The Consolidated Recycling Co., Inc. (CRCI), in Troy Indiana, reclaims between 5 and 6 million gallons of used ethylene glycol from spent antifreeze every year. The facility removes contaminants to generate ethylene glycol with chemical and physical properties equivalent to the virgin counterparts, but at significant savings to the customer and the environment.
 However, the CRCI vacuum distillation process generates ethylene glycol contaminated wastewater which must be treated prior to discharge to the municipal wastewater treatment plant. An existing aeration pond was originally employed for wastewater treatment; but the pond was vulnerable to cold weather conditions, rendering it incapable of consistently meeting compliance standards.
Dr. Sanjeev Ahluwahlia, Hydroxyl Laboratory Supervisor and Scientist, worked with CRCI in 2005 to conduct bench-scale testing at Hydroxyl's Testing Facility to determine both the biodegradability of the wastewater and also the kinetic design parameters for the treatment process. The treatability testing proved succesful, and Hydroxyl's Process Engineering team then worked with Hydroxyl VP Sales, Dan Turner, to design a cost-effective and robust treatment process for the glycol contaminated wastewater. This resulted in CRCI's 2005 purchase of a Hydroxyl ActiveCell™ aerobic free-floating biofilm carrier treatment process to upgrade their biological wastewater treatment facility.
Hydroxyl's ActiveCell system has been operating for approximately one year at CRCI's facility and has reliably produced effluent COD concentrations well below the required levels despite highly variable influent. The system has required minimal operator intervention and has produced high quality effluent since initiation of flow. Furthermore, full-scale results confirmed that laboratory treatability testing accurately reflected the process performance of the full-scale ActiveCell system. The results of this study are highly relevant to the treatment of spent aircraft de-icing fluid, a frequently encountered wastewater treatment challenge.
This installation is yet another example of Hydroxyl's focus on providing effective treatment solutions that not only provide a high degree of customer satisfaction but also preserve our environment.
Hydroxyl’s adaptable ActiveCell450™ medium is a rigorously engineered and tested biofilm carrier. Widely proven in standalone applications, or as a performance enhancement to existing and installed processes, the technology benefits from some unique design features. The high density polyethylene (HDPE) construction ruggedly protects an optimized surface-area to flow ratio, while its carbon black content resists photo-degradation.
With these traits, once fluidized, the ActiveCell medium’s toughness and durability can exceed that of commonly used probes. Routinely, these less robust devices are needed to measure and monitor critical performance values. Some simple steps can be taken to ensure proper functioning of all equipment.
Test apparatus common to wastewater treatment such as pH, DO, ORP-REDOX and other sensors need to be submerged during bench-scale experimentation, pilot or full-size operation analysis. The use of these instruments can be made effective and more reliable by isolating the sensitive elements from the circulating ActiveCell biofilm carriers. Where Infra Red devices are an option, there may be no need for protection; more field data will bear this out. Isolation can be achieved by enclosing the probe/sensor in a basket, cage or otherwise protected area. In the case of high solids, care must be taken to ensure that adequate flow is not restricted. Although some scouring is to be expected from the carriers, any permanent or long term installation of screening should be routinely inspected for blockage. The illustration above depicts how oxygen uptake measurements were taken using a probe shielded by stainless steel screen. The same effect can be had by using other configurations, such as PVC rods or other materials, to surround the probe temporarily when in use. To avoid possible interference, some attention should be given to the suitability of substances for specific test methods.
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| Technical wastewater treatment questions are welcome and can be directed to eNews TechForum editor Daniel Woods at dwoods@hydroxyl.com. |
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