Turning frequency regimes and inactivation of pathogenic microorganisms in municipal organic solid waste compost

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One of the simplest ways of reducing the ever-increasing amounts of municipal solid waste and inactivating the pathogenic microorganisms associated with them involves composting techniques to make the product hygienically safe to handle. An experimental waste management option was conducted to determine the best time interval within which when compost is turned will undergo optimum composting, eliminate pathogenic microorganisms and helminthes eggs and increase the CN ratio. In this study, municipal solid waste was sorted to separate the organic component from the inorganic portion. Eighteen compost heaps were made from the organic portion with three replicates each. These piles were subjected to six different turning frequencies at 3,5,7,10,14 and 15 days intervals. Temperature, moisture, C/N ratio, pH, faecal coliforms and total colifonns, and helminthes eggs were monitored to ascertain the effects of the turning frequencies on the compost. The results showed significant (p<0.05) reduction in microbial numbers for turning frequency 7 for faecal coliforms from logio 10.37/l00ml to log10 4.361100m1; total coliforms from logio 18.37/lOOml to logo 4.36/l00ml; and helminthes eggs from 80/10Og wt to 0/100g wt with a Carbon/Nitrogen ratio of 19.33. However, all other turning frequencies did not produce any significant (p > 0.05) differences in bacterial numbers. It is therefore recommended that at turning frequency 7, helminthes eggs would significantly be reduced even though compost produced in all the compost piles were of quality for improvement of arable soil.
A thesis submitted to the College of Science in partial fulfilment of the requirements for the award of Master of Science, 2005