The Water Industry Operators Association of Australia emphasizes that using chemical disinfectants like chlorine or chloramine in the “Disinfection of water, whether it’s potable or recycled, necessitates a specific period for the chemical to effectively react with and eliminate the targeted microbial pathogens. Ideally, this reaction time should be provided within a purpose-built reactor or contact tank, which is designed precisely for this purpose and offers a controlled and efficient process.
However, the reality often differs from this ideal scenario. In many instances, most water supplies rely on disinfection to take place within clear water tanks and reservoirs of varying sizes, featuring different configurations of inlet and outlet structures and experiencing varying degrees of short-circuiting. Consequently, the actual contact time for effective disinfection is often shorter than what is assumed.
Many water utilities use a target-free or total chlorine residual in their treatment systems to achieve a level of disinfection that they understand to be adequate. This approach to disinfection can be improved in most cases.
Corrosion is a natural phenomenon governed by chemistry, metallurgy, and electricity. Energy is added during the smelting and refining of iron ore to produce the steel used in the construction of potable water storage tanks. This causes an energy imbalance. Nature attempts to correct this imbalance by releasing energy in the form of electrons, causing the metal to corrode and return to iron oxide, also known as rust.
Three elements must be present for corrosion to occur. They are composed of a metal, an electrolyte, and oxygen. The term anode refers to the area of higher energy that corrodes, whereas cathode refers to the lower energy area that receives the released energy (electrons).
The anode and cathode can be made of the same alloy, such as steel, and can be attached to the same structure, such as a potable water storage tank. In these cases, the metal acts as the conductor, and the anodic areas of the steel corrode.
The medium (such as water, moist soil, or concrete) that surrounds the two metals and allows ion transfer and current flow is referred to as the electrolyte. This element has a significant impact on the rate of corrosion activity. A low conductivity or high electrical resistance electrolyte corrodes slowly, whereas a high conductivity and low resistance electrolyte corrodes quickly. Because the interior of a potable water storage tank contains a different electrolyte than the exterior, the level of deterioration in the two areas is not the same.
The corrosion activity on the outside of the water storage tank varies greatly. When there is no electrolyte present, deterioration stops completely. The composition of the electrolyte is primarily determined by atmospheric conditions.
Water (in solid, liquid, or vapour form) on the tank’s exterior causes periods of accelerated corrosion activity. Corrosion activity is increased when chloride or sulphide ions are present, as well as in tanks located in industrial or coastal areas.
The steel tank walls are almost completely submerged in water on the inside. The water’s alkalinity, pH, temperature, dissolved solids, and hardness may vary, creating an aggressive environment below the waterline. This type of corrosion also attacks buried pipelines and degrades the structural integrity of steel-reinforced concrete bridges, docks, and parking garages.
All water storage tanks are prone to corrosion attacks. Choosing the best coating for a potable water storage tank begins with an evaluation of the corrosive variables present both inside and outside the structure.
The interior and exterior corrosion of potable water storage tanks can be effectively controlled by using protective coatings and cathodic protection. Lower operating costs, fewer repairs, and longer design life are all direct economic benefits.
However, because potable water storage tanks are exposed to two very different corrosive environments, the protection method chosen for use outside the tank may not be suitable for mitigating corrosion inside the tank.
Coatings are the only accepted method of protecting the tank’s exterior. A coating’s primary function is to create a barrier that prevents chemical compounds and moisture from contacting the substrate. While an electrolyte is not always present in this area, water ingress prevention is critical for protection. Furthermore, the coating must have good adhesion, chemical and abrasion resistance, and the ability to withstand ultraviolet radiation.
Why Coating is Essential to Ensure the Quality of Water in Tanks?
– Corrosion Prevention.
- – Leakage Prevention. A properly applied coating helps seal any potential gaps or weaknesses in the tank structure, preventing leaks that can introduce external contaminants or compromise the water supply.
- – Microbial Growth Inhibition. Coatings can include antimicrobial agents that inhibit the growth of bacteria and other microorganisms within the tank, which can degrade water quality.
- – Chemical Resistance. Coatings can provide resistance to chemicals or substances that might leach from the tank material into the water. This is particularly important for industrial or chemical storage tanks.
- – UV Protection. For outdoor tanks, coatings can protect the tank material from UV radiation, which can degrade the tank material and potentially affect water quality.
- – Temperature Insulation. Some coatings offer insulation properties, helping to maintain a consistent water temperature. Fluctuating temperatures can impact the quality of water, especially for sensitive applications like aquaculture.
- – Smooth Surface. Coatings can create a smoother interior tank surface, reducing the likelihood of sediment buildup and facilitating easier cleaning and maintenance.
- – Compliance with Regulations. Many regulations and standards require tanks to have specific coatings to ensure water quality. Using the right coatings can help businesses and organizations meet these requirements.
- – Extended Lifespan. Coatings can extend the lifespan of the tank by protecting it from environmental factors and wear and tear. This longevity ensures that the tank continues to maintain water quality over time.
Coatings play a crucial role in maintaining the quality of water stored in tanks by preventing contamination, corrosion, and other factors that could degrade water quality. They also help ensure compliance with regulations and extend the lifespan of the tank, contributing to safe and reliable water storage.
Recommended High Quality of Coating in Water Tanks
Why shed a worry when your safety is truly guaranteed?
Raven Tanks are renowned for their high-quality water storage, which is safe, reliable, and certified, exceeding Australian standards and ensuring purity at its best. We offer tried and tested services in Sydney, Melbourne, Brisbane, Canberra, Dalby, Darwin and Geelong.