Comparing blower performances across different manufacturers and technologies has long been a difficult task. For many years, it was all too easy to present data that, although accurate, was potentially misleading. Manufacturers were selective about what information they published as well as what conditions they chose to specify performance. The result was a numbers game the buyer frequently lost. Fortunately, the Compressed Air and Gas Institute (CAGI), in cooperation with its members, has developed a tool for a fair comparison between blowers.
Circa 2010, Carollo Engineering designed and implemented expansions at wastewater treatment plants in Delano, California and Reedley, California to handle increased flows of up to 8.8 MGD and 5.0 MGD respectively. The proposals for both facilities specified a need for storage and processing of secondary sludge produced by the processes’ secondary clarifiers. Mazzei Injectors were selected to provide an efficient, zero maintenance method of freshening and mixing the sludge. Read the full case study to learn more.
The city of Black River Falls in Wisconsin used chemical treatment with ferric chloride (FeCl3) to achieve their effluent total phosphorus (TP) permit of 1.0 mg/l. Historically, the chemical dosing rate was manually adjusted on a daily basis based on the measured effluent TP concentration. The plant was upgraded with an OSCAR process performance optimizer control system with phosphorus controller, which uses continuous measurement of orthophosphate. Read the full case study to learn more.
Wastewater treatment plants (WWTP) are facing many challenges. Permits on nitrogen and phosphorus in the effluent water are progressively becoming stricter in order to protect surface waters from eutrophication. At the same time, plants are required to reduce both energy and chemical consumption and are often challenged with limited time and staff. In total, they are required to do more with less. In order to meet these challenges, a plant with a Sequencing Batch Reactor (SBR) in Green Lake, Wisconsin was upgraded with an advanced process control system – the OSCAR process performance optimizer with NURO controller.
Written by Kaeser’s system experts, this whitepaper compares rotary lobe and screw blowers, isochoric and isentropic compression, and how to properly apply these technologies for designing an energy efficient system.
Storey County, NV, just southeast of Reno, needed to replace an outdated wastewater treatment plant that serves the historic communities of Virginia City and Gold Hill. The new site was on the side of a hill, presenting challenges for the design of the plant and the orientation of its processes. Also, the new plant area was entirely within a district on the National Register of Historic Places. Read the full case study to learn how the new modular design allows for an efficient wastewater treatment solution.
The overall wastewater treatment process is complex, and each step is integral to ensuring water is properly purified. Effluent ends up in the plants, containing substances that must be removed before the water can be properly cleaned and returned for use. The range of potential contaminants is almost endless, and can include food, pulp, waste, or other substances. Afterwards, the water requires further scrubbing, with the aid of bacteria. It is in this part of the process that compressed air (ideally provided by energy-efficient rotary lobe blowers) plays a vital role.
The Escalon Industrial Waste Water Treatment Facility’s service area is seasonal and centered on tomato and pickle processing. The production season (roughly mid-July through mid-October) sees high hydraulic- and BOD loads that strain the facility’s capacity. During the high season highly variable BOD load depletes DO and causes permit violations and odor complaints. Praxair installed 4 X 15 HP Medium Velocity Oxygenation (MVO™ oxygenation system), with the ability to deliver up to 6 TPD of oxygen to supplement the existing aeration capacity at the facility.
A common first step in the secondary treatment process is to send wastewater to an aeration tank. In an aeration tank, bacterium is used to effectively break down pollutants into less harmful components. Wastewater aeration provides the appropriate oxygen level so that aerobic bacteria can thrive in degrading pollutants such as iron and manganese as part of the wastewater treatment process. Aeration can also be used to destroy anaerobic bacteria that perish in the presence of oxygen. Aerobes that can break down pollutants 10-100 times faster than anaerobes are used most frequently.
Aeration is also used to improve waste lagoons and other waterways such as lakes and reservoirs where oxygen deficiency contributes to taste, odor and pollutant problems. Equipment used for wastewater aeration includes low cascades, jet fountains, spray nozzles, blowers, submerged perforated pipe and porous plates or tubes. Whether the water is thrown into the air via a fountain or diffused by air bubbles being blown or drawn into the wastewater in an aeration tank, aeration works by increasing the area of contact between the oxygen in the air and water.
The most common wastewater aeration process in use today is the air diffusion process, where air is introduced from blowers through diffusion tubes suspended in a spiral flow tank, or in some cases, through diffuser plates in the bottom of the aeration tanks.