| Corrosion treatment is a kind of water treatment that serves the prevention of corrosion in plumbing systems of various materials, such as rustproof steel, carbon steel, copper and aluminum. |
Many drinking water and process water transporting pipelines have corrosion problems in open or closed ring pipes or cooling and heating processes as a consequence of the use of several metals, such as rustproof steel, carbon steel, copper and aluminum and as a consequence of badly conditioned water.
When two metals are connected with one another in the near of an electrolyte a reaction consists. This is called galvanic corrosion. The noble metal will corrode last during such a reaction.
Open plumbing systems
An "open system" means that the water in a plumbing system can come in contact with outside air and, as a result, with oxygen. The system is open because of a connection with an open storage barrel or a vertical pipe. Oxygen dust or contaminants may be added to the system in time through the openings.
Oxygen and contaminants that are added to the system can enhance microbial activity. Consequentially bio film formation may occur. This may cause negative effects, such as slime formation and stuffing of pipes and heat exchangers.
Lenntech can offer various solutions to these problems, for instance UV-disinfection, ozonization, bio dispersant dosing and other chemical solutions.
Next to these effects, corrosion may occur as a result of the application of various materials, such as copper or rustproof steel pipes and carbon steel pumps.
Lenntech can offer and dose corrosion inhibitors, to introduce corrosion protection in pipes and pumps. These inhibitors, which may be based on phosphates or phosphonates, will pacify and protect rustproof and carbon steel parts from corrosion. Lenntech often advises companies to use softened or demineralised water (low chlorine levels and no precipitation of hardness increasing salts) in the pipes. Lenntech also advises pH control and an increase of the pH of the circulating water to pH 9.2 - 9.5. The corrosion speed on metal is very low at this pH.
For systems that will often be out of order for longer periods of time we advice companies to maintain low but continuous water flows through pipelines, in order to prevent standstill corrosion.
We also often advice companies to apply partial stream filters for the removal of small suspended matter, which derives of peeled-off matter from the inside of the pipes and corrosion products. These filters were developed to continually filter the water of CV and cooling systems of building installations and to remove iron particles (iron oxide; rust particles) and sludge. The filters we recommend are a combination of magnet filters and bag filters that are fitted directly on the main returning pipe.
Closed plumbing systems
Within closed plumbing systems corrosion may also come about. Even though companies always make sure they use pure water as a starting-point and there is no possibility of oxygen addition to the system, corrosion can still occur on various sites in the plumbing system.
This kind of corrosion is called anaerobic corrosion. Anaerobic bacteria will reduce certain substances, such as sulphate, and consequently corrosion will come about. The anaerobic processes that cause the corrosion will function optimally at a pH of between 7 and 8. The resulting substances are a precipitate of iron hydroxide (Fe(OH)2) and iron sulphide (FeS).
Sampling equipment and measurements
Lenntech can supply companies with various test sets for the monitoring of several parameters, such as pH, conductivity, hardness, microbial contamination and inhibitor concentrations.
If you would like us to advice you on the situation of your plumbing system and the steps you can take to remove and prevent corrosion, please send us an overview of the arrangement of your system and your water analysis.
If necessary we could perform water analyses for you.