Amitkumar J. Shah, Prateek G. Shilpkar, Surendra N. Gohil1 and Mayur C. Shah
Abstract
Marigold (Tagetes) is an annual flower and bloom over the long season. Mostly, in India, it is used for worship of god in temple and at home. After that it is thrown outside on road or in rivers. Present study is an attempt to find out the Biochemical Methane Potential (BMP) of Tagetes flower to produce biogas and digested slurry. The experiment was carried out in 20 l capacity anaerobic digesters. The flower waste was blended with cattle dung in three different ratios of 25%, 50% and 75% and control set with flower (100% flower) and cattle dung (100% cattle dung) were put without blending. Care was taken to keep the total solids concentration in each digester at 8%. Biogas production was measured along with environmental temperature for 137 days by water displacement method and the proportion of methane in biogas was measured by Gas chromatography. The pH, organic carbon, nitrogen, phosphorus and potassium contents of digestion mixtures before and after anaerobic digestion were measured following standard methods. To understand the microbial activities total viable count in digested slurry has also been measured at 0 and 137 days. Since Biochemical methane potential has direct relationship with total volatile solids content so it was also measured at 0 and 137 days of digestion. Data were analysed statistically. Results show that among blending treatments highest Biochemical Methane Potential (317.27 ml CH4/g TVS used) was recorded in treatment receiving 25% flower waste blend with 75% cattle dung. This treatment also shows highest reduction in total volatile solids (51.91 g% at 137 day over 0 day) content. With progress in time the digestion materials become neutral to alkaline in pH in all the treatments except Tagetes flowers control. Content of total organic carbon decreased significantly with time whereas available nitrogen, available phosphorus and available potassium content increased significantly in all the treatments at 1% level of significance. Total viable counts were also increased significantly with time in all the treatments except Tagetes flowers control. It can be concluded that Tagetes flowers has good biochemical methane potential and can be used successfully to produce methane and nutrient rich digested slurry. This study will certainly achieve a significantly high economic value in big temples having bulk volume of Tagetes flower collection.