Technologies of Remediation Bieby Voijant T., PhD Jurusan Teknik Lingkungan FTSP - ITS 2016

Type of technologies Thermal Physical/Chemical Biological Thermal Treatment, In Situ Hot Gas Decontamination, Ex Situ Incineration, Ex Situ Pyrolysis, Ex Situ Thermal Desorption, Ex Situ Physical/Chemical Chemical Oxidation, In Situ Electrokinetic Separation, In Situ Fracturing, In and Ex Situ Soil Flushing, In Situ Soil Vapor Extraction, In Situ Solidification/Stabilization, In and Ex Situ Chemical Extraction, Ex Situ Chemical Reduction/Oxidation, Ex Situ Dehalogenation, Ex Situ Separation, Ex Situ Soil Washing, Ex Situ Biological Bioventing, In Situ Enhanced Bioremediation, In Situ Phytoremediation, In Situ Biopiles, Ex Situ Composting, Ex Situ Landfarming, Ex Situ Slurry Phase, Ex Situ

HOT GAS DECONTAMINATION, EX SITU Thermal Treatment HOT GAS DECONTAMINATION, EX SITU Introduction Hot gas decontamination is essentially a low temperature thermal desorption process. The process raises the temperature of the contaminated soil to approximately 260 °C for a specified period of time by exposing it to hot gases (i.e. heated air), volatilizing the contaminants, and destroying them in an afterburner. Advantage v      can be used to decontaminate equipment and structures that have been contaminated with explosive residues v      Contaminants are completely destroyed Disadvantage v      The largest concern is atmospheric emissions from the thermal oxidizer v      The furnace design must take into consideration possible explosions v      The cost of this method is higher than open burning

Technology Applicability Thermal Treatment HOT GAS DECONTAMINATION, EX SITU Technology Applicability v For decontamination of explosives-contaminated masonry, TNT or metallic structures.  v Mines & shells v Scrap material contaminated with explosives v Buildings associated with ammunition plants & arsenals v Products from the manufacture & processing of pyrotechnics, explosives, and propellants.

Introduction - Hot Air Injection Types of In Situ Thermal Treatment THERMAL TREATMENT – HOT AIR INJECTION, IN SITU Introduction - Hot Air Injection Air at about 700°F was introduced into three injection wells, two of which were slanted to address contamination beneath a building. Two vapor extraction wells eventually extracted a hydrocarbon-contaminated air stream at about 200°F through a thermal oxidizer, which operated at 1400°F to break down the petroleum hydrocarbons. Suitable for homogenous granular soil with a high permeability and hydraulic conductivity Advantage v creating an expanded in situ bioreactor. Given adequate oxygen, the volatilized hydrocarbons will biodegrade in these surrounding uncontaminated soils, increasing the fraction of contaminants biodegraded compared with an air extraction configuration. v can also be used in conjuction with other thermal enhancement technologies Disadvantage v has limited applicability to dioxins, furans and PCBs v Requires a high pressure multi-stage compression v Overheating and burning may occur Types of In Situ Thermal Treatment 1. Electrical Resistance Heating 2. Radio Frequency / Electromagnetic Heating 3. Hot Air Injection 4. Steam Injection 5. Conductive Heating

THERMAL TREATMENT – HOT AIR INJECTION, IN SITU Technology Applicability remove of volatile and semi-volatile organic compounds (solvents, certain pesticides, and certain petroleum hydrocarbons) present in the residual and/or free phase

Physical/Chemical Treatment SOIL FLUSHING, IN SITU Introduction Water, or water containing an additive to enhance contaminant solubility, is applied to the soil or injected into the ground water to raise the water table into the contaminated soil zone. Contaminants are leached into the ground water, which is then extracted and treated. Advantage v when performed under ideal conditions, can lead to a volume reduction of approximately 90% of the originally contaminated soil v the large volume of soil that is not contaminated after washing can be reused as backfill at the site v pH level and temperature of the soil being treated can be controlled and closely monitored v saves money and time and generally the process can be run at a very high rate of around 100 cubic yards per day Disadvantage v Flushing additives may leave small residuals in the soil or groundwater, and they should be evaluated on a site-specific basis. v Additives must be recovered from the underlying aquifer and, when possible, should be recycled. v Treatment of the recovered fluids forms residual sludges that must be treated or disposed. v Recovered groundwater may need treatment to meet appropriate discharge standards. v If used to extract volatile organic compounds (VOCs), air emissions should be treated. v Low permeability soils, such as clays, are difficult to treat with this method. v Surfactants may reduce soil porosity, and therefore they should only be used on a case-by-case basis.

Technology Applicability Physical/Chemical Treatment SOIL FLUSHING, IN SITU Technology Applicability Inorganics including radioactive contaminants. The technology can be used to treat VOCs, SVOCs, fuels, and pesticides

Physical/Chemical Treatment SOLIDIFICATION/STABILIZATION, IN SITU AND EX SITU Introduction Solidification/stabilization (S/S) treatment is used to treat hazardous wastes for disposal and in the remediation/site restoration of contaminated land. S/S is also an increasingly popular technology for brownfields (industrial property) redevelopment, since treated wastes can often be left on-site and to improve the soil for subsequent construction. Though S/S are used both in situ and ex situ, but their ex situ is most common Advantage v Low cost because the reagents are widely available and inexpensive v Can be used on a large variety of contaminants v Can be applied to different types of soils v Equipment is widely available and simple v High throughput rates Disadvantage v Contaminants are still in the soil, not destroyed or removed v Volume of the treated wastes usually increases significantly v Volatile organic compounds and some particulates may come out during treatment process v Delivering reagents deep into the wastes and mixing them evenly is difficult v In situ S/S site may not be redeveloped v Long-term efficiency of S/S is still uncertain

Physical/Chemical Treatment SOLIDIFICATION/STABILIZATION, IN SITU AND EX SITU Technology Applicability

Physical/Chemical Treatment SOLIDIFICATION/STABILIZATION, IN SITU AND EX SITU Stabilization/Solidification of soil using in-situ single auger mixing

Biological Treatment BIOVENTING, IN SITU Introduction Advantage remediation technology that uses microorganisms to biodegrade organic constituents adsorbed on soils in the unsaturated zone. Bioventing enhances the activity of indigenous bacteria and simulates the natural in situ biodegradation of hydrocarbons in soil by inducing air or oxygen flow into the unsaturated zone and, if necessary, by adding nutrients. Advantage v Uses readily available equipment; easy to install. v Creates minimal disturbance to site operations. Can be used to address inaccessible areas (e.g., under buildings). v Requires short treatment times: usually 6 months to 2 years under optimal conditions. v Is cost competitive: $45-140/ton of contaminated soil. v Easily combinable with other technologies (e.g., air sparging, groundwater extraction). v May not require costly offgas treatment. Disadvantage v High constituent concentrations may initially be toxic to microorganisms. v Not applicable for certain site conditions (e.g., low soil permeabilities, high clay content, insufficient delineation of subsurface conditions). v Cannot always achieve very low cleanup standards. v Permits generally required for nutrient injection wells (if used). (A few states also require permits for air injection.)

Technology Applicability Biological Treatment BIOVENTING, IN SITU Technology Applicability remediates soils contaminated with fuel, non-chlorinated solvents, some pesticides, wood preservatives, and other organic chemicals

Biological Treatment SLURRY PHASE, EX SITU Introduction Advantage Slurry phase biological treatment comprises of the treatment of excavated soil in a bioreactor. The soil is initially processed to separate out any stones and rubble that may be present. The soil is then mixed with water to a predetermined concentration depending on the concentration of the contaminants present, the rate of biodegradation, and the physical nature of the soils. Some processes pre-wash the soil to concentrate the contaminants. Clean sand can then be discharged; thus leaving just contaminated fines and washwater that requires treating. Normally, a slurry contains 10 to 30% solids by weight. Advantage v Good temperature control. v Good heat recovery. v Constant overall catalytic activity maintained easily by addition of small amount of catalyst. v Useful for catalysts that can't be pelletized. v Large heat capacity of reactor acts as a safety feature against explosions. Disadvantage v Reactor may plug up. v Uncertainties in design process. v Finding suitable liquids may be difficult. v ratio of liquid to catalyst than in other reactors.

Technology Applicability Biological Treatment SLURRY PHASE, EX SITU Technology Applicability used mainly to treat non-halogenated SVOCs and VOCs in excavated soils or dredged sediments. Sequential anaerobic/aerobic slurry-phase bioreactors are exploited to treat PCBs, halogenated SVOCs, pesticides, and ordnance compounds. Bioreactors are preferred over in situ biological techniques for low permeability soils - areas where underlying ground water may be hard to capture, or when faster treatment times are essential.

Daftar Pustaka http://www.eugris.info/FurtherDescription.asp?Ca=2&Cy=0&T=Ex%20situ%20treatment%20technologies&e=25 https://www.e-education.psu.edu/egee110/node/556