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COD Analysis

PeCOD™ from

What is PeCOD?
Photocatalytic vs. Dichromate Method
Laboratory COD - the L100
Portable COD for field use - the F100
Real Time Online COD - the P100

PeCOD™

The new way to measure COD Saves time, reduces cost.

PeCOD™ COD Analyzers

What is PeCOD™?

Aqua Diagnostic has developed a unique patented technology, PeCOD™, that can directly measure photocurrent / charge originating from the oxidisation of the organic contamination contained in a water sample. 

The core of the technology is the PeCOD™ sensor, which consists of a UV-activated nano-particulate TiO2 (titanium dioxide) photocatalyst coupled to an external circuit. The high electrochemical potential of the TiO2 gives it a substantial advantage over the modest chemical potential generated by the dichromate method.

The sample is introduced into a microcell containing the sensor. The TiO2 is irradiated by UV light, and a potential bias is applied. The UV light creates a photohole in the TiO2 sensor with a very high oxidizing power (3.1V). Thus an oxidiseable organic in the cell can be oxidised (the chemical potential of the dichromate method is only 1.6V).

The PeCOD™ COD Analyser exhaustively oxidizes all oxidiseable organics, and counts the electrons that are liberated to provide a direct measure of equivalent COD.

PhotoElec

Photocatalytic vs. Dichromate Method
Accurate When Results Matter

Aside from the clear advantages of the PeCOD™ technology being faster, greener, safer, and significantly more versatile than the dichromate method, PeCOD™ is also more accurate across a broader range of organics. You can trust the results for plant optimisation and environmental performance.

The powerful oxidation potential of UV-illuminated TiO2 ensures that almost all species will be fully oxidized giving a true measure of COD. By comparison, the dichromate method is unable to correctly measure certain common organic species such as simple alcohols, carboxy acids etc., as is demonstrated in the independently published data below by Kim et. al., Analyst, 2000, 125, 1915-1918. (Note: ThOD = Theoretical Oxygen Demand)

       PhotoCat         Dichrom

 

Laboratory COD
L100

L100
The PeCOD™ L100 COD Analyser is a simple-to-operate COD analyser, ideal for the laboratory. Operation of the L100 simply requires pushing the “run” button, and the COD result is displayed minutes later, making COD analysis simple enough for everyone to do.

A choice of “rapid” or “precise” modes means results can be obtained in approximately 3 minutes or 6 minutes.

Operators no longer have to undertake potentially hazardous operations such as digesting samples with boiling sulphuric acid containing dichromate, mercury and silver salts (the “dichromate method” of COD analysis). PeCOD™ makes the laboratory a safer place to work, by eliminating the use of toxic and hazardous reagents in COD analysis.

Real User Benefits:

  • Low cost per sample improves laboratory operating costs
  • Simple reagent handling by avoiding the use of toxic/hazardous reagents; only an electrolyte is required
  • No hazardous waste disposal of reagents
  • Complete oxidation of organic species ensures high accuracy and reproducibility
  • Excellent chloride tolerance; even seawater samples can be analysed
  • Fast analysis (~ 6 minutes) increases sample throughput, and gives “real-time” data
  • Unmatched sensitivity for COD (sub-ppm)
  • Small footprint (235 x 375mm), minimum bench space
  • Simple to operate
  • Results can be reported as COD or BOD

Fast is good

For waste receiving stations, the analysis of incoming COD of tankers and drums means that the driver can be given a COD ticket at the time of delivery, and customers can be accurately charged for the COD of their waste.

BOD Screening; the excellent correlation between BOD5 and PeCOD™ COD, means that a BOD value can be estimated in minutes using PeCOD™.

 

Portable COD - for field use
F100
Fast COD in Minutes

The PeCOD™ F100 COD Analyser is a field portable unit.  It is a light weight, battery powered unit suitable for use in the field or in a factory, whenever on-the-spot analysis is required.
This unit is identical to the PeCOD™ L100 except for the additional battery pack and carrying case, allowing it to be used in the field or in the laboratory.

Real User Benefits:

  • Small size and light weight make it easy to transport and use in the field
  • No sample digestion is required, making it a truly portable technique
  • The only reagent required in the field is a bottle of electrolyte
  • No transport of toxic/hazardous reagents
  • Robust and rugged
  • Fast analysis (~ 6 minutes) means easy on-the spot checks of COD, e.g. for troubleshooting a
  • wastewater plant, or in tracing the source of high COD
  • Able to analyse a wide variety of matrices, including those with high chloride concentration (e.g. seawater)
  • Simple to operate
  • Results can be reported as COD or BOD

 

Real-Time Online COD
P100

P100

The PeCOD™ online COD Analyser provides real time online, accurate measurements to enable effective plant optimisation and performance.

The unique PeCOD™ technology enables reliable unattended operation.

Online COD monitoring is all about saving costs through process optimisation, and by avoiding costs due to unexpected COD excursions.

A waste stream from industry or an influent stream to a wastewater treatment plant (WWTP) will vary in COD load, often over quite short time periods. Only real-time monitoring assists the identification of sources of COD excursions which cannot be done when the COD results come back in 3 hours or even the next day.

For industries this means identifying and rectifying the sources of COD excursions. This avoids regulatory fines, and also assists in process optimisation.

For WWTP’s, monitoring the raw influent forewarns of increased COD load on the plant, enabling the WWTP to optimise the plant operation to that load. Direct online measurement of COD of influent to secondary stage treatment permits aeration to be optimised by feed-forward control (as opposed to feed-back with DO probes) and so avoids problems associated with unexpectedly high COD loads, or running aeration unnecessarily high “just in case” of a COD peak.

Aeration accounts for half the total energy consumed during aeration in secondary domestic wastewater treatment facilities using activated sludge. In a large treatment plant, even a few percentage points of energy saved this way can be significant in terms of cost.

Real User Benefits

Saves Money across applications

  • The system samples a sample stream, performs an automatic dilution, analyses the sample, and relays the result by telemetry to the customers control centre
  • Fully self-contained in a weatherproof stainless steel box, requiring only power, clean water and compressed air utilities
  • Automatic backflush (using compressed air and water) of the sample probe suspended in the sample stream ensures removal of any biomass or solids accumulation
  • The system offers completely automatic and unattended operation. The only regular maintenance required is to replenish the electrolyte solution reservoirs, and to periodically replace the sensor
  • The PeCOD™ on-line COD system is a true on-line COD measurement; It is not an approximation such as TOD and TOC
  • Typical sampling frequency of 15 minutes
  • Unmatched sensitivity for COD(sub-ppm)
  • The PeCOD™ technology’s complete oxidation of organic species ensures high accuracy and reproducibility of COD measurement
  • Excellent chloride tolerance; even seawater samples can be analysed
  • Simple reagent handling by avoiding the use of toxic/hazardous reagents; only an electrolyte is required
  • No hazardous waste disposal required for the reagents
  • Can be configured to monitor a second sample stream
  • Results can be reported as COD or BOD

 

 


 


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