RED MUD SOLUTION
SABRBIOSOLVE PROCESS CONTAMINANTS MANAGEMENT OF BAUXITE & ALUMINA PROCESSING EFFLUENT AND RED MUD
The red mud by-product of Bayer process bauxite/alumina refining is extremely caustic, difficult, and expensive to treat with traditional technologies. ESSI has created and demonstrated solutions for red mud and associated leachate. The solution comprises multiple SABR reactors utilizing multiple biological manifolds or SABR symbiotic columns to effect remediation.
Dealing with Red Mud Waste
The financial cost and environmental risk of red mud waste and associated effluent historically and currently a significant issue, now has an economic, environmentally and societally acceptable solution. ESSI has demonstrated the ability to ameliorate red mud delivering multiple beneficial solutions utilizing the SABR process.
The cost benefits of using biosecure, all-natural endemic biological solutions in existing or constructed shallow dams or tank/closed systems to treat red mud effluent are significant. Further, ESSI are able to in-situ leach treat red mud stockpiles and dams to improve the effluent contaminant values allowing polishing through external SABR systems allowing reduced residency in the remediation process. This develops commercially acceptable applications for the treated red mud as agricultural and civil construction reducing the volume of at-risk waste, while providing secondary value for naturally treated red mud as a commercially viable product.
The neutralizing effect of the SABR system on red mud and associated effluent is demonstrated in the following graphed information.
The Effect of Degrees of Neutralization and Potential Commercial Gain
The ability of the SABR Process to achieve remediation of red mud and associated effluent reducing the pH from up to 14 pH to as low as 6.1 pH is the new reality reality in bauxite/alumina processing residue solutions. If red mud is completely neutralized, through the SABR process, (7 pH) the commodity no longer remains a risk and becomes available for secondary utilisation as a commercial asset. The neutralization demonstrated was achieved at flow rates an order of magnitude higher than would be normal in an operational system This was performed to identify potential failure characteristics following the initial demonstration of ability in a 7-day trial process to prove ability. The potential for SABR biological liquors as all-natural solutions utilized in flushing red mud stockpiles and tailings dams, in a primary remediation process in difficult locations is significant. It is considered to progress the partially treated effluents into SABR systems improving the precipitation of contaminants and continually reducing insitu risk while continually treating. It should be noted that at 7 pH the majority of alkali soluble metals will be removed from the effluent however, should some metal species remain in solution the SABR system has the ability to drop the pH well into the acid range then return the liquor to neutral; bio-stripping metals to levels allowing regulator approved water release.
Furthermore, it is important to realize that the effective process requires no chemical dosing, minimal to no additional pumping, and uses no costly or energy intensive RO or ion exchange stages. The process is self-sustaining, low cost, low energy, self-stabilizing and requires minimal servicing.
SABR-POLISHING WETLAND SUPPORT
As a useful, though not essential, addition for long term remediation projects, SABR can be implemented with an enhanced natural or artificial wetland for final polishing. Such systems work hand in hand with the SABR process to further lower contaminant levels, increasing dwell time to enable further testing of pre-release water stability should such be a requirement, and increase emergency containment in the unlikely case of a flooding event or inadvertent high flow rates.
As an added benefit an artificial SABR wetland system acts as a fully bio-diverse and natural species supportive wetland. In the case of a SABR co-opted natural wetland, biodiversity and support for natural species is increased parallel to enhancement of wetland quality.
A SABR co-opted wetland is a win-win for sustainable ecology, biodiversity and all benefits that flow from these key concepts. If a wetland polish is an appropriate part of a solution, ESSI can also design and implement specific SABR processes tailored to work with the wetland system already in place.