FAQ's
Rainwater disinfection – UV is a reliable and cost effective way to purify rain water.
You need to use good quality rain water filters to remove suspended particles. Adequate rainwater filtration is important before the rainwater UV disinfection unit.
The rainwater UV unit should be sized for minimum UV dose >300J/m2 at the end of UV lamp life at the max flow rate of water. If you want to purify rainwater for drinking, we would recommend UV dose> 400J/m2 t the end of UV lamp life at the peak flow rate of water.
Remember, UVT of the water affects the UV dose. So please feel free to send us a 100ml sample of the water for a UVT check at no charge. You can find our address here.
Depending on your application, you can further specify other UV options e.g. UV lamp fail alarm, UV lamp change reminder, UV intensity sensor, UV intensity monitor, etc.
When water is stored in tank, it can attract bacteria and other microbes. Stagnant tank water can easily lead to biofilm formation in tanks. It is very important to clean the water tanks is regularly.
Please use a good quality tank water filter before the tank water UV disinfection unit. It is pointless to try to save money with a cheap filter. This is important to prevent suspended particles from shielding the bacteria from UV light.
Estimate the maximum water flow rate from the tank and select a tank water UV unit to deliver min. 30mJ/cm2 at the end of UV lamp life at the maximum flow rate.
For drinking water, we recommend UV unit sized for min. 400J/m2 at the end of UV lamp life at the maximum flow rate, as per USEPA and DVGW drinking water standards.
As UVT of the water affects UV dose, please feel free to send us a 100ml sample of the water for a UVT check at no charge. You can find our address here.
In one word – NO! Even when you clean a drinking water tank, the next tank cleaning provides no protection against the next bacteria to arrive with water entering the tank.
Moreover, as water is drained from the tank, fresh air enters the tank through tank lid and vents. Any airborne contaminants like molds, airborne bacteria and airborne contaminants enter the tank.
The combination of heat, bacteria and other microorganisms from water and airborne bacteria and spores form biofilm in drinking water tank surfaces.
The best protection is cleaning the water tank regularly and using a filter and drinking water UV system to protect yourself.
Contrary to popular belief, just installing a shiny looking UV water purifier is not enough!
Selecting the correct UV system requires consideration of many factors. Important factors to consider when sizing a UV lamp unit are: Peak flow rate, UVT of water, target microorganism, desired UV dose, source of water, end use of UV treated water, installation details and more.
Feel free to contact us for a quick chat with our experienced and friendly team about your application, or with any UV sizing questions.
UV dose the most critical factor affecting disinfection performance of a UV sterilizer.
In a plug flow UV reactor, UV dose can be calculated as
UV Dose [mJ/cm2] = UV intensity [W/cm2] x Residence Time [s]
This is the theory. In real life, UV water purifiers are not plug flow UV reactors.
So, we have to consider UVC irradiance and different paths likely to be taken by water particles as they flow through the UV reactor. We use specialized software to calculate UV dose through our UV reactors. In addition, we apply real world experience gained from a few thousand industrial UV disinfection applications in India and many international markets to calculate UV dose likely to be actually delivered.
If used incorrectly, UV light is dangerous!
If eyes or skins are exposed to UV light, it will very likely cause damage your eyes or skin.
Never look at an operating UV lamp and never operate a UV lamp outside of its intended UV system. Never expose your skin to UV radiation.
If you follow these simple precautions, UV light is very safe.
As a matter of fact, no bacteria, virus or other micro-organism has been found to be able to resist adequate UV dose so far.
UV light is not radioactive like gamma rays and will not cause any harm if you use UV treated water for drinking.
Yes, we certainly supply a wide range of UV lamps, UV bulbs, UV lamp units, UV ballasts, UV quartz tubes, UV sensors and several miscellaneous UV spare parts.
Importantly, we offer our extensive experience and expertise to solve UV applications.
We can troubleshoot most brands of UV units in the Indian market, including most imported UV systems.
Total cost UV disinfection is surprisingly low.
UV disinfection cost in most cases works out to a few paise per m3, depending on the type of water, UV dose required, peak flow rate and details of the application.
Team Sukrut would be happy to provide installation and long term operation costs for your particular application if you contact us with the details.
When sized and delivered correctly, adequate UV dose can destroy residual Ozone.
The high energy UV light breaks down bonds of Ozone molecules.
UV de-ozonation, or UV Ozone destruction is important for success of many industrial applications to prevent residual Ozone from interfering with industrial processes. It is common to measure Ozone concentration before and after the UV Ozone destruction unit to verify the Ozone disassociation.
We have extensive experience with Ozone destruction UV units in pharmaceutical, food & beverage, cosmetics manufacturing, ultrapure water and other industrial applications.
Our experienced Team Sukrut would be happy to discuss your particular application if you contact us with the details.
The oxidizing power of Ozone also leads to one of the major limitations of Ozone. It is possible to calculate the theoretical Ozone requirement for a given application based on the type and quantity of contaminants to remove. However, like many things in life, it is hard to accurately predict the amount of contaminants and type of contaminants as they vary with operational conditions, seasonal variations in water quality and the like. So we are left with either too much Ozone or too less Ozone.
If excessive Ozone is left in water after ozonation, it may interfere with downstream processes e.g. it may oxidize parts of a pharmaceutical formulations, kill fermentation bacteria in a brewery or be outright dangerous if excessive residual Ozone is left in potable water. The “safe limit” for residual Ozone depends on application.
While rainwater itself may be pure, by the time it is collected and stored in a tank, it is likely to collect contaminants including bacteria or viruses. If the water is stored for some time the bacteria can grow in stagnant water, causing biofilm. Bacteria also tend to grow in the pipeline and in some filters especially if the rainwater is used intermittently. Rainwater can generally be used safely after adequate rainwater purification process to suit the end use.
At a minimum, rainwater should be adequately filtered and disinfected with a sufficient UV dose to inactivate all bacteria and other potential microorganisms.
Details of the rainwater treatment will depend on factors like
- Rainwater collection
- Likely rainwater contaminants
- End use of the treated rainwater
- Frequency of use of rainwater
- Peak flowrate of the rainwater through UV unit, etc.
Drinking water comes from rain, wells, canals, rivers and lakes.
As the water flows through rivers, it collects many contaminants along the way. Incompletely treated sewage flows into rivers. All types of rubbish flows into drinking water. Rain water flows into rivers and lakes, bringing even more pollutants. Rain water finds its way into bore wells through cracks in rocks.
As a result, many types of bacteria, viruses, protozoa and other microbes pollute the water. Drinking polluted water causes many outbreaks of diseases like cholera, dysentery, polio, hepatitis and more. Drinking water pollution is the most common way for spread of contagious diseases.
Therefore, we must reliably disinfect water before using it for drinking or cooking.
Drinking water contains many types of pollutants. So, purification requires different processes.
Filtering water is the most basic and first step. A good water filter removes suspended particles. However, it doesn’t protect us from microbes like bacteria, viruses. This is because the microbes are much smaller than the pores of most filters. As a result, the microbes easily flow through the filter.
To make things worse, a common filter traps some microbes. The microbes then colonize the filter and start growing on the filter itself. The water flowing through the filter brings more food for the microbes.This is how slimy biofilm grows on water filters.
Some microbes escape with the filtered water into our drinking water.
We will look at this in another blog post shortly. Until then, if you have any questions, please feel free to contact us for more information.