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August 16, 2009

Recycled drinking water 'a tough sell'

Western Australia's Opposition says the Government is going to have a tough job convincing Perth residents to drink recycled water.

The Water Minister, Graham Jacobs, has released a strategy to address the rapid decline of water levels in the Gnangara system, which provides 60 per cent of Perth's water supply.

If the recommendations are adopted, the groundwater system will be recharged with recycled water.

Dr Jacobs says West Australians need to get used to the idea, despite the 'yuck' factor.

The Opposition's spokesman for water, Fran Logan, supports the strategy, but says he is concerned about the public response to the longer-term recommendation to source water directly from waste water treatment plants.

"With respect to taking waste water directly from a sewerage works and then putting them through a recycling plant and turning it into straight drinking water, I think the Minister is going to have a big job on his hands convincing West Australians that's fine and that's ok to drink," he said.

Mr Logan says more money needs to be spent expanding the aquifer.

"The Minister has allowed his portfolio to be slashed," he said.

"If he [Graham Jacobs] stood up for his portfolio, he might be able to get some of that critical money poured into the infrastructure that we need to manage the state's water resources and ensure our water security into the future, particularly as we go into increasingly drying years."

The draft strategy is open for public comment for two months.

San Diego Learns How to Recycle Water

San Diego Learns How to Recycle WaterAbove: San Diego's North City Water Reclamation Plant (NCWRP) is the first large-scale water reclamation plant in San Diego's history and part of the single largest sewerage system expansion in the area. This facility can treat up to 30 million gallons of wastewater per day, which is generated by northern San Diego communities.

SAN DIEGO — The ultimate solution to California's water dilemma will draw on many sources. And one of them will be the supply of water we currently throw away. The water that goes down the drain, and down the toilet, can be reused. But finding the best way for San Diego to recycle is a technical and political question.

Recycling wastewater is nothing new. It's common and often unavoidable. Alan Rimer is a water reuse specialist with the firm Black and Veatch. He says wastewater reuse has taken many forms.

"I grew up in Pittsburgh Pennsylvania," he says. "And when I flushed my toilet, it went into the Ohio River with some treatment, and Cincinnati drank that water after taking it out of riverbank wells and treating it. And that's what we call indirect potable reuse."

To water reuse experts, San Diego is famous for the expression "toilet to tap." It arose about ten years ago when the city's first effort to reuse wastewater as potable water did a political crash and burn. But the reality of today's water shortage has put wastewater recycling back on the table. That's why San Diego is embarking on a plan to test a system for "reservoir augmentation." Wastewater will be purified to an advanced level so it could be piped to the San Vicente Resevoir, where it would become part of San Diego's supply of drinking water.

Marsi Steirer, with the San Diego Public Utilities Department, says, for now, the goal is test some new equipment at the North City Water Reclamation Plant.

"Basically what we're constructing as a temporary plant is a one million gallon a day advanced water treatment facility," she says.

The north city plant currently treats about nine million gallons of wastewater every day that's reused, mainly for irrigation. This kind of reuse requires a dual delivery system, since the North City plant doesn't currently treat its recycled water to the level of drinking water. The non-potable water flows through purple pipes to golf courses, parks and freeway medians. But the North City plant recycles less than half of what it could, due to a very limited distribution system.

Mixing highly treated wastewater with a city's drinking water supply, reservoir augmentation, is what they already do in part of Northern Virginia. Chuck Boepple is executive director of the Upper Occoquan service authority. He says his plant's wastewater is treated and discharged into the historic creek called Bull Run. That leads to a reservoir that provides drinking water for a million people in suburban Washington D.C. Boepple adds the water he puts in Bull Run is very clean.

"Our effluent, as a matter of fact, meets drinking water standards. Every parameter that EPA has on maximum contaminant levels for drinking water… we're beneath those levels," he says.

So why does Occoquan put safe drinking water in the reservoir where it'll just get dirty and need to be treated again? Beopple says doing a system where water really goes straight from toilet and tub to treatment to tap is still unacceptable to the public. Maybe so. But the water San Diego draws from the Colorado River contains lightly treated wastewater Las Vegas dumps into Lake Mead. Some say that the water people in New Orleans drink, that comes from the Mississippi River, has already been through about nine sets of human intestines.

Rick Gersberg is a public health professor at San Diego state, and he's on an advisory task force for the San Diego water recycling project. He says scientists can talk all they want to about actual health risks of recycled, drinking water. But what the public perceives as sanitary, is just as meaningful.

"Maybe a scientist would say 'Well, you know, risk is just the numbers we calculate.' But if you're dealing with risk and you're expecting to communicate and inform and have acceptance of a certain project, then that strictly science opinion is not the way it happens," says Gersberg.

Reusing wastewater has a political price and it has a monetary price. If the San Diego water recycling project becomes reservoir augmentation, it'll require a permanent treatment facility and a pipeline. The total cost would be at least $237 million.

ASME Encourages Water Recycling, Technology

ASME Encourages Water Recycling, TechnologyRecognizing the need to identify and implement technology solutions to enable the sustainable use and reuse of water, the American Society of Mechanical Engineers (ASME) has initiated an organizational plan directed at effective water management.

The plan, outlined in the 39-page "Water Management Technology Vision and Roadmap," aims to guide the society in developing products and services that benefit engineers, the nation, and the global community at large. ASME’s strategic plan highlights training, technology research and development, standards development, advocacy and public awareness, and collaborations with national and international groups.

“ASME will bring diverse partners together to find multidisciplinary solutions to water management technology issues that protect public health and the environment, while conserving precious water supplies and the infrastructure for future generations,” the organization says in the report, which is drawn from the analysis and assessments of selected experts in science and engineering.

The roadmap identifies five trends and drivers that will guide the society’s activities over the next five years. The trends relate to the role of water in energy production, supply scarcity due to shifting populations, decreased water quality, the use of recycled or “gray” water in some industrial sectors, and the role of ASME members and other engineering professionals in educating policymakers and the general public.

Among the society’s R&D objectives in water management is to stimulate technology development and to promote best practices, including standards development, for the safety and reliability of engineering components and equipment. The roadmap also encourages industry to use non-potable “gray” water to meet water conservation imperatives.

“Utilities, manufacturers, and municipalities can replace the use of freshwater with reclaimed or recycled water,” says ASME. Part of the society’s roadmap is to address the political, economic, social, and technological hurdles “in order to tap into the considerable potential that recycling and reuse offer an industry seeking to keep costs low and a nation seeking to conserve potable water resources.”

In the area of education and outreach, ASME plans to create training seminars and workshops on water technology, new technical journals, an industry-sponsored award, and a Water Management Technology Affinity Group comprised of ASME volunteers.

Going forward, ASME will engage in collaborations and partnerships with organizations that have a long-standing involvement in water technology and management, including the Association of Metropolitan Water Agencies, American Water Works Association, U.S. Department of Energy, and U.S. Environmental Protection Agency.

August 1, 2009

The Glass Recycle Process

Processing: Producing glass cullet

After the sorting stage, the next stage in the glass recycle process involves crushing and grinding the waste glass into tiny pieces. This finely crushed glass pieces are referred to as cullet.

Processing: Removing contaminants

The next stage in the glass recycle process involves the removal of contaminants from the glass cullet.
The glass cullet is passed through a magnetic field, where metal contaminants like metal bottle caps are removed from the glass. Other contaminants like paper and plastic are picked up manually or through an automated process.
Ceramic contaminants are removed from the glass cullet via a process known as fine sizing. The finely ground glass cullet is passed through various screens, leaving behind ceramic residues.
If, however, ceramic contaminants do pass through the various screens together with the glass cullet, the quality of the recycled glass will be affected. Ceramic contaminants in glass can lead to structural defects.

Processing: Making recycled glass

The cullet is then melted.
This glass cullet can then be used in manufacturing recycled glass products like new glass containers, bottles .

Processing: Decolorizing and dyeing

To produce recycled glass of the desired glass, the recycled glass has to undergo glass decolorizing in the glass recycle process, followed by dyeing.
The first step in the decolorizing process includes oxidizing the melted glass cullet.
For green glass, the oxidation process turns the deep dark green color to yellow-green color. A chemical known as manganese oxide is then mixed with the glass cullet to it grey. The grey base is usually used as the primary color to which various other coloring dyes or agents are added to develop glass of various colors.
For brown or amber-colored glass, zinc oxide is added instead to oxidize the brown glass cullet to blue or green cullet, depending on the quantity of zinc oxide added and the richness of the brown or amber-colored glass being recycled.
If the clear recycled glass is required, erbium oxide and manganese oxide are added to the glass cullet to help clear all the colors from the glass cullet.
Some of the most commonly used coloring agents for dyeing of recycled glass include borax, potassium permanganate, zinc oxide, erbium oxide, cobalt carbonate, neodymium oxide, and titanium dioxide.

Processing: Making recycled glass products

In the last stage of the glass recycling process, the recycled glass, colored or clear, is then molded into the various products and sold in the markets.

Other facts about recycling glass

An interesting point about the glass recycling process is that glass can be recycled as many times as required, without any deterioration in quality.
What makes glass recycling even more important is that glass never decomposes. If disposed of in the landfills and incinerators, they will contribute substantially to pollution. Hence, it is particularly to send your unwanted glass ware for recycling.