Regulatory Policy Implications of 1,4-Dioxane - Environmental Investigation and Remediation - page 471

and case studies, as well as some of the 1,4-dioxane occurrence and use information from Chapter 2
and fate and transport characteristics from Chapter 3 are summarized as follows:
1. Expect to i nd 1,4-dioxane at vapor degreasing sites that used 1,4-dioxane-stabilized
methyl chloroform and released vapor degreasing wastes.
2. Expect to i nd 1,4-dioxane at solvent recycling facilities.
3. Expect to i nd 1,4-dioxane further downgradient than the leading edge of the solvent plume.
4. Expect to i nd 1,4-dioxane in groundwater within silts and clays near the source zone, but not
usually in sands and gravels at release sites unless the spill is recent (it is often l ushed out).
5. Expect to i nd 1,4-dioxane in municipal, industrial, and particularly in university landi lls.
6. Expect to i nd 1,4-dioxane in landi ll leachate and landi ll gas condensate, and in ground-
water contaminated by landi lls.
7. Expect to i nd 1,4-dioxane at cement kilns that used solvent wastes for fuel.
8. Expect to i nd 1,4-dioxane in water bodies receiving efl uent from textile manufacturing,
resin production, plastics manufacturing, photographic i lm production, and cellulose
acetate membrane production.
9. Expect to i nd low levels of 1,4-dioxane (1-2 μg/L) in wastewater treatment inl uent, in treated
wastewater efl uent, and in recycled water that has not been subjected to advanced oxidation.
10. Expect remedial engineering challenges for 1,4-dioxane treatment, including high costs.
11. Expect adverse public reaction when the late discovery of 1,4-dioxane at cleanup sites is
publicized, especially where domestic wells have been contaminated with 1,4-dioxane.
Regulatory agency caseworkers and remedial project managers should consider these lessons
when drafting site cleanup orders, Records of Decision, or other cleanup requirements. Consulting
engineers and hydrogeologists performing remedial investigations and feasibility studies on behalf
of dischargers also stand to benei t from taking these lessons into account when recommending
solutions for remediating 1,4-dioxane and solvent releases to soil and groundwater.
10.4.4 1,4-D IOXANE T REATMENT T ECHNOLOGY R ESEARCH N EEDS
Remediating 1,4-dioxane is expensive and challenging, because the best options currently available
are primarily limited to groundwater extraction and ex situ treatment using advanced oxidation.
Success stories for the treatment of 1,4-dioxane ex situ include Applied Process Technology's
HiPOx™, Basin Water's Photo-Cat™, Trojan Technologies' UVPhox™, Calgon Carbon's Rayox ® ,
and others (see Chapter 7). New technologies successful at ex situ removal of 1,4-dioxane from
extracted groundwater include Liquid Separation Technologies and Equipment's LSTE-10, which
uses a multichambered vacuum aeration tank and a high-vacuum separator tower.
In-well treatment successes have been achieved with the ART In-Well system (see Section 7.1.2)
and Applied Process Technology's Pulse-OX TM (see Section 7.7.2). ISCO technologies include
FMC's persulfate solution, Klozur™ (see Section 7.7.5) and Isotec's Fenton chemistry solution (see
Section 7.7.4). Research continues in most of the treatment technology areas proi led in Chapter 7.
The greatest need for research in 1,4-dioxane remediation is to overcome the challenges to
achieving reliable in situ treatment of 1,4-dioxane using bioremediation and ISCO. The biodegra-
dation research proi led in Chapters 3 and 7 provides a solid foundation on which the state of
1,4-dioxane bioremediation science can be advanced. Research needs include the following:
1. Isolating and sustaining the growth of 1,4-dioxane-respiring cultures that can be accli-
mated to the in situ geochemical environment
2. Developing compound-specii c isotope analysis methods sensitive enough to detect
isotope ratios in 1,4-dioxane and its metabolites at environmentally relevant (i.e., low)
concentrations