Application of biosolids in civil engineering: State of the art

Abstract

Biosolids are the byproducts from the domestic/industrial sewage treatment processes, and contains solids and heavy metals. They are conventionally disposed by landfilling, ocean disposal, or incineration methods. However, owing to the cost of disposal and negative environmental impact, in recent years, efforts have been made by researchers to utilize biosolids for various applications. Many researchers have reported civil engineering applications of stabilized biosolids (lime / cement / crushed concrete stabilized biosolids) such as backfill material, fill for road embankment, brick and aggregate manufacturing. The studies have also reported that stabilized biosolids yields reduction in permeability, and improvement in shear strength, compaction characteristics (OMC and MDD) and California bearing ratio (CBR). This paper reviews in details the existing literature related to various aspects such as characterization of biosolids, its environmental impact and treatment/stabilization methods while emphasizing on its potential applications. The study concludes that stabilized biosolids have good potential to be utilized for various Civil Engineering applications, while minimizing the impact on environment and challenges related to disposal of biosolids.