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Disinfection

A Pathogen Primer

July 1, 2005By Michael Gerardi

Guidelines for reducing health risks related to exposure to disease pathogens at wastewater treatment plants

Wastewater operators are exposed daily to numerous health risks. These risks include exposure to gases, chemicals, endotoxins, exotoxins, and pathogens. Asphyxiating, irritating, and toxic gases produced through the anaerobic degradation of carbonaceous wastes include ammonia (NH3), carbon dioxide (CO2), carbon monoxide (CO), hydrogen sulfide (H2S), and methane (CH4).

Improving with Age

May 1, 2005By Tony Kobilnyk

Aging or underperforming conventional water treatment plants are retrofitting with UF membranes and benefiting from improvements in performance and operational cost savings

Too much chlorine. That's what the residents of two Tennessee cities said about their drinking water following a recent upgrade to their water treatment plant (WTP). As part of the upgrade, granular filter media from the conventional plant were removed and immersed, hollow-fiber ultrafiltration (UF) membranes were added to the plants treatment processes.

A Tailor Made Solution

March 1, 2005By James R. Graham, PhD

Using tailored activated carbons to treat perchlorate-contaminated water

In 1997, researchers first used newly developed contaminant analytical capabilities to detect low concentrations of the perchlorate ions in groundwaters and surface waters.¹ These tools helped substantiate the U.S. Environmental Protection Agency's (EPA) assertion that perchlorate is leaching into the drinking water supplies of approximately 15 million to 18 million Americans.

Choose Your Disinfection Weapon

September 1, 2004By Rudy Matousek

A closer look at the disinfection alternatives available for wastewater treatment

The 1972 Clean Water Act (CWA) was created to restore and maintain the integrity of the nation's water. One of the specific goals of the CWA is the complete elimination of pollutant discharge into navigable waters. The U.S. Environmental Protection Agency's (EPA) National Pollutant Discharge Elimination System (NPDES) Permitting Program, which supports the CWA, requires permitting for all point source discharges to U.S. waters (i.e., "direct discharges").

A Hole in One

November 1, 2003By Daniel Ramer

When the Oneida Indian Nation was expanding its operations from a small bingo/casino facility to a full resort complex, it began professionally designing new nine-hole and 18-hole golf courses. The two courses were initially designed to include both groundwater and public water systems to support their irrigation needs.

Keeping an Electrochemical Eye on Your Chlorine

November 1, 2003By Joseph Covey

Amperometry, an electrochemical method for water utilities to continuously measure free chlorine in drinking water, helps to ensure the proper amount of chlorine is being used in the disinfection process

Water utilities have been using free chlorine to disinfect drinking water for more than 100 years and have been measuring chlorine residuals for almost as long. Monitoring the product water ensures adequate chlorine is present for disinfection. It also helps the utility prevent taste and odor problems arising from overchlorination.

Heavy Metal Ultrafiltration

September 1, 2003By Francis J. Brady, Imran M. Jaferey

Ultrafiltration membrane technology can be an efficient and economical choice for removing heavy metals from industrial wastewater

Metals are commonly used in manufacturing plants and technical facilities. Production processes for the metal finishing, transportation (automotive, aviation, railroad, subway), electronics (including computers and semiconductor devices), telecommunications and mechanical parts fabrication industries consume vast quantities of heavy metals cadmium (Cd), chromium (Cr), copper (Cu), iron (Fe), nickel (Ni), lead (Pb), zinc (Zn), etc.) and metal-containing chemicals every day.

Let Your UV Light Shine

September 1, 2003

Research scientists overcome drinking water industry assumptions that UV radiation is ineffective for fighting Cryptosporidium and develop a UV treatment to battle the potentially deadly pathogen

The enormity of the problem facing the drinking water industry first surfaced in the United States in 1993, when Cryptosporidium, a single-celled parasite living in the intestines of warm-blooded animals, made its way into the drinking water in Milwaukee, leaving 403,000 people sick and 104 people dead.

No Sewers, No Problem

July 1, 2003By Patrick T. Gates, Todd M. Gates

Using onsite, submerged aerobic fixed film bioreactors to treat sanitary wastewater

Any company, land developer or individual who has attempted residential or commercial development in a rural suburban area is no stranger to the following scenario: "50 plus acres with good road frontage, high traffic count, public water and gas, but no sewer."

Can We Be MTBE Free?

May 1, 2003By Aaron Jensen

For years studies have shown the dangers of this once popular gasoline additive; now some in California and other parts of the nation might be taking the warnings to heart

Methyl Tertiary Butyl Ether (MTBE) is a gasoline additive used to oxygenate and add octane to gasoline. Since the late 1970s, lead has been banned from use in automobile fuel use due to its toxicity to humans, leading to the problem of low oxygenation in gasoline that has caused exhaust to be more easily trapped in urban airsheds.

A Texas-Size Toast to Pure Water

November 1, 2002By Rishabh Khara

Located in Dallas County, the largest ozonation facility in the world uses the ozone process to successfully control tastes and odors in drinking water

Currently, the process of ozonation is being implemented in drinking water purification in treatment plants around the globe. Ozone is a potent agent in the disinfection of raw water. When raw water is pumped into the treatment plant, it carries many bacteria and viruses. The use of ozone eradicates these harmful pathogens.

Using Your Membrane

May 1, 2002By Pierre Cote, PhD

Immersed ultrafiltration membranes as an alternative to traditional water processes

The most commonly used methods for water treatment have been around for more than a century and rely on large basins to accommodate the processes of sedimentation, sand filtration and the addition of chemicals. These methods often do not address the current pressures placed on water resources, falling short of stringent new drinking water regulations.