Comparative study of phosphorus in anaerobic fermentation process with carbon dioxide addition

Abstract

This research focused on the comparative study of phosphorus in anaerobic fermentation process with carbon dioxide addition. The objective of this study aims to compare the amount of phosphorus from carbon dioxide addition in anaerobic fermentation process from elephant dung, fermented slurry and elephant food wastes. In the experiment, the elephant food wastes are pineapple rhizomes and Napier grass. The mixture of materials consists of Napier grass : pineapple rhizomes : Elephant dung : slurry from biogas fermentation equal to 2.5 : 2.5 : 3.5 : 1.5 by volume. Lab-scale experiment was set as two conditions: 1) control reactor without carbon dioxide addition and 2) batch reactor with adding 2 L/min of carbon dioxide for 20 min, to operate anaerobic fermentation for 45 days in closed vessels. The results of this study showed that the physical characteristics of both composting reactors at the end of the 45-day period was brown liquid fertilizer and has a sour smell. The pH values of control reactor and batch reactor with carbon dioxide addition ​were 6.16 and 5.19, respectively. The moisture content of both sets is in the range of 75-85 percent. In terms of total phosphorus values It was found that in the control, the amount of phosphorus is higher than when adding carbon dioxide. With the percentage of 0.58 and 0.37 respectively. Adding carbon dioxide to the system causes some microbes that disfavor carbon dioxide, decompose organic matter by using phosphorus as a nutrient. Therefore, it causes more phosphorus to be used and then made the phosphorus in manure decreased.