Bio-based Pollution Controls Increase Applicability While Reducing Cost
Sometimes, when you have a tough job to do, you need to delegate; whether it’s to a subordinate, a consultant — or perhaps, to Mother Nature. That’s exactly what Envirogen Technologies has done in its quest to provide a comprehensive solution for controlling hazardous air pollution (HAP), volatile organic compounds (VOC), and odors, in order to allow industrial facilities to meet their obligations under state regulations and the Clean Air Act.
The company recently announced a new Sustainable Emissions Control offering that combines biological and enhanced adsorption treatment technologies.
This combined, one-two punch approach allows the company to offer a solution to address a broad range of contaminants including organic and inorganic, polar and non-polar emission constituents, all at varying concentrations and air flow rates.
Besides being broad in scope, this new emissions-control solution package offers reduced chemical and energy consumption, provides recycle/re-use options and lowers overall carbon footprint, all at a cost that can be an order of magnitude less expensive than those provided by traditional emissions-control technologies.
Initial offerings have been developed for the chemical and refinery operations, but the technology is well-suited to a wide range of manufacturing environments.
“Because of tight limits and complex manufacturing processes, meeting today’s air quality regulations often requires remarkably sophisticated technical solutions that can be very costly and difficult to manage,” said Rob Loken, vice president, product management for Envirogen. “With our Sustainable Emissions Control offering, Envirogen is putting our years of experience treating vapor-phase streams both biologically and with advanced adsorption technology to work in solutions that are the most sustainable on the market today. When we say sustainable, we mean that they are high performing, environmentally sound and safe. We also mean that these solutions feature very low long-term operating costs — costs that can be predicted and guaranteed.”
On the biological side, Envirogen has bio-filters and bio-trickling filters that can safely destroy VOCs and HAPS, and reduce odor. Bio-trickling filters consist of a packed bed of media supporting a mixed culture of pollutant-degrading organisms. These provide an attractive alternative to standard thermal, chemical, and adsorptive processes to treat air pollutants safely, reliably and cost effectively, with low capital and operating costs.
Foul air is collected and sent to the bio-filter where microorganisms fixed to a porous filter bed medium metabolize the target contaminants, consuming them as food, and cleansing the air stream in the process. The targeted action of the microbes tends to be far more efficient than the bulk action of more traditional approaches. The end products of this degradation are typically water vapor, carbon dioxide, and mineral salts. This type of treatment is ideally suited for contaminants that are water-soluble, polar, and readily biodegradable, and are particularly effective for low-loading applications at high flow volumes — including odors caused by hydrogen sulfide (H2S) and other reduced sulfur compounds.
The idea of using bio-filters for pollution is not new. Applications go back to the 1920s when they were first proposed to control hydrogen sulfide gas from a waste water treatment plant. The technolgy found commercial application in Germany in the 1950s, becoming popular over the next couple of decades. Bio-filters did not begin appearing in this country until the 1990s where they were initially used for water purification and odor control. Bio-filtration systems are now also used in urban applications to control storm water runoff.
On the adsorption side, Envirogen’s EnviroHPA Systems, which were introduced in November 2012, feature ultra-high performing adsorbent media in systems designed, guaranteed and operated by Envirogen under multi-year agreements. As part of the Sustainable Emissions Control offering, EnviroHPA Systems compete effectively with other technologies that handle non-polar compounds at high loading and flow rates. When dealing with industrial vapor-phase treatment applications, Envirogen employs adsorbents manufactured by Dow Chemical Co. These agents actually work through a combination of both adsorption and absorption.
Adsorbents work by binding molecules or particles to a surface, as opposed to absorbents, which fill pores in a solid. These materials offer a high surface area and optimized pore size distribution — characteristics that offer substantially increased adsorption capacity, rapid adsorption kinetics, a range of desorption options, as well as excellent physical and chemical stability. The resulting faster kinetics and higher contaminant loading capacities translate into higher hydraulic rates with a smaller system footprint – decreasing operations and maintenance costs for the treatment process and lowering initial capital expenditures for overall site improvements and utilities.
Enhanced desorption characteristics allow media to be regenerated in place with heat, steam, aqueous acids or bases, leading to an extended media bed life in use. In facilities that use a good deal of activated carbon, EnviroHPA Systems can offer cost reductions of up to 50 percent, with carbon footprint levels reduced by as much as two-thirds. In addition to these advantages, EnviroHPA Systems absorb less water than the alternatives and offer the option for recycle/re-use because of the desorption properties of the advanced media.
As part of its business model, Envirogen offers EnviroHPA Systems as a service in which system design and installation, media costs, regeneration, and disposal are charged as an operating fee over the life of the system. They can be offered with low- to no-capital investment, guaranteed performance, and predictable costs over the service life of the installation.
According to Loken, the complex nature of industrial emissions — which contain a variety of different types of contaminants with differing regulatory profiles and often require a tailored solution that applies the best technology for individual and combined emission streams. ”Within the realm of emissions-control technologies, different approaches have their niche in terms of cost/performance. With our Sustainable Emissions Control offering, we are bringing together two complementary technologies that are more efficient, more cost effective, and more sustainable than what is available on the market today. By pairing them, we can extend the applicability of these solutions and fit them into an overall plan for emissions control for an industrial facility. That plan can form the basis of a long-term, cost-effective, sustainable solution for the facility,” he said.
All of this goes to show that using nature as an ally rather than an adversary can pay big dividends, particularly when looking for sustainable solutions to challenging problems.
Envirogen, a member of the London-based Amplio Group, is involved in a number of markets including chemical processing, food and beverage, manufacturing, mining, groundwater remediation, and municipal and government applications. The company develops customer applications with lifecycle cost as the primary consideration. Among the numerous technologies Envirogen employs are ion exchange systems, regeneration, mobile treatment, fluidized bed reactors, as well as EnviroHPA Systems, bio-filters, and membrane bioreactors, which can be used in the treatment of numerous contaminants such as perchlorate, nitrate, arsenic, iron/manganese, chromium, radium, uranium, selenium, and organics. The company recently received a patent for a Fluidized Bed Reactor Treatment of Perchlorate-Contaminated Water.