Waste containers within the non-thermal treatment areas are managed in a manner to prevent container rupture or leakage and to minimize exposure of AMWTP facility personnel. Operating standards used in conducting non-thermal treatment activities include:

• All non-thermal treatment activities are performed by operating personnel trained to safely conduct the treatment and to respond to emergency incidents.

• All treatment activities are conducted with the knowledge of a supervisor and according to specific treatment procedures.

• The presence of liquids in supercompaction feed drums is minimized by prior RTR screening and liquid removal in the pretreatment lines.

• Special case waste is managed within the single case waste glovebox on a case-by-case basis, typically in small quantities and in a timely manner to reduce waste accumulation.

• The ventilation air is ultimately fed to banks of high efficiency particulate air (HEPA) filters and carbon filters prior to exhausting through the facility stack. The exhaust from the special case waste (SCW) glovebox is also fed through local carbon absorption units before exiting the facility stack.

• Secondary waste streams generated in the treatment areas are treated within the facility.

All drums destined for direct supercompaction undergo RTR analysis at the waste storage facility (WSF) Type 1 module for the presence of liquids or prohibited waste. Those drums potentially containing liquid waste are transferred to the drum line to remove the liquid prior to compaction. Frequent releases of liquid from drums during compaction are not expected. When liquids are released, they are handled on a case-by-case basis. Sloped glovebox floors and a sump are provided to collect any liquids produced during the compaction process. The leak-tight base of the glovebox containment has sufficient capacity to hold a worst-case leak of 55 gallons. The sump has a capacity of approximately 2.5 liters and is equipped with a sensor to detect liquid at two levels (low level to detect any liquid collected and an alarm level at 90 percent full). If liquid is detected, it is removed using a sump pump located in the post compaction glovebox and placed into barcode labeled collection containers. The collection containers are linked, via the barcode labels and DMS, to the original waste containers/pucks and their waste processing information (characterization data, U.S. Environmental Protection Agency (EPA) HWNs, etc.). When the collection containers are filled, they are transferred out of the glovebox and delivered to the SCW glovebox for treatment, as required. In the event large amounts of liquid are released during the compaction cycle and the sump capacity (2.5 liters) is filled, the compaction cycle is completed. After the ram is disengaged, the liquid in the sump is transferred to collection containers. If the next drum contains incompatible waste, the glovebox surfaces are visually inspected and any liquids remaining are removed and wiped up.

The macroencapsulation system provides for the application of surface coating materials to substantially reduce surface exposure to potential leaching media in the disposal environment. The process components are located in three areas: the grout preparation area, the puck drum grout filling station, and the drum cure area.

The grout preparation area supplies a cement-based grout to the grout filling station to encapsulate pucks and baskets of metal debris that have been placed into a puck drum. The grout completely encapsulates the waste and is resistant to degradation by the waste, its contaminants, and substances that may contact the waste form after disposal.

The cement powders (ordinary Portland cement and pulverized fuel ash [PFA]) are delivered to the receiving storage hoppers by bulk tankers and transferred into the respective weigh hoppers by the ordinary Portland cement/PFA transfer conveyors. The data management system maintains appropriate recipes for the production of the grout and calculates the correct volume of grout required for each puck drum based upon puck height. All grout preparations and grout filling activities are under programmable logic controller sequence control and are normally initiated from the central control room or from the local control area workstation. The quantity of each powder, which is dependant upon the formulation envelope, is screw-fed into the grout mixing vessel along with the required volume of water from the water feed vessel.

Prior to drum filling, clean puck drums are fed into the supercompaction cell from the clean drum feed route by a roller conveyor. The drum is identified by a barcode reader and transferred into the interfacing glovebox bagless transfer airlock by roller conveyor. A bagless transfer system is used to allow drum lid opening while maintaining glovebox ventilation conditions. Once the puck drum is within the airlock, an operator removes the bolt ring and outer lid via gloveports. The puck drum is then clamped centrally onto a drum positioning machine and raised into position at the bagless transfer mechanism. The bagless transfer port is opened with the inner drum lid attached (held in position by vacuum pump). The puck drum is pre-loaded with an insert and an anti-flotation device. The insert is used to prevent direct contact between the waste and the container, the anti-flotation device keeps pucks below the grout surface. Before pucks or baskets are loaded, the anti-flotation device is removed from the drum using the puck handler and parked nearby.

The data management system decides if a puck or metal debris basket can be loaded directly into the puck drum or if it requires placement into one of the five positions at the puck staging area. Pucks are loaded automatically into the puck drum using the puck handler. Recovery facilities are available within the postcompaction glovebox, along with hand operated tools, to deal with abnormal pucks that do not fit into the puck drum. Waste that escapes from pucks are manually collected through gloveports and placed into open mesh bags, which are inserted between pucks during puck filling and are encapsulated.

Baskets of non-compacted metal debris (requiring encapsulation) are loaded into an empty puck drum in a similar manner as the pucks. The baskets are transferred in open transfer drums through the compaction gloveboxes to the entrance of the postcompaction glovebox. At this point, the baskets are lifted out of the transfer drums using the puck handler and either placed into an empty puck drum or in one of the puck staging positions. The empty transfer drums are returned to the pretreatment lines.

After the puck drum is filled with pucks or metal debris baskets, the anti-flotation device is fitted and locked into position using the puck handler. A funnel device is then placed over the puck drum opening to prevent loose debris or grout from splashing onto the drum seal or through the purge area. Prior to grouting, the grout pipe is rotated down towards the puck drum to ensure that the grout flows directly into the drum. A pinch valve is fully opened and grout is pumped into the drum until the waste is covered. Level—control devices are used to prevent overfilling during the grouting process. At a predetermined level monitored by a laser (approximately 1 inch above the waste), the grout pump is stopped and the pinch valve partially closed. A second laser device is used to prevent drum overfilling by completely stopping all grout flow when the overfill level is reached. A disposable cleaning devise is manually loaded into the grout line and compressed air is used to blow the pig and the last of the grout down the line to the pinch valve. A rodding drive that pushes the pig into the puck drum along with the last of the grout is manually inserted through the changeover valve.

Excess grout is emptied from the mixing vessel and transferred into the grout waste collection tank. Periodic wash down of the process equipment is required. Additives to the excess grout that inhibit the cement mixture from curing may be used, enabling grout washings to be returned to the grout-mixing vessel and minimize effluent discharges.

When the grouting sequence is complete, the grout pipe is rotated out of the way, the funnel protector retracted, and the bagless transfer port closed and locked to allow drum lidding. The filled and grouted puck drum is then lowered from the glovebox to the drum lidding area, and the bolt ring and outer lid are fitted by an operator through gloveports. The puck drum is transferred from the bagless transfer airlock to the swabbing station by a roller conveyor. The puck drum is rotated and manually swabbed to check that the exterior of the drum is free from contamination and suitable for export. Externally clean puck drums (final waste form containers) are identified by a barcode reader and automatically transferred through an airlock to the drum cure area by a roller conveyor.

Within the drum cure area a drum transfer car moves the final waste form containers from an inlet conveyor to one of 15 staging bays. Each bay is a conveyer unit that holds two puck drums, for a total capactiy of 28 drums (one bay is reserved for puck drum transfers). The final waste form containers are allowed to cure for approximately 24 hours. After the final waste containers have cured they are transferred using the transfer car to the conveyor interface with the puck drum staging area, and then to the product certification area for external contamination monitoring and certification.

The SCW glovebox is provided for treatment of SCW on a case-by-case basis. This glovebox is fitted to treat containerized/free liquids from waste containers and residual liquids recovered from the various liquid collection devices located throughout the pretreatment lines and the postcompaction glovebox, and elemental mercury. Other waste streams that may require processing in the special case waste glovebox on an irregular basis may include such items as hydraulic fluids, gas cylinders requiring venting, polychlorinated biphenyls (PCB)-suspect electrical equipment, elemental mercury and wastes indicated as SCW in Table C-1-1 of Book 1 of the AMWTP Resource Conservation Recovery Act (RCRA) Permit Application.

SCW items removed from waste containers in the pretreatment lines are either labeled with barcodes or placed into barcode-labeled containers. Whatever information is recorded in the DMS for the waste container(s) present during the extraction of SCW is applied to the newly-generated SCW. The type of information entered into the DMS includes: the identification of the original waste containers(s) and waste characterization information. Item description code (IDC)/waste category (WC), approximate quantity of SCW removed from each waste container, applicable EPA HWNs, additional characterization or process knowledge obtained prior to treatment, and targeted treatment processes. SCW items are then placed into a basket/transfer container at the SCW export station and routed (via the material transfer system [MTS]) to the SCW treatment interface point. The transfer containers are moved into the transfer airlock and identified by a barcode reader. With the SCW transfer container in the airlock, the glovebox hatch is opened and an elevator lifts the transfer container up into the SCW glovebox. At this point, a hoist is used to retrieve the basket from the transfer container and move it to a basket set down area, where individual SCW containers can be removed and identified using a barcode reader. Residual liquids from the supercompactor are placed into small plastic containers and manually transferred to the glovebox and imported via bag/bagless transfer techniques. SCW from the pretreatment lines may also be manually transferred to the SCW glovebox (depending on size and quantities), however, the preferred route is via baskets/transfer containers and the MTS.

Once inside the glovebox, SCW is first identified using a barcode reader. Barcode labels are attached to the SCW containers not previously labeled in the pretreatment lines (e.g., SCW transfer containers filled with SCW items from a single IDC or drum may be placed into the same transfer container without labeling individual inner containers with barcodes; the bar-coded transfer container is used for tracking the SCW until received at the SCW glovebox). After all containers/items have been identified and labeled (if required), the exterior of the items are visually examined for clues verifying or identifying their contents. This is especially critical for inner containers containing unknown wastes streams. SCW items are then transferred using a combination of manual transfers and sample transfer mechanisms to various areas of the glovebox where further characterization and sampling activities can be performed.

Prior to further characterization and waste sampling, SCW containers are opened. Most of the SCW containers that need to be opened in the SCW glovebox are believed to be packaged in the small plastic containers, 1-gallon metal paint cans, or other containers without special opening requirements. When tools are required for opening containers, only tools that do not compromise the integrity of the gloves are used. A heavy-duty can opener is provided for any SCW listed in Table C-1-1 of Book 1 of the AMWTP RCRA Permit Application that may be packaged into rolled metal cans (similar to common produce cans).

After the SCW containers are opened, wastes are visually examined for phase separation, and pH and ignitability are measured. Multiphase liquids are separated by a settling/decanting process (if required) and placed into separate containers. Non-debris SCW is sampled using a variety of tools (spatulas, scoops, hand auger/coring devices, etc.), depending on the consistency of the HIS/organic homogeneous solids (OHS). Liquids are sampled using pipenes, syringes, etc. The samples are subjected to proximate analysis, bomb calorimetry, and X-ray fluorescence (XRF) analysis. SCW with unknown HWNs are also subjected to PCBs and organics analysis. Refer to Section C of Book 1 of the AMWTP RCRA Permit Application for a description of SCW analytical requirements. Sampled containers are placed into a staging rack until analytical results are available. Each position in the rack has separate containment properties and a segregated section of the rack is used to separate SCW with unknown HWNs from SCW with known HWNs.

If liquids are found to be acidic/basic, they are first neutralized. Neutralized liquids are mixed with an appropriate absorbent, based on analytical results. Absorbed liquids may be combined, if analytical results show them to be compatible. The following presents specific information on the treatment processes conducted in the SCW glovebox.

• The weight or volume of the waste, as specified in the treatment procedure, is determined and recorded.

• A pH measurement is taken to verify the initial reading recorded in the treatment procedure.

• The appropriate types and amounts of neutralizing agents are weighed/measured out and added according to the treatment procedure. The primary acidic neutralizing agents include sulfuric acid or hydrochloric acid. The primary basic neutralizing agents include sodium hydroxide or various limes (such as calcium carbonate).

• The treatment agents and waste are mixed according to the method and duration specified in the treatment procedure.

• A pH measurement is taken to verify results against the pH end-point established in the treatment procedure and to confirm treatment effectiveness.

• If treatment is not effective, the neutralization process is repeated.

Once neutralized, the liquid is mixed with appropriate absorbents as described below.

• The volume of waste to be treated is measured and verified against the volume stated in the treatment procedure.

• The amount of appropriate absorbent is measured as specified in the treatment procedure.

• The absorbent is added to the liquid waste in accordance with the treatment procedure.

• The absorbent and waste are mixed according to the method and duration specified in the treatment procedure.

• Treated waste is visually inspected for signs of free liquids. If no free liquids are present, the treatment is considered successful. If liquids are present, additional absorbent material is added and the waste is remixed.

The types of absorbents used vary with the type of liquid waste and are selected based on (1) recommended usage and specifications provided by manufactures and (2) compatibility with the waste. Absorbents may include natural materials such as vermiculite, silicates, clays, or cellulose; or synthetic materials such as activated carbon, polypropylene, or other proprietary components.

Containers with absorbed liquids are placed into transfer containers and routed to the incinerator for thermal treatment.

• The mercury is weighed, and results recorded to verify against the weight of mercury stated in the treatment procedure.

• The required treatment reagents are measured as required by the treatment procedure.

• Treatment reagents are added to the mercury in the sequence established by the treatment procedure.

• The mercury and treatment reagents are mixed according to the method and time specified in the treatment procedure.

• The mercury amalgam is allowed to cure in accordance with the time specified in the treatment procedure.

• Following the allotted curing time, the amalgam is visually inspected to determine whether or not a semi-solid to solid waste form was produced. If treatment results in a semi-solid to solid waste form, amalgamation is deemed successful. If not, additional treatment reagents are added to the mercury waste form, and the mixture is remixed and allowed to cure a second time. The treatment process is repeated until desired results are obtained.

• Amalgamated metal is transferred out of the AMWTP facility.

The AMWTP facility incinerator is used to treat solid wastes containing HWMA- and TSCA-regulated constituents. Three main categories of waste are processed in the incinerator: organic homogeneous solids, inorganic homogeneous solids, and soils. The incinerator is used to destroy organic hazardous constituents in the solid wastes.

Table B-2-1. Incinerator operating conditions for mixed waste.

Figure B-2-1. AMWTP facility incinerator schematic.

Figure B-2-2. AMWTP facility incinerator Air Pollution Control System.

• Demonstrate compliance with the current hazardous waste incinerator guidance (Guidance on Setting Permit Conditions and Reporting Trial Burn Results, EPA/625/6-89/019, January 1989) herein called the Incinerator Guidance

• Demonstrate the ability of the AMWTP facility incineration system to comply with the performance standards of IDAPA 16.01.05.008 (40 CFR 264 Subpart O).

• Provide emissions data for multipathway health risk assessment.

• Allow comparison of the AMWTP facility emissions to the proposed Hazardous Waste Combustion Maximum Achievable Control Technology (MACT) rule.

• Demonstrate the ability of the AMWTP facility incineration system to comply with the TSCA performance standards of 40 CFR 761.70.

The trial burn has been designed in accordance with the EPA's Incinerator Guidance series in pursuit of a certain set of desired operating conditions. The desired operating permit conditions, trial burn automatic waste feed cutoff set points, and the proposed means of demonstrating compliance are discussed in the AMWTP RCRA Permit Application, Book 4, Section D5-b.

• The incinerator and the refractory material that lines its interior will be gradually brought up to operating temperature using auxiliary fuel.

• On-the-job training will be conducted for process operators, in addition to the formal training program.

• Operating data will be reviewed to evaluate the performance of the incinerator and its APCS.

• The operators will be trained in the AMWTP facility incinerator system, the control system, the automatic waste feed cutoff system, and the Contingency Plan procedures.

The AMWTP facility incinerator system consists of the following primary components: waste feed system, primary combustion chamber (PCC), secondary combustion chamber (SCC), and ash removal system.

The refractory lined PCC typically operates between 1,500 to 1,600° F to dry, volatilize, pyrolyze, and combust the wastes and has been designed with precise flow control and air injection locations to minimize particulate entrainment in the offgas. Ash is continuously transported down the length of the PCC by an ash auger and is collected in containers in the ash removal system. These ash containers are sampled, lidded and then sent for assay before transport to the vitrification system feed hopper.

The SCC completes the combustion process with the addition of excess air at temperatures of 2,200 to 2,400° F. Conventional auxiliary heat burners maintain temperatures in the PCC and SCC.

Waste feed material is delivered to the thermal treatment process area on the central conveyor. The IHS, OHS, and soils are typically contained in polyethylene drum liners and received in reusable transfer containers. Each transfer container is lifted by an elevator mechanism and the contents dropped into the inlet of the size reduction system equipment. Prior to delivery of the waste drums to the size reduction system, unacceptable feed constituents are identified by RTR and/or visual inspection and removed in the box and drum lines. Items that violate the incinerator WAC include metals, aerosol cans, explosives, containerized liquids, and pyrophorics.

A crusher and a slow speed shear shredder comprise the size reduction system. Waste in the drum liners is delivered into the mouth of a crusher where it is crushed to approximately 4 inches in size. The crusher is equipped with a hoisting tool, which is used during maintenance or for removing large pieces of uncrushable material. An operator has the capability to stop the crusher before large, uncrushable metal pieces are introduced into the crusher. The crusher is designed with toggle plates that act as "mechanical fuses" or high torque detection that will protect the mechanism.

Crushed material drops from the bottom of the crusher into a slow speed shredder. The waste feed shredder uses a dual auger/cutter within a sealed enclosure that size reduces the incinerator feed material to less than 1-inch pieces. All waste fed to the PCC is maximum of 1-inch diameter, waste exceeding this criteria is sorted out in the anomaly removal station described below. The shredder is designed with torque limitation protection to prevent blade breakage if non-shreddable material that passes through the crusher falls into the shredder. The shredder detects high torque and reverses blade direction; this is a standard technique for shredder protection. If several reversals of the blades are detected, the shredder control system will stop the blades and signal a problem. The shredder will have glovebox access so that the uncrushable material can be manually removed from the blades (with the assistance of a tool), and placed in a drum for separate disposition. The size reduction system is contained within a glovebox to control the release of emissions during size reduction activities and direct volatile vapors to the SCC burner.

Waste exiting the shredder enters an anomaly removal station. The anomaly removal station is a vibratory conveying system contained in a glovebox. Operator stations are provided along the sides of the conveyor where metal or polythylene shreds that are unsuitable for the conveying equipment are manually separated and delivered back to the shredder inlet for further size reduction. Metal can alternatively be separated and placed in containers for separate disposition. A permanent magnet suspended above the conveyor collects ferrous metals such as nuts, bolts, or small solid metal scrap. This metal is separated and placed into a container for disposition to SC/ME. Metal that is contaminated with PCBs is sent to storage and campaigned with other PCB metal.

The size reduction system consists of two parallel trains with redundant crushers, shredders, anomaly removal conveyors, and permanent magnets. The redundant trains are provided in order to improve availability of the thermal treatment process by allowing one train to operate while the other undergoes maintenance or repair. Only one train operates at a time. The size reduction system is designed to process the contents of a single drum at a time. For the design feed rate, this corresponds to approximately one to two drums per hour. The size reduction system processes a single drum, and the contents are conveyed downstream from the shredder before the next drum is introduced to the system. There is very limited blending of waste from different drums in the feed system. In general, the system is designed for minimal waste hold up; however, areas where major holdup of waste could possibly occur are designed to be accessible through the glovebox or with access via tools to minimize waste holdup. The system is not cleaned between the passages of individual drums unless a waste incompatibility situation is present.

Material passing to the end of the anomaly removal system is collected in a small hopper and conveyed by the waste transfer conveyor to the incinerator feed hopper. A rotary valve is used at the connection to the incinerator feed hopper to provide an airlock between the size reduction equipment gloveboxes and the incinerator feed system. The waste transfer auger is driven by a reversible, torque-sensing, variable speed electric motor to detect jamming by obstructions. The waste feed hopper has the capacity to contain approximately one hour’s worth of feed for the incinerator. The hopper assembly includes ultrasonic sensing devices for maintaining an appropriate waste level within the hopper. A nitrogen supply line to the waste feed hopper maintains the hopper and the waste feed glovebox at low oxygen conditions when necessary. A rotating agitator is included to prevent waste from bridging or caking and thereby ensures adequate supply of waste to the primary feed auger. The purpose of the primary waste feed auger is to provide a constant volumetric supply of waste feed material to the secondary feed auger. The secondary feed auger has a uniform core and flight pitch at the waste receiving end, but a decreasing flight diameter to compress and compact the waste at the delivery end. The waste is conveyed uncompressed until it reaches the conical shaped tapered section near its exiting end. The speed ratio between the conveyor auger and compression auger is adjustable. This permits a variable compression of the feed exiting the waste feed system. Dense waste material requires little compression, whereas less dense waste requires more compaction to provide a seal in the incinerator feed tube. The average waste density for OHS, IHS, and soil is 55 pounds per cubic feet. The compression ratio is adjustable from a 1:1 ratio for non-compressible waste to a maximum of 5:1 for highly compressible waste. Pre-operational testing will determine the ideal compression settings for the various waste forms. The compressed waste provides a gas pressure seal between the PCC and the feed system of approximately 2 psi.

The waste feed cutoff valve provides emergency waste feed cutoff during upset conditions, when critical monitoring devices fail, or when it is necessary to isolate or remove the secondary waste feed auger from the PCC for feed system maintenance. The auger can be disassembled and retracted from the cutoff valve at its flange for repair or replacement while the PCC remains at operating temperature. The waste feed cutoff valve provides passive gas sealing between the feed system and the PCC, whenever compacted waste sealing is not available, as during startup conditions. The waste feed cutoff valve consists of an assembled valve body that houses a circular gate-blade with a sharp circular-edge ring made of carbide. A water-cooled tube flange extends from the valve body to prevent overheating of the valve, thus preventing premature combustion of the waste prior to entering the PCC. Internal switches and backup switch devices provide the position of the valve (open or closed) to the programmable electronic system (PES). An electric motor worm gear drive is sized to allow the valve to shear off all nonmetal waste materials while closing.

The auger is designed to operate outside the equipment critical speed zone to prevent excessive vibration. Periodic inspection for excessive noise and vibration is made after each week of operation. This is accomplished by manual inspection of each auger bearing assembly and monitoring for excessive noise.

The middle section of the auger is located inside the incinerator and contains the spiral conveying flights. The flights have sections cut out to permit unimpeded thermal expansion and slippage of the waste during rotation. Waste material bridging in the incinerator is avoided by providing the appropriate feeder/auger interface. The waste feed table is designed to receive the waste exiting the incinerator feed tube and channel the cascading waste down into the center part of the auger. The waste striking the auger flights either breaks up and falls between the flights or rides the flight down into the channel where it is exposed to the underfire air. In either case the waste is directed to the desired location for incineration. The waste contained in the auger is continually stirred by the flights to prevent bridging as it travels through the incinerator. As the waste is incinerated the residue or ash displaces less space, diminishing the ability to bridge. Synchronization of the waste feed augers and ash auger speeds prevents overfilling of the ash auger. Programming of the speed synchronization will be performed during prototype testing.

The tail shaft of the auger consists of a solid shaft having a welded connection flange and accommodations for an incinerator seal and bearing. A specially-designed split seal is located at each end of the incinerator where the auger shafts penetrate the chamber wall. Bleed air will provide a dust barrier and cooling for the seal section facing the chamber. The remaining part of the assembly with contain a spring-loaded carbon wipe seal.

The fourth subassembly is the auger cooling system. Cooling air enters and exits the drive shaft assembly through a cooling air junction box. Heat is transferred to the air, maintaining an allowable temperature and yield strength for the auger barrel located in a high temperature environment. Heated air exiting the junction box is used as secondary air and is mixed with the combustion gas exiting the PCC.

Crushed ash passing through the screen falls into the intake hopper of an aeromechanical conveyor and is conveyed to a fissile assay station. The aeromechanical conveyor consists of two parallel tubular housing approximately 4 inches in diameter that enclose a continuous steel rope loop. Discs are attached to the steel rope at approximately 8-inch intervals. The conveyor has two sprockets; one of them is the drive sprocket and is connected to a motor. The motor and sprockets move the steel rope and disc assembly in a continuous loop. Material is moved in a fluidized form by pockets of air between the discs, assisted by the mechanical force of the moving discs. Upon completion of the fissile assay the ash is dropped into the intake of another aeromechanical conveyor and sent for final disposition to the microencapsulation process equipment.

A glovebox enclosure surrounds the screw conveyor, rotary valve, ash crusher, and aeromechanical conveyor intake. The enclosure is vented to the Area 400 (west) glovebox ventilation system.

The ash transfer conveyor transfers the ash to a tramp metal removal and size-reduction station. Tramp metal is separated from the ash by a magnetic sorting device and the sorted metal is discharged into a container. Ash leaving the metals removal station proceeds to a conventional rotary jaw crusher for particle size reduction prior to being discharged into a container. The tramp metal removal and size-reduction station is shown on the piping and instrument design 1-05-55-510 found in Appendix D-3 of the AMWTP RCRA Permit Application.

The AMWTP facility incinerator has been designed with the capability to be remotely monitored and controlled. Remote operation is performed from the central control room by experienced operators. The system is continuously monitored by a programmable electronic system that has been programmed to receive transmissions from pressure, flow, temperature, and performance transmitters located throughout the system. Based on preprogrammed information and system parameters, the programmable electronic system transmits signals to process control devices and to warning lights and alarms within the central control room, indicating a system malfunction.

The APCS for the AMWTP facility incinerator consists of the following: a saturation quencher, a venturi scrubber, two absorbers in series, a WESP, an offgas reheater, redundant first stage HEPA filtration, carbon adsorbers, redundant second and third stage HEPA filtration, associated pumps and blowers, and an exhaust stack (see Figure B-2-2).

The combustion gas exiting the SCC at 2,200-2,400° F, by spraying the gas with scrub liquid. Cooling is accomplished by a concurrent atomized spray of recirculating scrub liquid through an array of three atomized spray nozzles oriented at a downward angle into the gas stream just below the top of the vessel. The average gas velocity through the offgas quencher is in the range of 12 to 16 feet per second. Average droplet size produced by these nozzles will be 400 to 100 m m. The total flow rate of liquid delivered through the spray nozzles is 4 to 6 times that required to saturate the gas stream. Liquid is also introduced at the top of the quencher through 12 spray nozzles to provide a continuous wetted wall. The quencher is a vertical vessel fabricated of corrosion-resistant alloy Hastelloy C-22 or equivalent. The hot gas inlet transition section of the quench vessel, immediately above the upper scrub liquid inlet zone, is line with refractory.

A medium energy venturi scrubber operating at 30 in. w.g. differential pressure is located immediately downstream of the quencher to receive the moisture-saturated gas existing the quencher. The scrubber removes greater than 1 m m particulate from the gas stream at approximately 99 percent efficiency by impaction with atomized scrub liquid droplets. Removal efficiency for coarser particulate at this differential pressure increases to greater than 99.9 percent for greater than 5 m m particulate. Most of the sub-micron particulate passes through the scrubber and will be removed by the condensing WESP further downstream. In addition to its primary function, the venturi scrubber removes some acid gas (primarily hydrochloric acid [HCL]) and mercury from the gas stream.

The venturi scrubber consists of a converging section, a differential pressure control valve to serve as the venturi’s variable throat, and a diverging section. Recirculating scrub liquid is atomized into the throat of the venturi for impaction with the particulate matter entrained in the gas stream. The venturi scrubber is oriented horizontally between the quencher and absorber No. 1. The gas- liquid mixture from the quencher is disengaged in the quencher sump so that only gas flows through the venturi throat, along with atomized recirculated scrub liquid. The venturi scrubber is fabricated of corrosion-resistant alloy Hastelloy C-22 or equivalent. The differential pressure across the venturi throat is controlled using an automatically actuated pinch valve.

The relatively particulate-free gas exiting the venturi scrubber undergoes scrubbing of the gas phase pollutants HCL and mercury in the first absorber. This first absorber, along with the quencher and venturi scrubber, operates with acidic recirculating scrub liquid controlled to a set point pH in the range of 2 to 3. Operation within this pH range avoids the reduction of mercuric chloride back to elemental mercury.

The main purpose of the first acidic scrub recirculation loop is to promote mass transfer of gas phase elemental mercury into the scrub liquid to form highly soluble mercuric chloride (HgCl₂) by reaction with sodium chlorite (NaClO₂) reagent. When acid gases are being formed in the incineration process from the combustion of chlorine-containing feed materials, the pH in this first scrub loop will be automatically controlled by addition of sodium hydroxide (NaOH) liquid. Sodium chlorite is added to this recirculation loop in slight excess of the estimated stoichiometric requirement for reaction with mercury. In the unlikely event that wastes with insufficient chlorine are fed to the incinerator for a prolonged period, the pH is maintained in the desired range by absorption of CO₂ to form carbonic acid. Makeup liquid to this loop to maintain a constant liquid inventory is from process makeup waste or recycled condensate as well as purge liquid from the absorber No. 2 recirculation loop. Purging of liquid or blowdown from absorber No. 1 is controlled primarily by continuous measurement of liquid density that corresponds to a dissolved solids concentration of about 4 weight percent or a suspended solids concentration of 1.5 weight percent, whichever is reached first. Blowdown to the brine evaporator feed tanks is also initiated to maintain constant liquid inventory in this loop.

In absorber No.1, the gas flows upward, countercurrent to the flow of cooled recirculating scrub liquid. Liquid is uniformly distributed to the top of the packing through a weir-trough type distributor to uniformly cover the entire cross-section of the top of the packing.

Absorber No. 1 also functions as a direct contact condenser to cool the offgas stream to a saturation temperature of about 100° F. The base of the absorber tower serves as a liquid sump for recirculation of the scrub liquid. If the offgas saturation concentration of mercury is exceeded in this first scrub loop (due to a mercury feed spike for example) elemental mercury will condense. A system is provided to gravimetrically collect liquid mercury in the low points of the quencher and absorber No. 1 sumps for periodic batch withdrawal by pumping to the mercury hold tank. Since elemental mercury is more dense than scrub liquid, mercury collects in the bottom of the mercury hold tank through a sight glass and double valves into a small transfer container and then transferred to the SCW glovebox for amalgamation.

Removal efficiencies of 95 to 99 percent for HCl and 90 percent for mercury are expected in this first scrub loop. The pressure drop across the absorber ranges from 2 to 4 in. w.g. Absorber No. 1 and all internal components, including packing, support plates, and liquid distributor, are fabricated of Hastelloy C-22 (or equivalent) for both corrosion and temperature resistance. There is no mist elimination device in this vessel.

Gas from absorber No. 1 flows to the base of absorber No. 2. This second absorber is physically configured similar to absorber No. 1, but has key operation differences. This second loop operates at a neutral to slightly basic pH in the 7 to 8 range. Operation within this pH range avoids absorption of CO₂ from the gas stream, which becomes significant above a pH of about 9. The purpose of this second absorber is to remove the remainder of the HCl in the offgas that passed through the acidic absorber No. 1 and to remove SO₂ that passes through the acidic absorber. No additional mercury removal is expected in this second absorber. Overall acid gas removal efficiencies for the wet scrub system (including the first and second loops) is expected to be greater than 99.9 percent for HCl and 90 percent for SO₂, depending on inlet concentrations of each pollutant. Absorber No. 2 has a mesh-pad type mist eliminator located in the upper section of the tower to remove fine mist droplets that would otherwise be entrained in the offgas. This mist eliminator is periodically flushed on an automatically-timed basis with fresh plant water from below through a wide-angle spray nozzle.

Caustic addition to the second loop is limited to that required for stoichiometric conversion of the absorbed acid to sodium chloride (NaCl) and sodium sulfate (Na₂SO₄) salts. Purging of liquid from this recirculation loop is based on a setpoint liquid density corresponding to a dissolved solids concentration of —2 weight percent. The purge or blowdown stream from this neutral pH loop is cascaded to the first or acidic loop. This approach provides an overall countercurrent flow of liquid with respect to the gas flow direction such that cleaner liquid (neutral loop) will pass to the less clean loop (acid loop) before being purged from the system.

As previously described for absorber No. 1, all internal components in this absorber, including packing, support plates, and liquid distributor, are fabricated of Hastelloy C-22 or equivalent for both corrosion and temperature resistance.

The condensing WESP located downstream of absorber No. 2 removes entrained fine scrubber liquid mist droplets and entrained submicron particulate matter in the gas stream. Without such a prefiltration device, moisture droplets that pass through the reheater with insufficient time to evaporate could condense on HEPA filters, a condition that can significantly shorten HEPA filter media life. The WESP achieves high removal efficiency for submicron solid particulate matter and submicron liquid mists so that the first stage HEPA filters achieve lifetimes on the order of months.

The WESP is a vertical vessel containing an array of 120 vertical 6-inch diameter x 6-foot long tubes through which the gas stream passes upward. High voltage (approximately 40 kV) is continuously applied to a 1-inch ionizing electrode located in the axial centerline of each tube to charge by corona discharge the particulate and mist droplets entrained in the gas phase. The charged particles and droplets are attracted to, and collected by, the cool falling liquid film on the inside surfaces of each tube, where they are removed permanently from the gas stream. The WESP outlet particulate loading is expected to be less than 0.0002 grain/dscf.

The WESP is water cooled to enhance collection of submicron particulate. Chilled water is recirculated on the shell side of the tube bundle within the WESP to promote condensation of moisture from the gas stream. A very thin falling film of condensate is uniformly maintained on the inside surfaces of the tubes to continuously collect the particulate that has migrated to the inside tube walls. This condensate, containing particulate, drains from the tubes and continuously collects in the WESP sump, where it flows by gravity to the absorber No. 2 sump. A timed periodic flush of the tube surfaces with fresh water from above will guarantee that the tube surfaces remain clean. All wetted parts associated with the WESP will corrosion resistant alloy or equivalent.

The saturated gas leaving the WESP at 88 to 100° F passes through an in-line electrical resistance reheater that raises the temperature of the gas stream to approximately 30° F above the gas saturation temperature. Raising the temperature prevents moisture condensation in downstream process equipment, including the HEPA filters. Two redundant offgas reheater housings are provided in series. Each reheater housing contains a single bank of electrical resistance heaters. Only one bank of heaters is in service at any time, as each heater bank is capable of raising the flue gas to the desired temperature.

Two parallel, redundant HEPA filter trains are located downstream of the reheater. Each train, sized to accept the entire offgas flow rate, consists of three stages. The first stage contains redundant parallel HEPA filter modules 1A and 1B, two roughing filters, and a water-repellant glass paper nuclear grade DOE certified HEPA filter. The HEPA filters have a manufacturer’s specified minimum particulate removal efficency of 99.9 percent for 0.3m m particulate. Removal efficiency for smaller and larger particles is higher.

Within each stage of each train, one filter element accommodates the gas flow rate. The circular cross-section cylindrical HEPA filters (518 organic debris [OD] x 624 mm long) are rated for 2,000 acfm, continuous service temperature of 392° F and a maximum temperature over short periods of 482° F. The HEPA filter housings for each stage are fabricated of epoxy-coated carbon steel and structurally reinforced to withstand the negative pressure with respect to ambient atmosphere.

The wet scrub system is expected to remove 90 percent of the elemental mercury (Hg⁰) from the gas stream entering the APCS from the SCC. However, to reliably achieve the emission standard for mercury, a fixed two-stage activated carbon adsorber downstream of HEPA filter stage No. 1 is required to collect the remainder of the mercury in the gas stream at this point. Located downstream of the first HEPA filter stage, the staged carbon bed adsorber remains relatively uncontaminated from radioactivity, making changeout of carbon simpler and safer.

The function of this carbon adsorber is to remove residual gas phase elemental mercury downstream of the wet scrub system. A non-dusting extruded carbon is used. Mercury loading ranges from 13 to 15 weight percent, based on total carbon bed mass. Unlike organic physical adsorption on non-impregnated carbons, mercury removal efficiency in impregnated carbon adsorbers is relatively insensitive to temperature up to about 180° F.

The carbon adsorber is a stand-alone vertical vessel that will incorporate both the first and second stages of carbon adsorption. The optimum vessel design configuration will be investigated and established during the detailed design phase. Addition of carbon occurs at the top of the vessel and gravity withdrawal occurs at the bottom. To maximize carbon utilization, when the first stage (lower) bed is withdrawn after mercury breakthrough, the second stage (upper) bed is transferred by gravity to the lower chamber to function as the new first stage bed. Fresh carbon is then added to the second stage (upper) bed.

Each stage is designed to achieve a bed gas residence time of 1 to 1.5 seconds with a pressure drop per stage of 2 to 6 inches w.g. Carbon particle size is approximately 4.0 milimeters.

Though the primary function is mercury control, activated carbon adsorbers can remove some chlorinated dioxin and furan as well. Carbon adsorbent changeout frequency is approximated once every 2 to 3 years, depending on average mercury input concentrations over the period, rated loading capacity of the specific carbon, and total bed volume. Spent carbon adsorbent is recycled to the incinerator. In the incinerator, mercury on the recycled carbon is thermally decomposed to elemental mercury and volatilized. The wet scrub system collects the mercury at 90 percent efficiency. As previously described, so that the primary mercury discharge route for the overall system is the scrub liquid blowdown and ultimately microencapsulation.

The carbon adsorber vessel is fabricated of corrosion-resistant alloy or equivalent. The perforated carbon support plates, where corrosion is most likely, is fabricated of Hastelloy C-22 or equivalent.

The second stage of HEPA filtration contains redundant parallel modules 2A and 2B and consists of a single roughing filter and a water repellant glass paper, nuclear grade, DOE-certified, HEPA filter. The pre-filter within this second HEPA filter stage protects the HEPA filter within this stage. Circular cross-section cylindrical HEPA filters (518 mm OD x 624 mm long) are used. All other specifications for the HEPA filters are identical to those for the first stage HEPA filters.

The third (final) HEPA filter stage is a stainless steel or high alloy HEPA filter. This durable third stage alloy HEPA filter provides environmental protection from any postulated temperature or pressure excursions within the process. Except for the metal filter media used, these filters are of the same size and particulate removal performance as the first and second sage HEPA filters. Following the third stage of HEPA filter modules, the flue gas passes to the induced draft fan where it is delivered to the stack. The parallel induced draft fans control the draft through the AMWTP facility incinerator and APCS. A variable speed drive allows control of the draft to maintain negative pressure within the incinerator system and to sustain the movement of the flue gas through the APCS. Only one induced draft fan is in service at any given time as each fan has the capacity to move the offgas at process flow rates from the incinerator system. The induced draft fan discharges the flue gas to the atmosphere via the stack.

The incinerator stack is located on the south side of the AMWTP facility. The stack has a nominal diameter of 7 inches and is approximately 90 feet in height. A description of the facility stack is provided in Section D of Book 1 of the AMWTP RCRA Application Permit. A continuous emissions monitor (CEM) measuring CO, CO₂, and O₂ is located in the incinerator stack. The CO and CO₂ are monitored using non-dispersive infrared (NDIR) analyzers. The oxygen is monitored using a paramagnetic analyzer.

The stack gas composition and the CEMs status is displayed by the PES at the operator console. The CEMs is equipped with automatic calibration systems to meet the requirements of 40 CFR 266 Appendix IX for daily calibration checks. After completion of the initial performance testing of the O₂ and CO instruments, the instruments calibration is adjusted if the daily calibration check indicates that the calibration drift exceeds the specification in 40 CFR 266 Appendix IX. As per the EPA performance specifications, a performance test will be conducted annually. The CEMs also transmits signals to the PES that indicate under-range, over-range, status, and instrument error conditions. The PES provides the operator with audible and visual alarms in response to these errors and initiates an automatic waste feed cutoff (AWFC) when required.

• The system accurately collects, displays, stores and reports necessary process and safety parameters in real time.

• The system alarms and shuts down the process safely on electric or pneumatic control malfunction as well as on predetermined deviations from normal operation.

• The system generates all required permanent and backup records which include magnetic media and hard copies when required.

• The system performs data reduction such as input averaging, parameter trend display, and data recording at the required logging rate.

• The system allows operation, startup, and shutdown of the system from the central control room.

• The system allows dial-in capability for remote monitoring of operating parameters by regulatory authorities.

• The system tracks and determines the status of all waste material processes through the facility.

Additional information on the control system and data management is provided in Section D of Book 1 of the AMWTP RCRA Permit Application.

Because a TSCA permit will be required for the AMWTP facility incinerator, the sampling and analysis plan has included provisions to demonstrate a 99.9999 percent destruction and removal efficiency of all PCB waste during the low temperature trial burn. Further details associated with the PCB sampling and analysis are included in Appendix D-5 of the AMWTP RCRA Permit Application. Included are calculations showing that the sampling times and methods are adequate to demonstrate the required destruction and removal efficiency.

• Adjust the item or unit in place.

• Repair item or unit by contact maintenance.

• Replace item or unit with spare unless it is more economical to perform remote maintenance or remove, decontaminate, repair, and return it to service.

The fast shutdown mode is activated when operation must be terminated as quickly as possible due to a likely threat to the health and safety of operating personnel or the environment. Fast shutdown mode can be initiated either manually by the operator pressing a button in the central control room, or automatically when one of the defined fast shutdown interlock limits has been reached. When activated, the fast shutdown mode automatically and immediately:

• Shuts off the waste feed

• Closes the waste feed cutoff valve

• Shuts off all PCC burners (secondary combustion chamber burners are maintained), and

• Stops the PCC air supply blowers.

In the event of a fast shutdown, stack ventilation would continue until thermal treatment process cooled to near ambient temperatures. Continued stack ventilation in this scenario would not affect the efficiency of the stack gas control system. TSCA compliance requires 99.9999 percent destruction of PCBs, which is primarily a function of incinerator temperatures and flame residence time. Because waste feed and fuel feed to the primary combustion chamber would be terminated in a fast shutdown scenario but fuel flow and combustion in the secondary combustion chamber (where most thermal destruction occurs) would continue, TSCA compliance would be maintained throughout this procedure.

In order to minimize the occurrence of automatic waste feed cutoff events, pre-alarms are used to indicate that an automatic waste feed cutoff parameter is approaching its limit. All of the automatic waste feed cutoff parameters have a pre-alarm. In the event of an automatic waste feed cutoff pre-alarm, operating personnel will take corrective action to prevent the automatic waste feed cutoff from occurring. The pre-alarm setpoints were chosen to allow the operator sufficient time to take corrective action prior to an automatic waste feed cutoff event.

The melter is used to treat the ash from the incinerator unit, as well as collected cyclone and HEPA filter solids from the melter APCS. Figures B-3-1 and B-3-2 provide simplified process flow diagrams of the melter and the melter APCS, respectively.

The following section describes: 1) the miscellaneous treatment unit, including its physical characteristics, operation, maintenance and monitoring procedures, inspection, closure, and operating standards, and 2) the environmental performance standards for this miscellaneous treatment unit, including waste types processed, containment systems, prevention of air emissions, and mitigative design and operating standards.

The treatment objective for the vitrification process is a glass waste form that will meet the Land Disposal Restriction standards based on the toxicity characteristic leaching procedure. The toxicity characteristic leaching procedure is used to determine the leach rates for HMWA metal constituents. A detailed performance test plan for the vitrification process is provided in the AMWTP RCRA Permit Application.

The vitrification process deploys one melter which includes a feed system, a melter, glass waste form handling system, and an APCS. The vitrification process is used to treat ash by-products from the incineration unit. The feed system handles ash material from the incinerator system as well as recycled solids from the vitrification cyclone and high temperature filters. The melter feed materials are dry solids. The waste solids are conveyed in lidded containers to the melter feed area by the plant central conveyor system. Once in the feed area, waste solids are conveyed by a roller conveyor to one of approximately 56 storage slots flanking the conveyor where they are temporarily staged until needed. When scheduled for processing, the waste drum is conveyed to a drum tipper which transfers the material into a waste storage hopper connected at the bottom to a waste feed hopper. The waste feed hopper delivers an operator-specified mass flow to a screw conveyor which conveys the material toward the melter. A separate entry port along this screw conveyor line delivers metered and operator-specified amounts of glass forming chemicals to the screw conveyor and the blended feed is then delivered into the melter.

The glass forming chemicals are stored and blended in an area external to the main building. They are mixed in defined batches and delivered to storage hoppers in the melter feed area. The glass forming chemicals storage hoppers deliver material through a specially-designed double dump valve to the glass forming chemicals feed hoppers which connect to the main screw conveyor as described above. The double dump valve arrangement is designed to isolate the non-contaminated glass forming chemicals line from the contaminated waste feed line.

The combined mixture of waste feed and glass forming chemicals feed, once in the main screw conveyor, is conveyed to its feed port where an auger feeder assists in delivering the solid material to the melt surface. The auger feeder incorporates an outer water-cooled jacket to thermally isolate the feed screw conveyor material from the melter plenum.

The design of the feed system is based on the assumption that glass forming chemicals will be delivered to the site in bulk by truck. The dry chemicals are pneumatically unloaded from the truck and conveyed into individual storage silos. Each silo provides a 30-day supply of material. The silos are located external to the main facility in order to provide easy truck access and minimize the inactive storage within the facility.

Figure B-3-1. Simplified process flow diagram of the melter.

Figure B-3-2. Simplified process flow diagram of the melter Air Pollution Control System.

The target glass melting temperature is less than 2,200 °F, which allows for Inconel electrode-based melter technology. The residence time for the AMWTP facility melter is at least 48 hours in order to allow for complete dissolution of the solid feed into the molten glass pool with agitation provided by compressed air bubblers. The melter plenum is maintained under constant negative air pressure via the offgas blower to minimize radioactive release into the surrounding melter cell’s ventilation system. Oxygen or enriched air is introduced into the melter plenum to convert any residual carbon from the incinerator ash to carbon dioxide. The melter lid is configured to minimize uncontrolled air in-leakage and permit glovebox maintenance on replaceable components. The melter is fitted with a film cooler to minimize the deposition of material in the discharge port. A water-cooled jacket around the melter is incorporated into the design to reduce the heating load to the melter cell’s ventilation system.

The solid waste, along with glass forming chemicals, is continuously fed to the melter and converted to a glass (vitrified waste), incorporating toxic metals. The glass is poured into a container forming a monolith, then overpacked into another container, and sent for product certification. Table B-3-1 summarizes vitrification process specifications including availability, feed rates, and waste loading.

Table B-3-1. Summary of vitrification process specifications.

The melter has three feed addition ports to provide for suitable dispersion of the feed material onto the molten glass pool. Each feed port has its own independent feed system consisting of a waste storage hopper connected to a waste feed hopper, a glass forming chemical storage hopper connected to a glass forming chemical feed hopper, a screw conveyor, and a melter feed auger. Waste material from the waste feed hoppers described above is metered onto the main screw conveyors at the desired operator-controlled mass flow rate. Once on the conveyor, the waste material is conveyed toward the melter. A second input port into the main screw conveyor delivers the desired operator-controlled amount of blended glass forming chemicals. The glass forming chemicals supply glass forming components otherwise deficient in the waste. Glass forming chemicals are added to the feed stream based on physical and chemical characterization of the waste. The glass forming chemicals are blended and added in amounts required to efficiently produce a durable glass, thus becoming the principal means of process quality control. The glass forming chemicals will be stored and mixed in an area adjacent to the main plant building and pneumatically transferred into the plant. The glass forming chemical mixing and addition system is designed so that the glass composition can be maintained in the desired range by changing the relative amounts of the glass forming chemicals. In this way, the glass forming chemical recipe can be changed as needed to maintain the melt chemistry of glass forming elements within the desired range. The large glass pool dampens fluctuations in the chemical composition of the melt resulting from variability in waste chemistry.

The transfer of glass forming chemical material from the glass forming chemical storage hopper to the glass forming chemical feed hopper uses a valve arrangement that acts to isolate the radiologically clean glass forming chemical transfer lines from the waste feed conveyor lines. The valve arrangement is designed so that air and material flow are balanced to prevent back contamination of the glass forming chemical transfer lines.

The combined mixture of waste and blended glass forming chemicals is conveyed along the main screw conveyor to the melt feed port. A vertical feed auger keeps the port from becoming clogged as the feed material comes off the screw conveyor. The auger is designed with a water-cooling jacket which serves the additional purpose of thermally isolating the feed material from the melter plenum. The feed auger tubes extend approximately 1 to 2 feet into the melter plenum to reduce the amount of carryover feed material into the offgas system.

Temperature within the glass pool is measured by six Inconel sheathed thermocouple assemblies. There are two thermocouple assemblies placed equal distant between the electrodes for each set of electrodes. Each assembly contains 10 type "N" thermocouples within an MgO packing. Starting at the wetted end, the thermocouples are evenly placed within the wetted assembly length. This arrangement places seven thermocouples within the glass pool and three thermocouples within the melter offgas plenum. Three thermocouples within the glass pool are used for melter temperature control purposes. Thermocouple outputs are converted to 4 - 20 mA signals proportional to transmitters. Should a thermocouple fail, the output from the transmitter is higher than 20 mA and an alarm is logged.

For each assembly, the three temperature signals from the middle level of the glass pool are used to make a log average for use by the control system to set the electrode voltage. Should a thermocouple fail, the system transfers to power control and uses the last valid electrode power set point to safely control the melter temperature. The electrode power is held at a constant value and the current is regulated to deliver constant power.

Each electrode pair is controlled by glass pool temperature feedback from thermocouples placed within the melter refractory package and directly in the glass pool.

The first refractory layer, the glass contact refractory, consists of two Monofrax K3 (or equivalent) layers. The primary layer is approximately 12 inches thick and the secondary layer is approximately 5 inches thick. Below the glass level Monofrax K3 (or equivalent) is used, and above the glass Monofrax H (or equivalent) is used because it provides better thermal properties and higher corrosion resistance.

The third layer, the electrical isolation barrier, consists of a 0.5 inch layer of mica (or other insulating material). This layer provides additional isolation between the glass pool and the outer shell of the melter.

Thermal expansion within the refractory package is controlled in two dimensions by an expandable water jacket. Refractory is allowed to expand away from the discharge chambers, and about the melter center line on the long axis. Expansion is controlled by guides and a series of springs and jackbolts located along the melter bottom and side edges. These springs and jackbolts allow the refractory to expand as it heats up, but also provide sufficient force to compress the bricks as the melter cools. Refractory expansion and contraction occurs during thermal cycling. The spring and jackbolt system acts to prevent excessive gaps from forming between the refractory bricks which could allow glass migration and accelerated brick erosion.

The discharge trough is fabricated from Inconel and lined with refractory fiberboard for thermal insulation. Glass entering the discharge chamber flows freely down the discharge trough and pours into a container positioned below at the canister filling station. The gas flow rate controls the rate of discharge. Gas bubbling is stopped at the end of the required discharge operation, and pouring is discontinued once the glass residue in the trough has discharged. The melter is never emptied once operations begin.

Discharge chambers are positioned adjacent to the electrodes to keep the discharge chambers and electrodes at the same electrical potential to avoid joule heating between the Inconel riser and refractory.

The operator samples melter glass at the fill station by inserting a sampling device into the molten glass stream. The sampling device is suitable for insertion into the X-ray fluorescence system. The glass sample is cooled and transferred out of the handling cell to the laboratory where sampling and analysis are performed. A detailed discussion of the sampling and analysis plan can be found in the AMWTP RCRA Permit Application.

The glass-filled drum is transported on rollers to a cooling station. The drum is cooled via a water or air cooling device for 1-2 hours so that it can be lifted by crane and placed back inside the 55-gallon drum overpack. The filled drum is smear tested for contamination. The drum is then transferred to the lid installation station where a 55-gallon lid is installed on the drum.

The glass discharge chamber contains a sealed glovebox with viewports and closed circuit television camera and access to aid the operator in viewing conditions inside the handler, such as glass level, commencement of discharging, discharging rate, and sampling and testing of the glass waste form as required. A stairway and platform with railings allows the operator access to the viewports and access areas.

The critical devices in the system that transmit signals to the central control room and programmable electronic system are listed in Table D-8-5 of the AMWTP RCRA Permit Application.

Toxic metals partitioning to the offgas during the vitrification process are in the form of solid particulates; therefore their release to the environment can be controlled by HEPA filtration. Use of HEPA filters also ensures that the particulate loading of gas leaving the melter offgas train meets regulatory requirements.

The melter APCS includes a film cooler, a cyclone separator, two parallel high temperature filters, two parallel shell and tube heat exchangers, two parallel conventional HEPA filters, and three parallel main blowers (see Figure B-3-2).

Components downstream of the cyclone are duplicated to reduce downtime and to allow maintenance without interrupting operation.

Due to the chemical composition variability of the AMWTP facility waste feed, the vitrification system is designed to handle a wide range of operating conditions. For example, the melter plenum temperatures range from 400 to 1,750^oF, depending on the size of the "cold cap" on top of the molten glass pool. The melter plenum effluent is contacted with film cooler air prior to its introduction to the cyclone. However, to maintain particle removal efficiency in the cyclone, its input volumetric flow rate (which depends on its temperature) should ideally be held constant. Hence, to meet this requirement, the film cooler’s air temperature and flow rate is adjustable over a wide range of operating conditions. This flexibility requirement is met by including electrical duct heaters able to heat the incoming film cooler air up to 850^oF.

The ceramic/metal gas module is a porous cordierite or sintered metal powder monolith which contains numerous parallel passageways extending from one end face to an opposing end face. During operation, the cyclone discharge gas flows through each passageway and particulate matter is collected on the inner surfaces. The filtered gas stream passes through the media and exits the filter by the downstream end face. As the differential pressure across the filters rises, the ceramic/metal gas filter is cleaned by a jet pulse compressed gas stream. The high temperature filter operates between 660 and 930° F.

This additional port through the melter lid permits bypassing of melter emissions from the melter plenum around the film cooler to the cyclone. During normal operations, this flow path is kept closed by valves. A small purge air stream is continuously injected into the port to the melter plenum to minimize potential blockage of this port by melter particulate emissions.

At upset conditions or during maintenance operations on the film cooler, the standby offgas port is opened when the melter plenum pressure reaches a predetermined threshold value. A pressure sensor is interlocked with a control valve which opens the melter plenum to the standby vent line when this threshold is reached. The waste feed to the melter is temporarily discontinued. Ambient air is introduced to the standby offgas port to maintain a constant flow rate to the cyclone. Note that this system utilizes the rest of the APCS for gas cooling and particulate removal. When the upset condition or maintenance operation on the film cooler is completed, the small purge air stream into the standby port is resumed and the control valves to the standby vent line are closed. Normal waste feed to the melter can then be resumed.

Vitrification sub-systems (feed conveyors, filters, APCS components, associated blowers and piping) are repaired or replaced in-place as required. In most cases, a temporary enclosure is used to isolate the work area prior to repair or replacement.

The melter is contained within a set of adjacent Zone 2 process cells. The first cell houses the melter and the rail mounted transporter. The second cell is situated above the first cell and provides access to the dry feed conveyors/mixers and the top of the melter.

A bagless transfer system is used as the system interface for drum access. An overpack drum containing a 40-gallon drum and an inner container lid is placed into the transfer system. A seal is provided between the top rim of the drum and the transfer system. An inner lid removal tool, positioned directly above the drum removes the inner drum lid. The underside of the lid removal tool is kept clean; hence, the top of the inner lid is also kept clean. Once open, the inside of the container becomes part of the contiguous Zone 3 area. An inner drum grappling device located inside the glovebox removes the inner 40-gallon drum and places it onto a conveyor. The conveyor positions the drum under the pour spout for glass waste delivery. Once full and cooled sufficiently for transfer, the 40-gallon drum is conveyed back to the inner drum grappling device for placement back into a container. The inner drum lid removal tool places the inner lid back onto the drum before the seal with the transfer system is broken. Operations personnel check the outside of the drum for contamination, and provide decontamination if needed, prior to placing the outer drum lid and locking ring onto the outer drum. The contamination survey and installation of the outer lid and locking ring are expected to occur within a glovebox. The drums are then transferred to the product certification area.

A system of monitors (e.g., closed circuit television cameras) and instrumentation (e.g., weigh scales or level controls) is provided to ensure maximum loading of each 40-gallon drum. A remote splatter removal tool is provided to clean spilled glass from the floor and walls of the glovebox.

Each of the high temperature filters and the cyclone incorporates an integrated hopper for recycle solids removal. The solids are dumped into containers for transport back into the melter feed system via the central conveyor system. The hoppers, drums, and conveyor are housed in a permanent glovebox with HEPA filtered exhaust.

The microencapsulation process would be used to grout and solidify the incinerator ash and salt from the brine evaporation in 55-gallon drums. The resulting 55-gallon drums of grouted ash are then ready for final shipping and disposal. The microencapsulation process (see Figure B-4-1) is similar in concept to the macroencapsulation process described in Section B-1.2.

There would be two microencapsulation drum lines located in the northwest portion of the building. Ash would be transferred from the incinerator area into the ash receipt hopper. The ash would be below 86° F and would be reduced in size to less than 6 millimeters. The receipt hopper has a nominal capacity of 1 day of ash production. Ash would then be transferred via screwfeeder to the ash blender. In combination with incinerator campaigns of high and low activity waste, ash blending ensures that the final product has a specific activity greater than 100 nCi/g.

From the ash mixing hopper, the material would be metered to the ash feed hopper until the required mass to fill one product drum has been received. Within this hopper, the material would be assayed to give the total fissile gram equivalent in the product drum. The ash would be transferred into a product drum via screwfeeder. The inside of ash hoppers and screw feeders are Zone 3 areas and would be maintained at a negative pressure to confine ash within the system.

Cement powder (ordinary PortlandÔ cement) and pulverized fuel ash would then be transferred for blending via an elevator to the cement intermediate mixing hopper. The cement mix would then be transferred to an intermediate cement hopper where the required quantity of cement for an individual drum is batched via screwfeeder into the cement feed hopper. The cement feed hopper would be weighed to confirm the correct mass and the material fed via screwfeeder into the product drum.

Next, product drums containing a mixing paddle and a bagless transfer inner lid would be supplied to the fill system. Chilled water is metered to the drum at the water addition station. The drum is moved to the in-drum mixing station and raised up to the bagless transfer port. The inner lid is removed by the lidding mechanism, and the top of the inner lid is kept clean by keeping it attached to the lidding mechanism throughout the fill cycle. The mixing head is lowered into position and coupled with the mixing paddle in the drum. The mixing paddle is then started, and the ash added to the water in the drum via the ash metering screwfeeder.

The process would be performed within a Zone 3 glovebox kept at negative pressure to confine any ash that may become airborne during loading. Chilled air is circulated around the outside of the drum in the Zone 2 area to cool the ash mixture. The drum mixing glovebox has a drip tray below the mixing drum to contain any liquid or powder spills.

Following mixing of the ash-water mixture, cement would be added to the drum, and the drum content mixed. The mixing paddle remains in the product drum. Samples of the mixture would be obtained before an inner lid is placed on the drum. Once the lid is in place, the drum is removed from the bagless transfer unit, manually swabbed for external contamination, fitted with an outer lid, and transferred to the drum cure area for curing.

• Level on ash receipt and ash blend hoppers
• Neutron assay in the ash feed assay hopper
• Weight in the ash feed assay hopper
• Weight in the cement feed hopper
• Level in the product drum
• Temperature in the drum mixing glovebox
• Weight in the product drum
• Pressure in all Zone 3 areas.

Operation of the AMWTP facility would generate additional wastes that would have to be treated. The amount of wastes and types are dependent on the throughput rates and the processes used in the facility. Tables B-5-1 and B-5-2 shows the operations throughput rates for the AMWTP facility processes for 65,000 cubic meters. Table B-5-3 show the secondary waste streams generated for the facility with the microencapsulation of incinerator ash process. Also shown is the proposed treatment for each of the waste streams. The AMWTP facility with vitrification of incinerator ash would generate more secondary waste as shown in Table B-5-4.

Table B-5-1. AMWTP unit operations total and annual throughput rates for 65,000 cubic meters.

Table B-5-2. AMWTP unit operations daily and hourly throughput rates for 65,000 cubic meters.

Table B-5-3. AMWTP facility with microencapsulation, secondary waste streams and treatment.

Table B-5-4. AMWTP facility with vitrification, secondary waste streams and treatment.