Description

WHAT IS PERACETIC ACID?

Peracetic Acid is a powerful oxidant with an oxidation potential, used as a measure of disinfection effectiveness, greater than that of common disinfectants such as chlorine and chlorine dioxide. It is produced by the reaction between acetic acid and hydrogen peroxide when dissolved in water, and degrades over time forming non-toxic water soluble products. The free radical degradants (bug killing species); hydrogen peroxyl and hydroxyl have high oxidising capacities and are generally believed to destroy bacteria via the protoplasmic oxidation mechanism resulting in bacterial cell wall disintegration. The safe degradation pathway and high oxidation properties make paracetic acid a popular disinfectant for many applications and industries.

Chlorination of water can be achieved using three chemical mediums; chlorine gas, calcium hypochlorite and sodium hypochlorite, all of which have proved useful in many applications.

There are, however, several factors which affect their viability and all three mediums have safety concerns which must be addressed, including; potential gas release, corrosive properties and stability under heat and sunlight. As a result of this, sites often spend considerable amounts of time and money implementing safety precautions such as the safe generation and storage of these chemicals.

Furthermore, chlorine reacts with natural organic compounds found in the water supply forming potentially harmful disinfectant by-products such as Trihalomethanes (THMs) and Haloacetic acids (HAAs). The potential health hazards associated with exposure to these by-products, particularly THMs, have resulted in extensive drinking water regulations across the developed world with a stipulation on regular monitoring of these compounds across the water distribution system. As paracetic acid usage only results in non-toxic degredants, no further costs are incurred on instrumentation to monitor potentially harmful residuals or by-products.

Although peracetic acid does still have some safety considerations, as with all disinfectants, it is widely accepted that storage, generation and stability is superior to using chlorine.

HOW THE SENSOR WORKS

The membrane amperometric paracetic acid sensor is a two electrode sensor which operates at an elevated applied potential, which eliminates zero drift. Its unique design means that no reagents or buffers are required at all and calibration is a simple point (no zero required) operation.

In applications such as pulp and paper food preparation and waste water, where there is likely to be a build up of solids in the sample, the ORAKEL peracetic acid sensor can be equipped to automatically clean itself at regular intervals with all the benefits of no operator intervention.

APPLICATIONS

Anywhere you have a requirement to measure residual CHз,COзH is a suitable application for the ORAKEL peracetic acid sensor. It is particularly suited to working in sites where reliability and ease of use are most important. Conductivity acids can be tolerated but the water must not contain any tensides.

• Peracetic acid dosing control
• Rinsers
• CIP plants
• Bottle washers
• Sea water
• Drinking water

PRODUCT SPECIFICATION

Type:Membrane covered, amperometric two-electrode system
Range:0-200mh/l, 0-500mg/l, 0-2000mg/l, 0-5000mh/l, 0-10000mh/l
Resolution:0.1mg/l, 0-1mg/l, (ppm) depending on the probe range
Reproducibility:<1%
Max working pressure:0.5 bar, no pressure impulses or vibrations
Flow rate:Approximately 0.5l/min (min 0.25l/min), small flow rate dependence is givenTemperature range:0 45°C (no ice crystals in the measuring water)
Temperature compensation:Automatically by an integrated temperature sensor
pH range:pH1 up to pH6
First-polarisation time:Approximately 60 min
Re-polarisation timeApproximately 15 min
Response timeT₉₀: approximately 180 seconds
Zero point adjustment:Not necessary
Calibration:At the device, by analytical determination
Housing material:PVC, stainless steel
Dimensions:Diameter approx. 25mm, length 190mm
Maintenance intervals:
Membrane: 12 months (depending on water quality)
Electrolyte: 3-6 months (depending on water quality)
Interferences:CI₂ does not interfere. O₃ is measured with a sensitivity of 2500 times. CIO₂ is also measured. Hydrogen Peroxide is measured with a sensitivity of 0.005 times. >1% Suphuric, Nitric or Phosphoric acid.