Vermistabilization of fecal sludge with organic enriched substrates for compost production using two earthworm species (Eisenia foetida and Eudrilus eugeniae)

Abstract

AbstractDeveloping countries are facing high generation of fecal sludge without adequate systems for proper treatment, leading to detrimental effects on the environment from its disposal. An emerging and innovative option in curbing this problem is the use of epigeic earthworm species to stabilize the waste into vermicompost, a value‐added resource. Substrate enrichment techniques can be applied to promote the sustainability and effectiveness of the vermicomposting process. This study was therefore carried out to determine the potential of two epigeic earthworm species (Eisenia foetida and Eudrilus eugeniae) to transform and stabilize fecal sludge into vermicompost using organic enriched substrates. Enriched substrates were prepared with 160 g of coconut coir, 120 g of fecal matter (65–70% dry matter) and 80 g of organic black soil. Three treatments of the vermibed substrates were prepared which were labelled T1, T2 and T3, with T1 containing Eisenia foetida, T2 containing Eudrilus eugeniae and T3, the control treatment, containing no earthworm. Treatments were triplicated and about 3‐week‐old 20 clitellated, E. fetida (live weight ∼255–275 mg) were introduced into the vermibeds for vermicomposting over a duration of 12 weeks. Physicochemical parameters such as pH, organic carbon (Corg), total nitrogen (Ntot), available phosphorus (Pavail), exchangeable calcium (Caexch), iron (Fe), lead (Pb), and aluminium (Al) changes in the setups at the beginning and end of the vermicomposting period were evaluated. Eisenia foetida demonstrated a higher Corg mineralization (67.59%) compared to Eudrilus eugeniae, which attained 67.22%. Eisenia foetida also showed 5% more mortality than Eudrilus eugeniae. The study revealed that the two epigeic earthworm species for the vermicomposting of fecal waste in the enriched substrates played significant role in stabilizing the waste into vermicompost that was rich in nutrients, with lower levels of metals, higher levels of microbial biomass and higher levels of enzyme concentration.