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On-Line Chemical Oxygen Demand (COD) monitoring

COD monitoring plays an important role when it comes to environmental and process water applications.  COD can be determined in the laboratory and on-line using various methods which differ significantly in the required analysis time and consumables and reagents used. 

Our LAR QuickCODultra Analyser system uses the Thermal Combustion Method where the sample is completely oxidised at 1200 degrees C.  With this method, the COD values are determined without correlation factors as the Analyser system monitors the amount of oxygen consumed during oxidation using a ZrO2 detector.    

With this method, NO REAGENTS are required, and results are available in 1-2 minutes.  Making this a truly RAPID COD Analyser system, perfect for on-line applications.  This Analyser system can handle particles and has a maintenance free sample preparation unit which means a representative sample will be monitored at all times. 

Recently a QuickCODultra Analyser system was installed on a blend tank in a process plant.  The results generated by the QuickCODultra Analyser was compared to the results on the same samples analysed at the plant laboratory.  The trend speaks for itself.

COD Result comparison



  • Measurement Range: 0.1 - 200 000mg/L COD
  • Method: Thermal Oxidation at 1200 degrees C
  • ASTM Method
  • Analysis Time: 1-2 minutes
  • No Reagents
  • Individually programmable user levels
  • Serial Interface: RS232
  • Analog Output: 0/4 - 20mA
  • Remote Control: Through TCP/IP Protocol
  • High resolution and back lit TFT touchscreen graphic display
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Cooling Water Monitoring with our ChemScan Analyser Systems

Cooling water, regardless of its source, contains various constituents.  These occur in different concentrations. 

The water quality will impact the operation of the cooling towers.  Equipment scaling, corrosion and fouling are some of the concerns. 

Our ChemScan® Analyser systems offer a wide range of analytical methods to cover important monitoring parameters for this applciation:

 ChemScan UV

 Important Water Quality Parameters:

  • Alkalinity
  • Ammonia
  • Chlorine
  • Copper
  • Hardness
  • Iron
  • Nickle
  • Ntrates
  • Nitrites
  • Organics
  • Zinc
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Rapid BOD Monitoring in Waste Water Treatment

BOD5 Measurements are internationally standardised, and the method is widely used in laboratories.  Due to the long incubation times required to perform this classic method, using BOD5 for timely control and monitoring of waste water, is not practical. 

With our LAR BioMonitor Analyser system, it will detect rapid changes in oxygen demand and with a response time of 3 - 4 minutes.  This Analyser system rapidly measure the total BOD including the oxygen demand for the nitrification as well as the activated sludge respiration (ASR).

Measurement Principle Explained:

Biomonitor Method

1) Measurement results are displayed on the Analyser screen (human interface). 

2) The aerated mixture of activated sludge and sample is pumped through the four reactors.  The O2 sensor determines the oxygen consumed during decomposition. 

3) The activated sludge is aerated and its respiration is determined (ASR). 



  • Measurement Range: BOD: 1 - 50 mg/L ; 1 - 200 000 mg/L and ASR: 0 - 5 mg/L/min
  • Method: Continuous 2 stream respiration measurement
  • Response Time: 3 - 4 minutes
  • Individually programmable user levels
  • Serial Interface: RS232
  • Analog Output: 0/4 - 20mA
  • Remote Control: Through TCP/IP Protocol
  • High resolution and back lit TFT touchscreen graphic display
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NEW QuickTOCuv Analyser System

Introducin our NEW QuickTOCuv Analyser system. This Analyser offers conitnious measurement of Total Organic Carbon (TOC), Total Carbon (TC) and Non-Purgeable Organic Carbon (NPOC) with the capability of correlating the Biochemical Oxygen Demand (BOD) and Chemical Oxygen Demand (COD)

LAR QuickTOCuvII left

For technical specifications, Contact Us or Visit

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Monitoring Dissolved Oxygen (DO) in water

Dissolved Oxygen (DO) Monitoring

Our range of  LAQUAact Handheld Dissolved Oxygen (DO)  meters offer state of the art portable systems that can be used for laboratory and field applications. 

Rugged design—but easy to use and dependable.


  • Measures dissolved oxygen (DO) concentration in ppm (mg/L) or % saturation - 0.01 mg/L or 0.1% resolution
  • Compensates for sample salinity and temperature and atmospheric pressure 
  • Auto log data; Built-in memory can store up to 1000 data points
  • Auto-shut off (programmable: 1 to 30 minutes)
  • Auto-Hold / Auto-Stable measurement
  • Large backlit LCD: 52mm x 64mm
  • RS232 for connecting to computer and printer
  • Casing is IP67 waterproof (for 30 mins immersion in 1m depth of water) and dustproof
  • Powered by 2 x AAA (LR03) or Ni-MH batteries or power adaptor
  • 2 years meter warranty
  • Carry case

Carry case with all accessories are included:

 Horiba LAQUAact carry case  om 71

For further product information or to request a quotation, please contact us

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Measuring Salinity of Water

Measuring the salinity or dissolved salt content of water is important as aquatic organisms, livestock and crops thrive at different salinity levels.  Freshwater has a salinity value of less than 0.5 ppt while seawater has an average salinity of around 35 ppt.  

 LAQUAtwin Salt EC

Salinity is the measure of the amount of dissolved salts in water.  It is usually expressed in parts per thousand (ppt) or percentage (%).  Within an estuary, the salinity levels are referred to as oligohaline (0.5 - 5.0 ppt), mesohaline (5.0 - 18.0 ppt) or polyhaline (18.0 - 30.0 ppt).  Near the connection with the open sea, estuarine waters may be euhaline, where salinity levels are the same as the ocean at more than 30.0 ppt.  

Salinity varies from place to place in the ocean, but relative proportions of most major dissolved constituents remain virually constant.  

Salinity is often derived from Electrical Conductivity (EC) measurements.  EC is measured by passing an electric current between two metal plates or electrodes in the water sample, measuring how readily the current flows between the plates.  The use of EC measurements to estimate the ionic content of seawater led to the development of the Practical Salinity Scale 1978 (PSS-78).

The PSS-78 has been considered by the Joint Panel on Oceanographic Tables and Standards and iis recommended by all oceanographic organisations as the scale in which to report future salinity data.  

The LAQUAtwin Salt 11 Pocket Meter measures the conductivity value of a sample then converts it to a salinity value based on the salinity standard curve selected.  The sensor has two titanium metals coated with platinum black that resist corrosion and a temperature sensor for accurate measurements.  The meter is programmed with two standard calibration curves - sea water and sodium chloride (NaCl).


Calibrate the LAQUAtwin Salt 11 Pocket Meter according to the instructions provided with the instrument, using the 0.5% (5 ppt) and 5.0% (50 ppt) NaCl Standard Solutions included in the kit. 

Prior to calibration, make sure to select the standard calibration curve (either NaCl or Seawater) and the unit (either % or ppt) depending on your application and reporting unit requirements.  If both the sea water curve and ppt unit is selected, calibrate the meter with the 5 ppt NaCl standard.  It is best to use 5 ppt and 50 ppt seawater standards if available. 

Sample Collection and Measurement

Place drops of water onto the sensor using the pipette which is included in the kit. Make sure the sample sell is completely filled-up with sample and that there are no bubbles formed.  Record the salinity reading once it is stable. 

Before testing another sample, rinse the sensor with DI (Distilled or Deionised) Water or with the next sample to be tested, and dab a soft tissue to remove the remaining water trapped inside the sample well. 

Results and Benefits

Salinity is an important measurment in seawater or in estuaries where freshwater from rivers or streams mixes with salty ocean water as aquatic organisms have varying abilities to survive and thrive at different salinity levels.  Saltwater organisms survive in salinity levels up to 40 ppt, yet many freshwater organisms cannot live in waters with salinity levels above 1 ppt. 

Salinity affects the dissolved oxygen (DO) levels in water.  The solubility of oxygen in water decreases as salinity increases.  The solubility of oxygen in seawater is about 20% less than it is in freshwater at the same temperature. 

For a copy of the full Application Note - Measuring Salinity of Water, please contact us

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Microtox FX Toxicity and Bio-contaminant Analyser

Portable / Laboratory Toxicity and Bio-contaminant detection

The Microtox FX Analyser system can perform a dual function; Toxicity Testing and Microbial Monitoring.  The Microtox FX system uses a strain of naturally occuring luminescent bacteria called Alivibrio Fischeri to provide acute toxicity detection.  The bacteria emit light as a natural part of their matabolism.  Exposure to a toxic substance cuases disruption of the respiratory process of the bacteria resulting in a reduced light output. 

For microbial detection, ATP testing is performed.  All organisms contain ATP (Adenosine Triphosphate) as their main energy source.  The amount of ATP in a sample is directly proportional to the biomass of the sample.  ATP reacts with luciferin/luciferase, the enzyme system present in firefly tails, to produce light.  In the reaction, each molecule of ATP produces one photon of light.  The light output of this reaction can be accurately measured using the Microtox FX Analyser system. 

 For any product information or to request a brochure, please contact us

Microtox FX


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Stories of Gold

Stories Of Gold

Gold Analysis was undertaken for a client who wanted to determine level of gold in their final effluent.  As they were refining gold, they needed to ensure that the gold levels in their final effluent was kept as low as possible.  You basically do not want your product to go down the drain.  

The instrument used to do this analysis was the PDV6000ultra.  This instrument was installed in the laboratory for this determination, but can also be used as a portable analyser in the field.  The system runs on VAS software when connected to a PC (the software is supplied free of charge to all users of the instrument).    


Case Study

A sample was collected from the site.  The sample appeared water like with a fine black suspension settled at the bottom.  The pH was very acidic at pH 0,65.

The sample was scanned and immediatly saturated the system with a huge Au signal, obvious sample dilution was required.  

A x10 dilution was employed and read directly against a pure standard.  

The picture below is a screenshot from the VAS Software.  The blue line is the sample resonse, the red is the Au Standard response: by simple peak height comparison the result generated an initial value of 30,94 mg/L (ppm) Gold.

Voltammogram of a x10 dilution sample compared to a Au (Gold) Standard:

Gold VA Results

Now that the sample was quantified, 3 standard additions were performed with the same Au Standard on this sample aliquot and the final resulting value was obtained through linear regression:

Gold STD Add

Gold value = 28,89 mg/L (ppm) 

Correlation Coefficient = 0,997357

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Modular Design Mobile Laboratory

New Modular Design Mobile Laboratory

Analysers On-Line has built a new Mobile Laboratory combining both Bench systems and On-Line Analysers. The Station is modular in its basic design and can be optimised as required to perform analysis in the field for acid mine drainage (AMD), spill detection or environmental monitoring as some typical examples.

The company has a whole array of suitable equipment for use in the Station or external equipment can be sourced, all enquiries are welcome.

The Station is complete with a suitable pump to provide a fast flow loop if real time monitoring is required. There is a built-in water reservoir and sink for washing purposes. The Mobile Station design is a proven one based and improved on our previous field designs featuring improved insulation and storage facilities.

As the name implies the Station is completely mobile and roadworthy for easy movement to site to site as required by the user’s program of test work. 

AOL mobile

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Mobile Laboratory Monitoring

Mobile Laboratory Monitoring 

Since 2013 the MOSA Mobile Laboratory has been successfully used in the field in various projects. With the use of suitable sampling devices, sample monitoring can be performed on-line or at-line. With on-line monitoring the sample water in a river or dam can be monitored 24/7 which allows for trend monitoring and a true picture of any discharge present to be assessed.

This specific Mobile Laboratory is equipped with LAR Instrumentation to monitor on-line a variety of water quality parameters such as TOC, COD, free ammonia, nitrate, pH, conductivity, redox and toxicity. Other additional bench parameters such as phosphate, sulphate and water hardness were also determined in the Station.

During one of these projects, the Mobile Laboratory was used to assist our German partners in monitoring water quality in the influent and effluent water from a mobile WWTP which enabled them to make the timeously adjustments to their plant.  

For another project, the Mobile Laboratory was used to monitor on-line water quality of a river inlet feeding a WTP. Other water samples of tributary streams and a WWTP in the area were also analysed successfully and the data obtained could be assessed and reacted on immediately.


For more information on our mobile laboratory offerings, please contact us

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Trace Metal Monitoring

On-Line Trace Metal Monitoring

Modern Water's Monitoring Division has recently delivered that division's single largest order to date, a purpose-built containerised trace metal monitoring system in the Middle East for a multinational company. To read the full press here


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The clean COD determination in the laboratory. Chemical-free.

QuickCOD lab Clean. Fast. Accurate.

The clean COD determination in the laboratory.

The environmentally friendly COD analysis.

You can now determine chemical oxygen demand quickly, cleanly and safely with the right measurement procedure – without any chemicals.

Chemical oxygen demand (COD) is one of the most important sum parameters in water analysis. It is considered as a reference for the organic
load of waste water, both in the industrial and municipal sectors. In general, analytical processes are based on the use of different reagents.
However, the safe and environmentally friendly procedure is thermal oxidation.

What COD means. Relevance and versatility.

Chemical oxygen demand (COD) describes the amount of oxygen that is needed to chemically oxidise organic compounds in water, using an (often environmentally dubious) oxidant. The aim is to determine the demand for oxygen, which is primarily required to oxidise organic matter.
This oxygen demand is relevant for the planning, control and cleaning efficiency of waste water treatment plants, as well as a basis for the calculation of sewage charges.

COD measurement methods. Still up-to-date?

The standard potassium dichromate method (DIN 38409 H41-H44) dominates the market. It is also available in a modified form as cuvette tests
(DIN ISO 15705:2003). Here, potassium dichromate is used as an oxidising agent, silver sulphate as a catalyst, as well as sulphuric acid. Mercuric chloride is also used to mask chloride interferences. This risky chemical cocktail is heated after the aqueous sample has been added, and then simmered for approx. two hours. The oxygen demand is calculated from the concentration of residual dichromate. The high consumption of hazardous substances has long been the subject of lively debate.

Contact us to arrange a demonstration or for further product information

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Problems with Algae or Algal Toxins?

Nutrient pollution in surface waters can cause algae to increase to potentially harmful levels.  Algae deplete oxygen and certain species of blue-green and red algae can be poisonous to aquatic life.  

Modern Water's algae and algal toxin detection technologies provide fast, accurate and quantitative results. 

Parameters Detection Range
Modern Water Product Selection
Chlorophyll a  0.1 to 100ppb AlgaeChek Ultra - Fluorometer Probe
Phycoerythrin (Red algae) 0.1 to 100ppb AlgeaChek Ultra - Fluorometer Probe
Phycocyanin (Blue-green algae) 0.1 to 100ppb AlgeaChek Ultra - Fluorometer Probe
Cylindrospermopsin 0.1 to 2.0ppb  ELISA plate EnviroGard

0.3 to 5.0ppb

0.1 to 1.6ppb

 ELISA tube EnviroGard

 ELISA plate EnviroGard

Okadaic Acid 0.2 to 5.0ppb  ELISA plate EnviroGard
Neo-Saxitoxin 0.03 to 1.0ppb   ELISA plate EnviroGard
Nodularin 0.04 to 1.0ppb  ELISA plate EnviroGard
Brevetoxin 0.1 to 2.5ppb  ELISA plate EnviroGard
Saxitoxin 0.02 to 0.32ppb  ELISA plate EnviroGard


Modern Water’s combination of plate and tube test kits offer high sensitivity, quick results and detect a variety of algal species. These immunoassay methods offer a cost-effective solution for high throughput sample testing. A yield of up to 80 samples can be achieved per 96-well microtiter plate, depending on batch size.

Process Explained

Different molecules absorb and emit light at specific wavelengths. In order to effectively use Fluorometry as a tool for environmental
analysis, the specific wavelengths of the absorbed and emitted light for the target molecules/compounds needs to be known. Modern Water fluorometers use LED light source to excite the molecules and then measure the emittance at the desired wavelength. The intensity of the emitted light provides the concentration of the target compound.

Immunoassay Kits (EnviroGard)
Immunoassay is an analytical method which uses an antibody as a reagent to quantitate specific analytes. The technique incorporates
the binding reaction of a target substance (antigen) with an antibody.

• Toxin-specific kits
• Use in field and lab
• Low-level detection
• Early warning before harmful levels are reached
• High sensitivity
• Rapid detection
• Easy to use
• Robust

For further product information or to request a brochure, please contact us

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Salt in Industrial Waste Water

Dissolved salts in water can be particularly challenging for On-Line Analyser systems.  With our LAR Process Analysers, we have an innovative method to deal with these challenges in the industrial environment.

Salts are used as primary products, processing material as well as final products in many industries.  Generally salts can be devided into organic and inorganic salts and most are soluble in water.  

Chemical Oxygen Demand (COD) and/or Total Organic Carbon (TOC) monitoing in many industries are regulated by law or required by the company itself. So the monitoring of these parameters when high salt concentrations are present, can be a huge challenge and historically Analyser systems tend to block up and require many hours or maintenance to clear these blockages.  

With our LAR Ultra Analyser system, high salt concentrations can easily be dealt with in the industrial environment with minimal maintenance.  Our  system works on the Thermal Combustion method with a very high furnace temperature of 1200 degrees C.  Any Analyser system using temperatues of 680-1000 degrees C requires catalysts to improve their oxidation potention because the temperature in the reactor is not homogeneous.  With our high temperature combustion (1200 degrees C), the temperature exceeds the melting point of common salts.  The sample will be completely oxidised and therefore no salts remain in the reactor.

The LAR Process Analyser system with the patented oven operation, is capable of handling high salt applications with ease.  High salt concentrations of up to 300g/L NaCl (30%) are easily handled by the robotic arm system and special high salt option.  So no additional sample dilutions are required on these Analyser systems.  

For further information on these systems please contact us 

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 +27 (0)11 827-0370