August 2010, Vol. 22, No.8


Study Shows Water Softeners Can Save Energy and Money

Water softeners can save money and energy in the home by helping preserve the efficiency of water heaters and other appliances and keeping showers and faucets unclogged. In 2009, the Water Quality Research Foundation (WQRF; Lisle, Ill.) commissioned the Battelle Institute (Columbus, Ohio) to perform a study on water softeners’ affect on household appliances, according to a WQRF news release.

The institute studied the effect of soft water compared to hard water in 10 gas, 10 electric, and 10 tankless gas hot-water heaters during 90 days; 10 showerheads and 10 faucets during 30 days; and three dishwashers and three washing machines during 30 days.

Unsoftened water tested contained 26.2 grains per gallon (gpg) of hardness and 0.99 ppm of iron. Softened water tested contained less than 0.55 gpg of hardness and 0.27 gpg of iron, according to the study.

Researchers measured water temperatures and flows, gas use and British thermal unit content variations, and watt-hour measurements of electricity consumption. During the testing, the appliances were run for an accelerated-scale test representing 12 years of average water use in households.


Water Heaters
Both the gas and tankless, or indoor instantaneous, gas hot-water heaters that were operated on softened water maintained the original factory efficiency rating, the news release says.

For gas heaters, the study found that for each 5 gpg of water hardness, there is a 4% loss in efficiency and 4% increase in cost when using 190 L/d (50 gal/d). For 30 gpg of hard water, this equates to 24% loss in efficiency in a 190-L/d (50-gal/d) heater and 48% loss of efficiency in a 380-L/d (100-gal/d) heater, compared to soft water.

The study found that tankless heaters failed to function after an equivalent of 1.6 years of 26-gpg hard-water use because of scale plugging in the downstream plumbing. The researchers found that using softened water in place of 20 gpg of hard water equates to a 34% savings and in place of 30 gpg of hard water equates to a 47% savings in the tankless heaters, the news release says.

The study found that up to 14 kg (30 lb) of calcium carbonate rocklike scale can accumulate in electric heaters over time and cause increased operating temperature, resulting in shortened life. Each 5 gpg of water hardness causes 0.4 lb of scale accumulation each year in electric storage-tank household water heaters, reducing the heaters’ performance.

Showerheads and Faucets
Faucets using softened water “performed well throughout the study; nearly as well as the day they were installed,” the news release says. Faucets on hard water could not maintain the specified 4.73-L/min (1.25-gal/min) flow rate because of scale collection in the strainers. The strainers on faucets using hard water were almost completely plugged after 19 days, the news release says. Showerheads using hard water lost 75% of flow rate in less than 18 months of use, the news release says.

Dishwashers and Washing Machines
Dishwashers and washing machines were operated for 30 days and on soft and hard water. Units using soft water were almost completely free of any water-scale buildup and were described in the report as able to be cleaned up to look like new. The appearance of the inside of the units using hard water showed the need for deliming and cleaning due to the buildup of scale and deposits.


Studies Show How To Minimize Antibiotic Contamination From Manure

A series of studies delving into the reactions of antibiotics in manure could help livestock producers design manure storage spaces that reduce environmental contamination.

U.S. Agricultural Research Service (ARS) scientist Scott Yates and his colleagues, including Delaware State University (Dover) researchers Qiquan Wang and Richeng Xuan, and University of California–Berkley researcher Wei Zheng, are studying how antibiotics administered to cattle break down.

Livestock producers give animals antibiotics to protect their health. In the United States, livestock generate approximately 57.9 million Mg (63.8 million ton) of manure each year, according to an ARS news release. The drugs are only partially absorbed by the animals’ digestive tracks before being excreted and could point to a source of antibiotic contamination in the environment, the news release says.

Yates has most recently been studying the degradation of oxytetracycline (OTC), a member of the tetracycline antibiotic family. One of his studies, published in the Journal of Agricultural and Food Chemistry, found that in controlled laboratory conditions, OTC in cattle manure degraded more quickly as temperatures and moisture content in the manure increased, the news release says.

The study also notes that OTC breaks down more quickly in manure than in soil because of higher levels of organic material and moisture in the manure, which supports the microorganisms that degrade the antibiotic. OTC breakdown slowed as saturation levels neared 100%, which Yates concluded resulted from oxygen levels not being high enough to fuel OTC biodegradation.

The research could help in the design of studies to evaluate the potential effect of lagoons, holding ponds, and manure pits on bacteria and antimicrobial resistance, the news release says.

Livestock producers also could use the study’s results to maximize breakdown of the organic materials and antibiotics in manure by designing storage environments with optimum temperature and moisture levels, according to the release.

© 2010 Water Environment Federation. All rights reserved.