Investigating the effects of vermicomposting process using earthworms on the reduction of parasites population.

PURPOSE

The existence of parasite agents in natural organic fertilizers can lead to health problems and infection transmission. The aim of the present study was to survey the parasites' population reduction during the vermicomposting of the mixtures of municipal sewage sludge (SS) and cow dung (CD) using earthworms.

METHODS

The vermicomposting process was performed by using earthworms of species. The composting process was conducted in 27 pilots for 3 months. The identification and counting of the parasites' population were carried out by Mac Master Slide, according to Bailenger method.

RESULTS

The results indicated that the type and number of parasite elements decreased with increasing vermicomposting time. The cumulative removal percent of parasites for sewage sludge (96.10%) was more than the SS + CD (93.65%) and CD (92.93%) treatments. The results showed that after 90 days of vermicomposting, the highest cumulative reduction in the number of parasites was obtained for the treatments with 40 earthworms (98.48%), while the corresponding value for the treatments without earthworms was (88.66%). The statistical analysis indicated that in terms of the parasite's population, a significant difference was observed for the three kinds of compostable materials ( < 0.05), however, this difference was not significant for the three levels of the earthworms ( > 0.05).

CONCLUSION

The results showed that the mixture of sewage sludge and cow dung in combination with sawdust could lead to greater and faster reduction in the parasite's population. In addition, the bio-transformed product can be used as useful manure.