Are there cheaper and more durable methods of removing Nitrate and Nitrite from borehole water other than ion exchange resins?
We are faced with very high concentrations of Nitrate and Nitrite in borehole water, far above permissible limits by WHO guidelines and Nigerian Industrial Standards (NIS) for drinking water.
Since Nitrates and Nitrites in drinking water cause the condition, called methemoglobinaemia which causes cyanosis and, at higher concentrations, asphyxia and children are at more risk than adults [Reference: WHO], how can I remove them?
Which technologies can I use to remove Nitrates and Nitrites other than using ion exchange resins?
I'm interested in sustainable solutions for communities less than 500 persons.
Does anyone in this thread have any examples of small communities that I could contact to get some feedback about solutions they might be implementing?
There are a number of possible cheaper alternatives depending on the severity of the concentrations, treatment process and end-use. Given enough residence time and sufficient aeration, nitrate and nitrite levels should naturally go down due to the de-nitrification process of bacteria. The most cost-effective way to do this is implementing fine and ultrafine bubble technology which can be powered by solar or diesel/grid systems or a combination of both. You could also explore the possibility of a membrane bio-reactor (MBR) if the residence time and footprint of your process is small. This essentially concentrates the process in a tank known as a 'bio-reactor' with membrane filtration in-tank as a tertiary treatment process. You could also explore media filtration, especially the use of zeolitic material which is known to be a good absorber of nitrates and nitrites.
If you are happy to share details of your unique issue, I can work with you to find the most cost-effective solution.
Usually RO Treatment would work in this situation or bioremediation methods with denitrification using aerobic bacteria but we would need to know the influent level and the effluent target to provide the best water treatment system in this case. Do you know what the source of the elevated Nitrogen is in the borehole? Source control is very important when it comes to elevated Nitrogen levels to prevent eutrophication or excess nutrient enrichment for receiving waterbodies that cause dissolved oxygen to be depleted and cause massive fish kills and public health impacts with such water impairment. Prevention is always the best method!
The Aquathin Reverse Osmosis Element has the ability to reject (92+% to 97+%, CTA style vs. TFC style @ 60F-70F @ 60-70psi) of the dissolved inorganics in water. Rejection is based on the degree of removal of Na+ and Cl-. Although the RO has a higher percentage of removal of di, tri and quatrovalenced elements (i.e. 99% Al), the monovalenced elements are rejected at the percentages referenced above. The Aquathin Patented RO Process also removes disease causing waterborne microorganisms.
RO is not as efficient (only about 50%-65%) for nitrates, nitrites and VOCs (volatile organic chemicals i.e. hydrocarbons such as benzene, ethylene, toluene, zylene, MTBE ). The nominal 8% or less of dissolved solids, mostly monovalent, and balance of any other inorganic and organic contaminates enter the four staged Aquathin Deionization Module. The DI resin is a manmade plastic bead that is chemically made anionic (OH-) and cationic (H+). This is a superior "nuclear grade" resin as opposed to the industrial type of cationic resin (Na+) that is utilized in a water softener. In a water softener a substitution reaction occurs whereby Na+ is exchanged for Ca++ and Mg++ at a 2:1 ration. In the proprietary Aquathin DI Module that is specially produced to compliment the Aquathin RO Membrane, H+ and OH- are exchanged for the monovalenced elements in the RO permeate. Therefore, all the Aquathin System puts into the water is H+OH- or H20.
The last three inches of the DI Module is granulated activated carbon (GAC), the same high quality adsorptive carbon made use of in the Aquathin MegaChar Total Home Filter. Its purpose is to enhance what some term a flat taste and to remove any organic that may appear in trace form from a partial degree of removal via the RODI processes. To date we know of no such organic that is not rejected by the RO and / or bond is broken and force into radical state and subsequently exchanged (substituted), or adsorbed in the DI Module. At that point the GAC participates as a failsafe for organic removal. The RODI water finally passes a .2 micron pad for backup bacterial protection in the unlikely event a membrane could rupture and simultaneously serves to prevent reverse migration of contaminates.
As per some reports of IWA..international water assocn..BIODEN using heterotrophic dentrifying bacteria works well with fixed bed filters,and aerobic conditions As well.
I believe in "Prevention is better than cure". So following the WHO guideline related to "Water Safety Plan" will help you to find the reason of having high concentration of nitrate and also to find solutions to stop polluting the water resource.
Please look at Lotic Technologies Aqua Rift technology- www.lotictech.ca. The technology is a molecular catalyst. We have great results removing Nitrites and Nitrates. Please email me at dmahowich@lotictech.ca. I can send you Analytical reports. We can further discuss the technology
Biological nitrate removal is probably your best option. You can do this in a normal filter and will have to dose a carbon source as food for the bacteria.
Have you considered running the borehole through reed beds to remove the nitrate and nitrite. Once the beds have been established there is little on cost other than harvesting the reeds every so often. The water could then be fed into a reservoir then further treated for drinking.
I agree with Roy Howard, depending on the other constituents in the water non ion exchange process option is reverse osmosis, specifically nanofiltration.
More than 20 years ago, it was installed in Greece a filtration using anaerobic bacteria (as media) for denitrification with excellent results in the start-up. But, especially this method, needs well educated and focused operating personel, which were not available at this municipal installation, resulting the method failure.
I do not have the knowledge of the used microorganisms, neither the feeding material needed for the start-up, but that method did not need any other feeding agent, as the microorganisms were multiplying by feeding from the nitrites that water was containing, at least as it was designed. As I do not have practical experience, I have to aggre with Mr. Mike Dempsey, concerning the by-products of such a system.
L'Anaérobie n'existe pas sur terre , l'anaérobie ne peut pas exister sur terre.
L'eau est composée de H2O. A partir du moment où il y a de l'eau il y a de l'oxygène et donc c'est aérobie. Les micros organismes ne deviennent pas de type sans oxygène comme cela par miracle. Ou se situe la barrière avec et sans oxygène? comment fait elle pour se matérialiser? comment fait elle pour se maintenir? Comment s'effectue la transformation d'une bactérie aérobie en bactérie sans oxygène? Les bactéries aérobies ne vont pas se diriger vers une zone sans oxygène quand elles peuvent vivre dans un milieu oxygène .
Dès l'instant ou un milieu voit son taux d'oxygène diminuer, les bactéries présentes meurent plus rapidement, ne se pérénisent plus, la matière organique méthanise et part en putréfaction.
Ce milieu en putréfaction n'est pas sans oxygène, simplement elle se fait rare.
Ce milieu en putréfaction perd petit à petit ses caractéristiques biologiques de Vivant. Je voie mal comment faire du Vivant, ( eau potable) avec un milieu en putréfaction.
Hello The anaerobic does not exist on Earth, the anaerobic cannot exist on Earth.
Water is composed of H2O. From the moment where there is water there is oxygen and so is aerobic. Micro organisms do not type without oxygen as it miraculously become. Where is located the barrier with and without oxygen? How does materialize? How does she stay? How does the transformation of aerobic bacteria in bacteria without oxygen? The aerobic bacteria will not move to an area without oxygen when they can live in an oxygen environment.
From the moment or a middle sees his oxygen levels decrease, the bacteria die more quickly, not to perenisent, organic material méthanise and going to rot.
This rotting is not without oxygen, simply it is scarce.
This Middle rotting gradually loses its biological characteristics of living. I see bad how alive, (drinking water) with a community in rot.
I agree with Mike. To better understanding of the problem you should give more information and also try to know the reason why you have such high level.
Nitrites can be removed by dosing high levels of chlorine then spraying the water into the air. The reaction produces chloramines, which are volatile are removed by the scrubbing action of the air and water. However this doesn't work with nitrates. The issue with nitrate and resin treatment is that it increases the chloride level in the water after the process and this can make the water unpalatable.
Not very practical. Nitrite is readily converted to nitrate (less potent) with a little chlorine, and it also disinfects. The bigger problem with high dose chlorine rather than chloride is disinfection byproducts.