Storey County, NV, just southeast of Reno, needed to replace an outdated wastewater treatment plant that serves the historic communities of Virginia City and Gold Hill.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.
A modern, master-planned community in the Texas Hill Country needed an affordable wastewater collection and treatment system that could be installed in phases and would perform as reliably as a large municipal system but without the cost, odor, or need for a full-time operator.
The Hagerstown Wastewater Treatment Plant in Maryland incorporated several plant modifications, one of which was the conversion of their disinfection process from the use of ozone to UV.
A leading fruit juice company had expanded over the past ten years and increased wastewater flow from 7,000 to 11,000 gallons per day (gpd), without upgrading its wastewater treatment plant.
The LeSourdsville WWTP in Butler County, Ohio, was required to meet their NPDES permit requirement of 6 mg/l dissolved oxygen at the plants Miami River outfall.
A carrot packing plant was having severe odor problems due to septic conditions in their truck washout water holding lagoon. In addition, nutrient and nitrogen levels were becoming an issue for land application of the wastewater for crop production.
The treated effluent from all wastewater treatment plants across the country must meet local dissolved oxygen (DO) limits before discharging into receiving waters.
A large vegetable processing facility was experiencing problems with its lagoon surface aerators. The company’s treatment process includes a collection and screening assembly, two anaerobic stabilization ponds and a 40 million gallon aerated lagoon.
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.