Interest in the use of ozone for drinking water treatment continues to expand, especially with increasingly tight regulation and the availability of stimulus money for infrastructure projects.
The Manistique, Michigan is looking at stimulus money to help fund ozone treatment at the city’s water/wastewater plant. Local officials report the Michigan Department of Environmental Quality has lowered the acceptable limits of disinfection byproducts. As a result, many Michigan communities will need new or additional water sources, or make major improvements to drinking water plants. The compliance dead line is October 1, 2013.
Manistique already has planned an upgrade at their drinking water plant, which will be funded with a loan/grant from USDA Rural Development. The city had previously planned to only do the second step, which is ozone treatment, if needed to meet the standards. With the availability of the stimulus money, the city is looking to apply for the funds to complete the ozone treatment, thus guaranteeing compliance.
Ozone generator systems can last 15 to 20 years with proper maintenance and thus are good long term investments. This makes them excellent applications for the stimulus money.
In our continuing series highlighting drinking water plants that use ozone for water treatment we are travelling to the greater Boston area. The Massachusetts Water Resource Authority (MWRA) runs the water system for the Boston area.
The MWRA gets its water from the massive Quabbin reservoir. The reservoir which holds a 5 year supply of water is protected by a large area of restricted land that acts as a natural filter.
The water is drained off relatively slowly, so it stays in the reservoir for a long time, which allows sediments to settle and allows the sun’s ultraviolet rays to work on the water to destroy some bacteria.
Then the water flows to a state of the art treatment plant in Marlboro. Over 200 million gallons a day on average come to the Carroll treatment facility where it is treated primarily with ozone. The ozone is generated on site using ozone generators.
Besides disinfecting the water, the ozone also removes naturally occurring organic matter dissolved in the water. When this water gets to the home it’s one of the cleanest and best tasting tap waters in the country.
As in our recent post on Billerica, MA, we will continue form time to time to point out drinking water treatment systems that use ozone. The Portland Water District of Maine is one such organization.
Sebago Lake is the deepest and second largest lake in the U.S. state of Maine and is the primary water supply for the Portland Water District, which serves the Greater Portland region and about 15% of Maine’s population. Water inflow is estimated at 544 million gallons per day and outflow at 498 million gallons per day, of which 24 million gallons/day are for the water district.
The lake water is treated with ozone as the primary disinfectant to kill bacteria and parasites, such as giardia, which can cause diarrhea. As with all ozone applications, the water district generates the ozone on site using ozone generators.
Water additives are also included in the water for corrosion control, along with a secondary disinfectant, chloramine, to help keep the pH level of the water at 8. The remaining water moves onto the hypochlorite, or bleach system, which is used as another disinfectant.
Spartan Environmental Technologies supplies ozone generators for drinking water treatment.
People often ask what ozone is used for in water treatment. In Billerica, MA it is used at the Billerica Water Treatment Plant.
The plant, which opened May 18, 2006, draws water from the Concord River, the town’s water supply, and then screens it through a raw water pumping station.
The water is ozonated – treated with ozone– in order to remove the brown color. Ozone is stronger than chlorine, decomposes into oxygen and produces low to no concentrations of any carcinogenic by products, according to a public works report.
Color removal is a common application for ozone in drinking water treatment along with taste, odor, Fe, Mn and hydrogen sulfide removal. Ozone is also an excellent disinfectant for drinking water.
Spartan Environmental Technologies supplies ozone generator systems for drinking water and other applications.
Water recycling is becoming an increasing important issue. Ozone water treatment is among several techniques that are being studied for this application. Work done by Black & Veatch indicates that membranes combined with ozone water treatment may be a good solution.
Ceramic membranes used in conjunction with ozone produce significant benefits for water recycling. Jonathan Clement of Black & Veatch, revealed this research result to the Australian Water Association’s (AWA) third specialty conference on membranes and desalination held in Sydney, Australia, on 11-13 February 2009.
“Over the last decade, membranes have become the dominant technology for the filtration of drinking water,” Clement said. “Although costs of maintaining and operating membranes in water treatment systems have come down in about the last five years, polymeric fibres in membranes have a relatively short lifespan of only 5-8 years and need replacing regularly.”
Early results indicate that ceramic membranes used in conjunction with ozone produces significant benefits that help in water recycling, he said. This, coupled with the increase in lifespan of the membranes as a result of the durability of ceramics, could help to reduce the costs of water recycling facilities.