- By Jason Goodman
- September 01, 2006
This article originally appeared in the 09/01/2006 issue of Environmental Protection.
Management at drinking water treatment facilities looking for an alternative to gaseous chlorine (Cl2) or sodium hypochlorite (NaOCl) should seriously consider dry chlorine in the form of calcium hypochlorite briquettes. Drinking water treatment facilities switching from sodium hypochlorite to calcium hypochlorite for disinfection are finding this alternative to be an efficient solution for ensuring consistently accurate chlorination while eliminating many long-standing operations, maintenance, and safety concerns associated with NaOCl use.
- By Jim Brennan
- July 01, 2006
This article originally appeared in the 07/01/2006 issue of Environmental Protection.
On Jan. 23, 2006, the arsenic rule was implemented with a new limit of 10 parts per billion (ppb) (the old standard was 50 ppb). The new rule has a broad reach; it affects large and small drinking water treatment systems, including non-community water supplies.
- By Darin St. Germain
- June 01, 2006
This article originally appeared in the 06/01/2006 issue of Environmental Protection.
Groundwater and soil contamination are among the most time-consuming and costly environmental remediation challenges facing our communities today. Solvents, metals, organic compounds, and other chemicals remain in the soil and seep into groundwater long after the facilities that used or created the contaminants have stopped operating.
- By Joseph L. Devary
- January 01, 2006
This article originally appeared in the 01/01/2006 issue of Environmental Protection.
Arsenic (As) removal from drinking water by adsorptive media has been a proven technology for years. In the western and southwestern United States, however, much of the As-tainted groundwater has a pH value that is high enough to significantly reduce the operating capacity of adsorptive media, including the iron-, alumina-, and titanium-based media commercially available to municipalities.
- By Peter Ritchey
- January 01, 2006
This article originally appeared in the 01/01/2006 issue of Environmental Protection.
Over the past few decades there has been an increased awareness of the importance of water quality. Many municipalities and industrial facilities have upgraded or installed new technologies to meet the demand for clean water. Advances in water quality science show that further improvements are needed to ensure a plentiful water supply and to protect the natural environment.
- By W. Wesley Eckenfelder, William Ney Hansard
- October 01, 2005
This article originally appeared in the 10/01/2005 issue of Environmental Protection.
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.
- By Tony Kobilnyk
- May 01, 2005
This article originally appeared in the 05/01/2005 issue of Environmental Protection.
Since the late 1990s membrane bioreactor (MBR) technology has rapidly entered the wastewater treatment market. The technology is a simple combination of an activated sludge process and a membrane filtration step. The separation of activated sludge and effluent is achieved by using porous membranes that are able to remove all the suspended solids from the biologically cleaned water.
- By Klaus Vossenkaul, PhD
- March 01, 2005
This article originally appeared in the 03/01/2005 issue of Environmental Protection.
The full cost of ownership related to operating a water or wastewater treatment facility consists of the initial capital, commissioning, training, spare parts, maintenance, and calibration costs for the lifetime of the equipment.
- By James E. Gallagher
- September 01, 2004
This article originally appeared in the 09/01/2004 issue of Environmental Protection.
Creosote and other non-aqueous phase liquids (NAPLs) are responsible for high pump-and-treat costs in groundwater remediation because, due to their molecular size, they tend to clog activated-carbon pores quickly. The result is frequent change outs, which renders the pump-and-treat method too expensive.
- By George R. Alther
- July 01, 2004
This article originally appeared in the 07/01/2004 issue of Environmental Protection.
Access to safe drinking water and contamination of surface water bodies is a major problem in many areas of the globe. In the year 2000, approximately 1.1 billion people (18 percent of the world's population) lacked access to safe drinking water, and 2.4 billion (40 percent of the total population) lacked adequate sanitation.
- By Ellen Bohon Zeytoun
- July 01, 2004
This article originally appeared in the 07/01/2004 issue of Environmental Protection.
In-situ biological treatment (bioremediation) systems have now gained widespread acceptance for dealing with sites impacted by petroleum hydrocarbons. However, at many remediation sites, the need to pump groundwater to maintain gradient control still generates a stream of contaminated water requiring treatment, even if in-situ technologies are being employed.
- By Scott D. Wallace
- June 01, 2004
This article originally appeared in the 06/01/2004 issue of Environmental Protection.
This is the second article in a two-part series on membrane elements and treatment systems. "Demystifying Membranes - Part I" was published in Environmental Protection's July-August 2003 issue and is accessible online at no charge under "Archives" at www.eponline.com. The first article compares the advantages and disadvantages of four types of membrane separation technologies. Part II clears up some common misunderstandings about the properties of membrane technologies.
- By Peter S. Cartwright, P.E.
- May 01, 2004
This article originally appeared in the 05/01/2004 issue of Environmental Protection.
Fiberglass composites have become the material of choice in many water or wastewater treatment operations. For mild to severe corrosion service, they can often be the materials of choice for economy and durability.
- By J. Albert Rolston, PE, FAIChE
- March 01, 2004
This article originally appeared in the 03/01/2004 issue of Environmental Protection.
Water treatment plants and pumping stations supported by variable-frequency drives (VFDs) may be unwittingly threatened with power system problems including interruptions, interference, downtime and even disruption of instrumentation and other sensitive equipment due to an elusive culprit called harmonic distortion, an undetected condition that has been said to cost between $16 to $40 billion in annual losses due to downtime, equipment failures and malfunctioning systems.
- By John Cherney
- March 01, 2004
This article originally appeared in the 03/01/2004 issue of Environmental Protection.
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.
- By Joseph Covey
- November 01, 2003
This article originally appeared in the 11/01/2003 issue of Environmental Protection.
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.
This article originally appeared in the 09/01/2003 issue of Environmental Protection.
Implementation of a new Laboratory Information Management System (LIMS) has helped the Portland, Ore., Bureau of Water Works meet regulatory requirements while increasing laboratory throughput. Water quality laboratories across the country face the need to perform a higher volume of testing and improve data security in order to ensure the safety of the nation's water supply.
- By Michael Lehtola
- September 01, 2003
This article originally appeared in the 09/01/2003 issue of Environmental Protection.
Activated carbon is well known for its ability to remove organic compounds from water through a process known as adsorption, remove chlorine and chloramine through various chemical reactions and serve as a general filter media; however, its use for reduction of bromate is unclear.
- By Kimberly Thompson, Neal Megonnell
- July 01, 2003
This article originally appeared in the 07/01/2003 issue of Environmental Protection.
Groundwater contamination has been an area of environmental concern for decades. Underground storage tank and process line leaks, product spills and intentional dumping have been the greatest contributors to the problem.
- By Duygo Tokat, Arturo A. Keller, PhD., Reid H. Bowman, PhD., Peter Herlihy, Michael J. Joy
- July 01, 2003
This article originally appeared in the 07/01/2003 issue of Environmental Protection.