28 Feb 95
hazardous wastes unless they still exhibit a hazardous
(2) The Comprehensive Environmental Response, Compensation,
and Liability Act (CERCLA). CERCLA established a procedure for
responding to releases of hazardous substances which ultimately
involves site remediation actions potentially utilizing the S/S
technology. CERCLA requires contaminated sites to be
investigated, prioritized, and remediated. Requirements of other
integrated into the CERCLA process when evaluating alternative
Applicable or Relevant and Appropriate Regulations (ARARS). The
Superfund Amendments and Reauthorization Act (SARA) was enacted
in 1986. SARA reauthorized and further defined the CERCLA
on-site treatment methods which reduce the toxicity, mobility or
volume of hazardous substances. S/S is an applicable treatment
technology based on these criteria since it reduces the mobility
c. Reagents. Reagents are the materials which are mixed
with contaminated soils, sludges, and liquids to reduce the
mobility of the contaminants by chemical and physical reactions.
There are two basic types of S/S reagents, organic and inorganic.
Organic reagents have rarely been used for the cleanup of
hazardous waste sites. Therefore, this ETL will focus on the use
of inorganic reagents. The normal processing steps when using
inorganic reagents are to 1) chemically react with all the water
present, 2) chemically react with the contaminants to render them
insoluble, and then 3) encapsulate the products.
(1) Inorganic Reagents. Inorganic reagents most often used
for S/S include portland cement, fly ash, lime, phosphates, and
kiln dust from lime and cement production. All of these reagents
far as S/S reactions are concerned. These active ingredients
include SiO2, CaO, MgO, Al2O3, and Fe2O3.
(2) Organophillic Clay. Organophillic clay has been
proposed for use to adsorb organic contaminants so that they can
be trapped in a solidified matrix. Lab tests have indicated that
some organophillic clays chemically bond to organics. However,
the strength of this bond is of concern. In most cases, the
mechanism by which the organics are trapped is merely physical
adsorption. Organophillic clays show some promise in combination
with other reagents for the treatment of organics.