vvEPA
United States
Environmental Protection
Agency
EPA/540/MR-93/501
February 1993
SUPERFUND INNOVATIVE
TECHNOLOGY EVALUATION
Demonstration Bulletin
perox-pure™ Chemical Oxidation Treatment
Peroxidation Systems, Inc.
Technology Description: The perox-pure™ chemical oxidation
treatment technology was developed by Peroxidation Systems, Inc.
(PSI), to destroy dissolved organic contaminants in water. The technol-
ogy uses ultraviolet (UV) radiation and hydrogen peroxide to oxidize
organic compounds present in water at parts per million (ppm) levels.
This treatment technology produces no air emissions and generates
no residue, sludge, or spent media that require further processing,
handling, or disposal. Ideally, end products are water, carbon dioxide,
halides (for example, chloride), and in some cases, organic acids. The
technology uses medium pressure mercury vapor lamps to generate
UV radiation. The principal oxidants in the system, hydroxyl radicals,
are produced by direct photolysis of hydrogen peroxide at UV wave-
lengths.
The perox-pure™ chemical oxidation treatment system (Model
SSB-30) used for the SITE technology demonstration was as-
sembled from the following portable, skid-mounted components: a
chemical oxidation unit, a hydrogen peroxide feed tank, an acid
feed tank, a base feed tank, a UV lamp drive, and a control panel.
The oxidation unit has six reactors in series with one 5-kilowatt UV
lamp in each reactor and has a total volume of 15 gal. The UV
lamp is mounted inside a UV-transmissive quartz tube in the
center of each reactor so that water flows through the space
between the reactor walls and the quartz tube.
To Discharge
or Disposal **
A schematic flow diagram of the perox-pure™ chemical oxidation
unit is shown in Figure 1. Contaminated water enters the oxidation
unit through a section of pipe containing a temperature gauge, a
flow meter, an influent sample port, and hydrogen peroxide and
acid injection points. Contaminated water is dosed with hydrogen
peroxide before the water enters the first reactor; however, a
splitter can be used to add hydrogen peroxide before any of the
six reactors within the oxidation unit. In some applications, acid is
added to lower the influent pH and shift the carbonate-bicarbonate
equilibrium to carbonic acid. This equilibrium is important because
carbonate and bicarbonate ions will scavenge hydroxyl radicals.
After chemical injections, the contaminated water flows through a
static mixer and enters the oxidation unit. Water then flows through
the six UV reactors, which are separated by baffles to direct water
flow. Treated water exits the oxidation unit through a pipe equipped
with a temperature gauge, an effluent sample port, and a base
injection point. Base may be added to the treated water to adjust
the p^H to meet discharge requirements.
Circular wipers attached to the quartz tubes housing the UV
lamps are used periodically to remove any solids that have accu-
mulated on the tubes. Solids may accumulate as a result of
metals oxidized by the treatment system (such as iron and man-
ganese), water hardness, or suspended solids that may precipi-
UVLamp
Baffle
Reactor
Static Mixer
Oxidation Unit
Figure 1. perox-pure™ chemical oxidation treatment system flow diagram.
Printed on Recycled Paper
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tale out of the water. Accumulated solids could eventually coat the
tubes, thus reducing treatment efficiency.
Waste Applicability: The perox-pure™ technology has been
used to treat landfill leachate, groundwater, and industrial waste-
water all containing a variety of organic contaminants, including
chlorinated solvents, pesticides, polynuclear aromatic hydrocar-
bons, and petroleum hydrocarbons. In some applications, where
the contaminant concentration was too high [about 500 milligrams
per liter (mg/L)] for the perox-pure™ system to handle alone, the
system was combined with other treatment technologies.
Demonstration Approach: The perox-pure™ chemical oxida-
tion technology was demonstrated at Lawrence Livermore National
Laboratory Site 300 in Tracy, California, over a 3-wk period in
September 1992. During the demonstration, about 40,000 gal of
groundwater contaminated with volatile organic compounds (VOC)
was treated. The principal groundwater contaminants were
trtehtoroethene (TCE) and tetrachtoroethene (PCE), which were
present at concentrations of about 1,000 and 100 micrograms per
liter (u,g/L), respectively. Groundwater was pumped from two wells
Into a 7,500-gal bladder tank to minimize any variability in influent
characteristics. In addition, cartridge filters were used to remove
suspended solids greater than 3 microns from the groundwater
before H entered the bladder tank. Treated groundwater was stored
In two 20,000-gal steel tanks before being discharged.
The technotogy demonstration was conducted in three phases. Phase
1 consisted of eight runs, Phase 2 consisted of four runs, and Phase 3
consisted of two runs. These phases are described below.
The principal operating parameters for the perox-pure™ system,
hydrogen peroxide dose, influent pH, and flow rate (hydraulic
retention time), were varied during Phase 1 to observe treatment
system performance under different conditions. Preferred operat-
ing conditions, those under which the concentrations of effluent
VOCs were reduced below target levels at the least cost, were
then determined for the system.
Phase 2 Involved spiked groundwater and reproducibility tests.
Groundwater was spiked with about 300 |ig/L each of 1,1-
dtehtoroethane (DCA); 1,1,1-trichIoroethane (TCA); and chloro-
form. These compounds were chosen because they are difficult to
oxidize and because they were not present in the groundwater at
high concentrations. This phase was also designed to evaluate the
reproducibility of treatment system performance at the preferred
operating conditions determined in Phase 1.
During Phase 3, the effectiveness of quartz tube wipers was
evaluated by performing two runs using spiked groundwater.
During the demonstration, samples were collected at the following
locations: treatment system influent, effluent from Reactor 1, effluent
from Reactor 3, and treatment system effluent. These samples were
analyzed for VOCs, semivolatile organic compounds, total organic
carbon, total carbon, purgeable otganic carbon, metals, pH, alkalinity,
and hardness. In addition, samples of influent to Reactor 1 and
treatment system effluent were collected and analyzed for acute
toxicity to fresh water organisms. The hydrogen peroxide, acid, and
base solutions and spiked groundwater were also sampled and ana-
lyzed to verify concentrations.
Key findings of the SITE demonstration, including sample analyti-
cal results, will be discussed in detail in the Applications Analysis
Report and the Technology Evaluation Report. Results will also
be summarized in a project summary report and a videotape.
During the SITE demonstration of the perox-pure™ system, the
following preliminary findings were noted:
• Preferred operating conditions from Phase 1 (determined by
quick turn-around analyses for selected compounds) were as
follows: the influent hydrogen peroxide was 40 mg/L; the
hydrogen peroxide in influent to Reactors 2 through 6 was 25
mg/L; the influent pH was 5.0; and the flow rate was 10 gal/min.
• During the three reproducibility runs, average removal efficien-
cies for chloroform, DCA, PCE, TCA, and TCE after Reactor 1
were 46.1%, 70.3%, 95.9%, 21.0%, and 98.4%, respectively.
After Reactor 6, removal efficiencies for chloroform, DCA, and
TCA increased to 85.6%, 96.3%, and 75.6%, respectively.
• System setup and shakedown took about 5 days. The system
required little or no attention after operating conditions were
established. There were no major operational problems that
affected system performance.
For Further Information:
EPA Project Manager:
Norma Lewis
U.S. EPA Risk Reduction Engineering Laboratory
26 West Martin Luther King Drive
Cincinnati, OH 45268
(513) 569-7665 (FAX: 513-569-7620)
United States
Environmental Protection Agency
Center for Environmental Research Information
Cincinnati, OH 45268
Official Business
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EPA
PERMIT No. G-35
EPA/540/MR-93/501
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