SOLUTIONS FOR IN SITU BIOREMEDIATION
Bioremediation Frequently Asked Questions
This page answers common questions about product selection, electron donors, bioaugmentation, site conditions, application methods, and technical support. It is designed as a practical resource for environmental professionals working on in situ bioremediation projects.
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1. In Situ Bioremediation Basics
1. What is in situ bioremediation?
In situ bioremediation treats contaminated soil or groundwater in place, without excavating the soil or pumping groundwater out for treatment. Microorganisms are used to break down or transform contaminants, often with the help of electron donors, buffers, oxygen-control products, or specialized microbial cultures.
Related links: Bioremediation | What Does In Situ Mean? | Products
2. How do I select a bioremediation product for a contaminated groundwater site?
Product selection depends on the contaminants present, treatment goals, groundwater chemistry, geology, groundwater flow, and biological conditions at the site. Some sites need long-term electron donor retention, while others require rapid stimulation, pH control, oxygen removal, bioaugmentation, or a combination of approaches.
Related links: Products | Contact RNAS
3. What information does RNAS need to recommend a treatment product?
Useful starting information includes target contaminants, treatment goals, contaminant distribution, site geology, groundwater chemistry, competing electron acceptors, pH, oxidation-reduction potential (ORP), and dissolved oxygen (DO). RNAS may request additional site information after reviewing the project.
Related links: Contact RNAS
4. What is an electron donor and how is it used in bioremediation?
An electron donor provides food and energy for microorganisms during anaerobic bioremediation. As microorganisms consume the donor, they create the biological conditions needed to degrade contaminants and support processes such as reductive dechlorination.
Related links: Newman Zone EVO | Newman Zone QR75 | Products
5. What is the difference between fast-release and slow-release electron donors?
Fast-release electron donors provide readily available substrate for rapid biological activity. Slow-release electron donors remain available longer and support treatment over an extended period. The best choice depends on site conditions, remediation goals, and delivery approach.
Related links: Newman Zone EVO | Newman Zone QR75 | Products
2. Electron Donors & Site Conditions
6. When should I use Newman Zone EVO versus Newman Zone HRO?
Newman Zone EVO uses small droplets and is well suited to fine-grained soils and lower-permeability formations. Newman Zone HRO is a high-retention oil formulation better suited to coarse soils, fractured bedrock, and higher groundwater-flow conditions where greater retention is needed.
Related links: Newman Zone EVO | Newman Zone HRO
7. What is the difference between Newman Zone QR75 and QR90?
Both are fast-release electron donors. QR75 contains at least 75% fermentable material and is non-hazardous for storage and transportation. QR90 contains at least 90% fermentable material, provides more hydrogen, and contains ethanol, making it a flammable liquid. Product selection depends on performance goals and handling requirements.
Related links: Newman Zone QR75 | Newman Zone QR90
8. How long does an electron donor remain active in the subsurface?
That depends on the formulation and the site. Fast-release donors are designed for rapid biological stimulation, while slow-release oils can support activity much longer. Groundwater flow, geology, microbial activity, amendment distribution, and dosing all influence how long a donor remains effective.
Related links: Newman Zone EVO | Newman Zone HRO
9. How does groundwater flow or soil type affect electron donor selection?
Groundwater flow and soil permeability influence how an amendment moves through and remains in the treatment zone. More mobile formulations may be preferred in tighter soils, while higher-retention products may be more appropriate in coarse soils or high-flow environments where a donor might otherwise move out of the treatment area too quickly.
Related links: Newman Zone HRO | What Does In Situ Mean?
10. When is a buffer such as Neutral Zone needed?
Biological activity can lower groundwater pH enough to inhibit microorganisms. Neutral Zone is a colloidal calcium carbonate buffer designed to help maintain favorable pH during biological treatment and provide buffering capacity within the treatment zone.
Related links: Neutral Zone
11. How can dissolved oxygen or chlorine interfere with anaerobic bioremediation?
Dissolved oxygen and free chlorine can interfere with anaerobic biological processes and can harm sensitive microbial cultures. Newman Zone OS is used to remove dissolved oxygen and free chlorine before injection so anaerobic conditions can be established and maintained.
Related links: Newman Zone OS | Oxygen Scavenger
3. Bioaugmentation
12. What is bioaugmentation?
Bioaugmentation is the addition of specialized microorganisms to contaminated soil or groundwater to support contaminant degradation. It is often used when native microbial populations are absent, too limited, or unable to complete the required degradation pathway.
Related links: SDC-9 | TCA-20B | SDC-9+ | Bioaugmentation
13. When should SDC-9 be used?
SDC-9 is used for groundwater contaminated with chlorinated solvents such as PCE, TCE, and DCE. It contains multiple strains of Dehalococcoides mccartyi (Dhc) and supports complete anaerobic dechlorination to ethene, especially when the necessary microorganisms are absent or present at low concentrations.
Related links: SDC-9
14. What is TCA-20B used for?
TCA-20B is a bioaugmentation culture designed for chlorinated ethanes, including 1,1,1-TCA. It contains Dehalobacter spp. and other halorespiring microorganisms that support complete dechlorination to ethane without accumulation of 1,1-DCA or chloroethane daughter products.
Related links: TCA-20B
15. When would a site require SDC-9+ instead of SDC-9 or TCA-20B?
SDC-9+ is a 50/50 blend of SDC-9 and TCA-20B intended for mixed contaminant sites that contain both chloroethenes and chloroethanes. It combines the microbial capabilities needed to support complete dechlorination of both contaminant groups.
4. Contaminants & Treatment Applications
16. Can RNAS products treat PCE, TCE, DCE and vinyl chloride?
RNAS provides electron donors, oxygen-control products, buffers, and bioaugmentation cultures used in anaerobic treatment of chlorinated solvents including PCE, TCE, DCE, and vinyl chloride. The most appropriate product combination depends on site conditions and remediation goals.
Related links: SDC-9 | Reductive Dechlorination
17. What contaminants can RNAS electron donors be used to treat?
RNAS electron donors are used in remediation programs involving chlorinated solvents, nitrated explosives, perchlorate, nitrate, and selected metals. Product selection depends on the contaminant, treatment mechanism, site conditions, and remediation objectives.
Related links: Products
5. Application & Equipment
18. How are RNAS products injected into groundwater?
Application methods depend on the product and the site design. RNAS products may be delivered through direct-push injection, permanent injection wells, circulation systems, or co-injection approaches, depending on treatment objectives and subsurface conditions.
Related links: Newman Zone EVO | SDC-9 | Equipment
19. Does RNAS provide injection equipment?
Yes. RNAS rents equipment for subsurface application of remediation products, including single-channel, four-channel, ten-channel, and microdosing systems for different project requirements.
Related links: Equipment | Single-Channel Injection System | Ten-Channel Injection System
20. What product sizes are available?
Packaging varies by product and application. RNAS products are available in formats including 1- and 5-gallon pails, 275-gallon totes, and kegs or drums, depending on the product.
Related links: Products | Contact RNAS
6. Technical Support & Resources
21. Does RNAS provide technical assistance with product selection and application?
RNAS provides technical support to help environmental professionals evaluate product selection, dosing, application methods, injection strategy, and site conditions. The goal is to match the treatment approach to the contaminants, subsurface conditions, and project objectives.
Related links: Contact RNAS | About RNAS
22. Are RNAS products available internationally?
RNAS has supplied remediation products for use at sites worldwide Argentina, Australia, Belgium, Brazil, Canada, Czechia, Denmark, France, Germany, Spain, Italy, Mexico, the Netherlands, South Africa, Switzerland, and the U.K. for more than 20 years. Availability can vary by product and region, so contact RNAS for project-specific shipping and support information.
Related links: About RNAS | Contact RNAS
23. Which RNAS products are USDA Certified Biobased?
Most RNAS products are certified under the USDA BioPreferred Program, verifying the use of renewable, crop-derived materials through independent testing. Check the individual product pages or contact RNAS for product-specific certification information.
24. Where can I find product sheets and Safety Data Sheets?
The RNAS Resources section contains Product Information Sheets, Safety Data Sheets, patents, and technical references for remediation products. It is the central location for product documentation and technical information.
Related links: Resources
Discuss Your Remediation Project
Contact RNAS to discuss product selection, site conditions, application methods, packaging options, equipment rental, or technical support. Our team works with environmental professionals on practical in situ bioremediation solutions for real site conditions.