Dynatec provides High Quality Discharge MBR system for Retirement Home

The retirement community consists of independent living homes and apartment homes in rural Maryland. The facility is in horse country, in a valley among rolling hills, and shares the area with high-end homes.

Previously, the facility had two septic tanks, and a recirculated sand bed filtration system. This created odors and caused mosquito infestations in summer. The facility chronically missed discharge limits, and thus was paying frequent fines. The sand bed filtration system was high maintenance, constantly flooding and requiring maintenance.

Replacement Criteria

In deciding on a replacement system, several criteria were important to the facility and to State regulators. The plant must be aesthetically pleasing. Odors must be minimized and if possible, eliminated. The plant had to achieve high levels of treatment to meet present and future discharge requirements. Future use of the treated water for irrigation is planned. The plant had to be operator friendly, and be capable of being monitored remotely, since full-time staff would not be available. The plant must be cost effective, from both capital and operating standpoints. Finally, the plant must be modular, in that future expansion of the facility must be accommodated in the design.

The initial plant sizing was nominally for 50,000 gallons per day of treatment capacity and has been expanded to 100,000 gallons per day.Membrane BioReactor for Sanitary Wastewater

System Design

After a review of the available treatment options, the owners of the facility decided on the (MBR) Membrane Bioreactor option. Due to the modular design of the system, they also chose the out-of-basin membrane module concept provided by the Dynatec MBR system. This process combines ease of use with all the requirements of both the owners and the regulators.

Odor control is achieved by using closed tanks vented to atmosphere. Air from the screening room is used to provide aeration to the reactors and the membranes, using the biomass as a biofilter. The negative pressure in the screen room ensures that there are no fugitive odors from the area. Mixing and aeration of the EQ tanks (the existing septic tanks) ensures no odors from that area.

Design Compatibility with the area: due to the nature of the area, the plant was designed to be installed in a “horse barn”, or at least a building that looks like a horse barn, but in fact, contains both the treatment plant and space for landscaping and other equipment.

High Levels of Treatment have been achieved since the plant’s inception in early 2007. Performance has been maintained since that time. Future plans include treatment for Total-N and Total-P to comply with Maryland’s “flush tax” requirements.

Cost Effective Installation was achieved using standard above-ground HDPE tanks, rather than the more common concrete tanks

Plant Expandability was achieved by the installation of one half of the plant, and the addition of a second membrane rack. No modifications to tanks or other work were required in 2009.


Since completion and startup in early 2007, the plant has reliably performed, always producing high-quality water.

The Dynatec MBR concept provides economic advantages due to the modular design and the use of standard tanks. The cost of operation is modest when compared to alternatives.

Contact Dynatec Systems today to discuss your sanitary wastewater solution.


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