UV disinfection for sea water entering RO system
UV disinfection for sea water entering RO system
(OP)
HI all. We are currently bidding for a big (at least for our company) size RO sea water desalination plant, 60.000 m3/day with 45% recovery i.e. the inlet sea water to the plant is 5555 m3/hr, and this water has to be disinfected before the filtration + RO membranes. We are used to dose NaOCl as disinfection method, but we are worried about the operating costs for such plant (running is also within our scope of work)and huge amounts of chemicals required. So i was fancying about UV sterilization. Apart from installation costs and power consumption, which is low compared to the other plant systems, do you have any feedback about existing plants, drawbacks, problems, etc. with using such technology instead of typical chemical dosing? Thank you in advance for support and wishes of happy new year to all!
Andrea
Andrea





RE: UV disinfection for sea water entering RO system
Probably the following site may be of help:
ht
RE: UV disinfection for sea water entering RO system
Have you thought of generating NaOCl from NaCl? Once you buy the equipment then you have to evaporate sea water
I wish us all A Happy and Prosperous New Year
RE: UV disinfection for sea water entering RO system
I would suspect you would be better off with a low pressure mercury arc system, even though this will mean large numbers of lamps, because the medium-pressure mercury UV units generate a greater fraction of their light below 254 nm where seawater may be unproductively absorptive.
The absorptivity of seawater to 254 nm light may not be the biggest problem. The potential for fouling of the lamp sheaths has to be considered and dealt with by design.
RE: UV disinfection for sea water entering RO system
he referred to a light transmittance of 90%, but i guess this should be more a parameter HE fixes on the basis of my water characteristics, rather an input value I should give him. What is your opinion?
RE: UV disinfection for sea water entering RO system
I recommend using the vessel with internal electrodes as opposed to using the pipe as one of the electrodes. I have experience of the pipe rupturing in the later case.
In the past I have seen the effectiveness of uv sterilisation improved by using a "water bell" over the uv lamp. This was at the research phase when I saw it but believe that it has been implemented in industry. The bell is formed by impacting the water onto a plate and a thin skin of water forms a bell that is stabilised by an internal pressure (air). The advantages are no contact with uv lamp and a thinner film of water reducing the absorption by solids etc.
RE: UV disinfection for sea water entering RO system
For a UV light system that does not use a traditional lamp, and you must wear a welder's helment with #14 filter installed to look at the arc see the Plasma Whirl Arc Light at:
www.oxilume.com
The system also produces copious amounts of ozone and hydroxyl radicals. A 100 KW system is currently in operation with a flowrate capacity of up to 1660 m3/hr. The ArcLight can be built with power supplies upwards of 5 MW with only one ArcLight in a vessel. This should easily disinfect and reduce organic loading for the influent to your RO system at a flowrate of 5555 m3/hr.
respectfully,
Todd
Todd
www.oxilume.com
RE: UV disinfection for sea water entering RO system
Tickle is correct about chlorine generation by application of current salt water chlorine generator technology.....this is a preferred method in recreational water systems. Though these are far smaller volume systems than yours, the technology should be a direct scale-up, and might be best addressed via slipstream treatment where the optimum sodium chloride concentration can be maintained by RO water dilution. No additional chemical input is required.
Orenda
RE: UV disinfection for sea water entering RO system
Since you are dealing with seawater you need to read up on using Br.
Many systems use one treatment method regularly, and then periodicly treat with a different process/chemical just to make sure that things stay clean. If you choose to just use one treatment you need to have a way of burst treating at a higher level once in a while.
= = = = = = = = = = = = = = = = = = = =
Corrosion never sleeps, but it can be managed.
http://www.trenttube.com/Trent/tech_form.htm
RE: UV disinfection for sea water entering RO system
RE: UV disinfection for sea water entering RO system
As the inventor of the "ArcLight," I sure would like to know where you saw that installation. The "ArcLight" is not a standard UV light system.
Todd
Todd
www.oxilume.com