Industrial Utility Efficiency
When a facility plans for a wastewater treatment plants, they typically design based on population and industry growth twenty to thirty years into the future. Regulatory requirements often dictate designing the activated sludge process equipment based on future-state influent flow and loading conditions, resulting in decades of constrained, inefficient, and suboptimal operation.
With the recent and future increases of the cost of energy, operating a wastewater treatment plant (WWTP) as efficiently as possible has become one of the most important factors that operators and managers are facing today. The implementation of a properly designed aeration control system has been reported by the United Sates Environmental Protection Agency to reduce aeration energy by 25 to 40 percent.
We have industrial accounts where we mix chemicals and acids. Our favorite is blending wine and spirits using compressed nitrogen. The old way to blend was to use “air rousing.” This was done by installing rows of perforated pipes in the bottom of the tank and attaching an air pipe to this grid. Since the typical mixing cycle was 45 minutes, copious amounts of air and energy were used.
In recent years, there have been many changes in wastewater treatment. Most modern processes control three cycles: DO, NH4, and NO3, and all of the processes require high volumes of air. Undeniably, the low pressure air system uses more electrical power than the rest of the wastewater treatment plant combined. The blower packages in these systems can be equipped with low noise enclosures, fixed speed or variable speed drives, and can include all the instrumentation needed for self-protection.
Aeration systems at wastewater treatment facilities present significant, cost-effective energy savings opportunities. Aeration—the introduction of air into the wastewater stream to support anaerobic bacteria and mixing—is a key function at the majority of wastewater treatment facilities in North America. Aeration accounts for 25-60 percent of total energy consumption at wastewater treatment facilities , and a significant piece of operating budgets sector-wide.
Blower & Vacuum Best Practices® Magazine interviewed Ms. Julie Gass P.E., Lead Process Mechanical Engineer, from Black & Veatch on trends in the wastewater treatment industry especially pertaining to new technology aeration blowers and energy efficiency.
The Focus on Energy Water and Wastewater Program was developed to support the industry because of the enormous potential to reduce energy use without compromising water quality standards. Through the program, numerous water and wastewater personnel have learned that energy use can be managed, with no adverse effects on water quality. Most locations that have saved energy have found improved control and treatment.
The concept offers new possibilities for generating positive pressure or vacuum in a variety of applications. “By applying screw compressor technology to low-pressure air compression, we’ve greatly improved efficiency,” said Pierre Noack, President and CEO of Aerzen USA. The Delta Hybrid has seven patents or patent applications, making it one of the most innovative products in compression technology.
The object of this article is to look at some very typical industrial water treatment processes and various compressed air and energy savings projects that have worked well for our clients over the years. The basic fundamentals with regard to compressed air usage are similar to municipal water treatment – a good starting point.
A new cogeneration system installed at the Budd Inlet Treatment Plant by the LOTT (Lacey, Olympia, Tumwater, and Thurston County) Clean Water Alliance late last year uses treatment by-products as fuel to generate electricity and heat energy. This renewable energy system, combined with an aeration blower retrofit currently underway at the Budd Inlet Treatment Plant, is expected to save LOTT more than $228,000 per year in utility costs.
"The Numbers Don’t Lie". It’s a popular saying everyone has heard before, applied to a variety of situations – political statistics, figures backing up an athlete’s performance and budget data.
Thirty percent is a big number. Applied to the above scenarios, it could entail a landslide victory or a hitter gaining entry into the Baseball Hall of Fame. But just imagine, if the manager of a wastewater treatment facility were to trim 30 percent from their operating costs, he or she might also consider that a landslide victory of their own.
