Three Valleys Municipal Water District (Three Valleys) is one of 26 water agencies that comprise the Metropolitan Water District of Southern California (MWD). Three Valleys is the primary source of supplemental water for the Pomona, Walnut, and East San Gabriel Valleys.
With the United States Environmental Protection Agency (USEPA) now requiring arsenic levels of 10 ppb for drinking water, reducing high levels of arsenic in one of its community’s water supply had been a challenge for Eureka County. Find out how a community, who once searched for silver, hunted down a way to remove high levels of arsenic from its drinking water.
When the City of Midlothian, Texas, was ready to expand their water treatment plant to accommodate a growing population, they carefully considered and investigated their water disinfection options.
Researchers examine the feasibility of treating hexavalent chromium — the carcinogen made famous by the movie “Erin Brockovich” — with strong base anion exchange (SBA-IX).
The Water Environment & Reuse Foundation introduces a “bundle of research” to help direct potable reuse and its practitioners reach full potential.
Reverse osmosis, or RO, is one of the finest technologies to purify water containing high total dissolved solids (TDS) levels of more than 500 ppm. Reverse osmosis plant exporters explain the technology as a separation technology where dissolved and invisible impurities in water are separated with the help of semi-permeable membrane or RO membrane that works under high pressure.
The City of Somersworth has a historical background dating back to the early 1900s when it became the first community to start using chlorine to disinfect it’s drinking water.
In April 2013, City Utilities started up three Microclor Model MC‐1500 skid systems, each rated at 1,500 pounds per day of free available chlorine.
A water quality audit revealed that two of the largest drinking water plants in the City of Montreal were out of compliance with Quebec’s latest water quality rules. Both drinking water facilities were located in heavily populated areas; consequently, plant modifications had to be accomplished within their existing infrastructure footprints.
Aqua Engineers is a local Hawaiian company founded almost 40 years ago which delivers operations, engineering, and construction management to the water and wastewater industry throughout Hawaii. Also, as an owner and operator, Aqua Engineers is keenly focused on the return on investment for process equipment decisions, but also on the safety of its operators and surrounding community. Read the full case study to learn why Aqua Engineers chose the Microclor OSHG system provided by UGSI Solutions for both their sites in 2016.
When the Cobb County-Marietta Water Authority (CCMWA) anticipated the need to upgrade the Hugh A. Wyckoff water treatment plant, they turned to granular activated carbon (GAC) technology after vetting several alternatives. The plant, a wholesaler in a two-plant system, processes up to 72 million gallons per day and serves about 350,000 people. Comprising of Wyckoff and the James E. Quarles treatment plant, CCMWA is the second largest water provider in Georgia.
Bluebonnet Rural Water Corporation (BRWC), a subsidiary of Bluebonnet Electric Cooperative, serves approximately 1,094 water meters in northeast Washington County, TX, but had a water storage problem not unfamiliar to even the largest water utilities in Texas.
This municipality disinfects 1-1.5 million gallons per day of drinking water, and is currently transitioning from a small system serving <10,000 people to a large system serving >10,000 people. Chlorine gas was used as the primary disinfectant for the raw water entering the plant.
The design team for the intermediate ozone system at Buckingham Water Treatment Plant, Quebec, had limited space available for ozone contacting for the plant’s 1.3 – 7.4 MGD flow, so a standard fine bubble diffusion basin for ozone disinfection was not an option.
The removal of contaminants from public drinking water systems in the US is mandated by the Environmental Protection Agency’s (EPA) National Primary Drinking Water Regulations. These are legally enforceable standards that protect public health by limiting the levels of contaminants in drinking water. Similar regulations are managed by agencies worldwide to protect their citizens from drinking water contamination.
There are a plethora of drinking water contaminant removal technologies that public and private water systems use to comply with the EPA’s drinking water regulations. These include reverse osmosis, membrane, nanofiltration, ultrafiltration, chlorine disinfection, UV disinfection and Ozone-based disinfection practices.
The EPA’s list of drinking water contaminants is organized into six types of contaminants and lists each contaminant along with its Maximum Contaminant Level (MCL), some of the potential health effects from long-term exposure above the MCL and the probable source of the drinking water contaminant.
The six types of contaminants are microorganisms, disinfectants, disinfection byproducts, inorganic chemicals, organic chemicals and radionuclides.
Examples of microbiological, organic contaminants are Cryptosporidium and Giardia lamblia. Both of these microorganic pathogens are found in human or animal fecal waste and cause gastrointestinal illness, such as diarrhea and vomiting.
A common disinfectant used in municipal drinking water treatment to disinfect microorganisms is chlorine. The EPA’s primary drinking water regulations require drinking water treatment plants to maintain a maximum disinfectant residual level (MDRL) for chlorine of 4.0 milligrams per liter (mg/L). Some of the detrimental health effects of chlorine above the MCL are eye irritation and stomach discomfort.
Similarly, byproducts from the chlorine-based disinfection methods used by public water systems to remove contaminants can be contaminants in their own right if not removed from the drinking water prior to it being released into the distribution system. Examples of disinfection byproducts include bromate, chlorite and total trihalomethanes (TTHMs). Not removed from drinking water, these disinfection byproducts can increase risk of cancer and cause central nervous system issues.
Chemical contamination of drinking water can be caused by inorganic chemicals such as arsenic, barium lead, mercury and cadmium or organic chemicals such as benzene, dichloroethane and other carbon-derived compounds. These chemicals get into source water through a variety of natural and industrial processes. Arsenic for example is present in source water through the erosion of natural deposits. Many of the chemical contaminants are derived from industrial wastewater such as discharges from petroleum refineries, steel or pulp mills or the corrosion of asbestos cement water mains or galvanized pipes.
Radium and uranium are examples of radionuclides. Radium 226 and Radium 228 must be removed to a level of 5 picocuries/liter (PCI/L) and Uranium to a level of 30 micrograms/liter (30 ug/L).