PLANTECO has developed cost-effective technologies for addressing perchlorate and explosives contamination problems in soil/sediment, groundwater and surface water.
Effective Bioremediation Options For Perchlorate- and Explosives-Contaminated Soils and Water
Rationale: The field data PLANTECO has obtained and reviewed for most perchlorate-contaminated sites indicate that the source of the perchlorate in groundwater and surface water is perchlorate-contaminated soils. This situation occurs because perchlorate slowly leaches into groundwater via infiltration water and runoff. Thus, the amount of perchlorate in groundwater at many sites often tracks the amount of perchlorate in the contaminated soils. Often, the highest perchlorate concentrations in groundwater have been detected directly below or down gradient of very highly contaminated soils. The highest perchlorate concentrations in water have mostly been detected in groundwater.
There is immediate need for suitable treatment technologies for perchlorate-contaminated soils, groundwater and surface water at a number of Superfund and RCRA sites in the United States. Ongoing cleanup efforts are focused on contaminated groundwater. In California, Nevada and Texas, fluidized bed reactors are currently used to pump-and-treat perchlorate-contaminated groundwater. Phytoremediation and in-situ bioremediation of groundwater are undergoing field-testing at other sites. While this approach may be appropriate for sites where only groundwater is contaminated with perchlorate, such efforts may be costly, if the contaminated soils are not treated as well. Treating perchlorate plumes in groundwater and surface water without addressing the source areas (soils) cannot and should not be considered as a cost-effective permanent remedy. If perchlorate in soils is ignored and the groundwater beneath is treated, the contaminated soils will continue to act as a source of further the groundwater contamination. Groundwater security can only be guaranteed by treating both contaminated soils and groundwater to ensure that the treatment is permanent.
Soils: PLANTECO has demonstrated that in-situ bioremediation of perchlorate-contaminated soils can be achieved cost-effectively by delivering suitable carbon/electron sources to stimulate rapid biodegradation of perchlorate at different depths in vadose zone soils (Patent Pending). No dig and hull is involved. Our R&D team has successfully tested the efficacy of this innovative in-situ soil bioremediation approach (called SAMNAS®) in the field. The demonstration study confirmed that perchlorate-contaminated soils could be remediated in less than one year. Our team has developed quick screen test to obtain design parameters for different types of soils and sediment (Ref: Hazardous Waste Consultant, Volume 21, Issue 6, 2003 - see article in pdf format). Under suitable field conditions, phytoremediation can be coupled with SAMNAS® to remediate a multitude of organic and inorganic contaminants in soils and groundwater simultaneously. View a short video showing the decrease of perchlorate in soils during an 8 month demonstration of SAMNAS® st the Longhorn Army Ammunition Plant in Karnack, TX. Perchlorate was not detected in followup samples collected at this site 12 months later.Groundwater: PLANTECO’s R&D team pioneered the use of plants to remediate perchlorate-contaminated groundwater (phytoremediation). Pilot testing of phytoremediation is underway at field sites in California and Texas. PLANTECO’s R&D team has recently shown that phytoremediation of co-contaminants consisting of chlorinated solvents and perchlorate is feasible. PLANTECO has engineered the root zone of woody plants to enhance rapid rhizodegradation and minimize uptake of the contaminants by plants.
The in-situ injection of suitable electron sources to stimulate biodegradation of perchlorate in deep aquifers is another promising approach we have demonstrated in laboratory studies.
Surface Water: Constructed wetlands and constructed microbial mats have been shown to rapidly degrade perchlorate. In fact, PLANTECO has shown that perchlorate is more rapidly biodegraded in constructed wetland systems than with upland tree plantations. Microbial mats (a consortia of cyanobacteria and related heterotrophic bacteria) are very effective for the remediation of perchlorate-contaminated water, which may also contain other pollutants. Biomats® reduce and sequester redox sensitive metals (Ag, As, Ba, Cd, Co, Cr6+, Cs, Cu, Fe, Mn, Ni, Pb, Sr, U6+, Zn) and metabolize organic compounds (TNT, RDX, HMX, NDMA, chlorinated organics, pesticides and hydrocarbons). Our constructed microbial mats (Biomats®) are available in multiple forms (floating mats, immobilized mats on inert fiber or in silica) to facilitate their use in different treatment system designs. The advantage of Biomats® compared with other systems using active microorganisms is the integration of photosynthetic bacteria into the microbial consortium, creating a self-sustainable system with minimal need for supplemental nutrition. Biomats® will grow in both fresh and salt water, as well as in brine solutions. Biomats® utilize nitrate, sulfate, phosphate, and trace metals present in these waters as growth nutrients.
In Situ Bioremediation of Explosives: In field studies, PLANTECO's SAMNAS® technology has been shown to be effective for simultaneous in situ biormediation of perchlorate and explosives (e.g., TNT and its metabolites). Based on the success of SAMNAS®, we are offering a performance guranteed to our clients using this technology to cleanup these contaminants.
PLANTECO
Environmental Consultants, LLC