Scientific phenomena
– radio waves for example – can appear magical to some people,
but there is real, solid science behind them. So, too, are the
several perchlorate-removal techniques. A new method has come to
light recently that leaves no residue besides harmless oxygen and
nitrogen and is said to cost less than
currently used treatments such as ion exchange, bioreactors and
filters. An important feature would allow wells currently
contaminated with perchlorate (and nitrates) to continue in use
instead of waiting the 30 or 40 years some other cleanup methods
would take.
Scientific phenomena – radio waves for example – can appear magical to some people, but there is real, solid science behind them. So, too, are the several perchlorate-removal techniques.
A new method has come to light recently that leaves no residue besides harmless oxygen and nitrogen and is said to cost less than currently used treatments such as ion exchange, bioreactors and filters. An important feature would allow wells currently contaminated with perchlorate (and nitrates) to continue in use instead of waiting the 30 or 40 years some other cleanup methods would take.
Having usable perchlorate-free water available would mean San Martin residents could sell or refinance their properties, something they are having trouble with now. The arrival of the chemical – in small amounts – at three more Morgan Hill municipal wells north of the former Olin Corp. site at Tennant and Railroad avenues has not affected home sales there.
The city has is seeking alternate sources of perchlorate-free water that includes drilling new wells or acquiring water elsewhere. It has asked the Santa Clara Valley Water District if it could supply treated water from the San Luis pipeline or a temporary treatment plant to treat surface water in South County – by summer – Jim Ashcraft, city public works director said this week. A longer-term solution, Ashcraft said, might involve the water district providing treated state water to Morgan Hill and San Martin.A small San Jose company called EXTi (Electro Oxidation Technologies) bases its patented procedure on the electrolysis of water, which has thousands of common applications, including electro-plating.
The perchlorate-removing technology could be applied to Olin’s problem, according to Roy Hays, EXTi president. Olin has not said how it intends to clean up the local site but pumping and treating water as a hazardous material is widely used elsewhere in the state.
“Our system can treat that today,” he said. “We would need a discharge permit from the local sewer district or from the Regional Water Quality Control Board, but that should not be a problem.”
Beyond the local discharge permits, EXTi system would need no further certification or permits since the company presently treats contaminants in water for several large corporate entities. The company is in the process of becoming certified for drinking water systems.
“If Olin were to attempt soil remediation (digging up the contaminated soil for treatment),” Hays said, “if they choose to wash the soil, we could treat and recycle the wash water.”
The electrolysis of water has been around since 1800 when the principle of the electric cell was discovered by Italian physicist Alessandro Volta. Shortly afterward, English scientists William Nicholson and Sir Anthony Carlisle broke water down into oxygen and hydrogen, performing the first electrolysis. The duo placed wires from the poles of a battery in a container of water.
Current flowing through the water released bubbles of gas, thus the duo became the first scientists to observe electrolysis. At the (positive) anode pole, oxygen was released; at the cathode (negative) hydrogen appeared. Electricity had separated the molecules that make up water.
THE PROCESS
The EXSYS process oxidizes organic contaminates and reduces inorganics to their basic and harmless elements. By-products, depending on the original contaminant, can be oxygen, nitrogen, water, carbon dioxide, hydrogen and non-toxic salts. Perchlorate is a toxic salt and is rearranged to form nontoxic chemicals. The resultant harmless byproducts – nitrogen and oxygen – are vented into the atmosphere in the form of invisible microbubbles, Hays said.
The system was originally built to deal with the chemicals or compounds that polluted water surrounding industrial use: MTBE, TBA, gasoline, diesel fuel, benzene and ethylbenzene, toluene and xylene and others.
Water treated with the EXTi method finds the levels of perchlorate and nitrate contamination reduced, in most cases, to below the “action levels” – to nondetect. Results from tests last month on a well in San Martin reduced the perchlorate from 10 parts per billion to nondetect (below 4 ppb) and nitrates from 45 parts per million to 7.2, 8.3 and 9.0 ppm. The different results were caused by different amounts of voltage applied to the water.
“Different voltages get different results,” Lee Deckard, EXTi’s vice president said. “It depends on the contaminant.”
The electrolysis of water occurs when an electrical charge is introduced into water. The chemical components of water (two hydrogen atoms – H2 – bound to one oxygen atom – O2, thus H2O) are separated by the charge into their two parts, hydrogen and oxygen. Using this technique, the EXTi scientists separate the hydrogen and oxygen elements from perchlorate and nitrates, reorganize them into harmless byproducts and leave the water contaminate free.
EXTi takes a tank of any shape – it can be rectangular or cylindrical – and collects water to be treated. It uses a set of electrodes that conduct electricity. The company’s particular electrodes can be of any shape and can be made from any electroconductive material. They can capture and use the intermediate products of electrolysis which, according to Deckard, enhances the technology’s efficiency and reduces its cost.
Electricity is provided by an electrical power supply, the size of which is determined by the size of the unit. Mineralized water acts as an electrolyte as it does in both the traditional electrolysis cell and EXTi technology.
Electrolytes have positive or negative ions that conduct the electricity through water and produce the intermediate products of electrolysis for the treatment of pollutants in water.
During the process, electricity splits up some of the water being treated into its atomic parts. This process is called hydrolysis. Perchlorate contains four atoms of oxygen, which break off and combine with the generated ions to form water again, and in a complete reaction, leaving only the chloride ion (a part of table salt, which is sodium chloride). This system works in a similar manner on nitrate. In this reaction, nitrate becomes water and nitrogen gas.
CLEAN WATER
So, essentially, what would happen when the technology is adapted and approved for drinking water systems is that a tank would be installed, depending on the size of the job, at a municipal well, a private well serving a few residents or a single residence. Water would be collected in the tank – during the night on the smaller units so normal household water use is not disturbed.
The electrodes would zap the collected water with predetermined voltage, destroy the perchlorate and nitrates and shoot the clean water out into the system.
Deckard said he has no definite idea yet about the cost of units designed to treat drinking water but he is confident that the process will be less expensive and more efficient than other methods currently in use. He said $12,000 is a possible charge.
Four situations are targeted for design and treatment: an entire municipal system (such as Morgan Hill’s or the two in San Martin) multiple houses on one well, a single house on its own well and an under-sink unit.
The new product must be reviewed and certified by the NSF, the National Sanitation Foundation, before EXTi would be able to offer to treat drinking water. That would take about 10-12 weeks, depending on where the systems are manufactured, and other considerations, Deckard said.
“We are working as quickly as we can,” said Hays, who has an advanced degree in Environmental Management. “It takes a couple of years to get complete approval.” The state Department of Health Services requires a pilot project for each location in order to become comfortable that the system will work anywhere. EXTi could, for example, set up a three-week long test at a Morgan Hill or San Martin municipal well site, and, if the results pass muster in Sacramento, be ready to go.
“They (the DHS) wants to be sure that it works,” Hays said. “We are prepared to do those now.” EXTi is currently working with the DHS on a California Water Service Company treatment project in Porterville.
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Contact Lee Deckard at 971-7655, In**@**ti.biz or visit the website at www.EXTi.biz WHERE TO GO FOR INFO • Santa Clara Valley Water District: www.valleywater.org or 888-HEY-NOAH (888-439-6624) • San Martin Neighborhood Alliance: www.smneighbor.org • Rancho Cordova perchlorate project: www.perchlorate.org • Environmental Working Group: www.ewg.org
