Lowering the Total Coliform of Vermicompost From Solid Waste Materials Produced By African Night Crawler Worm Eudrilus Eugeniae

Abstract

Vermicomposting is an established ecological sanitation program of Bayawan City in Negros Oriental, Philippines that aims to produce low-cost organic fertilizers as an alternative to expensive commercial fertilizers. However, the vermicomposts from biodegradable and human sludge contain high total coliform levels above the limit set by WHO. The study developed coliform-reducing strategies such as agricultural and hydrated lime applications at three concentrations (1:1, 1:0.5, 1:0.25) in two types of vermicomposts. Prior to the experiment, a preliminary study for 15 months made use of air drying and direct sunlight exposure
as methods to reduce total coliform levels. Results show that aeration and exposure to the environment did not reduce coliform levels in vermicompost produced by the African Night Crawler earthworm Eudrilus eugeniae. From an initial level of 54,000,000 cfu/100 mL, the levels of total coliform were 208,000 and 307,000 cfu/100 mL using these methods, respectively. Application of lime, either agricultural or hydrated, significantly reduced the levels of coliform beginning 30 days after treatment. Between Day 45 and Day 60, total coliform levels were reaching zero values and near zero values in both types of lime application. Post hoc analysis indicated higher total coliform levels in vermicompost applied with lower lime concentration. The study recommends the use of agricultural lime over hydrated lime as it reduced coliform levels without impairing the NPK levels of the vermicompost.