The Effect of Adding Corn Silage at Different Ratios to Orange and Tangerine Wastes on Biogas Production Efficiency
Abstract
In this study, biogas production efficiencies of mixtures obtained by adding corn silage (CS) to citrus industrial wastes at different ratios were determined. Orange (OJPW) and tangerine processing juice wastes (TJPW) (crusts and shells) were selected as materials in the study. 25%, 50%, 75% of CS was added to these selected wastes. Changes in the obtained mixture chemical properties (dry matter, dry organic matter, crude ash, crude protein, crude oil, Acid Detergent Fiber (ADF), Neutral Detergent Fiber (NDF)), biogas production and methane content in the biogas were investigated. The results of the study showed that the highest crude protein content was found in 100% TJPW (10%), raw fat percentage in 100% TJPW (5.14%), dry matter content in 100% CS (93.56%), ADF in 100% CS (22.74%) and the NDF in a mixture of 25% OJPW + 75% CS (45.08%). The highest methane production was determined for a mixture of 100% TJPW and 50% TJPW + 50% OJPW (0.46 m3 kg-1 ODM). Also the highest biogas production was determined in a mixture of 50% OJPW + 50% TJPW (0.90 m3 kg-1 ODM). The mixing of CS in TJPW and OJPW reduced significantly the production of methane and biogas in the mixture. As a result of the statistical analysis, significant differences (P≤0.05) were found in both methane and biogas production of agricultural wastes.
- Introduction
Today the gradual decrease of fossil fuel resources has increased the need for renewable energy sources (Üçok et al 2016). In recent years, due to its contribution to the sustainable development of countries, there is increasing interest in the energy obtained from biomass, especially biogas (Mansourpoor & Shariati 2012; Üçok et al 2016; Mojtaba & Ahmad 2012). Wastes emerged from agriculture, and related industry is major sources of biogas production. Application of biogas technology provides not only the disposal of waste but also energy production (Deublein & Steinhauser 2008).
Citrus fruits are among the most grown and consumed fruit group in the world. In this regards, China ranks first with about 32 million tons followed by Brazil with 20 million tons and the USA with 10 million tons. Turkey is ranked the eighth with 3.7 million tons (FAO 2015). Approximately 85% of citrus production in Turkey is produced in the Mediterranean region (TUİK 2015). Turkey has an important position in the production of citrus fruits especially regarding exports to the Middle East (Iraq, Saudi Arabia, and Iran), Russia, Ukraine, Romania, Poland, and Bulgaria. However, there are significant problems in the export of products grown in recent years due to political and geopolitical problems among these countries, to which exports have been made. Therefore, most of these products can not be consumed due to excess supply in the domestic market (Çallı 2012).
Processing the citrus fruits into juice, a large part of the separated pulp consisting of crust which is rich in cellulose and pectin can be utilized in bioprocesses with the aid of preprocessing. This may create an opportunity for the fruit juice industry in Turkey for the valorization of wastes (crusts and pulps) existed from the processing of orange and tangerine regarding the production of biogas.
The efficiency of biogas production from fruit processing wastes can be increased by cofermentation with wastes which have higher biogas potential (Elaiyaraju & Partha 2012). This may encourage the establishment of small-scale biogas plants in the region, leading to the prevention of environmental pollution and the utilization of significant energy resources. In Europe, there are many central biogas plants that are operated successfully, producing biogas from thousands of farm-type and organic household and industrial wastes producing biogas from animal wastes and energy plants (Çallı 2012). Although numerous studies on the usage of fruit pulps and wastes for biogas production have been carried out (Aslanzadeh & Özmen 2009; Elaiyaraju & Partha 2012; Nguyen 2012; Wikandari et al 2014a; Wikandari et al 2014b), there are limited studies on co-fermentation of two plant-based materials to increase biogas production efficiency concerning fruit pulps and wastes.
In this study, it was aimed to determine the biogas production efficiencies of the mixtures obtained by adding corn silage to citrus industrial wastes at different rates. For this aim, corn silage has been added to the orange and mandarin wastes produced during fruit juice industry production activities at different rates. The chemical properties of these obtained mixtures, biogas productions and methane rates in the biogas have been determined.
The Effect of Adding Corn Silage at Different Ratios to Orange and Tangerine Wastes on Biogas Production Efficiency
Metin DAĞTEKİN Ali AYBEK Serdar ÜÇOK Abdullah BEYAZ
Year 2018, Volume 24, Issue 4, 531–538
