Some facts about Eliminite Recirculating Trickling Filter

Introduction:

Eliminite was developed in Bozeman, Montana in 1994 in response to evolving water quality regulations developed by Montana Department of Environmental Quality (MDEQ).   The new regulations identified nitrogen, due to its potential mobility in the vadose zone, as the contaminant of primary concern.  Between 1994 and 2004, no formal classification for nutrient removal systems existed in Montana. However, early results from the Eliminite technology were so promising that MDEQ allowed them to be installed on a case-by-case basis until the formal rules were prepared.  By the time MDEQ finalized the regulations, Eliminite systems had been in use in residential, commercial and community applications throughout Montana for 10 years.  Also during this time, the Department of Natural Resources and Conservation (DNRC) completed an in-depth field study of four onsite treatment technologies, including Eliminite, which focused on identifying wastewater treatment technologies capable of meeting Montana’s maximum allowable effluent nitrogen concentration of 24 mg/L and 60% minimum nitrogen removal.   At the conclusion of the 18-month study, Eliminite was recommended for approval at the highest classification in Montana, Level II treatment.  Three patents have been issued for the Eliminite system and its proprietary components, including MetaRocks lightweight treatment media for growing microorganisms.

Eliminite are now used in hundreds of homes, businesses and government facilities in Montana, Colorado, New Mexico and California. 

Description:

Eliminite is a fixed-film biological reactor with recirculation and alternating aerobic/anoxic treatment processes.  While many models and configurations targeting a variety of wastewater constituents are available, the most basic configuration consists of a single primary tank (septic tank) and a single Eliminite treatment tank.  The treatment tank houses the fixed-film bioreactor, recirculation/storage volume, level control and effluent pump(s).  

MetaRocks fixed-film media:

Eliminite systems utilize patented, proprietary treatment media called MetaRocks.  MetaRocks media represents a significant improvement over other types of trickling filter media common to the industry.  Long-term use has proven that MetaRocks possess superior treatment characteristics which are absent from other types of fixed-film systems, including the following:

·         High specific surface area in excess of 60 ft²/ft³ provides ample surface for microbial attachment and biofilm development.

·         Large void volume exceeding 70% ensures low headloss for efficient air transfer through entire media bed.

·         Large average pore diameter of 0.5 to 1.5 inch translates to nearly zero clog potential.

·         Rough surface speeds time to maturation and enhances water holding characteristics.

·         High hydraulic loading capacity, 250 gal/(min* ft²).

·         Polar surface is hydrophilic and wets completely with water.

·         Thin liquid surface film allows oxygen to penetrate into the full depth of the developed biofilm.

·         Light weight at 7 lb/ft³ allows for deep media bed with no additional structural requirements imposed on the tank manufacturer.

·         MetaRocks are free-flowing and take the shape of the vessel they occupy while retaining their superior hydraulic and biological properties.  This allows for their use in virtually any type of tank.

Advantages:

Versus suspended growth systems

·         Fixed-film systems are known to be significantly more resistant to upsets caused by flow variation and varying influent wastewater strength.

·         Because nitrifying organisms prefer to embed into a biofilm, fixed-film systems provide superior nitrification capability. This leads to reduced potential for microorganism washout during high flow periods.

·         Operational complexity of suspended growth systems demands skilled operators be available for frequent monitoring, adjustment and maintenance in order to keep the system functioning at adequate levels.  Eliminite is naturally biologically complex but mechanically simple.  No special skills are necessary to operate the system and achieve exemplary results.

·         Small scale suspended growth system have almost no operational control and are therefore incapable of responding to, or being manually manipulated to accommodate, wastewater characteristics that deviate from design parameters.  Eliminite is designed with many degrees of freedom allowing a good deal of control and manipulation.  It is possible to “fine tune” the system with a high degree of precision.

·         Air blowers are energy hogs and suspended growth systems with their large, noisy blowers will consume far more energy than an Eliminite fixed-film system.

·         Cold weather slows biological activity and the only pragmatic method for improving treatment levels in a suspended growth system is to increase oxygen to the aeration basin.  This results in greater quantities of cold air being injected into the system and further degradation of the treatment process.  Heaters are commonly employed in suspended growth systems during winter months to alleviate this problem.  Obviously, heating wastewater, will add significant operational expense.  Eliminite was developed in, and designed for, a cold climate and does not exhibit the severe, cold weather, degradation in effluent quality seen with suspended growth systems.

Advantages:

Versus other fixed-film systems

·         Most commercially available fixed-film systems are manufactured around a “pod” arrangement.   Pod based system leave little flexibility to the design engineer other than the specification of more or fewer pods.  Pods are generally manufactured out of state and potentially in another country, providing scant benefit to the local economy.  Eliminite works with local engineers and suppliers to develop a wastewater treatment system configuration that fits the clients project and meets budget demands.

·         Rather than stringing multiple pods together, Eliminite prefers to simply install a larger single tank.  This reduces piping complexity, O&M procedures and helps conserve heat vital to the treatment process.

·         Eliminite uses patented MetaRocks trickling filter media which have large open passageways for air transfer.  Textile, foam cube, peat moss and other similar media exhibit high porosity but this porosity is comprised of very small pores.  Biological organisms and even liquid will quickly bridge these miniscule voids rendering them ineffective for air transfer or treatment.  

·         MetaRocks have a rough polar surface because the surface is highly textured sand and recycled glass.  Textiles and foam cubes are smooth and, because they are manufactured from plastics, are non-polar.  It has been shown that a rough surface will develop a biofilm more quickly than a smooth surface meaning that MetaRocks will reach optimum treatment levels more quickly.  Surface polarity relates to a materials ability to be wet with water.  The sand and recycled glass surface of MetaRocks are polar and therefore easily wet.  A non-polar surface, in contrast, is wetting resistant and water will bead, much like water on a waxed surface.  Beading is an undesirable characteristic of plastic media systems.

·         MetaRocks do not require cleaning or replacement.  Textiles must be washed and cubes require fluffing because they cannot support their weight plus the weight of the biofilm.  Textiles have a tendency to stretch over time and will need to be trimmed periodically.  Manipulating the media in a system that has been in use is a dirty and potentially hazardous job.

·         MetaRocks have structural integrity and are suitable for deep trickling filter beds.  A deep bed has many advantages including smaller footprint, superior resistance to cold temperatures and highly efficient nitrification potential.

·         Eliminite can use fewer small access risers and lids because MetaRocks do not require invasive maintenance procedures.  This means lower heat loss in cold weather and dramatically reduced visual impact.  Fewer access points also reduce the potential for unauthorized entry into the system and results in a less visually obtrusive end product.

·         Eliminite does not require a telephone up-link.  One can easily be added, reporting any number of parameters, if desired.

·         MetaRocks were designed specifically for use as a fixed film media. Their size, shape, surface characteristics, weight, and structural integrity are specific to their purpose. Most other media used in the industry use materials that were intended for other uses

and have various drawbacks when applied to the wastewater industry.