United States
Environmental Protection
Agency
EPA/540/MR-95/503
April 1995
&EPA
SUPERFUND INNOVATIVE
TECHNOLOGY EVALUATION
Demonstration Bulletin
ZenoGem™ Wastewater Treatment Process
ZENON Environmental Systems
Technology Description:Zenon Environmental Systems (Zenon)
has developed the ZenoGem™ process to remove organic compounds
from wastewater by integrating biological treatment and membrane-
based ultrafiltration. This innovative system combines biological
treatment to remove biodegradable organic compounds with
ultrafiltration to separate residual suspended solids from biologically
treated effluent. Zenon claims the technology reduces organic
contaminants in wastewaterto nondetectable levels, improves effluent
quality, and reduces the quantity of sludge for disposal. The major
components of the ZenoGem™ system are an influent holding/
equalization tank, an enclosed biological reactor (bioreactor), a pH
buffer tank, a nutrient solution tank, an ultrafiltration module, an air
blower, an off-gas carbon filter, a permeate carbon filter and process,
feed, and metering pumps (Figure 1). A pilot-scale ZenoGem™
system, contained in an 8-ft by 48-ft ZenoSite™trailer, was used forthe
demonstration.
Contaminated wastewater is continuously introduced into a stirred-
tank bioreactor that contains an acclimated aerobic microbial culture.
The aerobic suspended-growth environment is maintained by diffused
aeration, which continuously mixes the bioreactor's contents. The
mixture of organic contaminants and microbes, called mixed liquor, is
retained in the bioreactor for a period of time sufficient to allow the
microbes to metabolize the organic contaminants into inorganic end-
products and intermediate by-products.
The biologically treated effluent is continuously pumped from the
bioreactor into the ultrafiltration module. The ultrafiltration module
consists of 1 -in. diameter tubes connected in series and contained in
a 12-ft by 4-in. diameter polyvinyI chloride housing. The tubes support
the ultrafiltration membrane, which filters dissolved contaminants and
suspended solids (concentrate) from the biologically treated effluent.
Concentrate accumulating on the membrane surface is detached by
cross-flow water movement. The concentrate is then continuously
recycled to the bioreactorto maintain adesired biomass and to further
degrade higher molecular weight organic compounds. Ideally, the
filtered effluent (permeate) passing through the membrane does not
containparentorganiccontaminants. However, the system isequipped
with a permeate carbon filter that removes trace organics before the
final treated effluent is discharged. According to Zenon, the treated
effluent water may be disposed of at a publicly owned treatment works
(POTW), reused on site, or discharged directly to surface water under
an appropriate National Pollutant Discharge Elimination System
permit.
Demonstration Approach: The ZenoGem™ technology was
demonstrated at the Nascolite Superfund Site in Millville, NJ from
September through November 1994. Groundwater at this 17.5-acre
site is contaminated with methyl methacrylate (MMA) and other
volatile organic compounds (VOCs) from manufacturing polymethyl
methacrylate plastic sheets, commonly known as plexiglass.
During the demonstration, contaminated groundwater was pumped
from four production wells into a 6,000-gal equalization tank to
minimize variability in contaminant concentrations during the
demonstration. Following equalization, the contaminated groundwater
was pumped to the 1,100 gal influent holding/equalization tank located
in the ZenoSite™ trailer. During full-scale operation, Zenon uses the
influent holding tank as the equalization tank prior to treatment. The
contaminated groundwater was then pumped into the bioreactor for
WASTEWATER
TREATED
PERMEATE EFFLUENT
LI-
ULTRAFILTRATION
MODULE
CARBON
FILTER
Figure 1. The ZenoGem™ technology as demonstrated.
Printed on Recycled Paper
-------
United States
Environmental Protection
Agency
EPA/540/MR-95/503
April 1995
vvEPA
SUPERFUND INNOVATIVE
TECHNOLOGY EVALUATION
Demonstration Bulletin
ZenoGem™ Wastewater Treatment Process
ZENON Environmental Systems
Technology Description :Zenon Environmental Systems (Zenon)
has developed the ZenoGem™ process to remove organic compounds
from wastewater by integrating biological treatment and membrane-
based ultrafiltration. This innovative system combines biological
treatment to remove biodegradable organic compounds with
ultrafiltration to separate residual suspended solids from biologically
treated effluent. Zenon claims the technology reduces organic
contaminants in wastewaterto nondetectable levels, improves effluent
quality, and reduces the quantity of sludge for disposal. The major
components of the ZenoGem™ system are an influent holding/
equalization tank, an enclosed biological reactor (bioreactor), a pH
buffer tank, a nutrient solution tank, an ultrafiltration module, an air
blower, an off-gas carbon filter, a permeate carbon filter and process,
feed, and metering pumps (Figure 1). A pilot-scale ZenoGem™
system, contained in an 8-ft by 48-ft ZenoSite™trailer, was used forthe
demonstration.
Contaminated wastewater is continuously introduced into a stirred-
tank bioreactor that contains an acclimated aerobic microbial culture.
The aerobic suspended-growth environment is maintained by diffused
aeration, which continuously mixes the bioreactor's contents. The
mixture of organic contaminants and microbes, called mixed liquor, is
retained in the bioreactor for a period of time sufficient to allow the
microbes to metabolize the organic contaminants into inorganic end-
products and intermediate by-products.
The biologically treated effluent is continuously pumped from the
bioreactor into the ultrafiltration module. The ultrafiltration module
consists of 1 -in. diameter tubes connected in series and contained in
a 12-ft by 4-in. diameter polyvinyI chloride housing. The tubes support
the ultrafiltration membrane, which filters dissolved contaminants and
suspended solids (concentrate) from the biologically treated effluent.
Concentrate accumulating on the membrane surface is detached by
cross-flow water movement. The concentrate is then continuously
recycled to the bioreactor to maintain a desired biomass and to further
degrade higher molecular weight organic compounds. Ideally, the
filtered effluent (permeate) passing through the membrane does not
containparentorganiccontaminants. However, the system is equipped
with a permeate carbon filter that removes trace organics before the
final treated effluent is discharged. According to Zenon, the treated
effluent water may be disposed of at a publicly owned treatment works
(POTW), reused on site, or discharged directly to surface water under
an appropriate National Pollutant Discharge Elimination System
permit.
Demonstration Approach: The ZenoGem™ technology was
demonstrated at the Nascolite Superfund Site in Millville, NJ from
September through November 1994. Groundwater at this 17.5-acre
site is contaminated with methyl methacrylate (MMA) and other
volatile organic compounds (VOCs) from manufacturing polymethyl
methacrylate plastic sheets, commonly known as plexiglass.
During the demonstration, contaminated groundwater was pumped
from four production wells into a 6,000-gal equalization tank to
minimize variability in contaminant concentrations during the
demonstration. Following equalization, the contaminated groundwater
was pumped to the 1,100 gal influent holding/equalization tank located
in the ZenoSite™ trailer. During full-scale operation, Zenon uses the
influent holding tank as the equalization tank prior to treatment. The
contaminated groundwater was then pumped into the bioreactor for
WASTEWATER
Figure 1. The ZenoGem™ technology as demonstrated.
PROCESS
PUMP
Printed on Recycled Paper
------- |