Removing boron from wastewater

A. We have had success with AMD using some probiotics in concentrations as low as 1-3 ppm. They run approx. $60. for 2.5 gallons. Would you like a sample? I have been testing these products in the lab so I have a little left over.

A. Hi Jamie.

Thread 153/07 seems to indicate that this may be possible with highly specialized ion-exchange resin, although it's capacity is very low, so you'll need to manufacture then landfill an awful lot of expensive and exotic specially polymers to achieve it.

Can anyone explain what justifies this expenditure of resources? I'm no medical expert or epidemiologist, but in a world with many natural waters not even approaching this low level, and it seeming to be far below even the level accepted as of negligible effect, what justifies this burden on sustainability? Thanks!

Luck & Regards,


Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
publicly reply to Ted Mooney

Thanks. We will be most happy to print here any non-commercial findings you or the good doctor from the University of Hartford release!

RO and Microfiltration

A. We are currently researching boron treatment. There appears to be some limited evidence that boron reduction (10 to 30% depending on the concentration - >10 mg/L and process) can be achieved in some conventional treatment plants. No reduction data for boric acid. Research is for a landfill with 10 to 15 mg/L boron levels. Treatment objective is less than 5 mg/L. At levels greater than 50% reduction, literature suggests a micro-filtration process.

A. If you're interested in high removal rates of Boron, the way to go is EDI (Electro deionization). Another option is to use two step R.O. which will leave you with 25% remaining in the feed (75% removal). Good luck and greetings from the Netherlands

A. We are removing boron from wastewater, using an RO system operating with preconditioned effluent, it is on service since January with consistent results below 10 ppm

A. We are currently removing Boron from 200 ppm to 6 ppm by using crossflow microfiltration after chemical pretreatment.

A. Hello, I found on the internet some answers. You can change pH to 9 or higher to receive more borate ions. It gives more efficiency on Reverse osmosis membranes.
I hope that was helpful.

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A. I do research on removal boron from wastewater. I'm using RO and then use the sample after RO treatment, do the adsorption with activated carbon. The result so great ... less than 1 ppm boron.

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Zeolite / Bentonite

A. You might want to try filtration using zeolite medium. Or use bentonite clay chemicals. Results are very good.

Chemical Precipitation

A. Boron compounds are reduced under high pH. Depending on the process and objectives, pH precipitation is likely indicated and advisable. There are some ion exchange compounds that can achieve the desired level, again subject to objectives.

For example: a zeolite process with caustic soda ⇦liquid caustic soda in bulk on Amazon [affil link] may raise the pH to 9.5 or 10. This may precipitate elemental boron by 60%. Complex boron or bound boron complexes may require a higher pH, and caustic soda may not be a suitable agent. If reductions at 98% level are required, suggest another agent to raise pH to 11, then design neutralization complex to suit (i.e. sulfuric acid or carbonization...subject to cost efficiency process selection).

A. Your solution is by oxidizing with Electrolytic Catalytic Precipitation (ECP) removing method. In this method we will oxidize the metals by overdosing the wastewater with oxygen and electrolytic breaking of the molecules. The results are solid metal oxides and gases and water.

? What is the formula for that oxide of boron that you will be forming, Mr. Dinu? Is it B₂O₃? I was under the impression that this oxide dissolves in water, forming boric acid. What oxide of boron will efficiently precipitate please? Thanks.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2004
publicly reply to Ted Mooney

A. It is difficult to remove boron from water. It is not significantly removed by conventional precipitation processes. There is a selective ion exchange resin that will remove boron to < 1 mg/L and concentrate the boron, but it has a low capacity and is expensive, and will still result in a waste solution that must be dealt with.

In situations like this, it is usually best to deal with the problem as close to the source as possible. Sometimes the best solution is to use a DI or an evaporative recycling system to recycle the water and to eliminate boron from the discharge. Like the selective ion exchange mentioned earlier, this may still result in a boron containing waste that must be hauled off-site for ultimate treatment and disposal.

Good luck in finding the best solution.

A. We have significant results about boron removal from wastewater with ECP (Electrolytic-Catalytic Precipitation).
A way to solve it is to fit an ECP unit to you for testing or to do testing some samples to our partner in Scotland on a sample wastewater quantity (about 5 US Gallon).
Please send me other wastewater analysis and flow rate.

Regards,

A. Mr Kirman has given you sound advise, that the use of selective ion exchange for the removal of the boron. It does create a concentrate (and the loadings factors of the resins are low comparatively to other resins), however it is likely the only means by which you may achieve the discharge concentration desired. He also provides to you sound advice that you should probably look upstream for the sources to minimize the capital requirements, which are typically based on hydraulic flows as much or more than the concentration based criteria.

Boron does not convert to an oxide by means of electrocatalytic precipitation nor any other means of electrolytic oxidation. It is stable in solution. This is proven time and time again in the plating of nickel and other metals that rely on boric acid as a buffer. Please show us the data supporting this approach.

A. Here is an excerpt from a UN report on Boron. You may find some insight. I can run some thermodynamic equilibrium curves on the concentrations, if I knew more about the water chemistry. In the absence of such data, I can suggest you add a little phosphoric acid to the water in a beaker/jar test and see if the precipitation performance gets better. I suspect the borate ions are adsorbing onto the calcium, which already has limited surface availability when you use lime, and not CaCl2. The concentration and pH would drive the reaction in that direction. If I find any more references, I will post them.

"Boric acid is a very weak acid, with a p Ka of 9.15, and therefore boric acid and the sodium borates exist predominantly as undissociated boric acid [B(OH)₃] in dilute aqueous solution below pH 7; above pH 10, the metaborate anion B(OH)₄ becomes the main species in solution. Between pH 6 and pH 11 and at high concentration(>0.025 mol/litre), highly water soluble polyborate ions such as B₃O₃(OH)₄, B₄O₅(OH)₄, and B₅O₆(OH)₄ are formed.

Biggar & Fireman (1960) determined that the fixation of boron in soils occurs by one of three mechanisms: physical (molecular) adsorption, in which the boron is held to the surface of the soil by van der Waals bonds; anion exchange; or chemical precipitation. Chemical adsorption involves ionic and covalent bonding. The investigators speculated that the initial adsorption is probably molecular in nature, followed by the formation of surface compounds that result in an increase in adsorption sites, particularly at higher boron concentrations in the soil solution. At higher concentrations, chemical bonding of borate ions with hydroxyl ions on the soil surface results in boron fixation to soluble aluminium, silicon, and iron.

This same mechanism (chemisorption) was observed by Couch & Grim (1968) for the uptake of borate ions to clay mineral surfaces. The presence of calcium ions, drying, and high pH values will tend to increase the amount of fixed boron. Wetting and drying of the soil will increase the maximum adsorption capacity and bonding energy of the soil for boron."

A. Boron and Fluoride do indeed form complexes. My experience on this subject comes from the treatment of fluoborate
(BF₄^-) plating bath rinses. It is just about impossible to meet a total fluoride limit when treating these rinses. The BF ₄^- ion hydrolyzes rapidly to BF₃(OH)^- and then to BF₂(OH)₂^-, and then very,very slowly after this. Since most of these fluoborate solutions have been replaced by methane sulfonic acid solutions, this particular fluoride treatment problem has largely disappeared.

It is likely that you are forming some borofluoride complexes such as BF(OH)₃^-. These complexes are not precipitated by calcium chloride or by lime. However, in a total fluoride analysis, preceded by a distillation step, it will test as fluoride ion.

Is it possible to locate the source of the boron and isolate it from the fluoride? That would probably make the lime precipitation work.

Other possibilities include adding some phosphate to your precipitation process, or a final polish using activated alumina. Phosphates such as hexametaphosphate and sources of phosphate like bone char have been used to enhance fluoride removal in precipitation systems.

Activated alumina is used as an ion exchange media that can remove and concentrate fluorides. The fluoride ion can also be regenerated off of the media and sent back to the lime treatment system. Activated alumina is capable of removing fluoride to < 1 mg/L.

A. Muhamed Jaffar
Sr. Process Engineer - Leachate Treatment Plant - Malaysia

For the Fe problem you should use chlorine dioxide to oxidize the sulfides; I would add it into the stream entering your holding tanks

A. Dear Pamela,

Please warn your friends NOT to use the well water as it is contaminated with Boron. Boron has been known to cause low fetal weight and also atrophy of the male and female sexual organs. Please be very careful.

A. Removing boron from drinking water can be very expensive -- typically out of the realm of affordable for most people. It doesn't respond well to ion exchange or reverse osmosis. The best one might be able to do is use bottled water for drinking, along with contacting your local, State, and Federal regulatory agencies (DOH, State env. dept., EPA, even USGS). Check EPA's website for information to find out if the occurrence might be related to a site or facility. It could be naturally occurring.
Do your friends have the option of connecting to a public water source? Again, I would contact the agencies listed above first and foremost.

A. Chemical precipitation is the best way to remove boron. Usually precipitates out at ph above 9+ followed by acid adjustment.

A. We have used peat for boron removal, in the first stage we compared four kinds of adsorbents Basalt, peat,compost and activated carbon and we found peat is the best. the result of this part of our study will be published in journal of environmental technology "INVESTIGATION OF ORGANIC, INORGANIC AND SYNTHETIC ADSORBENTS FOR THE PRE TREATMENT OF LANDFILL LEACHATE". Then we compared three kind of peat to find which one has the best performance and finally we did field studies. The result of this part of the work will be submitted to publish very soon, too. Also we compared the effect of environmental factors on adsorption of boron from landfill leachate. The result has published "Adsorption of boron from landfill leachate by peat and the effect of environmental factors".

A. Using ion exchange resin you can reach 0 ppm of Boron