Irrigation water includes water required for the growth of crops both outside and indoor in more controlled environments. Sanitisers are often used in controlled irrigation systems to prevent the introduction of pathogens to crops.
There is a lot of pressure on surface-water and ground-water resources from agriculture. Irrigation water for use in outside agriculture represents a major use of water, which often means that irrigation waters are of marginal quality and require disinfection prior to use. Therefore, the source of water and often the season (rainy vs. dry) plays an important role in the quality of the water and disinfection requirements.
Various methods are available for irrigation water disinfection, including chlorine, chlorine dioxide and peracetic acid (PAA).
Chlorine is a low-cost and readily available sanitiser for the use in horticultural and hydroponic systems. However, monitoring pH is important to ensure the most effective chlorine speciation.
Chlorine dioxide is an effective sanitising agent and is used to remove established biofilm is damaging to the wider system. A low concentration can be applied to inhibit algae and diseases. However, it has high reactivity in the presence of high organic loads and is known for reacting with iron and manganese to form particulate solids.
PAA products can be used for sanitation of greenhouse surfaces, shock applications for tanks and piping, continuous application at a low concentration, and also as a bactericidal or fungicidal application to plant foliage or roots.
Many local regulations require validation of disinfection for irrigation systems, but monitoring disinfectants is also critical to deliver high standards of safety, efficiency and quality.
Ensuring that the correct concentration of sanitizer is important to successful operation of the system. Many process control and HACCP procedures will prescribe the concentration and type of sanitiser to be used, which will need to be recorded and acted on accordingly. Too much sanitiser may affect the crops, whilst too little will not reduce the microbial or algal load in the water.
Some sanitisers can cause damage to crops when dosing is too high, whilst dosing levels too low can be ineffective and lead to contamination of produce.
Kemio Disinfection tests for chlorine, chlorine dioxide, chlorite and PAA on one instrument; enabling producers to use multiple sanitisers if necessary. A truly simple operation with on screen instructions and results in 1 minute, Kemio is helping to improve safety and efficiency in many global food and beverage companies. Find out more here.
Kemio uses the same technology to the sensor technology range, but the calibration method is different. Kemio sensors may give a result on your instrument, but it will not be accurate, as it is using the wrong batch information.
Check standards are used to determine if an instrument is still within calibration.
Photometers work by sending light through the sample, check standards for these instruments are usually either Coloured Solutions or Neutral Density Filters (NDF). Both types have known and certified transmittance or absorbance values so they should give these values when read in a photometer. To make the checking process even simpler some instruments will convert these to a parameter such as chlorine and give the value mg/L. The ‘target’ value is on the certificate supplied with the set of Check Standards.
Kemio and sensor instrument check standards verify that the instrument correctly measures electric signals. As with electrochemical sensors in samples, the instrument applies a voltage to the check standard and measures the resulting current. Check standards include verified resistors, which produce a consistent electric current. Kemio validates the measured current internally. Sensor instruments display the corresponding concentration value, which is compared manually to target values on the certificate supplied with the set of check standards. Check standard kits come with four standards to test across the measurement range.