Successful water treatment – setting the scales straight
20 September 2016
Conducting effective ongoing maintenance of commercial and industrial water-treatment systems requires attention to detail, customisation and preparation to ensure that the scales are perfectly balanced at all times.
Similar to humans, each water system is different to the next, requiring tailored treatments that are individual to each independent system.
This is where continuous and accurate monitoring provides the perfect balance. Direct analysis response technology (DART) constantly monitors and adjusts the water treatment programme to ensure industrial water-cooling systems stay free of corrosion, mineral scale and microbiological contamination.
Industrial applications including food manufacturing, continuous production environments, commercial buildings and facilities cannot successfully treat their water systems if they are unaware of which water problems need treating and why.
The lack of information often leads to cooling systems being treated with the wrong chemicals at the wrong dosage levels, which can be counterproductive in the battle to maintain a clean system.
While the accuracy of the water treatment program may not immediately appear concerning, ongoing build up of scale, corrosion and microbial growth can lead to serious consequences that can affect a business’s productivity, profitability and compliance.
So, how are these different problems caused and how can businesses successfully treat them?
Scaling deposits form within water-cooling systems due to over-concentration of scaling salts, improper maintenance practices or the incorrect choice of inhibitors.
While scaling initially may not seem problematic for plant and facilities managers, its growing presence reduces the efficiency of heat transfer throughout the water system causing significant increase in energy costs while simultaneously reducing cooling capacity.
The deposits present within the system can also cause oxygen differential cells to form, accelerating corrosion, which results in process-equipment failure. What may initially seem like a small problem can ultimately bring an industrial plant to its knees.
Failure to manage scale appropriately can have significant financial and environmental repercussions on a business, leading to prolonged downtime and costly new investment in additional cooling equipment and/or replacement of parts.
While many water treatment products are available in the market, choosing the right treatment products for the right type of scale, dosed at the right levels is not as straightforward.
Using a ‘one size fits all’ approach can often make things worse and incorrect dosing frequently results in increased water treatment chemicals costs, reduced efficiencies and the acceleration of aggressive corrosion or scale depositions.
DART technology automatically measures the chemical concentrations within the system, making micro adjustments in real time without human intervention that successfully targets scaling.
Managing the corrosion problem
The global cost of corrosion, or rust as it is most commonly known, accounts for approximately $2.2 trillion (€2 trillion) every year. The presence of rust often goes unnoticed in water-cooling systems until it has developed into a significant problem, at which point it may already have caused significant loss of efficiency and structural damage.
Tuberculation is caused due to the accumulation of corrosion by-products inside the lining of a pipe that can reduce the pipe’s capacity and lead to increased pumping costs, reduced system pressure and even structural failure.
While at first it may only necessitate minor pipe replacement, temporarily shutting down a factory’s operations to repair damage not only unnecessarily halts production but it also affect brand reputation through increased lead times.
Tuberculation can also be caused by bacteria, which can be very aggressive, accelerating the process of corrosion and pipe destruction.
So how can plant managers prevent corrosion from occurring? By using accurate and controlled chemical dosing that directly targets corrosion, scale and microbiological contamination.
Using a dosing system such as aquaDART from NCH Europe, which works in combination with a range of fluorescent dyes, plant managers can precisely maintain chemical dosing levels within tight control parameters, preventing the formation of corrosion cells and tuberculation.
With aquaDART, each chemical inhibitor used within the dosing regimen contains dyes in trace amounts (ppb level), making it invisible to the naked eye. An in-line fluorometer uses a beam of light to excite the fluorescent dye molecules, causing them to emit light at different wavelengths.
Based on the intensity of the remitted light, the system can adjust the feed rate automatically to control the concentration of inhibitor present within the cooling water at an optimal level.
The system automatically measures the concentration of the treatment to make micro adjustments in real time, ensuring that scale, corrosion and slime are kept at bay. The system’s remote monitoring and control software provides plant operators management with peace of mind by adjusting the inhibitor level to the optimum level or alerting the operator if a chemical pump stopped working.
By implementing optimised dosing, businesses can reduce operating costs while enabling greater environmental compliance.
Although successful water treatment is a balancing act, it does not need to be the business itself that does the juggling. By using intelligent and innovative water-treatment approaches, business leaders can remove the stresses and strains associated with water treatment, providing constant and consistent monitoring that leads to successful results.
Dr Simona Vasilescu of the Water Treatment Innovation Platform at water, energy and maintenance solutions provider NCH Europe.