Stabilisation of biosolids with admixtures for potential use as an embankment fill material

Biosolids are an end product of the wastewater trea tment process and contain many of the constituents removed from the influent wastewater. This paper is based on a proje ct currently implemented in Victoria to assess the viability of using biosolids as engineered fill material for road emba nkments. A series of geotechnical lab tests were co nducted to evaluate the engineering properties of biosolids samples ret rieved from Western Treatment Plant (WTP) in Victoria, Australia. The laboratory tests undertaken include particle de nsity, moisture content, organic content, Atterberg limits, particle-size distribution, proctor compaction, California Bearin g Ratio (CBR) and consolidation tests. Geotechnical laboratory tests were carried out on untreated biosolids as well as biosolids stabilised with 1%, 3% and 5% by weight o f cement and lime. The test results were subsequently compared w ith the existing local road authority specification for embankment fill material.