ANOLYTE AND CATHOLYTE
Envirolyte machines are large volume, on-site systems, utilizing electro-chemical activation (ECA) to produce two solutions – Anolyte, a potent biocide and Catholyte. Patents derive from research in Russia from 1972. Machines are currently produced in Estonia and are distributed throughout the world throughout the world see distribution map at the bottom of this page.
Electrochemical activation is similar to electrolysis where electric current is used to produce a chemical change. The key innovations are the interposition of an ion-permeable membrane between the positive and negative electrodes and the design of and materials used for the electrodes.
Oxidation occurs at the positive anode, where negatively charged anions give up electrons.
Reduction occurs at the negative cathode, where electrons are emitted and react with positively charged cations in the solution.
The membrane allows the removal of solutions from each electrode separately – Anolyte from the anode and Catholyte from the cathode.
Typical reactions are as follows:
(See Picture Titled Typical Reactions at Bottom of this page))
The machines require mains water, saturated sodium chloride solution and single phase power.
(see diagram at bottom of this page)
Anolyte contains 0.05% hypochlorous acid / hypochlorite, 0.26% sodium chloride and 99.69% water. Most importantly it also contains small amounts of highly chemically active, metastable compounds of chlorine and oxygen (mixed oxidants: O2, O3, Cl2, O2˙, OH2˙, Cl˙, ClO˙) giving it significantly greater biocidal activity against bacteria, viruses, protozoa, algae, fungi and spores than sodium/calcium hypochlorite. Neutral Anolyte can be produced in the pH range 6.5 – 8.5, has a free chlorine level of 500 mg/L and maintains oxidation reduction potential (ORP) levels of 700 – 900 mV for several months in appropriate storage.
In general, Anolyte:
The extreme effectiveness of the mixed oxidants in Anolyte over sodium hypochlorite was apparent in testing conducted by the Battelle Memorial Institute for the US Military. Their most widely used decontaminant, sodium hypochlorite, with active chlorine concentration of 5000 mg/L, took 30 minutes to destroy anthrax spores and required respiratory protection. Anolyte with active chlorine concentration of 350 mg/L killed the spores on contact and required no respiratory protection (In killing Bacillus anthracis spores, Anolyte, with comparable free chlorine levels, was over 100 times more effective than sodium hypochlorite).
HOCl ↔ H+ + OCl‾ pKa = 7.5
As a disinfectant, HOCl is about 80 to 100 times more effective than OCl‾.
Disinfection Endpoint Determination
Besides direct measures of pathogen reduction, free chlorine and ORP (oxidation reduction potential) have proven useful control parameters.
Free Chlorine (FAC) can be determined by a variety of chemical and physiochemical methods; need to be aware of chemistry, stability, range, interferences, accuracy, precision, etc.
ORP is the tendency of a chemical species to acquire electrons and thereby be reduced. A solution with a higher (more positive) ORP than the new species will have a tendency to gain electrons from the new species (ie, to be reduced by oxidizing the new species) and a solution with a lower (more negative) ORP will have a tendency to lose electrons to the new species (ie, to be oxidized by reducing the new species). ORP, like pH represents an activity and does not characterize the capacity of the system for oxidation or reduction; in much the same way that pH does not characterize buffering capacity. (See Technical Bulletins 18, 24 and 32 from Aquarius Technologies Pty Ltd (www.aquariustech.com.au.)
Catholyte contains 99.3% Water, 0.413% NaCl, 0.14% NaOH, and 0.0735% H2O2‾, has a pH 11–13 and ORP ~ -800 to -900.
The capacity of the required machine is dependent on volume to be treated, contaminant level and desired residual (free chlorine or ORP). Manual and automated models are available; specifications are available on the Envirolyte Industries International Ltd website www.envirolyte.com and www.waterculture.com.au
These costs are based on domestic costs for salt, water and electricity. Commercial costs would probably be less and would need to be determined in each situation. For an EL 3000 machine producing 300 L/hour of straight Anolyte:
Electricity 4.3 kWh for 3000 L (@ 11.979 cents / kWh) = 0.017 cents/L
Salt 8 g/L (@ $274 / 1000 kg) = 0.219
Water 1 L (@ $0.89 / 1000 L) = 0.089 cents/L
TOTAL 0.325 cents/L or $0.00325/L or $32.50 per 10,000 L. (At 1% dilution, this 10,000 L is sufficient to treat 1 ML of water.)
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