ZENON ENVIRONMENTAL INC.

(ZenoGem™ Process)

TECHNOLOGY DESCRIPTION:

ZENON Environmental Inc.'s, ZenoGem™ Process integrates biological treatment with membrane-based ultrafiltration (see figure below). This innovative system treats high strength wastes at long sludge retention time but short hydraulic residence time. As a result, the bioreactor's size is significantly reduced. Membrane filtration reduces the turbidity of the treated wastewater to less than 1 nephelometric turbidity unit.

ZenoGem™ Process

In the ZenoGem™ Process, wastewater contaminated with organic compounds first enters the bioreactor, where contaminants are biologically degraded. Next, the process pump circulates the biomass through the ultrafiltration membrane system, or ultrafilter. The ultrafilter separates treated water from biological solids and soluble materials with higher molecular weights, including emulsified oil. The solids and soluble materials are then recycled to the bioreactor.The ZenoGem™ Process captures higher molecular weight materials that would otherwise pass through conventional clarifiers and filters. The ZenoGem™ Process pilot-scale system is mounted on a 48-foot trailer and consists of the following six major components:

• Polyethylene equalization/holding tank: reduces the normal flow concentration fluctuations in the system
• Polyethylene bioreactor tank: contains the bacterial culture that degrades organic contaminants
• Process and feed pumps: ensures proper flow and pressure for optimum system performance
• Ultrafiltration module: contains rugged, clog-free, tubular membranes that remove solids from treated water
• Clean-in-place tank: includes all the necessary valves, instrumentation, and controls to clean the membrane filters
• Control panel and computer: monitors system performance

The treatment capacity of the pilot-scale, trailer-mounted system is about 500 to 1,000 gallons of wastewater per day; however, a full-scale system can treat much larger quantities of wastewater. The trailer is also equipped with a laboratory that enables field personnel to conduct tests to evaluate system performance. The system is computer-controlled and equipped with alarms to notify the operator of mechanical and operational problems.

WASTE APPLICABILITY:

The ZenoGem™ Process is designed to remove biodegradable materials, including most organic contaminants, from wastewater to produce a high quality effluent. The process consistently nitrifies organics and can denitrify organics with the addition of an anoxic bioreactor. The process is limited to aqueous media and may be used to treat high strength leachates, contaminated groundwater, and soil washing effluent.

STATUS:

The ZenoGem™ Process was accepted into the SITE Demonstration Program in summer 1992. The ZenoGem™ Process was demonstrated at the Nascolite Superfund site in Millville, New Jersey from September through November 1994. Groundwater at this 17.5-acre site is contaminated with methyl methacrylate (MMA) and other volatile organic compounds from manufacturing polymethyl methacrylate plastic sheets, commonly known as Plexiglas. The Demonstration Bulletin (EPA/540/MR-95/503) and Technology Capsule (EPA/540/R-95/503a) are available from EPA. The Innovative Technology Evaluation Report will be available in 1997.

Since the development of the ZenoGem™ technology in 1987, ZENON has performed pilot tests for government and private clients on several different types of wastewater, including oily wastewater, metal finishing wastes, cleaning solutions containing detergents, alcohol-based cleaning solutions, landfill leachate, aqueous paint-stripping wastes, and deicing fluids. Information about the two demonstrations conducted in Canada and the United States is available from ZENON.

DEMONSTRATION RESULTS:

During the 3-month demonstration, sampling results showed that the system achieved average removal efficiencies of greater than 99.9 percent for MMA and 97.9 percent for chemical oxygen demand. MMA concentrations measured in the off-gas emission stream indicated insignificant volatilization. The ultrafiltration system effectively dewatered the process sludge, which yielded a smaller waste volume for off-site disposal. Sludge dewatering resulted in an approximate volume reduction of 60 percent and a solids increase from 1.6 to 3.6 percent. The process effluent was clear and odorless, and accepted for discharge by the local publicly owned treatment works. During the demonstration, the system was left unattended at night and on weekends, demonstrating that computer control is practical for extended operating periods.

FOR FURTHER INFORMATION:

EPA PROJECT MANAGER:
Daniel Sullivan
U.S. EPA
National Risk Management Research Laboratory
2890 Woodbridge Avenue
Edison, NJ 08837-3679
908-321-6677
Fax: 908-321-6640

TECHNOLOGY DEVELOPER CONTACT:
F.A. (Tony) Tonelli or Philip Canning
ZENON Environmental Inc.
845 Harrington Court
Burlington, Ontario, Canada
L7N 3P3
905-639-6320
Fax: 905-639-1812