Screening and application of microbial inoculants for sludge composting in expressway service area of northwest China

Taking sludge in northwest China’s expressway service area as the research object, four dominant strains, including Bordetella sp. M05, Ochrobactrum sp. M06, Bacillus subtilis M07 and Staphylococcus sciuri M09, were obtained through specific screening. These microbes were prepared into inoculants and effectively promoted sludge composting. The time for the fermentation temperature of the composting process to reach 50°C was 3 days earlier than that of the control group. The high temperature (>50°C) lasted for 12 days and the highest temperature reached 63.5°C. After composting, the product was dark in color, free from odor, and the contents of organic matter, nitrogen, phosphorus and potassium increased by 44.1%, 125.9%, 311.1% and 269.2%, respectively, which made the composted product meet standards of GB/T 23486–2009 Sludge for Landscaping .