In 2006, engineers at HDR began planning efforts to increase capacity at the city of St. Charles, Mo.’s Missouri River Wastewater Treatment Plant. The landlocked plant had limited opportunities for physical expansion. HDR needed a solution that fit within the existing infrastructure, which included three parallel-operated oxidation ditches, each 12 ft deep with 1.06-million-gal capacities.
Founded in 1989, the Long Trail Brewing Co., one of the top 25 craft breweries in the nation and a local attraction, quickly outgrew the capacity of its basement location at a woolen mill in the town of Bridgewater, situated in Vermont’s Green Mountains. In 1995, the brewery relocated to a larger facility nearby with a wastewater treatment plant designed to treat high-strength wastewater with a BOD5 concentration of approximately 10,000 mg/L.
The town of Grand Junction, Iowa, uses a groundwater source to provide water to 850 people. The water quality from a 365-ft-deep well is generally good, with iron concentrations of about 0.3 mg/L and hardness of about 273 mg/L. In the early 1930s, the town installed a vertical pressure filtration system with a softener to treat the water. The filter media, however, eventually became completely clogged and stopped operating properly. Water quality became poor, and there were issues with maintenance of the distribution system.
When the city of Malibu, Calif., decided to turn a former lumberyard site into a high-end shopping center, it needed to build a wastewater treatment plant (WWTP) to serve the 30,000-sq-ft retail center, as no city wastewater treatment facility was available. The new plant had to meet Los Angeles Regional Water Quality Board (RWQB) water quality requirements and stringent subsurface discharge requirements.
When it comes to tanks at wastewater treatment plants that contain solids slurries—whether for anaerobic digestion or sludge storage—a key factor in proper system design, operation and maintenance is mixing. Anaerobic digesters routinely operate with solids concentrations in the range of 3% to 5%. Sludge storage tanks can have solids concentrations exceeding 5% dry solids and, in some extreme cases, settled solids at the bottom of these tanks can be as high as 10% to 12% dry solids.
Predicting future power costs to determine wastewater treatment processesWe hear a lot lately about the rising cost of energy and even more about green and sustainable technologies that are on the market to minimize power use in a wastewater treatment plant. This article demonstrates a methodology used to estimate the future cost of power in each U.S. state. It also will show why an accurate power cost estimate can change the selection results for wastewater treatment processes, depending on the unique inflation rate in each state.
Groundwater replenishment system weighs its expansion options California’s Orange County Water District (OCWD) operates the Groundwater Replenishment System (GWRS), an advanced wastewater treatment facility located in Fountain Valley, Calif. As an indirect potable reuse facility, the GWRS provides 70 million gal per day (mgd) of purified wastewater for groundwater recharge and maintenance of a seawater intrusion barrier for protection of the local groundwater basin.
Figure 1. In the Multiwash process, media separator baffles prevent the media from entering the trough so that only backwash water laden with contaminants is allowed to leave the basin.
The city of Rock Hill, S.C., has a 24-million-gal-per-day (mgd) surface water treatment plant that had been struggling with a variety of filter performance and capacity issues. There were three generations of filter designs dating back as far as 1899. Upgrades in 1912, 1913, 1919 and 1994 were incorporated and additional cells added as capacity needs increased.
California mountain town doubles up on disinfectionIn the summer, vacation traffic along California Highway 108—also known as the Sonoran Pass Highway—can get thick with urban vacationers winding their way up to campgrounds in the Sierra Nevada. They have no idea what impact they have on the wastewater treatment plant (WWTP) or its difficulty in keeping up with the disinfection demands to protect the environment.
When the Colorado City, Colo., Metropolitan District needed to expand its drinking water treatment plant to accommodate the rapidly growing population, it required a solution that would include design, equipment and construction.
To better serve residents and complete the project quickly, the district decided not to apply for funding through the Drinking Water State Revolving Fund. Instead, it partnered with a single supplier that could offer design-build-financing capabilities.