DETERMINATIONS OF SOME TYPHA MINERAL COMPOSITION AND ORGANIC LOADING RATE FOR ANAEROBIC DIGESTIONS

Abstract

Choice of good substrate and organic loading rate in anaerobic digestion of biomass for biogas generation was among the critical factors needed to achieve a stable biogas system. This study determined some nutrient compositions require by anaerobic microorganism for biogas production from typha biomass and evaluate biogas production at different organic loading rates under laboratory condition. The nutrients compositions from typha plants were determined from standard laboratory procedures while the organic loading rate a single factor experiment was design in completely randomized design (CRD) at four level of organic loading rate: 0.2, 0.4, 0.6, and 0.8 g/100 ml and hydraulic retention time of 34 days. The experiments were repeated three times for four weeks. The results were analysed using statistical analysis Software (SAS). The digesters were feed after 4 - 5 days intervals and the system operated at mesophilic temperature (38 – 39 ^oC). The system has a total volume of 125 ml with a working volume of 105ml. Volume of biogas produced from each unit of the digester was measured using a glass syringe while the methane was measured with the used of sodium hydroxide solution. The study established that the plant has a nitrogen content of 0.34 - 1.58%, while organic carbon had 52.42 - 55.78%. Calcium concentration found to be 0.69 -1.36 % and phosphorous, magnesium, potassium, and sodium obtained to be: 0.03 - 0.29, 0.07 - 0.23, 0.73 - 3.13 and 0.13 - 1.21%, respectively. Similarly, iron was within the range of 196 - 707 ppm while manganese 261 - 752 ppm. The zinc range was 7 - 26 ppm while copper 2 - 9 ppm. Neutral detergent fiber (NDF) varies from 59 - 75%. Acid detergent fiber (ADF) ranged 34 - 60%, while lignin concentrations range 12 - 21%. High carbon to nitrogen ratio obtained with the range from 34 – 162/1. Ash content was 5.05 - 10.74%. For the gas generation, 0.6 g produced the highest cumulative volume of gas while 0.4 g with the highest methane yields. However, 0.2 g has the highest efficacy with the gas yield of 366 ml/ g volatile solid (VS). It is advantageous to operate with 0.2g due to higher volatile solid.