The city of Fort Lupton a growing Front Range community located along the South Platte River in Colorado, began operation of a new 5 MGD (18.93 MLD) membrane filtration system in 1997.
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.
Historically, Lyon County Utilities, Nevada, applied 12.5% bulk sodium hypochlorite for disinfection at each of their well sites. Always looking to improve system efficiency, Lyon County staff reexamined on‐site hypochlorite generation to determine if the use of the 0.8% sodium hypochlorite solution could mitigate the challenges associated with dosing high strength sodium hypochlorite.
A combination of growing demand, aging infrastructure and regulatory requirements acted as drivers for a new ozone system at the Miramar Water Treatment Plant in San Diego, CA.
Chatsworth Water Works Commission provides both water and wastewater services to the 5,000 residents of the cities of Chatsworth and Eton, GA.
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.
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.
Our nation’s record of progress in advancing public health under the Safe Drinking Water Act is significant.
What would happen if there was an emergency in the U.S. that caused radioactive material to contaminate drinking water supplies? What steps could your utilities and government take?
Ensuring the quality and safety of drinking water across the U.S. EPA-monitored 155,000 public water systems has become a national issue.
Located 30 minutes North-East of Montreal, Canada, the City of Terrebonne has the last drinking water intake of the many cities along the Rivière des Milles-Iles.
For Robert Stout, general manager of Mid-Arkansas Utilities (MAU), the primary water provider for a three-county rural area spanning 2,220 square miles, the reason to switch to a dry calcium hypochlorite feeding system was simple, “using chlorine gas was not only dangerous for us, it was a big hassle and time-consuming.”
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.
NDMA is an organic chemical that can mix with water and is defined as both toxic and carcinogenic. NDMA is sometimes formed when water is disinfected with chloramines.
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).