California recently became the first U.S. state to regulate hexavalent chromium in drinking water. Will others follow suit?
When a series of water crises in 2014 disrupted conventional utility services in the coastal Argentine city of Caleta Olivia, the city needed a way to ensure an uninterrupted water supply.
Rapid detection of changes in water quality is critical in water delivery systems, wastewater treatment, and industrial plants for process optimization, environmental regulatory requirements, and consumer health.
For the Village of Lombard’s Water Division, consistently delivering high-quality tap water to the community’s nearly 44,000 residents and the businesses serving them was once quite a juggling act: constantly fixing old, temperamental analyzers; feeding reagents into the old analyzers; and staying ahead of callers complaining about “musty” water tastes and odors. Not today.
Sometimes technology innovations come along which cause a paradigm shift in how products are designed.
An electrical engineer does the math on coagulation process control, using computational modeling to determine best practices.
Faced with a tight capital budget, a city in British Columbia required a new design for a water treatment plant capable of a maximum daily water production of 21 MPG during peak demand periods, with an ultimate demand of 29 MGD.
In February 2010, the Dempsey E. Benton Water Treatment Plant (DEBWTP) added 16 million gallons per day (MGD) of capacity to the water utility operated by the city of Raleigh, North Carolina.
Water is disinfected before it enters the distribution system to ensure that dangerous microbial contaminants are killed.
Chromium is a naturally occurring metal common in the earth’s crust. There are multiple forms of chromium, and one form, called chromium‐3, is actually a required nutrient for human health, in the right amount.
The city of Florence, Colorado Water Treatment Plant (WTP), located 75 miles south of Denver, uses blended surface water taken from the city’s southernmost water reservoir.
Like many municipalities, Hamilton, Ontario, is wary of harmful algal blooms and toxic cyanobacteria. To mitigate the threat and protect drinking water, a proactive, risk-based plan was developed.
Interested in converting to biological drinking water treatment? Here’s what you need to know.
With the town of Johnstown, CO's, water treatment plant began operating its circular clarifier systems at maximum capacity to meet summer peak demand rates, consultants recommeded increasing plant capacity and using dissolved air flotation technology for their clarification process.
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).