Brine Treatment for Desalination

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Brine Treatment for Desalination

Brine is a water solution with a very high concentration of salt or sodium chloride. The term also applies to solutions with other salts. The most common applications known to consumers are highway deicing or as refrigerant in the refrigeration industries.

However, the brine generated as waste in industrial processes is a difficult problem that industries are facing.  Its treatment poses numerous difficulties and purification of saline wastewater is not very effective by means of the technology usually employed:   physicochemical or biologic treatments etc.

Different alternatives, such as membrane separation technologies, do not provide the desired results in the case of brine treatment. This is mainly due to the high amount of rejects generated and the inconvenience caused by the presence of organic contaminants in filtration membrane.

Therefore, vacuum evaporators have proven to be, by far, the most successful technology for the treatment of this type of wastewater. On the one hand, this system enables the highest degree of concentration possible, up to the point of salt drying up completely; and on the other, it generated purified effluents, which are compliant with usual discharge limits, because of their extremely low conductivity and organic contaminant contents.

The management of the concentrate is the most compromised aspect of the treatment. The aim is to minimize it as much as possible in the most cost-effective way, as the final destination will be a waste manager unit (if it is a highly concentrated brine) or a landfill, if salt precipitation happens to occur.

In any case, vacuum evaporators already have a proven track record for effectively treating brines generated by the following industries:

• Food industry:

– Hams and prepared meat products
– Meats, canned fish and shellfish,  fish farms
– Pickles, olives and other pickled foods
– Lupines, pine nuts, almonds, and other canned vegetables
– Animal offal

• Chemical and pharmaceutical industry

• Leather tanning industry

• General industry: rejects from reverse osmosis

• General industry: eluates from decalcifier regeneration

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https://plus.google.com/u/0/+LivDong

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2 Comments

  1. Hi Liv,

    To make thing clearer, brine management (or "brine treatment") needs to be thought of as a two part process:

    1. Volume Minimisation (Process Technology Intensive)

    2. Brine/Salt Disposal (Civil Infrastructure Intensive) or Resource Recovery & Sale (Process Technology Intensive).

    The technology used in step one (which may include multiple process units) will affect what you do at step 2; vice versa.

    Regarding your recommended technology, vacuum evaporation is one of the tools in the toolbox and each technology needs to be considered on a case by case basis. 

    If you are starting with a brackish or saline solution I'm sure you can reduce the cost of the project (CAPEX & OPEX) by placing an RO (or EDR) up-front of a thermal process which will then treat the resultant brine.  You will however increase the complexity of the overall process. 

    If you are starting with brine and disposing of mixed salt via landfill, the typical approach is to use a falling film evaporator (FFE), then create a salt slurry via a forced circulation crystalliser (FCC) and you will usually use a centrifuge for dewatering.  There are many variations of this treatment train regarding the pre-treatment.

    Cheers,

    Matt.

    Dr Matthew Brannock CEng, CSci, MIChemE, RPEQ

    matthew@​​​saltwatersolutions​​​​​.​com.au ​ ​​

    www.​​saltwatersolutions​​​.​com.au  ​​

    www.aqmb.net 

     

    2 Comment replies

    1. I have just been hired by a pickle company who is having issues with wastewater salt brine going into the municipal treatment plant. I have been asked to uncover options for disposal, recycling, reuse of the brine, and am bringing myself up to speed.    I found the Water Network and am starting here.   

       

      Currently They dispose of 12,000 gallons per day of 8% brine (3-16%) and  organics from the pickling process. We run 300 days per year and expect this volume to grow in the near future.

       

      We  are within eyesight of a landfill,   Our soil is sandy and flat, and acreage available for options like settling ponds evaporation ponds.  Recydling has potential.  Concentrating is being considered also.  We have no concentration equipment at this facility yet. 

       

      I'm not a wastewater specialist, so I'm fishing for options, opportunities, ideas to consider, and more importantly, what not to consider as we move forward.

       

      thanks,

       

      jonathan D Smith, PhD

      Oh Snap Pickle Company / ?GLK Foods

      2230 Bohm Rd

      Little Chute, WI 54140

      jsmith@glkfoods.com

      jsmith@ohsnappickle.com     

       

  2. Hi Liv

    The vacuum evaporators is expensive system for recovery of brine and use for small recovery system,I suggested you about EDR for recovery of brine 

     

    2 Comment replies

    1. Hi Ali,

      By "EDR", are you referring to "Electrodialysis Reversal" for volume minimisation?  If so, EDR typically isn't economical for feed streams where the TDS is higher than 3,000-10,000 mg/L TDS (i.e. the upper bound at about 50% recovery producing a brackish reject stream of 20,000-25,000 mg/L TDS).  EDR does have advantages in terms of scale avoidance for non-ionic species (particularly silica). 

      Above a ~10,000 mg/L TDS feed and producing a brine reject stream of 60,000-100,000 mg/L (lower bound for sodium chloride dominated solutions and upper bound for sodium carbonate/bicarbonate dominated solutions), reverse osmosis is more economical for volume minimisation, dependent on the chemistry and pretreatment. 

      You might be able to increase the recovery of the EDR or RO system by instigating a precipitation or seeding step.  This can be either interstage (e.g. HiPro by Aveng Water) or in a recycle loop (e.g. GE's NTBC system, Desalitech's CCD) but these aren't yet in common use and are heavily dependent on the chemistry, which also needs to consistent (especially seeded processes).

      Above 60,000-100,000 mg/L TDS feed, you'd typically have to use a thermal process (there are many forms to choose from) or consider more novel technologies (e.g. humidification-dehumidification, membrane distillation etc).

      If you are referring to "Electrodialysis Metathesis" (EDM), the sophisticated cousin of EDR, the economics of resource recovery (i.e. a revenue stream) may mean that you'd go above the 10,000 mg/L limit for the feed.  This also isn't a common process.  Typically thermal crystallisation is used for resource recovery from brine streams.

      Cheers,

      Matt.

      Dr Matthew ​Brannock ​CEng, CSci, ​MIChemE, RPEQ ​

      matthew@​​​​saltwatersolutions.​com.​au  ​ ​​

      www.​​​saltwatersolutions​​​​​.​com.​au   ​​

      www.aqmb.net