Wakarusa Water Reclamation Facility
Eco Machine Option: Permit Levels, Cost, Performance
17 January 2006
Wakarusa Water Reclamation Facility: Advantages of the John Todd Ecological Design Systems
In response to questions from John Keller, Project Manager, Black & Veatch
1. (John Keller) Can the Eco Machines meet the following permit limits: TN of 8 mg/L & TP of 1.5 mg/L. These are the limits that must be met. The Eco Machines need to meet these limits reliably.
Yes, we can reliably meet those standards although we may have to resort to traditional means of TP reduction at certain time of the year. The exact methods of TP reduction used in the design will be based on the professional assessment of our engineering and design staff taking into account the specific site conditions.
2. (John Keller) Have the Eco Machines met these limits before? If so, where are they currently doing this?
Yes, there are Living Machines in operation presently that have met those TN standards. The TP parameters are a new standard and most of the LM’s were designed to achieve < 5 mg/L. However, we think that a reliable effluent TP of 1.5 mg/L can be met through a system of integrated treatment methods mentioned below.
3. (John Keller) List of experience, capacity, & contact information for all Eco Machines. The bigger the better.
We are working on putting a comprehensive list of LM,s in operation. In the meantime I will send a copy of the Mott Report that evaluates their performance. We have forwarded for your review copies of case studies of built projects that demonstrate the viability of these technologies. (the PAC Eco Machine Subgroup has provided these case study documents in a larger proposal packet).
4. (John Keller) How much area would be required to treat 7 mgd.
This would vary greatly depending on the design goals of the project. As a rule of thumb the less land used in a design the more energy. With more space we can take advantage of passive biological processes. We can design our systems to closely match the footprint of an activated sludge plant. In terms of estimated area and costs, we believe the following is a reasonable assumption to start thinking about the necessary land areas if we utilize both polishing lagoons and sub surface constructed wetlands:
To treat 7 million gal./day, this would require approximately 80 acres.
To treat the final build out estimate of 50 million gal./day, this would require approximately 574 acres.
In both these scenarios, much of the treatment area could be dispersed throughout a larger land area.
The above estimates are subject to change based on a study of the specific site conditions and any changes in the regulatory schemes from the present.
In terms of a very preliminary idea for a range of costs for these systems, it is possible to build the sort of systems mentioned above for anywhere between 6 to 10 $/gallon treated effluent.
Cost range for 7 million gallons would be approximately $42 to $70 million. For the final build out of 50 million gallons/day, the cost range would be approximately $300 to $500 million.
Naturally, these costs do not include the cost of purchasing the land itself and are subject to a study of the particular site conditions.
Wakarusa Water Reclamation Facility: Eco Machine Option
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5. (John Keller) If we look at future flows for ultimate build-out of the area, how does the area of the Eco Machines change? Please remember that we are buying property for the future. If we said that the maximum flow in the future is 50 mgd, how much space would be needed? Ultimate flows could be higher or lower. This is one of B&V's current tasks right now. We are trying to put a total capacity together for ultimate build-out. But the point is that we need to see how the machines change as the flow increases.
See above. The ability to adjust to increasing or decreasing flows is one of the main advantages of an Eco Machine. With proper planning new trains (process digesters) can be designed to be brought on line with the projected growth of the area. This can be very cost effective for a community in regard to up front capital costs that the full build out of a standard treatment facility would require. Economics is one of the primary drivers for the Wakarusa Water Reclamation Facility to employ a biological system.
The six basic economic reasons to build biological sewage treatment systems can be reduced to:
· They cost less to build.
· They cost less to operate.
· They can be implemented in phases and proactively planned to integrate with the build out of future municipal sewage facilities. This means they will not require upfront capital costs for future build out.
· They can be decentralized. This can greatly reduce the infrastructure costs of the development.
· They generate less sludge then conventional WWT plants, thus reducing the cost of disposal.
· They generate secondary small business economic opportunities.
The financial benefits of a biological wastewater treatment facility include about 20-50% less first cost to construct compared to a conventional water treatment facility, and at about 50-80% less energy to operate, resulting in significant monthly operational savings. In a biological system, plants and ecosystems are doing the lions share of the work; aided by only minimal aeration. Thus, biological wastewater treatment facilities eliminate the need for energy intensive mechanical equipment and harsh chemicals such as chlorine and alum.
This sustainable approach to wastewater treatment is also more environmental because it will allow multiple smaller facilities to be located strategically around the jurisdiction. There is a strong economic argument for this as well: as opposed to large Sequencing Batch Reactor systems which do not ramp up well incrementally, Eco Machines and biological treatment in general can be sized to match each phase of development and then expanded to accommodate increased flows. This allows for the city and cooperating jurisdictions to only finance the immediate development as opposed to building all future infrastructure up front.
Decentralized systems have added economic and environmental benefits compared to relying on one main facility that everything must be pumped to and from. Decentralized facilities will eliminate both the first cost and the habitat disturbance normally required if sewage from the entire jurisdiction had to be pumped to one location. Over the long term, the decentralized facilities will also allow for reduced pumping costs as the water may be used for irrigation or sold to golf courses near the facility where it is generated.
The ecological wastewater treatment plant will also provide for the natural treatment and removal of sludge. The biological treatment plant can utilize sealed reed beds and earthworms to process the sludge. In dense cultures and large quantities, earthworms can handle virtually any biological waste and offer a viable alternative for sustained commercial operation.
Wakarusa Water Reclamation Facility: Eco Machine Option
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Earthworms will devour post treatment biological waste, thus decreasing disposal problems, while at the same time they produce two new products – earthworm castings known as vermicompost, and more earthworms. Vermicompost is odorless, non-toxic, organic fertilizer and is one of the highest quality soil amendments available across the U.S. The value-added production of vermicompost, earthworms, fish (should any greenhouses or fishponds be used), and tropical plants all have the potential of creating secondary business opportunities which can be run by local business people with virtually no production cost other than maintenance of the facilities.
Jonathan Todd
Vice President
John Todd Ecological Design
P.O. Box 497
Woods Hole, MA. 02543
508 549 2545
jonathan.todd2@verizon.net www.jtecodesign.com