Whether large or small pumps, there comes a debate when multiple drive motors are used to
cover a broad range ofoutput flow requirements: use one Variable Frequency Drive (VFD) plus
a number of softstarts, some small and some large pumps with or without VFD’s, one or more
VFD’s on a group ofpumps, and all combinations in between. Equipment rotation and
maintenance, starts per hour, starts per day, minimum flows, maximum demands, etc., all are
considerations and decisions to be made. Many of these combinations invoke unintended
hydraulic consequences. The focus ofthis paper is the benefits of synchronous, closed transition
hand-off between VFD’s and utility powered devices in multi-motor applications. Using off-theshelf,
standard, available equipment that can synchronize drive output with across-the-line loads,
the best of numerous options can be had while reducing power costs, protecting personnel and
equipment, and achieving process control.
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Posted: May 20th, 2011 | Filed under: Uncategorized | Tags: Energy Efficiency, Equipment Protection, Lower Capital Cost, Personnel Protection, Reduced Power Costs, Smaller Carbon Footprint | No Comments »
Bryan Wastewater Treatment Plant
Bryan, Ohio
Many communities are faced with considering a change in how their boisolids processing and disposal
programs will operate in the future. This discussion is coming about due to many biosolids processes that
were installed in the 1970s and 1980s under a different era of reuse and regulation and reaching the end of
their useful life.
To move forward there needs to be the establishment of objectives and goals that an evaluation is to be
built around for the future needs of biosolids processing for the owner/authority. The evaluation should
indentify the process that will be the most cost effective in capital and operation and maintenance costs. In
addition, with today’s concerns regarding climate change every evaluation should evaluate the carbon
footprint created by the various processes.
This is a case study of one evaluation done by the author that turned into a thermal dryer project that has
now been in operation for over six years.
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Posted: May 20th, 2011 | Filed under: 100K-500K, Waste Water Treatment | Tags: Cost Effective Solution, Decreased Gas Consumption, Improved Plant Sustainability, Smaller Carbon Footprint, Solids reduction | No Comments »
The conversion of raw sewage sludge into valuable biosolids for beneficial reuse requires a
suitable pre-treatment process. However, traditional technologies are causing high investment
costs, operation costs, and energy demand; or are not fully meeting the demands of the market.
As recent experiences from the world’s largest solar drying and solar-assisted drying plants in
Palma de Mallorca, Spain and Oldenburg, Germany show, solar drying is an effective alternative
for large facilities. Drying costs and energy consumption are less than half, maintenance is low,
and operation is simple and safe at these facilities when compared to traditional thermal dryers.
Also, carbon dioxide (CO2) emissions are reduced by a factor of seven when compared to
conventional dryers. By using waste heat from other processes, the area requirement can be
reduced by a factor of three to five. The final product is suitable as fuel for Waste-to-Energy
(WTE) plants, coal power plants, or cement kilns. It can also be used as a Class-A fertilizer for
agricultural use, or land application.
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Posted: May 20th, 2011 | Filed under: Waste Water Treatment, Water Treatment | Tags: Cost Savings, Decreased Energy Consumption, Plant Sustainability, Smaller Carbon Footprint | No Comments »
Magna Water District
Magna, Utah
Aeration accounts for up to 60% of the total energy required for a typical activated sludge wastewater plant. A new process was developed that decreases aeration demand during secondary wastewater treatment. This process, called BIOBROx, blends oxidant-laden residuals with screened municipal wastewater followed by treatment in a fixed-bed (FXB) bioreactor. Pilot testing showed that the BIOBROx process was effective at removing perchlorate and nitrate from membrane residuals. Considerable biochemical oxygen demand (BOD) and suspended solids were also removed across the process. A 3.8-mgd BIOBROx demonstration facility is now operating at the Magna Water District. The BIOBROx train treats 1/3 to 1/2 of Magna’s total wastewater flow, uses no aeration, has an empty-bed contact time of 10 minutes, and has a footprint that is one-twentieth the size of the conventional secondary processes. Preliminary data show effluent that even under these conditions, BOD5 and TSS levels in the effluent from the BIOBROx process are similar to those in Magna’s conventional secondary treatment effluent.
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Posted: May 20th, 2011 | Filed under: <50K, Sanitary Sewer, Stormwater, Water Treatment | Tags: Cost Savings, Decreased Aeration Demand, Decreased Energy Consumption, Plant Sustainability, Smaller Carbon Footprint | No Comments »
26th Ward WPCP
New York City, New York
Simulation studies were conducted for three scenarios at the 26th Ward WPCP in New York City: no side-stream treatment, side stream treatment with an Advanced Biological Treatment (AT3), and side stream treatment with a physical chemical process, ARP. The models incorporated anaerobic sludge digestion and sludge dewatering to simulate the release of ammonia and organic nitrogen related to sludge destruction and their return to the wastewater treatment process. An extensive literature search was performed to find GHG emission factors for each of the processes. Use of the physical/chemical ARP displayed benefits intrinsic to the use of a non-biological method of nitrogen reduction. The model demonstrates that the two categories of side stream treatment have materially different benefits. Very large emissions of GHG were found for AT3. The physical-chemical processes used by ARP lowered GHG emissions relative to the base case as well as relative to AT3. The ARP alternative will produce about one-quarter (3,500 metric tons CO2eq per year) less direct GHG emissions than the Baseline alternative and 48 percent (9,300 MT/yr) less than the AT3. Source: WEFTEC 2009 Proceedings
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Posted: August 27th, 2010 | Filed under: 100K-500K, Waste Water Treatment | Tags: Environmental Impact, Increased Ammonia Removal, Reduced Greenhouse Gas Emissions, Smaller Carbon Footprint | No Comments »
Joint Effort by California Department of Water Resources and California Energy Commission
Sacramento, California
In 2005, California, led by the California Energy Commission, began a serious look at the waterenergy-greenhouse gas relationship in the state. Saving water saves energy. Saving energy saves water, both where there are cooling towers on buildings and at thermal power plants which use water for cooling. You save more in Southern California than in Northern California because of the energy attached to imported water. Saving water used outdoors is good (pumping, treatment and delivery), saving water used indoors is better (no waste removal, treatment and discharge) and saving hot water is still better (no energy to heat the water too). This paper will build on the work done by the California Energy Commission by presenting information on both sides of the connection: energy for water and water for energy. Source: WEFTEC 2009 Proceedings
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Posted: August 27th, 2010 | Filed under: Electric, Waste Water Treatment, Water Treatment | Tags: Energy Savings, Environmental Impact, Plant Sustainability, Reduced Greenhouse Gas Emissions, Smaller Carbon Footprint, Water Conservation | No Comments »