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ABL ENVIRONMENTALPRODUCTS
 
 
Biopyramid Greenhouse Treatment System
 
ABL has developed a biological pyramid treatment technology, the ABL Biopyramid Greenhouse Treatment System, for polishing wastewater treatment plant effluents. The concept is essentially a native wetland in a greenhouse, and was developed from our observations that natural wetland systems provide reliable, stable polishing treatment at a low operating cost.
 
Previously available greenhouse aquatic systems tended to focus on tropical and semi-tropical plant species, and were consequently extremely expensive to heat through Canada's winters. ABL biologists selected native plant species capable of surviving winter conditions without heat, and a greenhouse enclosure designed to preserve heat to the greatest extent possible.
 
Wetlands are essentially low rate technologies with a long hydraulic retention time. ABL utilizes an established high rate technology to reduce the load to the enclosed wetland system, thereby reducing the facility size requirements and cost. This provides a more reliable and economic approach to the issue of enclosed greenhouse treatment systems and addresses the problem of improving the quality of effluent from both existing treatment plants and new installations, at a lower cost than providing effluent filters.
 
Designs for ABL's Biopyramid were selected for Keltic Lodge in Ingonish and for the Milton STP in Nova Scotia, but these installations are not proceeding. The first ABL Biopyramid Greenhouse System has been used successfully since 1997 to treat 5,000 GPD from an apartment complex in Fall River, Nova Scotia.
 
The ABL Biopyramid Greenhouse Treatment System offers a unique, flexible arrangement of common and time proven technologies, and may consist of:  
  • An ABL-SBR (sequencing batch reactor), with an influent equalization tank.
     
  • An effluent equalization tank, with or without aeration, to prevent hydraulic overload to downstream processes.
     
  • Shallow macrophtye tanks containing macrophtyes (large aquatic plants as opposed to algae), with roots providing both a living filter to remove suspended solids (SS) from the water column and a location for fixation of natural bacteria (to reduce BOD).
     
  • An aerated subsurface flow wetland with gravel bedding and rooted plants, to further treat macrophyte tank effluent by providing additional areas for bacterial attachment and encouraging removal and conversion of nutrients. Evaporation of water, the highest form of treatment, is maximized.
     
  • An aquatic filter, consisting of a slow sand filter with macrophytes to protect the filter from light penetration, which would cause algal growth and early plugging. The tanks may also be stocked with higher life forms including mollusks, bivalves, and fish which serve to increase the duration between manual cleaning of the filter.
     
  • UV disinfection of the filtered effluent
     
  • discharge or re-use of the effluent.
     
    NOTE:
     
  • The greenhouse enclosure will vary with the client's demands. As a minimum the macrophyte tanks, wetland and aquatic filter must be enclosed and heated. Though the SBR process does not require enclosure, it greatly improves plant aesthetics.
     
  • The SBR produces biological sludge which must be disposed of. The plant can be provided with aerobic digesters and sludge drying beds, which are designed according to criteria of USEPA or the regulatory body having authority. We recommend enclosure of sludge drying beds within the greenhouse, while the sludge digester, if required, is not placed in the greenhouse. Dried sludge can be added to plant compost or used in site landscaping.
 
The essence of the ABL system is that each stage provides a safety device for the previous stage. Thus the higher the level of treatment required the greater the number of stages. The ABL-SBR alone can treat to better than 20/20 BOD/SS. Where the effluent must be guaranteed to achieve 10/10 or better at all times the addition of macrophyte tanks, which must be enclosed in a greenhouse in a northern climate, is recommended. For even higher levels of treatment (5/5) for effluent discharge to sensitive environments, an aquatic filter is also recommended.
 
Housing the process within an attractive greenhouse enclosure enhances community acceptance, and if desired the facility can be partially open to the public to increase environmental awareness and community participation. The grounds could be integrated with public gardens and parks, with plant compost used for soil amelioration.
 
The process developed by ABL offers a unique, flexible arrangement of common and time proven technologies, which has found a niche application in upgrading wastewater treatment plant effluents at a lower cost than providing effluent filters.
 
ABL currently offers the following products:
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