Enhancement of the quick lime‐based solidification/stabilization of oily wastes using modified clay

Abstract

BACKGROUND: This research investigated the solidification/stabilization process (S/S) efficiency of contaminated soil by total petroleum hydrocarbons (TPH) in the waste of a used oil treatment plant using quick lime (QL) as a binder and modified clay (MC) as an additive. Several objectives were considered, including reducing the mobility and leaching of TPH, investigating the effect of MC on the QL hydration process in the presence of organic matter, the possibility of S/S waste reuse, and estimating the S/S cost for the optimum mixture. RESULTS:The unconfined compressive strength (UCS) increased about 45% by increasing 25% of QL without MC, but these S/S wastes did not satisfy the waste reuse standards. Additionally, adding any ratio of MC to samples containing QL increased UCS significantly. The UCS of all samples at the age of 28 days with different QL and MC proportions obtained more than 350 kPa (the minimum UCS required for S/S waste disposal in the landfill). Moreover, the toxicity characteristic leaching procedure (TCLP) test revealed that TPH leaching of contaminated soil was 3.8 mg L −1 but adding only 15% of QL could reduce TPH leaching to less than 1 mg L −1 , which is the maximum allowable TPH leaching.CONCLUSION: The combination of QL and MC decreased TPH leaching, significantly. The scanning electron microscopy analysis also showed that QL hydration was improved by increasing the amount of MC. Finally, a sample with 35% QL and 15% MC was selected as an optimum sample due to its cost of $80.5/ton.

Remediation of a clay soil contaminated with phenanthrene by using MgO and forced carbonation

“…Figure 1 shows a schematic diagram of tests that were conducted for S/S of the contaminated soil. UCS and SEM were the experimental tests as used by researchers such as Jebeli and Heidarzadeh, 20 Heidarzadeh et al , 21 González‐Santamaría et al , 22 and Botta et al 23 . The main aim of conducting the UCS tests was to use the results as an indicator, to determine the resistance of solidified and stabilized materials against loading.…”

“…Figure 1 shows a schematic diagram of tests that were conducted for S/S of the contaminated soil. UCS and SEM were the experimental tests as used by researchers such as Jebeli and Heidarzadeh, 20 Heidarzadeh et al, 21 González-Santamaría et al, 22 and Botta et al 23 The main aim of conducting the UCS tests was to use the results as an indicator, to determine the resistance of solidified and stabilized materials against loading. Also, scanning electron microscopy (SEM) tests were conducted to study the microstructure of the clay under different conditions (different percentages of MgO, curing times, and durations of CO 2 injection) and to determine the produced carbonate materials.…”

Remediation of a clay soil contaminated with phenanthrene by using mixture of bentonite and cement

“…Organic clays are usually used in the S/S technique for remediation of contaminated soils with organic substances. Botta et al, 30 Zhu et al, 31 and Heidarzadeh et al 32 indicated that organophilic clays can be effective as an adsorbent for hazardous organic waste. Al‐Tabbaa and Perera 33 used a combination of cement and organophilic clay as a binder for remediation of a soil that was contaminated with hydrocarbons.…”