Effective use of microbes in waste soil stabilisation considering natural temperature variations

Abstract

ABSTRACT Dredged soils are waste deposits left unutilised in huge quantities. In order to effectively utilise such weak deposits, proper improvement techniques need to be adopted. In this study, four different bacillus microbes namely Bacillus pasteurii, Bacillus megaterium, Bacillus sphaericus and Bacillus subtilis along with cementing solution at different molarities (0.5 and 1 CSM) have been incorporated into the soil at an optical density of 1.5 (108 cells/ml). Unconfined compressive strength (UCS) and permeability tests have been performed on the soil samples. The samples were provided treatment (48 h) and curing (7 and 14 days) in natural conditions. The UCS test results at 0.5 CSM and 7 days curing revealed a noticeable enhancement. Permeability reduced by one order at 14 days of curing and 1 CSM. Three different ranges of temperature depending upon natural climatic variations were designated for testing, and it was concluded that 18–23°C was the optimum temperature for all the treatment processes. This study puts forth the importance of green eco-friendly technology in improving dredged soils from wetland peripheries thus helping indirectly in restoring its balance. Scanning electron microscopy (SEM) along with energy dispersive spectroscopy (EDS) provided conclusive support to the experimental investigations.