It’s well known the beneficial role that particular groups of microorganisms have in the food and beverage industry. Similarly are the beneficial aspects that either engineered or non-engineered biological treatment systems have in the drinking water production process.
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.
California recently became the first U.S. state to regulate hexavalent chromium in drinking water. Will others follow suit?
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.
Sometimes technology innovations come along which cause a paradigm shift in how products are designed.
Sulfate concentrations in water have come under increasing scrutiny from regulatory authorities over the past two decades.
The user population of a Central Texas resort system does not reach its peak until summer and the resultant levels of peak and low usage vary widely. This fluctuation impacts levels of disinfectant residual and, consequently, water quality — especially at the end of the line. Manual flushing of the utility's hydrants to maintain water quality has resulted in excessive time and labor as workers must access the outlying areas.
To ensure treated water complied with the most stringent drinking water standards, including the Environmental Protection Agency (EPA) Stage 2 Disinfectants and Disinfection Byproducts Rule (State 2 DBPR), the City of Cambridge, MA, WTP decided to implement a robust multibarrier treatment solution.
Chlorination in all of its forms — gas, liquid, or solid — has been the primary way for treatment plants to disinfect the treated wastewater. The treatment plants that use gas chlorination must face federal regulatory oversight in the form of a Risk Management Program (RMP). Liquid chlorine plants trade in the regulatory oversight for a more expensive and less effective product. While chlorine in its solid form is good for small treatment facilities known as package plants (named for their mobility). However, ultraviolet (UV) technology is rapidly altering the landscape of disinfection throughout the industry.
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.
Providing large cities with drinking water is never an easy task. Outdated systems can cause problems such as leakages or contaminations.
Our nation’s record of progress in advancing public health under the Safe Drinking Water Act is significant.
Located in the high desert plateau of southwestern Colorado, Pagosa Springs is famous for its geothermal hot springs, which draw visitors worldwide to soak in the mineral-rich water. The Utes called the sulfur springs “Pah-gosah,” meaning “healing waters.” You might say the town’s potable water system is healed now as well.
Phoenix is one of the country’s fastest growing metropolitan areas and has one of the most arid desert climates. Population growth coupled with increasingly stringent water regulations pushed the city to proactively address future water supply concerns. The decision was made to build the Lake Pleasant Water Treatment Plant (WTP) and include oxidation and disinfection treatment barriers.
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).