What is Bioremediation | How Bioremediation Works | Bioremediation Classes | Strategies of Bioremediation | Who Uses Bioremediation | Benefits of Bioremediation | Equipment for Bioremediation
Human activities produce a tremendous variety of byproducts. Agriculture, mining, manufacturing and other industrial processes leave organic and inorganic residual compounds behind. Some are inert and harmless, but many are toxic and highly destructive to the environment, particularly the soil and groundwater. Fortunately, our planet has built-in environmental remediation systems. Unfortunately, natural groundwater and soil remediation take a long time.
Bioremediation technology is invaluable for reclaiming polluted soil and water. In the simplest terms, bioremediation is a waste management process using live organisms to neutralize or remove harmful pollutants from contaminated areas.
Bioremediation is an environmental science that amplifies natural biological actions to remedy or remediate
polluted groundwater and contaminated soil. Rather than using expensive environmental remediation equipment to remove untreated toxic materials and dispose of them elsewhere, bioremediation techniques use biological microbes to do the cleanup work.
Microbes are tiny organisms naturally found in the environment. These bacterial microorganisms are nature’s helpers in decomposing, recycling and rectifying imbalanced chemical conditions in soil and water. For countless years, nature has been correcting itself, while humans continue to display a profound ability to make a mess and ignore their damage. But now, science has found an effective way to remediate bad soil and groundwater conditions by applying natural organic substances and using their inherent properties.
According to the Environmental Protection Agency, bioremediation is a water and soil treatment technique using naturally occurring organisms to attack hazardous materials and change them into less toxic substances. Often, highly contaminated sites can become toxin-free using proper bioremediation steps and specialized equipment.
The Biological Remediation Process – How Does Bioremediation Work
The bioremediation process is a biological process that stimulates helpful microbes to use harmful contaminants as their source of food and energy. Certain microorganisms eat toxic chemicals and pathogens, digesting them and eliminating through changing their composition into harmless gases like ethane and carbon dioxide. Some contaminated soil and water conditions already have the right counter-microbes. Here, human intervention can speed up the natural remediation by boosting microbial action.
In other cases where the right microbes are low in numbers or entirely absent, bioremediation is introduced by adding amendments — microbial actors like fungi and aerobic bacteria that are mixed into the soil or water. This simple process is called bioaugmentation, and it’s highly effective to correct conditions quickly, as long as the right environmental conditions are present. Critical conditions for bioremediation include:
- Host microbial contaminants that provide fuel and energy to parasitical microbes
- Parasitical microbes that feed off their harmful hosts and destroy them
- Oxygen in sufficient amounts to support aerobic biodegradation
- Water, either in liquid form or in soil moisture content
- Carbon is the foundation of microbial life and its energy source
- Temperature, not too cold or hot for microbial life to flourish
- Nutrients like nitrogen, phosphorous, potassium and sulfur to support microbe growth
- Acid and alkaline proportions or pH ratio in the range of 6.5 to 7.5
When all these conditions are in the right proportions, microbes grow at enormous rates. If the optimum conditions are off-balance, microbial action is too slow or can die off altogether, and the contaminants remain until nature eventually restores a balance. Re-balancing can take a long time in highly polluted conditions. But proper treatment processes rectify most situations in relatively short time. That can be anywhere from a few years to several decades.
Oxygen has a strong effect on bioremediation. Some microbes thrive on air, while others are hindered when exposed to excessive oxygen. This effect depends entirely on what particular toxin is being remediated and what type of microbe is being encouraged. There are two groups or processes of oxygen levels in soil and water:
- Aerobic is the presence of oxygen needed for microbial development. In contaminated soil conditions, regularly tilling the soil is one aerobic enhancement method. This technique is also a main activity in composting to oxygenate helpful fungi. Aerobic action is also introduced mechanically through passive bioventing or by forcing compressed air into soil or under the water table with biosparging.
- Anaerobic is the absence or reduction of oxygen in water or soil. This bioremediation form is uncommon, except in heavy metal conditions such as mitigating sites polluted by polychlorinated biphenyls or trichloroethylene. Anaerobic remediation is a specialized form requiring advanced techniques and precise monitoring.
There are two main classifications of bioremediation. This refers to where remediation is carried out, not the actual bioremediation technique classes. Bioremediation is done either:
- In situ, where all bioremediation work is done right at the contamination site. This can be polluted soil that’s treated without unnecessary and expensive removal, or it can be contaminated groundwater that’s remediated at its point of origin. In situ is the preferred bioremediation method, as it requires far less physical work and eliminates spreading contaminants through trucking or pumping away to other treatment locations. Bioventing, biosparging and bioaugmentation are the main technique classes.
- Ex situ means removing contaminated material to a remote treatment location. This classification is less desirable. It involves the big job of excavating polluted soil and trucking it offsite. In the case of contaminated water, ex situ is rare, except for pumping groundwater to the surface and biologically treating it in an enclosed reservoir. Ex situ bioremediation poses a hazard to spreading contamination or risking an accidental spill during transport. Once at an ex situ treatment site, three technique classes can be applied. One is landfarming, where soil is spread and biologically decontaminated. Another is composting, which is an age-old process. The third class involves biopiles: a hybrid of stacking material in silos, then composting as a biological treatment.
Bioremediation technique classes are the prescribed physical activities or strategies used in microbial remedies. The overall process starts with isolating contaminated site conditions and characterizing what resident microbes exist. Scientists watch how these microbes already interact with the pollutants, then conduct lab testing to map out colonization requirements. Catabolic activity is studied in the lab, from which a field plan is developed. Once that’s implemented, the bioremediation process is monitored, and adjustments are made as necessary.
Bioremediation strategies plan how the field work is done. There are different technique applications that depend on the site’s saturation degree and what contaminants need removal. They also depend on site conditions such as soil composition, compaction and groundwater tables, as well as runoff characteristics and whether in situ work is possible, or if the contaminated material requires ex situ removal.
Thanks to today’s advanced technology, most polluted properties can be treated onsite. There are three main bioremediation strategies, each with individually designed equipment. The three applications are:
- Bioventing is the most common approach. This process involves drilling small-diameter wells into the soil that allows air ingress and passive ventilation where ground gases produced by microbial action are released. This approach can be used for both soil and groundwater problems, as it lets oxygen and nutrient rates be controlled by adjusting the vent rate.
- Biosparging involves high-pressure air injection forced into the soil or under the groundwater table. This process increases oxygen concentration and enhances biological Air sparging is highly effective and affordable, compared to excavating and tilling contaminated soil or circulating polluted water through pumps and filter tanks.
- Bioaugmentation is often used to add extra indigenous microbes or to implant exogenous species to the site. Augmentation works in conjunction with both bioventing and biosparging applications, but has limitations. Non-indigenous microbes are not usually compatible with indigenous bacteria, so much of the bioaugmentation additives are additional microbes to those already at work.
There are other bioremediation strategies for contaminated soil and groundwater sites. Oil and petroleum waste is a big problem in many spots. So is gassing off from methane produced by biological action. Most regulatory bodies are strict about adding other pollutants into the environment, which is a side problem for the bioremediation process.
Oil is lighter than water and notoriously floats on the surface, creating a hazard for runoff and secondary pollution. Methane gas is smelly and highly offensive when released in large quantities. This frequently happens when contaminated soil is stirred, but passively occurs through bioventing and biosparging. Three techniques are available to control bioremediation side effects:
- Oil/water separators skim surface petroleum pollutants and separate them for containment and recycling. Decontaminated water is then recirculated back on the site.
- Air strippers work to pull air from soil and clean it before releasing it back into the atmosphere. This remediation assistance prevents polluted air from escaping the soil and getting out where it can’t be contained.
- Soil vapor extraction is a process where contaminated gases are collected from the soil and dissipated through mechanical devices. This technique is often used alongside biosparging. Like oil water separators and air strippers, soil vapor extractors are specialized pieces and require experienced operators.
Bioremediation has become the main choice for contaminated site recovery in America. It’s commonly used around the world for all sorts of situations where previous human activity has left the location damaged and unusable without remediation. As the country’s population grows, there are less available landfills to relocate polluted material. This makes bioremediation very attractive. Thanks to advancing science, bioremediation is also economical.
Contaminants in polluted soil and water cover a broad range of organic and inorganic compounds. They also cover bacteriological and even radioactive parameters. Some of the uses for bioremediation intervention include these site types:
- Petroleum stations can have corroded underground tanks. Gasoline and diesel fuel leach into the ground and remain long after the station’s service life expired. Petroleum products are particularly receptive to bioremediation.
- Industrial sites where chemicals used in production are spilled or discharged in effluent. Heavy metals like lead and chromium are tough to remediate, but many lesser pollutants are biologically neutralized.
- Landfills that overfill and leach or are decommissioned are well-suited to bioremediation. Methane gas is a common byproduct, but can be controlled through air stripping and scrubbing.
- Farms where over-fertilizing occurs are excellent candidates for bioremediation. This includes chemical fertilizers and animal waste products.
- Lumber processing yards are often polluted from wood preservatives. They commonly leach into the soil and groundwater, but can be cleaned up through bioremediation efforts.
- Onsite sanitation systems contaminate soil and groundwater when septic tanks and disposal fields fail. These sanitary system overflows are highly responsive to biological treatment.
- Mine site tailings can be extremely toxic. Bioremediation efforts have proved very successful in detoxifying old mine quarries and pits.
- Accidental chemical spills alongside transportation routes have been remediated through biological treatment. This includes petroleum discharges and even road salts.
Advantages of Bioremediation
The biggest benefit from using bioremediation processes is its contribution to the environment. Bioremediation uses nature to fix nature. Properly applied by knowledgeable people using specialized equipment designed for bioremediation, this is the safest and least invasive soil and groundwater cleanup available.
Bioremediation works for organic pathogens, arsenic, fluoride, nitrate, volatile organic compounds, metals and many other pollutants like ammonia and phosphates. It’s effective for cleaning insecticides and herbicides, as well as saltwater intrusion into aquifers.
The major benefits of bioremediation are:
- Completely natural process with almost no harmful side effects
- Carried out in situ for most applications with no dangerous transport
- Quick turnaround time to make soil and water useful
- Minimal equipment needed except for specialized pieces
- Positive public acceptance due to organic process and little disturbance
- Cost effective to maintain and economical to input
- Lowers liability, as contaminants are less likely escape
- Little energy consumed compared to incineration and landfilling
- High acceptance from regulatory authorities
Specialized Bioremediation Equipment
There are certain specialized pieces of bioremediation equipment available. Some of it takes knowledgeable operation by trained and skilled people, but much bioremediation equipment is relatively easy to use. Training and maintenance service is easily available from the right supplier and manufacturer of bioremediation equipment.
This specialized equipment is also relatively inexpensive when compared to heavy machinery and trucks required excavating and hauling off polluted soil. There is also no need for complicated pumps and reservoirs needed for decontaminating groundwater. Here are examples of some specialized bioremediation equipment:
- Soil and groundwater remediation systems offer fully integrated, pre-wired and pre-piped turnkey operations that are factory tested and ready to use in the field. They’re available with air sparging, biosparging and soil vapor extraction systems. These systems also handle air stripping and oil-water Complete systems are mounted on exposed or enclosed trailers and can be custom-designed to specific needs. They’re the latest in bioremediation technology.
- Fully integrated custom environmental remediation systems go a step beyond. They set the standard for the entire industry. These complete custom-built systems include standard air sparging and soil vapor extraction. There are dual-phase extraction systems with thermal catalytic oxidizers, along with liquid and vapor-phase carbon adsorption.
- Dual-phase recovery systems fill the gap. They do two jobs in one by using a vacuum blower and a moisture separator. Gauges, NEMA IV control panels and lever controls can be custom-designed to exacting specifications. Options include filter vessels, oxidizers and manifolds with flow indicators. These can be conveniently trailer-mounted.
- Soil vapor extraction systems include a blower and vacuum pump. All components are fully integrated with marine-grade aluminum skids. They can also be mounted on an enclosed trailer to protect the investment.
- Air sparging systems have both a compressor and blower. Heat exchangers are available if required. All controls, gauges and indicators can be custom-ordered and designed to individual needs.
- Low-profile air strippers have a turbo tray design. They’re high-performance and low-maintenance.
- Air/water separators are structurally sound to withstand full vacuum applications. They’re corrosion-free and can be used in any site condition.
- Enhanced oil/water separators are used above the ground for surface spill cleanup.
- Mobile dewatering aerators efficiently remove hydrocarbons at flow rates up to 500 GPM.
Make ESD Waste2Water Your Bioremediation Equipment Provider
ESD Waste2Water is a worldwide leader in environmental remediation and industrial wastewater treatment equipment. We design and manufacture cutting-edge technology environmental protection equipment at our factory in Central Florida. We also install, service and train customers in safe and responsible methods of biologically protecting the earth and water.
Let our wastewater systems and wastewater recycling team help you choose the right bioremediation equipment for whatever contamination site you have. We can also custom-design any piece you require, and we can build you a complete system. We also provide technical support and preventive maintenance packages to make sure you stay in business.
Please view our environmental remediation products and choose what’s best for you. If you can’t find the right equipment, we’d be pleased to make it for you. Contact EDS Waste2Water today at 1-800-277-3279 or online.