United States
Environmental Protection
Agency
EPA/540/MR-93/506
March 1992
SUPERFUND INNOVATIVE
TECHNOLOGY EVALUATION
Demonstration Bulletin
PO*WW*ER™ Wastewater Treatment System
Lake Charles Treatment Center
Chemical Waste Management, Inc.
Technology Description: The PO*WW*ER™ system developed
by Chemical Waste Management, Inc. (CWM), reduces the volume of
aqueous waste and catalytically oxidizes volatile contaminants. The
PO*WW*ER™ system consists primarily of (1) an evaporator that
reduces influent wastewater volume, (2) a catalytic oxidizer that oxi-
dizes the volatile contaminants in the vapor stream from the evapora-
tor, (3) a scrubber that removes acid gases produced during oxidation,
and (4) a condenser that condenses the vapor stream leaving the
scrubber. Rgure 1 presents a flow diagram of the PO*WW*ER™
system pilot plant.
Aqueous waste to be treated by the PO*WW*ER™ system pilot plant
is stored in a stainless steel feed tank The feed tank is equipped with
an agitator mounted on the top of the tank to mix additives into the feed
waste. To control foaming in the evaporator, an antifoam agent can be
added to the waste in the feed tank or sprayed directly into the
evaporator. Also, the pH of the waste is monitored and adjusted in the
feed tank Once the feed waste is suitable for treatment, it is pumped
to the evaporator.
The evaporator consists of three main components: the heat ex-
changer, vapor body, and entrainment separator. As feed waste is
pumped to the evaporator, it combines with heated process brine. The
feed waste is then further heated in a vertical shell-and-tube heat
exchanger. Heat is provided by steam generated in a boiler. In the
heat exchanger, the feed waste is heated to its boiling temperature.
However, boiling does not occur in the tubes because of back pres-
sure created by a designed gravity head.
After passing through the heat exchanger, the feed waste enters the
vapor body, where boiling occurs. During boiling the feed waste
separates into a vapor phase and a brine phase. When the vapor
temperature reaches a value corresponding to a specific brine boiling
point, some brine is wasted by gravity into a waste brine drum. The
vapor exits the vapor body to an entrainment separator. The remaining
brine is recirculated.
In the entrainment separator, the vapor passes through a mesh pad
that entrains droplets and particles. The mesh pad is periodically rinsed
and the rinse water combines with the heated brine and is recirculated
in the evaporator.
The next step in the PO*WW*ER™ system is the oxidation of volatile
organic and inorganic contaminants in the vapor stream from the
evaporator. The vapor is heated to its oxidation temperature by the
reactor heater, which is a direct-fired propane burner. The heated
vapor then enters the oxidizer and passes through a catalyst bed
where oxidation takes place. The oxidizer can operate with a catalyst
Noncondensible
Gases
Feed
Waste
Key
O Sampling Locations
Figure 1. Schematic diagram showing sampling locations for the PO*WW*ER™ pilot plant.
Printed on Recycled Paper
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in either a fluidized or static bed mode. The static bed mode was used
during the Superfund Innovative Technology Evaluatbn (SITE) demon-
stration. Possible oxidation products include carbon dioxide (COJ,
carbon monoxide (CO), water, hydrogen chloride (HCI), sulphur dioxide
(SO2), and nitrogen oxides (NOx).
After oxidatbn, the vapor stream exits the oxidizer and passes through
a scrubber. The scrubber consists of a packed bed in which the vapor
passes countercurrently through a caustic solution to neutralize the acid
gases. Scrubber blowdown is returned to the feed tank. Scrubber vapor
is cooled and condensed in a shell-and-tube condenser. The tempera-
ture of the product condensate ranges from approximately 130 to 160
°F. The product condensate is transferred to a stainless steel product
tank. The product condensate can either be reused as boiler or cooling
tower makeup water, or discharged to surface water, if appropriate. The
noncondensible gases are vented to the atmosphere.
Waste Applicability: According to CWMs claims, the PO*WW*ERTM
system can effectively treat the following types of wastewater: (1)
landfill leachate, (2) contaminated ground water, (3) process wastewa-
ter, and (4) low-level radioactive mixed waste. CWM also states that the
PO*WW*ER™ system can handle wastewater containing volatile and
semivolatile organic compounds (VOC and SVOC), pesticides, herbi-
cides, solvents, heavy metals, cyanide, ammonia, nitrate, chloride,
sulfide, plutonium, americium, uranium, technetium, thorium, and ra-
dium.
Demonstration Results: The PO*WW*ER™ system SITE demon-
stration was conducted in September 1992 at CWMs Lake Charles
Treatment Center (LCTC) in Lake Charles, LA During the demonstra-
tion, landfill leachate from LCTC was treated by the PO*WW*ER™ pilot
plant at a processing rate of 0.21 gal/min. Six test runs were conducted,
each lasting approximately 9 hr. The first three replicate runs were
conducted with unspiked leachate. The last three replicate runs were
conducted with spiked leachate. The leachate was spiked with the
following compounds: methylene chloride, tetrachloroethene, and tolu-
ene, phenol, mercury, cadmium, copper, nickel, and iron.
During each test, samples were collected from the feed waste, product
condensate, and brine. Also, continuous emissions monitoring (CEM)
was performed on the noncondensible gas stream. Feed waste, prod-
uct condensate, and brine samples were analyzed for total suspended
solids (TSS), total dissolved solids (TDS), ammonia, cyanide, VOCs,
and SVOCs. Samples of feed waste and product condensate were
also analyzed for acute toxicity. CEM of the noncondensible gas
stream included monitoring for total nonmethane hydrocarbons, CO2,
CO, NOx, SO, and oxygen. Additional analyses were also performed to
characterize further the feed waste, product condensate, brine, and
noncondensible gas stream.
Key findings of the SITE demonstration including analytical results will
be discussed in detail in the Applications Analysis Report (AAR) and
the Technology Evaluation Report (TER). The SITE demonstration
results will also be summarized in the Demonstration Summary Report
and videotape. Key preliminary results of the SITE demonstration are
presented bebw:
• The ability of the PO*WW*ER™ system to concentrate aqueous
wastes was evaluated by the volume reductbn and concentratbn
ratb achieved. The volume of brine wasted and sampled during
each 9-hr test period was about 5% of the feed waste volume
processed and sampled during the 9-hr period. The concentratbn
ratb, defined as the ratbof total solids (TS) concentratbn in the brine
over the TS concentratbn in the feed waste, was about 32.
• The feed waste contained concentratbns of VOCs ranging from 270
to 110,000 mbrograms per liter (g/L); SVOCs ranging from 320 to
29,000 |og/L; ammonia ranging from 140 to 160 milligrams per liter
(mg/L); and cyanide ranging from 24to 36 mg/L No VOCs, SVOCs,
ammonia, or cyanide were detected in the product condensate.
• The noncondensible gas vent emissions were as follows: (1) the
average CO emissbns ranged from 1.1x10~3to3.92x10'3 Ib/hr, 9.58
to37.3parts permillion by volume (ppmv), and the 60-min maximum
CO emissbns ranged from 1.27x1 a3 to 4.28x1Cr3 Ib/hr, 11.1 to 40.8
ppmv; (2) the average SO2 emissions were less than 5.1 x10^* Ib/hr,
<2 ppmv, and the 60 min maximum SO2 emissions ranged from less
than 5.1 x1 O^to 8.36x104 Ib/hr, <2to3.49 ppmv; and (3)the average
NOx emissions ranged from 3.47x1 0* to 5.03x1 a2 Ib/hr, 233 to 292
ppmv, and the 60-min maximum NOx emissions ranged from
3.59x1 a2 to 5.34x1O'2 Ib/hr, 241 to 309 ppmv. The noncondensible
vent gas emissbns for these parameters met the proposed regula-
tory requirements for the LCTC site.
• The PO*WW*ER™ system removed sources of feed waste toxbity.
The feed waste was acutely toxic with median lethal concentrations
(LC50) consistently bebw 10%. The product condensate was
nontoxic with LC50s consistently greater than 100%, but only after
the product condensate was cooled and its pH, dissolved oxygen
level, and hardness or salinity were increased.
For Further Information:
EPA Project Manager:
Randy Parker
U.S. EPA Risk Reduction Engineering Laboratory
26 West Martin Luther King Drive
Cincinnati, OH 45268
(513) 569-7271 FAX (513) 569-7620
United States
Environmental Protection Agency
Center for Environmental Research Information
Cincinnati, OH 45268
Official Business
Penalty for Private Use
$300
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POSTAGE & FEES PAID
EPA
PERMIT No. G-35
EPA/540/MR-93/506
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