrogen Sulphide. In Table (6) showed the highlighted. In Table (1) and Fig. (4), maize silage has composition of the substrates at 41 days. According to comparatively higher volatile solids content, expected the table the percentage of Methane of Mixed substrate to produce the highest amount of biogas. Since the was much similar to the silage in individuals. The other maize contains a significant amount of polysaccharides compound was almost equal as compared to each one and proteins and their hydrolysis and acidification except the amount of the Hydrogen Sulphide. The separate from the methanogenic phase can accelerate amound of Hydrogen Sulphide was high in Silage than the anaerobic degradation. In the mixed fodder oil contents, mixed substrate. crude proteins, dry matter content and the water portion are approximately higher than the single silage Carbon Nitrogen Ratio: The results show that carbon to experiment.
nitrogen ratio affects the volume of the generated biogas.

Chemical Composition of Produced Gas:
According to (C)/nitrogen (N) ratios were determined. The results the Fig. (6) and Table (2), at the 6th day the percentage of showed that applying chemical fertilizers (NPK) or Methane of Mixed substrates were much higher than the chemical fertilizers increased the N content and decreased silage in individuals but the amount of Hydrogen Sulfide the C/N ratio of maize silage (Table 3). th th high than the mixed one (Table 2). In Table (3) showed the th percentage of Methane of mixed substrates was high than th Maize silage was collected from studies, their carbon

DISCUSSION
gas production in the experiment. In conclusion, it can be The composition of maize substrate was found mixed fodder seems to be an attractive method for through the lab analysis and mixed fodder was collected agricultural waste utilization and energy generation if the as a Secondary data. Authors should discuss the proportions of these substrates are properly selected. results and how they can be interpreted in perspective of previous studies and of the working hypotheses. Oleszek, M. and I. Krzemiñska, 2016. Enhancement of found to be suitable feed stock for biogas production at biogas production by co-digestion of maize silage laboratory scale as well as at the field experiment. In this with common goldenrod rich in biologically active work a brief review of biogas production technologies and compounds. Bio