This bacterium has plagued plant growers for years and up until now the only option was chemicals. Chemicals are not necessarily bad when kept in check. However, this is very difficult to do when you have thousands of acres of plants that need water often. The EPA has started to enforce laws for the use of chemicals due to the fact they wind up in our rivers, lakes and our underground water supply. This being said, there is an alternative for killing this pathogen: ultraviolet light. UV rays have a killing effect on microorganisms. UV light is selectively absorbed by nucleic acids (DNA, RNA) in organisms, resulting in genetic and physiological damage. Absorption is maximal at approximately 254 nm, and UV damage to cells is a well-known process, leading to skin cancers in humans. All cells possess chemical repair mechanisms that can correct the damage to nucleic acids caused by UV. However, very high exposure doses will exceed the repair capacity of cells, leading to physiological disruption and death. Exposing zoospores of Phytophthora to emissions from a low pressure UV for as little as 5 seconds can cause a 100% mortality. The dose of radiation required to kill a particular microorganism is generally expressed as mJ/cm2 and is the product of radiation intensity and exposure time.
UV light is active against fungal and bacterial pathogens once the water to be treated is sufficiently clear to avoid UV quenching. Thus, UV is best suited to situations where the water supply is either clear of organic matter and turbidity or cleaned of debris prior to treatment, such as a pre-filter before the UV. The latter is the most common way to use UV.
Advantages
- Low capital outlay
- No residual run off
- Generate UV on site
- Does not effect PH
- Short treatment time
- Continuous flow systems
- Easily maintained
- Cost effective to operate
- EPA loves it
- Complete pathogen control
- Heavy-duty commercial equipment
- Years of use