COMPARISON OF COMPOST MATURITY, MICROBIAL SURVIVAL AND HEALTH HAZARDS IN TWO COMPOSTING SYSTEMS

Abstract

Data collected on germination index, temperature, moisture content, pH, total viable count, total coliform count and total fungi count were determined during composting in HV and FA systems at VREL Farms for a period of thirteen weeks and analysed to ascertain the effects of temperature, moisture and pH on compost maturity and microbial survival. There were no significant differences in germination index, pH and moisture content values for both systems as ANOVA results at α = 5% yielded p-values of 0.17, 0.98 and 0.13 respectively. Moisture content and pH values ranged between 40%-70% and 7.20 - 8.30 respectively. Temperature values recorded however were significantly different (p-value = 1.2 x 10-5, α = 5%) in both systems and affected the microbial distribution during the process. The temperature recorded in HV and FA systems ranged between 45.19 ºC – 65.44 ºC and 29.00 ºC – 50.83ºC respectively. Germination Index values were >150% in different systems at the end of week 12. Listeria spp., known to be zoonotic, and Staphylococcus spp. survived in compost processed in FA system; and Penicillium spp. in both systems.