Brine waste treatment is becoming more and more common, not only as a means of achieving compliance with increasingly rigorous discharge regulations, but also for the cost benefits that waste minimization strategies can provide. But “is it necessary to treat brine waste before discharge or disposal?”
In many cases, treating brine effluent is necessary, though the reasons for doing so may vary. This article will help you understand common reasons for treating brine waste and how a targeted brine waste treatment strategy might impact your facility.
What is brine waste treatment?
By definition, brine waste treatment is a set of one or more processes used to separate out salts and other contaminants out from the liquid water content of a brine effluent stream. Waste brines can arise from use as process liquids or ingredients in manufacturing, from use as regenerants for ion exchange (IX) resins, and as byproducts of various industrial processes, including desalination, boiler and cooling tower feedwater treatment, reverse osmosis (RO), and acid mine drainage, among others. Because brines are used in such a wide variety of applications, waste brine treatment strategies are often highly individualized, drawing on a number of different technologies and processes.
Why treat brine waste prior to disposal?
Brine effluent will typically require some form of treatment prior to disposal, however, the specific type of treatment required will depend upon a few factors, including:
- stream content and contaminants;
- the chosen method of disposal; and
- relevant environmental and discharge regulations, standards, and limitations.
An ideal brine waste disposal strategy will balance the costs associated with each of these factors.
Brine waste stream contents
All waste brines share in their high salinity (or salt concentration), but streams might vary significantly from one to the next in terms of the constituents present. This is because various materials can end up in the brine stream in the course of normal operations.
Common contaminants found in brine waste include:
- suspended solids and particles
- antiscaling agents
- heavy metals
- organic material
- oil and grease
Contaminants such as these pose a threat to human health and can also damage ecosystems at the discharge site. If toxic or hazardous materials are present in your brine stream, chances are that some form of brine waste treatment will need to be implemented.
Brine waste discharge methods
Approaches to brine waste treatment can vary depending not only on the contents on the stream, but also on the discharge or disposal method to be used. Brine waste treatment needs may range from minimal to intensive depending upon the chosen means of disposal, such as:
- Sewer discharge: Discharging brine waste to a publicly owned treatment works (POTW), or sewer, is generally a low-cost disposal option, but access to the POTW depends upon a facility’s location. Additionally, the brine stream may need to be treated to suit the discharge standards of the POTW. Depending on the volume and the size of the receiving POTW, sufficient dilution of the brine waste stream may be achieved as it is combined with all the other streams entering the POTW.
- Surface water discharge: Brines can sometimes be discharged to lakes, rivers, or other bodies of surface water. While a relatively low-cost solution, facilities must typically comply with regulatory guidelines when discharging to waterways, which can mean adopting treatment strategies to remove certain contaminants or adjust the salinity, sometimes by dilution. Depending on the volume and the size of the receiving body of water, it is possible that a brine waste stream may be satisfactorily diluted by all the other streams entering the receiving body. If permitted by regulatory agencies, such a disposal arrangement may mean minimal to no brine waste treatment is necessary.
- Evaporation: Evaporation ponds collect spent brine and leverage solar energy to remove water content through heat exposure. They require minimal investment in terms of operations, maintenance, energy, and compliance, but can take up a large footprint. New technologies, such wind-aided intensification of evaporation (WAIV), can reduce the footprint needed for a traditional evaporation pond and speed up the evaporation process. Brine waste treatment may still be necessary if toxic contaminants are present or if there is a large volume of waste brine.
- Recycling and reuse: Brines are commonly recycled for additional use, including industrial cooling, acid and caustic production, and many other applications. Increasingly, industrial plants are partnering with municipalities and other external entities to recycle brine waste in innovative ways, such as leveraging cheese brine for road deicing or using brine waste for irrigation of salt-tolerant land and vegetation. Brine waste streams often need to be treated prior to reuse, though the extent of treatment needed may be minimal (e.g. removing or reducing organic contaminants).
- Deep well injection: Deep well injection is typically reserved for applications requiring disposal of high volume brine waste streams, such as those produced by hydraulic fracturing operations. This controversial disposal method involves pumping spent brine into porous rock formations found deep underground, and is not permitted in all states. Deep well injection requires brine waste treatment for total suspended solids (TSS), oils, and greases, so as to prevent blockages in receiving wells. Additionally, deep well injection entails substantial costs associated with drilling, permitting, and monitoring the well, making it an impractical disposal option except for certain high-volume, high-salinity waste streams.
In some locations, costs for liquid waste disposal can run quite high. If this is the case, it may be worth considering zero liquid discharge (ZLD) systems, which remove all liquid components to minimize discharge volumes so as to cut costs. ZLD systems for brine waste treatment typically include a brine concentrator and crystallizer. While ZLD systems have relatively high capital and energy costs, they can more than make up for it by minimizing liquid waste disposal costs, as well as by facilitating reclamation of valuable materials.
Environmental impact & regulatory compliance
Waste brines pose risks to the environment due to their high concentrations of salts, which can harm aquatic life when improperly discharged to the sea or surface waterways, and can cause significant damage to soil and vegetation on land as well. Additionally, waste brines can contain toxic chemicals that may be harmful to humans and the environment. For this reason, disposal of waste brine is often strictly regulated and can be costly where large volumes are concerned. It is always best to verify discharge, monitoring, and reporting requirements at your specific location to ensure that a chosen brine waste treatment solution will help your facility to stay in compliance with National Pollutant Discharge Elimination System (NPDES) permit standards or other discharge requirements. Depending upon the conditions at your facility, an effective brine waste treatment system may be necessary to avoid hefty fines or environmental remediation costs later on.
Can SAMCO help?
SAMCO has over 40 years’ experience in identifying appropriate brine waste treatment solutions to help lower costs and waste volumes while increasing recycling and reclamation of valuable materials. For more information or to get in touch, contact us here to set up a consultation with an engineer or request a quote. We can walk you through the steps for developing the proper solution and realistic cost for your brine waste treatment system needs.