US-based safe water disinfection company MIOX – a Johnson Matthey company – designs and manufactures on-site chemical generators, which are an alternative solution to using hazardous chemicals, and its many benefits can be applied positively in South Africa, suggests MIOX senior applications engineer Mike Botros.
The electrolytic cell of a MIOX on-site chemical generator uses salt combined with water and electricity to generate a disinfectant at the point of use.
“The chemicals are generated at less than 1% concentration. Because the on-site generation process uses only salt, water and electricity, water treatment facilities no longer have to transport and store hazardous chemicals, such as chlorine gas or bulk bleach, typically associated with the disinfecting of water.”
MIOX offers two different types of on-site chemical generators. Hypochlorite systems are engineered to provide the absolute lowest-cost and most reliable disinfectant available on the market, while mixed-oxidant solution systems are engineered for maximum disinfection efficacy using a proprietary cell design, controlled power and cell geometry.
Botros explains that MIOX systems can be used in various applications for a range of products, cost effectively producing a disinfection chemistry with capacities ranging from 1 kg/d to 906 kg/d of free available chlorine using only one on-site chemical generator. Multiple on-site generators can be used in series to provide higher chlorine capacities based on the application requirements, making these systems very flexible.
The applications of the products are wide ranging. Municipal applications include drinking- water treatment ranging from small communities to cities of ten-million people, as well as wastewater treatment. Industrial processes include large industrial cooling towers and district cooling systems; oil and gas water treatment; food and beverage applications; and clean-in-place and process water. Additional applications include legionella prevention at hotels, casinos, universities and hospitals (legionella bacteria causes a respiratory disease called legionellosis).
Botros says MIOX systems provide four key benefits. Firstly, it ensures improved operator safety. Other water disinfection systems traditionally use chlorine sources that pose a variety of hazards to operators, such a toxic chlorine gas; as well as industrial strength bleach, which is caustic. MIOX systems use only water and salt.
“This ensures that it produces only nonhazardous oxidant solutions with a chlorine content that typically contains less than 1% free available chlorine, which is generally considered a safe concentration. Therefore, treatment plants using these typically have to face less oversight from State health agencies, provide less safety training for operators and have less of an insurance issue, compared with those using traditional forms of chlorine.”
Secondly, using high-quality chemicals ensures longer usage time, Botros says. He explains that, while chemicals used in other methods are more susceptible to degradation, owing to factors such as sunlight or long storage time, MIOX systems typically produce only a two- to three-day supply of chlorine at a time, thus providing a potent disinfectant. “As salt does not decompose, long-term requirements can be met by storing enough salt to comply with regulations.”
Thirdly, Botros highlights the greener applications of the system, compared with traditional chlorination methods. This is because, in addition to the reduction in use and potential accidental release of toxic chemicals, transport of chemicals from factories to the water plant is also reduced.
“For example, it takes one delivery of salt to produce the same amount of chlorine as four to five deliveries of 12.5% sodium hypochlorite solution. This, therefore, lessens the carbon footprint of the plant because less fossil fuel is needed to supply the plant with disinfectant,” Botros says.
The fourth benefit is cost savings, as MIOX systems typically produce chlorine at a much lower cost than traditional methods, primarily because there is no need to continuously buy expensive chlorine chemicals. Botros emphasises that this is especially the case for systems using calcium hypochlorite.
While there are upfront capital equipment costs, most water plants can realise a return on investment within about three years, he notes.
Further, Botros says these chemical generators require less maintenance, thereby making the more technically inclined operators available for other tasks; and they also provide a smaller footprint, superior disinfection, improved biofilm control and oxidation.
MIOX is represented by filtration products agents Filcon Filters in South Africa and there has been a positive uptake of the generators in the food processing industry. Filcon Filters currently has an order for a large MIOX unit for a country in Central Africa. It has also recently completed an installation at a food processing company and is awaiting an order for more units from this company.
While uptake has been slow by local municipalities, Filcon Filters is proactively aiming to spur this on by conducting more presentations at municipalities.