Phosphate Corrosion Control in Drinking Water


The metals in the pipe tend to rust when they come into contact with dissolved oxygen in the water. This fact results in the formation of stable metal oxides. Corrosion in water distribution systems can affect the health of consumers, the costs and the aesthetics of treated water. Older systems may include lead-based solders that must be protected to prevent high concentrations of lead. In fact, this is how it is regulated by Directive (EU) 2020/2184 of the European Parliament at 5 ug/l, since it is very harmful to health.

Corrosion inhibitors such as inorganic phosphates in the form of polyphosphates, orthophosphates, glassy phosphates and bimetallic phosphates are often used. The addition of phosphates can form a protective layer on the pipe and contain corrosion. To guarantee a correct dosage of phosphate that allows adequate corrosion control, monitoring with a reliable analyzer is required. This also achieves a reduction in operating costs.


Corrosion control with Phosphate.

Phosphate is commonly used to minimize corrosion in drinking water distribution systems. We refer here to residential, commercial and industrial drinking water pipes. Phosphate is also used to reduce lead corrosion and to meet government standards. To achieve passivation of new or previously untreated systems, phosphate is typically dosed at > 3.0 mg/L as orthophosphate. The typical maintenance dose to ensure corrosion control is 0.5 to 1.5 mg/L.


Monitoring treatment with phosphate.

It is necessary to monitor the phosphate concentration to ensure adequate corrosion control. Manual monitoring is possible. However, to avoid underfeeding or overfeeding during periods of fluctuating system flow, continuous monitoring is advantageous. Phosphate dosage control with an online analyzer allows:

  • Minimize corrosion to meet regulatory requirements
  • Reduce costs of added chemicals


The graph above shows underdosing of phosphate (blue line) while the flow rate increases with the manual feed system. The results are an increased risk of corrosion in the distribution network and a higher concentration of lead in drinking water. A continuous system with automatic feed allows maintenance of a desired set point regardless of flow rate fluctuation.

An automatic phosphate measurement provides all the necessary information. This makes it easy to keep proper control of the corrosion inhibitor to minimize corrosion and cost.


OUR SOLUTION: AMI Phosphate II Analyzer

Online analyzer, from the Swiss company SWAN ANALYTICAL INSTRUMENTS, for the automatic and continuous measurement of dissolved orthophosphates. Ideal for monitoring and controlling the phosphate dosing process. Measurement range: 0.01 to 10 ppm PO4

Its overflow chamber and continuous flow photometer eliminate coating and clogging problems. Optional cleaning module reduces maintenance efforts.

Built-in monitoring functions generate alarms if the measurement is invalid. Typical problems are lack of flow, empty reagent reservoirs, valve and photometer functionality.

No data loss after power failure. All data is saved in permanent memory. It has protection against overvoltages of inputs and outputs, and galvanic separation of measurement inputs and analog outputs. The analyzer is factory tested and ready to be installed and run.

Monitoring of iron and manganese in drinking water

The chemical elements iron and manganese

Manganese is naturally present in soil, surface water, and groundwater. Manganese is an important cofactor for many classes of enzymes.

Enzymes are proteins that act as biological catalysts, speeding up chemical reactions.
Manganese is an essential dietary element for humans due to its role as a coenzyme in various biological processes, including macronutrient metabolism, bone formation, and free radical defense systems. The human body contains about 12 mg of manganese, mainly in the bones.

Iron is the first metal most abundant in planetary mass. That’s because the planet, in its core, concentrates the largest mass of native iron, equivalent to 70%. The body of an adult human contains approximately 4 grams (0.005% of body weight) of iron, mainly in hemoglobin and myoglobin. These two proteins play an essential role in the metabolism of vertebrates; the transport of oxygen by the blood and the storage of oxygen in the muscles respectively. To maintain the necessary levels, human iron metabolism requires a minimum of iron in the diet.


The health risks of iron and manganese

The health risks from iron and manganese are small; however, there are risks associated with bacteria that cause high concentrations of iron due to corrosion. The lethal dose of iron for humans is 200-250 mg / kg of body weight, which would cause extensive gastrointestinal bleeding. Iron intake with drinking water is too low to pose health problems, making iron toxicity rare. However, iron oxides may be responsible for increased arsenic levels.

Water sources, such as groundwater, often contain iron and manganese. Manganese is usually present in much lower concentrations than iron. Controlling manganese and iron ensures that tap water does not discolor or taste bad. Customer complaints, subsequent investigation, and agreed-upon actions can be very costly. Turbidity monitoring can generate alarms in case of accidental events (advances, storms, floods) or by trends and monitoring of the final product. More specific measurements must be made to satisfy customer satisfaction in terms of taste, color or hardness.


About application: iron and manganese control in drinking water.

In Chile, the local regulatory limit for iron is 0.3 ppm and for manganese 0.1 ppm. If the levels are above these limits, critical penalties would be applied. Therefore, measurements are located at the outlet of drinking water plants and / or after the filtration system. Normally, there is no increase in the value of iron and manganese in surface water, however water wells can be a problem as higher values ​​are expected. The client is one of the main drinking water providers in southern Chile.

The main measure to ensure that the levels are below the legal requirements, must be done after the filtration system of the water sources. Each drinking water plant has 3 water sources, but in all cases only 1 water source has problems with iron and manganese. Therefore, only the water source with high levels of iron and manganese is individually monitored (see number 1 in the image below).

In addition, to ensure quality, the exit point is also monitored (see number 2). This point should always have iron and manganese levels equal to or lower than the previous measurement points.


The Swan Chile facility

Many plants continue to perform manual sampling in the laboratory, being discontinuous can cause delays in the detection of iron and manganese levels. The customer wanted to increase quality assurance and therefore switched to continuous online monitoring with Seres OL’s Topaz Iron analyzer (Swan group company).


OL Topaz Iron and Topaz Manganese Seers monitors at customer site for end product monitoring.


Commissioning and delivery of Topaz Iron and Topaz Manganese monitors with the customer


For any questions you can contact SWAN ANALISIS IBERICA,

Organic load control in drinking water – Second part

Objectives that we will develop in this article:

Objectives that we will develop in this article:

  1. Improved efficiency in the addition of chemicals in the coagulation-flocculation process
  2. Detection in time of the saturation of the activated carbon filters.
  3. Decrease in energy consumption in the control of UV disinfection and increase the durability of the lamps.
  4. Water storage: ensuring the quality of drinking water by continuously measuring the
    organic contaminants prior to distribution


Let’s remember where we can measure the organic load in a drinking water plant


The water intake was dealt with in the first part.



Coagulation / flocculation followed by sedimentation / filtration is a process to remove suspended solids of an organic and inorganic nature from drinking water.


  • Monitoring of the effective removal of natural organic matter (NOM) in the coagulation and sedimentation process
  • Improved process monitoring, improving the efficiency and effectiveness of chemical addition and energy consumption.

Microorganisms + NOM + disinfectant ———> Destroyed microorganisms + disinfection by-products (DPB), associated with various types of cancer. Limited in RD 140/2003.

The following graph shows the formation of the main and most elemental of these by-products, chloroform, depending on the chlorine applied and contact time, in a given water




  • Monitoring of the effectiveness of the process in activated carbon filtration allowing to improve the prognosis in the extent of filter saturation, which minimizes unexpected downtime.
  • Measurement before and after the Active Carbon filter.

Tendency to decrease the difference between input and output.


Correct levels of SAC 254nm at the outlet of the activated carbon filter



Verify and optimize proper UV disinfection.

  • Process control, improved by monitoring the effectiveness and efficiency of UV disinfection.
  • UV light with wavelength <280nm destroys the DNA of microorganisms.
  • The efficiency of disinfection is given by the formula:
    UV intensity (expressed as energy per unit area) x resistance time.
    The proper UV dosage for each application must take into account water quality, arc tube aging, industry specifications, and microbiological standards.
  • Decrease in energy consumption in the control of UV disinfection and increase the durability of the lamps




  • Ensures the quality of drinking water by continuously measuring organic contaminants prior to distribution.
  • Controlling organic load is especially important if chlorine is used as a disinfectant, as it reacts with organic substances and forms disinfection by-products that are potentially carcinogenic, such as trihalomethanes (THM) and haloacetic acids (HAA).

A correlation with various carbon-based parameters is also possible, as long as the composition of the water pollutants remains constant.

Common correlations:

COD chemical oxygen demand
TOC: total organic carbon
BOD. Biochemical Oxygen Demand



  1. In surface water, the natural organic load can be very variable, so its detection online can be very important, to optimize its treatment and constantly ensure high water quality.
  2. Anticipation and reduction of disinfection by-products (SPD)
  3. Optimization of the consumption of flocculants and / or coagulants.
  4. Checking the operation of decanters.
  5. Status trends of activated carbon filters.
  6. In case of using UV disinfection, analyze the SAC 254, it allows to know the state of the disinfection

Organic load control in drinking water – First part

Objectives that we will develop in this article on organic load control in drinking water:

  1. Improved identification of possible organic pollutants at the plant entrance
  2. Improvement of the efficiency in the addition of chemical products in the coagulation-flocculation process
  3. Early detection of filter saturation by activated carbon.
  4. Decrease in energy consumption in the control of UV disinfection and increase in lamp durability.
  5. Water storage: ensure the quality of drinking water by continuously measuring the
    organic pollutants before distribution.

What is organic load?

Drinking water comes from very diverse sources, such as rivers, lakes, aquifers and reservoirs, and usually contains natural organic matter (humic, fulvic, tannic acids, etc.). Thus we can define the organic load as the content of carbon compounds in an effluent. Said carbon compounds are chemical structures where carbon is bound to hydrogen and other elements such as sulfur, oxygen, nitrogen, phosphorous and chlorine, etc. There is no single structure and the number of carbon atoms can vary from one, as in the case of methane, to millions, as in DNA.

Imagen 1: F. J. Stevenson: Humus Chemistry. Genesis, Composition, Reactions. 2. Auflage . John Wiley and Sons, New York (1994)

One of the main objectives of the drinking water treatment process is to eliminate these dissolved organic substances.

How do we measure organic load?

From Matelco we propose you the AMI SAC254 analyzer, from the Swiss company SWAN ANALYTICAL INSTRUMENTS, it monitors dissolved organic matter by UV absorption at 254 nm (Based on DIN EN 38404-4) since many organic substances absorb UV light at that length cool. This allows an accurate analysis of trends in the concentration of organic matter, facilitating the quality control of drinking water with greater security. Thanks to its simplicity of use and low maintenance, the AMI SAC254 analyzer is an ideal solution for on-line control of organic load.


Technical characteristics:

  • AMI transmitter in IP66 aluminum box
  • Overflow flow cell, with adjustment valve
  • Flowmeter photometer
  • Low maintenance and easy handling
  • Factory pre-calibrated and ready for use
  • Measurement range: 0,05 a 60 Abs m-1
  • Variable optical path length 10 to 100 mm to adjust the measurement range
  • Measurement time: 1 min
  • Optional cleaning module, by adding chemical agents, to prevent biological growth in the flow cell and photometer. Cleaning frequency controlled from the transmitter


Applications in water treatment plants (ETAP)


Water intake


Installing the AMI Sac at the entrance of the ETAP allows us to:

  • Monitoring of changes in the organic load of raw water for trend analysis.
  • Early identification of organic contaminants for immediate handling and adjustment of the process.

Example of measurement of river water after the first filtering where a significant peak is detected after a strong storm.

In the next installment we will continue to look in detail at the other applications.

If you need to resolve any doubt or question you may have about this analyzer, you only have to fill out the form on our website and one of our experts will contact you as soon as possible.

For the quality ISO 9001:2015

Gestión de la calidad según la ISO 9001:2015

More than 20 years in Matelco implement the management system ISO 9001 . It was 1997, and the goal was to increase customer satisfaction while unequivocally demonstrate our ability to deliver products and services according to their expectations.

Time has passed. Changes have happened, advances, there are new needs of our customers, and Matelco continue to work with the main objective of maintaining the ISO 9001: 2015 . So we continue analyzing, reviewing and improving our processes to find new ways to remain efficient and provide better and optimal service to our customers.

In this regard, we have worked Matelco seven principles of quality management , perfecting and improving them, which are as follows:

  1. Customer focus: to understand their needs and expectations, and dedicating resources to learn more about how to meet them .


  1. Leadership: creating the conditions for people to get involved, guided by the same objectives.


  1. Commitment of people working in Matelco: committed at all levels is essential to enhance their ability to create and deliver value to the organization.


  1. Process approach: streamlining the functioning of MATELCO, optimizing our processes to achieve better results.


  1. Continuous improvement at all levels of the organization, setting new goals and objectives that conduct a significant improvement steadily.


  1. Making decisions based on analysis and evaluation of data in order to get the best conclusions and actions to follow.


  1. Managing relationships with our customers and suppliers. Because we greatly appreciate your feedback, we listen to each and every one of your requests, applications and suggestions for improvement.


Thus in Matelco we remain committed to quality, implementing the new ISO 9001: 2015. Involving each and every one of our employees, strategies, actions and visions of MATELCO. Implementing continuous improvement in all our areas. This is our commitment to customer satisfaction.

The First IN SITU Hydrogen Analyzer in the World

Anlizador de hidrógeno

Hydrogen control IN-SITU was considered impossible. Never more!

First in the world, NEO Monitors ( developed the solution for measuring hydrogen in situ, using the TDLS (Diode Laser Absorption Spectroscopy) method. The underlying technology has already been used successfully in many industrial applications.

Our new product, LaserGas ™ II SP H 2 , opens horizons to new opportunities in process control with an exceptional response time. And even more: the cost of control is significantly reduced compared to traditional methods.


Fig. 1 LASER SP GAS II (in-situ)

LaserGas ™ II SP H 2 with LaserGas ™ II MP H 2 , an extractive solution MULTI-PASS for applications where more sensitivity or where an in situ solution is not feasible required.


Fig. 2 GAS LASER II MP (extractive)

– The CEO of Neo Monitors, Gorm Ketil Paulsen says: “We’ve been working toward this moment for years, building step by step. It was an almost impossible goal but we made it! ”

The hydrogen molecule (H 2 ) it has been long considered as nonabsorbable in the infrared band. This theory was incorrect and, by redesigning our analyzers , we have achieved an unprecedented sensitivity absorption minimum levels required in a hydrogen analyzer.


“Our new scanner is the perfect solution for a wide variety of applications and, in turn, opens up opportunities for better process control flows of reagents, toxic and corrosive gases,” said Paulsen.


Real – time measurement .

Our new solution for the measurement of hydrogen in-situ , can be applied to any chemical plant or refinery, wherever it is. The industrial sector of gas and oil and other chemical producers will benefit from real – time measurement of hydrogen levels.

LaserGas ™ II SP and MP H 2 we provide control and monitoring of the concentrations of hydrogen with a response time of less than 2 and 20 seconds, respectively. The solution maintains all the advantages of technology LaserGas ™ , proven, flexible and reliable. LaserGas ™ II SP and MP H 2 can detect leaks and increase the efficiency of control processes increases safety.

– LaserGas ™ II SP and MP H 2 ensure us free operations management problems for both refineries to chemical plants, thanks to its quick response and minimal maintenance they require. Our new analyzers can be used to detect leaks, improve process control and a wide range of other applications where continuous monitoring is necessary and accurate hydrogen. Ultimately, LaserGas ™ II H 2 may be the direct reason why accidents are prevented, as detailed Paulsen.

The LaserGas ™ technology has no zero drift, you have the option to control the good performance of the laser and does not require any consumables, which means that the maintenance cost is very low for our new analyzers.

Most LaserGas ™ II SP and MP’s analyzers include:

• Control of H 2 In situ and extractives
• Detection of H 2 in open spaces
• Applicable for complex matrices gases and variables.
• No field calibration is required.

Ask us any questions about the operation of these analyzers and solutions for measuring hydrogen in situ, and our team of experts in analytical gas will advisetechnically to give the most appropriate solution.

Prevention of legionellosis in industrial facilities from water analysis

  1. Legionella
  2. Major outbreaks of legionella infection
  3. The importance of preventive measures against legionella



It is a bacteria present in surface waters such as rivers, lakes and ponds. Since these natural reservoirs bacteria happens to colonize supply systems of cities, and through the distribution network water is incorporated into healthcare systems water (cold or hot) or others that require water to operate and can generating aerosols.

These are usually facilities that sometimes favor water stagnation and accumulation of products that nourish these bacteria, such as sludges, organic material, corrosion material and amoebas, forming a biolayer newly.

At certain temperatures, this biofilm favors the multiplication of legionella turning it into a source of infection for humans. Especially if a producer mechanism reaches aerosol, where bacteria can spread and for people to become ill when inhaled with contaminated aerosol.


Major outbreaks of legionella infection

Facilities identified as a source of infection most common forms are:

  • Systems hot water: mains and tanks, accumulators, boilers, heaters,
  • Domestic cold water systems: mains and tanks, accumulators, tanks, cisterns, tanks, wells …
  • Cooling towers
  • evaporative condensers
  • Air conditioning ducts
  • Respiratory therapy as respirators and nebulisers
  • humidifiers
  • heated pools, with or without movement
  • thermal baths
  • Decorative fountains
  • Irrigation systems
  • firefighting equipment
  • Cooling elements outdoor aerosolization
  • Other devices that can collect water and aerosolizarla


The importance of prevention and control of legionella in industrial installations

Measures to prevent legionella focus on avoiding conditions favoring colonization, proliferation and dispersed, such as temperature, water stagnation and accumulation of substrates.

In April 2017, the CTN 100 AENOR UNE 100030 updated on the criteria to be considered for the prevention and control of bacteria legionella at certain facilities and equipment located in buildings, to avoid the risk of legionella infection; a disease that can be fatal.

These criteria are focused on proper maintenance of the elements of each installation, eliminating and reducing the dirty areas that can serve as food for bacteria by water treatment. A daily tasks installation according to control levels of free chlorine, pH, turbidity, conductivity, and biocide in a representative number of installation points.

In this regard and in order to provide antimicrobial protection, Matelco has portable chlorine analyzers continuously measuring free chlorine, combined chlorine and total chlorine and turbidity analyzers, conductivity … .garantizando the required level by regulations.

Because health is first.