Introduction
The hypothesis of the research is based on previously done studies. Although some results were similar, some results were slightly different from the previously conducted investigations. The research was done using an organic fraction of municipal solid waste (OFMSW). OFMSW contained organic compounds like food and inorganic materials like lignocelluloses. The first prediction was the significant materials of the waste that can be changed to ethanol were lignocellulose and starchy compounds. Lignocellulose accounted for approximately 20.2%, and the starchy materials 58.6% of the OFMSW (Mahmoodi, Karimi, & Taherzadeh, 2018).
The theoretical changing of the starchy compounds to ethanol yield is 0.567g per g starchy compound, and the production of 364g of ethanol from each kilogram of waste is possible. The fermentation tests were to be done in two repeat experiments. In addition, OFMSW contained other materials like lipids, protein, pectin, and ashes. Lipids accounted for 6.45%, proteins 8.30%, and pectin 10.15% of the OFMSW. The research hypothesis was that the potential biomethane was calculated to be produced as 383. L from the OFMSW. The waste also contained 8.61% total lignin, which could not be changed to in the least stated biofuels.
Another hypothesis of the research is that removal of Xylan could occur at the conditions of 1% of sulfuric acid, 160, for about twenty-five minutes (Mahmoodi et al., 2018). The forecast is based on a previous research experiment. The prediction did not come out as expected as the total removal of Xylan occurred at the conditions of 1% sulfuric acid, 160, for thirty to sixty minutes. The research experiment had three hypotheses that guided it.
The Aim of the Research
The research was aiming at producing efficient ethanol from waste and biofuel from the residue. Dilute-acid treatment under varied circumstances was assessed for the hydrolysis of the starchy compounds, and lignocelluloses were pretreated for ethanol making. Dilute-acid treatment eliminated the purpose of hydrolyzing the starchy compounds with enzymes. However, enzymatic hydrolysis was used for the cellulosic materials. The hydrolysates were then fermented using Mucur indicus to produce ethanol (Mahmoodi et al., 2018). The liquid from the fermentation broth and residual solids from the hydrolysis were subsequently exposed to anaerobic digestion to produce biofuel.
In addition, the study aimed to increase the yield of biogas. The research realized that untreated waste had higher volumes of biogas than other materials that are pretreated. The reason was the presence of biodegradable materials that could be anaerobically digested. In comparison with other research, the yields obtained were much higher, which indicated overall better results of dilute-acid pretreatment on the end products. Dilute-acid treatment increased the production of biofuel and ethanol from the waste as the research aimed to increase the results of biogas and ethanol by using diluted acid at the optimum conditions. The conditions were 1% sulfuric acid at one hundred and thirty degrees Celsius for sixty minutes (Mahmoodi et al., 2018).
Moreover, the research was aiming at ways of reducing the cost of converting the wastes into biofuels. The goal was to test the best conditions for producing optimum fuels, thus reducing the cost of production. When the process of using the dilute acid was done under the best conditions, hydrolysis occurred whereby 46.7g/L of total sugars is hydrolyzed. Besides that, the hydrolysis of using enzymes yield to the cellulosic materials was raised to ninety-six percent because the lignocelluloses structures improved (Mahmoodi et al., 2018). There is no need to use amylolytic enzymes for starch hydrolysis when dilute-acid treatment is done. This reduces the cost of production and raises the output.
Additionally, the research aimed at coming up with a remedy for reducing the OFMSW that kept accumulating in the environment. OFMSW posed a great danger to the environment (Mahmoodi et al., 2018). Most of its components contained biodegradable materials which could be respired and changed to biofuels. By converting this OFMSW to biofuels, they are reduced in the environment the risk they pose to the environment is reduced. Biofuels can be used in industries and homes for lighting, recycling is realized, and no wastage is seen.
Main Implication of the Results
Significant amounts of biofuels could be produced from the waste when dilute-acid treatment is done. This could reduce the cost of the process, keeping the higher amounts of production. The research revealed that when the process of using dilute acid at the best and most favorable conditions is done, it results in substantial hydrolysis of starch with 46.7g/L overall sugars. When the dilute-acid treatment is used, there is no need to use amylolytic enzymes for starch hydrolysis. In addition to the substantial hydrolysis of starch, the hydrolysis of cellulosic materials by enzymes is raised to 96% due to the lignocelluloses structures improving.
The hexoses present in the mixture are converted without detoxification into ethanol. Afterward, all the materials from fermentation and hydrolysis processes are changed efficiently to biomethane through anaerobic respiration, which results in the increased production of biofuels. 10.4MJ energy is realized from each kilogram of dry OFMSW. Therefore, the conversion of wastes to biofuels can be done at a lower cost, but the yields are significant. However, the optimum conditions and dilute-acid treatment should be used to realize achieve this production.
Reference
Mahmoodi, P., Karimi, K., & Taherzadeh, M. J. (2018). Efficient conversion of municipal solid waste to biofuel by simultaneous dilute-acid hydrolysis of starch and pretreatment of lignocelluloses. Energy Conversion and Management, 166, 569-578. Web.