Field Trials of Ex Situ Smouldering Treatment (STARx) of Oil Sludge
Abstract
Growing environmental concern and regulations around petroleum producing and refining facilities, along with the divesting of legacy properties, have necessitated the need for rapid, high capacity, and cost-effective treatment technologies for remediating these sites and their produced wastes. Self-sustained liquid smouldering – known as STAR technology - has been studied extensively at small scales and has been proven as an effective in situ remediation technique for heavy hydrocarbons. However, STAR as a large-scale ex situ waste disposal method (STARx) has yet to be demonstrated. Here STARx is evaluated for the first time in soil pile configurations, using an engineered base concept called HottpadTM, at both the prototype (0.35 – 1.3m3) and field (80 – 160m3) scales. The treatment was applied to oily sludge from crude oil tank bottoms and oil water separation processes mixed with sand or soils at concentrations from 4 020 – 115 000mg/kg total petroleum hydrocarbons (TPH). The relationships between initial soil concentrations, off-gas production, mass destruction rates, cycle times, and peak temperatures provide important insights into the performance and costs of applying the technology at field scale. STARx was shown to successfully destroy the wastes to below laboratory detection limits, with contaminant mass removal efficiencies of greater than 98% being observed. Overall, this work demonstrates for the first time that STARx is a viable large-scale option for hydrocarbon sludge treatment.