Secondary Waste Form Screening Test Results?Cast Stone and Alkali Alumino-Silicate Geopolymer

Abstract

Executive SummaryWashington River Protection Solutions (WRPS) is responsible for the design and construction of upgrades to the Effluent Treatment Facility (ETF) at Hanford necessary to support the 2018 operation of the Hanford Tank Waste Treatment and Immobilization Plant (WTP). Upgrades to ETF will include a Solidification Treatment Unit (STU). The ETF is a Resource Conservation and Recovery Act (RCRA)-permitted multi-waste treatment and storage unit that can accept dangerous, low-level, and mixed wastewaters for treatment. Addition of the STU to ETF will provide the additional capacity needed for ETF to process the increased volume of secondary wastes expected to be produced by WTP. Although the current baseline calls for solidification of the ETF evaporator concentrate in a cement-based waste form, an evaluation is being conducted to identify and characterize other candidate stabilization technologies that are mature enough and have the potential of successfully treating the WTP's secondary liquid waste stream.Pacific Northwest National Laboratory (PNNL) is initiating a waste form testing program to support the evaluation and selection of waste forms for stabilization and solidification of the liquid secondary waste stream from the WTP. A literature survey was conducted to identify candidate waste forms. The candidate stabilization technologies selected include Cast Stone, Duralith alkali-alumino-silicate geopolymer (Geopolymer), fluidized-bed steam reformer (FBSR) granular product encapsulated in a geopolymer matrix, and a Ceramicrete phosphate bonded ceramic. These wastes forms have been shown to meet waste disposal acceptance criteria, including compressive strength and universal treatment standards for RCRA metals (as measured by the Toxicity Characteristic Leaching Procedure [TCLP]) to be acceptable for land disposal. Previous testing reported in the literature indicated there were some formulation issues that needed to be addressed for the Geopolymer and Ceramicrete waste forms, and information is needed on all four waste forms with respect to their ability to minimize the release of technetium. Technetium is a radionuclide predicted to be in the secondary liquid wastes in small quantities, and a recent risk assessment analyses for the Integrated Disposal Facility (IDF) showed technetium has the largest contribution to the estimated IDF disposal impacts to groundwater.To support a final waste form down selection, PNNL is conducting screening tests on the candidate waste forms to provide a basis for comparison and to resolve the formulation and data needs identified in the literature review. This report documents the screening test results on the Cast Stone cementitious waste form and the Geopolymer waste form. Screening tests on the Ceramicrete phosphate bonded ceramic and the encapsulated FBSR material will be conducted and documented as those materials become available. Later, more comprehensive and longer term performance testing will be conducted, following the guidance provided by the secondary wa...

Waste Acceptance Testing of Secondary Waste Forms: Cast Stone, Ceramicrete and DuraLith

“…The Cast Stone waste form is the current baseline technology for solidifying the liquid secondary wastes from WTP. Pierce et al, (2010b) demonstrated that the Cast Stone is a viable waste form for immobilization of the WTP secondary wastes. Sundaram et al (2011) conducted additional work to develop and start the optimization of Cast Stone for the secondary liquid wastes to be treated at ETF.…”

“…The EPA 1313 test method (EPA 2009a) has been used on Cast Stone and DuraLith samples tested during the Phase I investigations of candidate secondary waste forms (Pierce et al, 2010b). Therefore, in this set of tests, EPA 1313 leaching was conducted on only Ceramicrete samples.…”

“…In 2009, preliminary screening of waste forms was conducted to assess the viability of alternative waste forms for solidifying the liquid secondary wastes (Pierce et al, 2010a(Pierce et al, , 2010b. A testing program was initiated to further develop, optimize, and characterize the Cast Stone, Ceramicrete, and DuraLith waste forms to stabilize/solidify the anticipated liquid secondary wastes.…”

Data Package for Secondary Waste Form Down-Selection—Cast Stone

“…The projected WTP secondary waste compositions have varied over time as flow sheets and assumptions have changed. More details on the derivation of the WTP secondary waste compositions can be found in the two previous Cast Stone reports (Pierce et al 2010b;Sundaram et al 2011). The compositions of the dissolved species in secondary waste simulants in general are dominated by sodium and hydroxide with significant concentrations of nitrate and oxalate (represents all organic matter) present in many.…”

“…In 2009, preliminary screening of waste forms was conducted to assess the viability of alternative waste forms for the solidification of the liquid secondary wastes (Pierce et al 2010a;Pierce et al 2010b). A testing program was initiated to further develop, optimize, and characterize the Cast Stone, Ceramicrete, and DuraLith waste forms to stabilize/solidify the anticipated liquid secondary wastes.…”