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HomeMy WebLinkAboutCOM 0582.025 2004-2006Harry Kim Mayor June 19, 2006 Barbara Bell Director Nelson He Deputy Director aunty of cK Cttfunii DEPARTMENT OF ENVIRONMENTAL MANAGEMENT 25 Aupuni Street, Room 210 • Hilo, Hawari 967204252 (808) 961-8083 • Fax (808) 961-8086 email: cohdemAco.hawaii.hi.us N Mr. Gary Safarik, Chair and Members of the Environmental Management Council Committee 25 Aupuni Street Hilo, HI 96720 SUBJECT: Documents Requested in Today's Environmental Management Committee Meeting Dear Chair Safarik and Committee Members, Enclosed are the following documents that were discussed in your Committee meeting today: • Anaerobic Digestion Questions and Answers Memo from R. W. Beck received by the County on May 8, 2006 • Revised Draft Technical Memorandum from R. W. Beck dated April 10, 2006 If you have additional questions, please don't hesitate to contact me at 961-8083 or Finance Director William Takaba. Sincerely, l Barbara Bell DIRECTOR enclosures cc: Harry Kim, Mayor Stacy Higa, Chair, County Council William Takaba, Finance Director Mike Dworsky, SWD Chief ,Y)4 Hawaii County is an equal opportunity provider and employer. comm. No. &M2-.2-00 Ref. To: Ref. Date -JUN 20 MEMORANDUM To: Waste Reduction Project Team From: Bob Bingham Subject: Anaerobic Digestion Questions & Answers Date: May 5, 2006 This document is intended to provide answers to questions related to anaerobic digestion (AD) that have been raised during the procurement phase of the Hawaii County Waste Reduction Facility Design -Build -Operate Project. 1. What does the current operating experience of anaerobic digestion facilities (in Europe and elsewhere) tell us about the use of MSW Feedstocks? The majority of AD facilities are designed to process organic waste only. Homogeneous waste products such as vegetative waste, sewage biosolids and manure require only shredding and mixing as a preprocessing step. Mixed waste such as municipal garbage, on the other hand, requires extensive preprocessing to separate the organic fraction of the waste from materials that cannot be digested. This preprocessing step is costly and often only partially effective. For this reason out of the total number of Anaerobic Digesting facilities currently operating, only a small percentage (less than 5%) use mixed municipal waste as the feedstock. Attempts have been made to design AD facilities that are effective in preprocessing MSW to remove inorganic materials prior to the digestion process. These have been only partially successful and have not been effective in avoiding contamination of the digester residue. One system which has shown promise uses a water "bath" to gravity separate materials. It has been used successfully in Israel for several years; however it does not have an operating history on U.S. municipal solid waste. The County will continue to monitor these developments and determine how they may offer solutions to Hawai`i's solid waste management needs. 2. What collection systems are most beneficial for anaerobic digestion facilities? The best collection system for AD are systems that include separation of inorganic (glass, metals, plastics, paper, and hazardous materials) and/or provide separate collection of organics such as green waste, biosolids and food waste. The collection systems that most thoroughly and effectively isolate the organic fraction of the waste stream for digestion are the ones that will produce the most beneficial byproducts (digester residue and biogas or energy) and will maximize the waste reduction capabilities of anaerobic digestion. Waste from collection systems that do not effectively isolate the organic portion require varying Anaerobic Digestion QA.doc 1001 Fourth Avenue, Suite 2500 Seattle, WA 98154-1004, Phone (206) 695-4700, Fax (206) 695-4701 MEMORANDUM May 5, 2006 Page 2 levels of material preprocessing prior to digestion depending on the extent of the isolation and the desired quality of the byproducts. 3. The Tech Memo states that a volume reduction of 60% could be achieved if a beneficial use could be found for the resulting residue. What are the issues related to finding a beneficial use for the residue? The principle concern with respect to the beneficial use of AD residue is related to the presence of chemical and inorganic contaminants. Specifically beneficial use of the residue is affected by: • Presence of plastic debris that make the residue unsightly and unsuitable for horticultural purposes, ■ Presence of chemical contamination that exceeds health standards or recommended limits for use in horticultural applications such as use as a soil amendment, and ■ Difficulty in obtaining long-term contracts with product users; long-term contracts are typically a prerequisite for public financing. In addition to beneficial use of the residue, effective volume reduction requires that markets/uses be found for materials (glass, paper, metals, etc.) that are source separated or removed in preprocessing. In cases where markets are not found, these materials would be landfilled and would significantly reduce the amount of waste reduction achieved. 4. The Technology Memo states that European Systems are "more focused on keeping toxics out of the waste stream than programs required by RCRA Subtitle D". How does this affect anaerobic digestion and the solid waste system? Are any such options available for Hawaii to implement? RCRA Subtitle D regulations set out specific procedures and protocols that state and local governments are to follow to ensure the proper disposal of materials that pose a potential hazard to human health. These regulations define clearly the specific materials that are hazardous or potentially hazardous and are followed by current solid waste operations in Hawaii. In Europe, solid waste management regulations and collection programs are more focused on efforts to create a waste stream suitable for use in alternative waste management technologies such as AD. Legislation seeks to ensure that as much reuse, recycling, and recovery as is possible occurs. There is detailed legislation on specific waste streams, such as waste oils, sewage sludge, batteries, packaging, polychlorinated biphenyls and polychlorinated terphenyls, junk vehicles and electrical and electronic equipment. This focused regulatory effort has resulted in collection systems and waste management techniques that remove more toxics than systems currently in place in the U.S. These circumstances result in much better and more beneficial residues and biogases resulting from an AD Facility. 1001 Fourth Avenue, Suite 2500 Seattle, WA 98154-1004, Phone (206) 695-4700, Fax (206) 695-4701 MEMORANDUM May 5, 2006 Page 3 Implementation of more stringent screening and diversion practices could be undertaken by Hawaii County but would require some significant expenditures in training, education, and facilities and would require several years to implement. Many other options could only be effectively implemented if done on a state-wide basis. 5. Certain anaerobic digestion processes are in use outside of the U.S. and seem to be working well. One such technology uses a wet separation system as a way of removing materials that cannot be digested. Has the County considered these developments? For the purposes of the Hawaii County WU DBO Project, the selection of technologies was based on two principal criteria: ■ The technology must have a proven track record in achieving a very high level of volume reduction that will minimize the shipment of waste from East Hawaii to West Hawaii for disposal. • The technology must be supported by a financially strong contractor/developer that is willing to provide financial and performance guarantees such as are typical on municipal utility projects. The fact that AD systems are operating successfully outside the U.S. is a very promising development. History has shown however, that when new solid waste technologies are brought to the U.S., there are often unanticipated technical and operational problems. This is mostly due to the differences in waste stream characteristics. In time, many of these problems can be overcome provided the company supplying equipment, constructing, and operating the project is willing to provide the expertise and financial resources required. In the future, anaerobic digestion may provide an attractive management option for municipal solid waste. However, after extensive review of the current status of commercial anaerobic digestion facilities, the County does not believe that AD is a viable option at this time because AD does not have a proven successful track record on U.S. municipal waste and there does not appear to be any private companies willing to provide the financial guarantees necessary to assure project success. An additional consideration is that if the RFP were to include technologies, such as AD, that do not have the desired minimum qualifications, other viable companies offering technologies that meet these qualifications may decide not to participate in the Project. The County will continue to monitor developments related to AD and other emerging waste reduction technologies as possible future solutions to its waste management needs. 6. What would be required, in the short-term and the long-term, for anaerobic digestion to be implemented effectively on Hawaii's MSW? For AD to be implemented to effectively, the County would need to modify its current collection systems, accept higher levels of trash hauling the Pu'uanahula landfill from East Hawaii and accept higher financial and technical risk than currently proposed. 1001 Fourth Avenue, Suite 2500 Seattle, WA 98154-1004, Phone (206) 695-4700, Fax (206) 695-4701 MEMORANDUM May 5, 2006 Page 4 Short -Term To meet these criteria in the short-term, the County would need to focus on its collection system and infrastructure in place to isolate the organic material. This could be done by implementing an aggressive recycling program that may include single -stream or dual - stream source separation of recyclables, separate collection of organics like yard and food waste, and/or potential incorporation of Material Recovery Facilities (MRFs) for processing of the MSW. This step will also require effort to educate and empower citizens to recycle and to approach waste diversion aggressively. The County would need to deliver waste to the anaerobic digestion facility that is of similar composition as that which is received at existing facilities that are operating successfully. The track records for successful AD facilities show that, based on the current state of the technology, extensive diversion of non -digestible materials is required to meet the County's goals. Also, any guarantees by an experienced developer using a proven anaerobic digestion process would require that the feedstock meet certain minimum requirements, these requirements could only be met with significant changes to the existing collection system and waste management infrastructure. Long -Term In the long-term, the County would have more flexibility to wait for the AD technology to mature and for demonstration of operational success in the U.S. to occur. There are many promising developments occurring in this area and it is reasonable to assume that as existing facilities continue to advance and new pilot programs are brought to full commercialization, AD may develop into a method for processing MSW that meets the County's needs. This success will also bring financially strong developers eager to provide financial and performance guarantees 1001 Fourth Avenue, Suite 2500 Seattle, WA 98154-1004, Phone (206) 695-4700, Fax (206) 695-4701 REVISED DRAFT TECHNICAL MEMORANDUM To: William Takaba, Barbara Bell From: Bob Bingham Subject: Update of Technology Assessment Date: April 10, 2006 Introduction and Summary of Conclusions This revised draft Technical Memorandum summarizes R.W Beck's review and update of the technology assessment contained in the Integrated Solid Waste Management Plan (Plan) for the County of Hawaii dated December 31, 2002. The intent of this review is to further describe and refine the conclusions of the previous studies and assess the current status of each technology with respect to: ■ Applicability of the technology to the specific needs and objectives established for the County's Waste Reduction Facility, including the capability to reduce the quantity of waste requiring landfilling. ■ Commercial status, and ■ Risks associated with each technology. We have also provided an overview description and discussion of waste products and emissions controls to assist the County in the implementation of the EISPN process. The specific technologies reviewed included: ■ Waste -to -Energy (combustion) ■ Thermal Gasification ■ Anaerobic Digestion ■ Aerobic MSW Composting; and ■ Bio -Refining Based on our review, three principal issues should be considered in deciding whether or not to eliminate the consideration of a particular technology at this time: ■ Extent of Pre-processing Required. There have been many advancements in the technologies discussed in the Plan since 2002. Even with these advancements however, the potential use of any of these technologies on an MSW feedstock would be highly dependent on the ability to separate the organic fraction of the waste from the inorganic fraction and to produce an organic feedstock that is relatively free of contaminants. (Indeed most of the technological advancements have been made with organic feed stocks other than MSW.) Commercial Status. One issue that we evaluated was the extent to which any of these technologies can be considered to be "fully commercialized." A fully commercialized 011278 11-01067-10000/20011 Revised Draft Technology Memo41406.doc 1001 Fourth Avenue, Suite 2500 Seattle, WA 98154-1004, Phone (206) 695-4700, Fax (206) 695-4701 REVISED DRAFT TECHNICAL MEMORANDUM technology would be where: 1) the technology has been proven at "full scale"; 2) a number of plants and all support facilities necessary for a commercial operation have been developed and have established a successful operating record; 3) vendors are willing to provide guarantees that are sufficient to obtain non-recourse financing (financing where the only security is the project itself); and 4) adequate market financing is available. While Waste -to -Energy is a fully commercial technology, the status of the other technologies is less well defined. For example: 1. MSW Composting, once considered a fully commercial technology, is becoming somewhat problematic because of plant shutdowns due to odor problems and unwillingness of vendors to provide needed guarantees to obtain financing. There have also been problems obtaining markets for the compost product which can be visually contaminated with small pieces of plastic. Some level of front-end process to remove inorganics and plastics would be preferable, although some processes attempt to remove compost contaminants by screening the final compost product. 2. There are currently a few full-scale Thermal Gasification demonstration projects using MSW as feedstock. Plasma arc technology on MSW is currently in the research and development stage. 3. While Anaerobic Digestion is fully commercialized for sewage sludge, livestock waste, agricultural waste, and less commonly food waste, Anaerobic Digestion of MSW is a relatively new application of the technology. To our knowledge, there are no full-scale operating Anaerobic Digestion facilities using MSW as feedstock in the U.S. There are, however, several facilities in commercial operation outside the U.S, and these facilities are reported to be operating successfully as they rely on an organic feedstock. The lack of U.S. commercial operating experience for anaerobic digestion is significant because one of the unknowns for this technology is whether or not it can produce a clean marketable end product using municipal solid waste with the composition typically found in the U.S. We are not aware of any vendors offering performance guarantees for Anaerobic Digestion systems using MSW as the primary feedstock 4. Bio -Refining has not been commercially proven. The County's Solid Waste Management Plan identified a full scale project that was proposed for processing MSW and sewage sludge in Middletown, New York. However, this project has yet to be developed. ■ Volume Reduction). For each technology, we evaluated its ability to reduce the volume of waste to be landfilled. This was done using the County's waste stream composition, determined from a Waste Characterization Study conducted in August 2001. Of critical importance in the assessment of volume reduction (i.e. not landfilled) is: 1. Whether or not the materials removed in the preprocessing step have viable markets and 2. Whether or not there are beneficial uses for the process residue produced (i.e. will the residue be used in some beneficial manner or will it end up in the landfill?) 2 R. W. Beck Revised Dmft Technology Memo41406.doc 4/18/06 REVISED DRAFT TECHNICAL MEMORANDUM Secondary materials produced in Hawaii, when recycled or recovered are sent either to the mainland or to Asia. For several years, markets for recovered materials on the island of Hawaii have been generally limited to high value materials such as aluminum and certain types of paper. However, trends show an increase in demand in west coast markets on the mainland and in Asia (specifically China) which may translate to more stable and profitable secondary materials markets in Hawaii in the future. With respect to beneficial uses for process residues, both Anaerbic Digestion and Composting produce a residue that can be used as soil amendments. Unfortunately, on a number of other projects in the U.S. these residues have experienced contamination which has prohibited their use as a soil amendment. In some cases this problem has been addressed by using the residue as landfill cover. This is not an acceptable long-term option for the County however, because once South Hilo Landfill closes, it will result in significantly more truck traffic to Pu'uanahulu. Revised Draft Technology Memo41406. doe 4/18/06 R. W. Beck 3 REVISED DRAFT TECHNICAL MEMORANDUM Technology: Waste -to -Energy (Combustion) 1. Overview Description Waste -to -Energy (WTE) facilities combust MSW and use the heat of combustion to produce steam, which in turn, is used to generate electricity. WTE systems typically consist of five basic components: • Waste Pre -Processing Area, where non-combustible items and unacceptable waste is removed and the remaining materials are pre-processed for combustion. While combustors can receive the full MSW stream, materials such as large appliances are removed. Attempts may also be made to remove toxic materials, such that occur in electronic equipment, through disposal bans or other means. • Combustion/Boiler, where combustion occurs and the heat of combustion is used to heat water and produce steam. ■ Power generation, where steam is used to power turbine generators. • Ash handling and disposal which involves collection of residue from the combustion chamber and emission control system and landfill disposal. • Emissions control, which involves a number of process controls and treatment so that emissions can meet regulatory and permit requirements. The two basic technologies used are mass burn, in which MSW is burned with little or no pre-processing , and refuse -derived fuel (RDF) in which MSW is reduced in size and processed into a more uniform fuel (typically "fluff' or pellets): Mass Burn facilities tend to use less complex mechanical feed and combustion systems so that they can accommodate a wide range of materials into the combustion process. The two basic combustion processes used are starved air and excess air. The particular process used at any given installation will depend upon a number of factors including size (capacity), manufacturer, and waste characteristics. Mass burn facilities typically range in capacity from very small up to about 300 tons/day. They generally can accept up to 98 percent of delivered material (The two percent represents waste such as appliances). They typically reduce the amount of waste that is delivered by about 75 to 90 percent on a volume basis and by about 70 to 80 percent on a weight basis. (As an example, if 100 tons of MSW were delivered to the Reload Building, about 96 to 98 tons of material would actually be combusted.) An illustration of a typical mass burn process is included at the end of this section. RDF facilities use more complex waste feeding systems and typically are more efficient than mass burn facilities. That is, RDF facilities typically generate more electricity per ton of waste processed than mass bum systems. However, the increased mechanical complexity and more efficient boiler systems add additional capital cost. RDF projects are also more labor intensive, require more staff and have higher operations and maintenance costs. As a result, RDF facilities are generally 4 R. W. Beck Revised Dreg Technology Memo41406 dm 4/18/06 REVISED DRAFT TECHNICAL MEMORANDUM used for larger facilities (300 tons/day and greater) where they can realize economies of scale. RDF systems typically reduce the amount of waste that is delivered by about 65 to 80 percent on a volume basis and by about 50 to 70 percent on a weight basis. (This means that if 100 tons of MSW were delivered to the Reload Building, about 75 tons of material would actually be combusted and between 30 and 50 tons of ash and non-combustible wastes would need to be disposed of at the landfill.) An illustration of a typical RDF process is included at the end of this section. 2. Waste Products/Environmental Controls WTE facilities produce a number of air pollutants that are the by-products of combustion. Accordingly, air emission controls are a critical component of these facilities and can represent up to about 30 percent of the system cost. The specific control systems required will depend on plant size, combustion type, waste characteristics and local air quality regulations. Typical emissions controls include: • Temperature and residence time system controls to limit the production of dioxin (tested for annually per EPA Clean Air Act regulations), • Ammonia (or urea) injection into the combustion gas stream for nitrous oxide (NOX) control, • Carbon injection into the gas stream after it exits the boiler area for mercury control, • Hydrated lime slurry wet/dry scrubbers (or sodium bicarbonate dry/dry scrubbers) for acid gas control, and • Fabric filter baghouse for removal of particulates and other contaminants. The principal solid waste product of combustion is ash. Ash is generally not a hazardous waste, but owner/operators must perform an initial characterization of the ash to demonstrate that it is not hazardous, and then test the ash on a periodic basis to confirm that the ash does not exceed standards for solid waste disposal. 3. Applicability to the County of Hawaii WRF Project Volume Reduction MSW combustion would provide an effective means of reducing the volume of waste requiring transportation and disposal in west Hawaii. Given the expected size of the facility, mass bum would be the most likely technology. With mass burn, the volume of material delivered to the Reload Building tipping floor would be reduced by between 70 and 80 percent (see Table 4). Materials that would continue to require landfill disposal include ash resulting from the combustion process and materials, such as appliances and bulky waste, removed at the Reload Building tipping floor. In a RDF system, significantly more material would be removed during pre-processing, compared to mass burn, in order to produce a uniform fuel. The overall volume reduction for a RDF facility would be on the order of 65 to 80 percent (see Table 4). Revised Draft Technology Memo41406.doc 4/18/06 R. W. Beck 5 REVISED DRAFT TECHNICAL MEMORANDUM Operational Issues A mass bum facility would generally be compatible with the County's planned Reload Facility in that presorting to remove undesired items could be conducted on the Reload Building's tipping floor. It is expected that a RDF facility would utilize the Reload Building tipping floor for removal of appliances and bulky items, and would likely require an estimated 10,000 to 12,000 square feet of additional pre-processing space and processing equipment. 4. Commercial Status MSW combustion is a fully commercialized process and has been widely implemented in the U.S. and worldwide. Approximately 90 WTE projects are operating in the U. S., most of which are fairly large (900 tons per day average). Many small plants (less than 100 tpd) have been closed in recent years due to poor economics except in more isolated areas such as Alaska. 5. Approximate Cost The capital cost of a mass burn facility with a capacity of 250 tons per day (200 tons per day average) is expected to be between about $30 and $40 Million. Operations and maintenance costs for the facility are expected to range from about $35 to $45 per ton (excluding residuals disposal). Total cost per ton (amortized capital and operations costs) is expected to range from $68 to $89 per ton. Capital cost for a RDF facility with a capacity of 250 tons per day (200 tons per day average) is estimated at about $35 to $45 Million. For operations and maintenance, costs per ton are expected to range from $45 to $50 excluding residuals disposal. The total cost per ton is therefore expected to range from about $84 to $100 for amortized capital and O&M costs. This difference in cost between a RDF and a Mass Burn facility is due to the more complex systems and the more extensive pre-processing required for RDF. Overall, we would expect a facility in Hawaii to be on the higher end of these ranges due to size and location. However, vendors may have specific business objectives (a desire to break into a particular market for example) that could make pricing more competitive. The potential energy production from a WTE plant is expected to be between 80 and 100 net MWHr per day for mass burn and between 90 and 110 net MWHr per day for RDF. 6. Risks The principal risks associated with WTE facilities include Technology • Waste processing capacity less than specified. • Volume reduction less than predicted. • Energy production less efficient than expected. • Unscheduled maintenance exceeds estimates. • Unreliable/inconsistent energy production. 6 R. W. Beck Revised Draft Technology Menno41406 doe 4/18/06 REVISED DRAFT TECHNICAL MEMORANDUM Environmental • Exceedance of air quality permit limits. • Potential contamination of ash with metals or other materials. ■ Odor from RDF pre-processing. Financial • Lower than projected energy sales or prices. ■ Higher than projected operating costs. Revised Dmft Technology Memo41406.doc 4/16/06 R. W. Beck 7 w S = D z� W m U 6 0 Z O m LU J Q U Z uj W F F D O LU U) LU w REVISED DRAFT TECHNICAL MEMORANDUM Technology: Thermal Gasification 1. Overview Description Thermal Gasification involves heating a carbon based feedstock in a controlled oxygen environment to drive off reduced or partially oxidized gases. Thermal Gasification processes involve high pressures and temperatures and require containment vessels, pumps, and other equipment to maintain these conditions. To be commercially viable, MSW Thermal Gasification systems would include the following basic components: • Waste Pre-processing Area, to remove materials that cannot be thermally degraded (such as metals, glass, and concrete) and to pre-process remaining materials into a uniform feedstock. Size reduction, densification, and drying the waste may be involved. • Reactor/Gas Refining, where gasification reactions occur and the resulting product (gases, oils) is refined, as needed, to produce gas of suitable quality. The gas produced is often referred to as "synthesis gas" or "syngas", because it is predominantly a combination of methane and hydrogen. • Power Generation or Chemical Production, using the syngas and/or oils as a fuel or feedstock. Unrefined or minimally refined gas can be burned directly in boilers with heat recovery to produce steam for electricity generation. More refined gas can be used in reciprocating engines, gas turbines, or for chemical production. • Emissions Control on units combusting the gas produced. • Ash, Char, or Slag Handling and Disposal. Several specific processes fall into this group including: Pyrolysis, which heats a carbon -based feedstock in a sealed pressurized chamber (drum, kiln, or tube) in the absence of oxygen to produce char, oils, and gas. Because of the lack of oxygen, no combustion occurs but an external heat source is required to drive the reaction. Temperature, pressure, and other factors are used to control the products of pyrolysis. For example, heating at lower temperatures primarily produces oils while heating at higher temperatures primarily produces gases. Gas produced by a pyrolysis reaction typically contains methane, carbon monoxide, hydrogen, carbon dioxide, and water. The gas is typically refined and can then be burned to produce electricity or for use in the production of organic chemicals. Design variations include flash pyrolysis which involves contact with extremely high temperatures and rapid vaporization of the feedstock and slow pyrolysis which can take several minutes. (Slow pyrolysis is typically used to produce charcoal, activated carbon, and coke.) Pyrolysis has been used in industrial applications for many years to manufacture products such as charcoal, activated carbon, carbon black, and coke. Pyrolysis has been used on 10 R. W. Beck Revised D,e4 Technology Memo41406.doc 4/18/06 REVISED DRAFT TECHNICAL MEMORANDUM wood, coal, and homogenous waste streams such as shredded tires and coconut shells. Pyrolysis has also been used on MSW; but requires significant pre-processing to create a uniform fuel. In addition, the feed systems have had significant technical problems related to their ability to uniformly and continuously feed material into the pyrolysis chamber. • Conventional Gasification, which heats a carbon -based feedstock with a controlled input of oxygen or air to produce syngas that, in turn, can be used to produce electricity or organic chemicals. Because some oxygen is introduced, a small amount of combustion occurs. The heat from this combustion then thermally degrades the remaining materials to form char, oils, and syngas. The gas produced in these systems typically contains methane, carbon monoxide, and hydrogen. Several design variations exist for gasifiers in which various technologies are used for moving material through the gasifier and for introducing oxygen or air. For example, fixed bed gasifiers involve moving the feedstock through the system over stationary or moving grates while fluid bed designs involve filling the gasifier with inert particles, such as sand, and entraining and suspending the feedstock throughout the bed. Updraft gasifiers inject oxygen or air from the bottom, and gas exits from the top. Downdraft gasifiers introduce oxygen or air at the top with gas exiting the bottom. Gasification has been used for over a hundred years in various applications, including production of gas for street lighting and cooking, production of organic chemicals, and electricity generation. Typical organic feedstocks include coal and uniform biomass waste such as rice hulls, wood waste, and other agricultural wastes. MSW gasification has had limited success due to several factors. First, because MSW is not uniform, significant pre-processing is required to create a uniform feedstock, such as RDF. Without such pre-processing, constant delivery of material to the gasifier is problematic. (Historic attempts at using minimally processed MSW as a feedstock ran into technical problems with handling and uniform feeding of the feedstock to the gasifiers.) Other issues have included temperature, process control, and cost. Another factor is the need to keep impurities out of the feedstock. • Plasma Arc, which discharges high voltage electricity to "super heat' a gas (such as air, oxygen, nitrogen, hydrogen, or argon) to temperatures above 7000 degrees F. The hot ionized gas (plasma) then comes in contact with the feedstock, producing syngas, which in turn can be used for the production of organic chemicals or the generation of electricity. Plasma arc gasification requires a closed, pressurized reactor and "torches" to produce the high voltage electrical discharge. The amount of air or oxygen introduced is controlled in order to promote certain chemical reactions. A number of design variations are possible. Some designs involve the production of plasma outside of the reactor vessel. Plasma and feedstock are then introduced into the vessel. Other designs create plasma inside of the reactor vessel. Plasma are technology has been used for stabilizing hazardous and medical waste by creating an in inert vitrified material that does not leach contaminants. As discussed Revised Draft Technology Me=41406.doc 4/18/06 R. W. Beck II REVISED DRAFT TECHNICAL MEMORANDUM below under "Commercial Status", use of plasma arc/gasification technology on MSW is still in the research and development (R&D) phase. An illustration of a typical Thermal Gasification process is included at the end of this section. 2. Waste Products/Environmental Controls Air emissions and disposal of residual solids (ash, char, and slag) are the principal environmental concerns for Thermal Gasification processes. Typical emissions controls include: • Where syngas is burned in a boiler, reciprocating engine, or gas turbine, temperature, and residence time system controls to limit the production of dioxin (tested for annually per EPA Clean Air Act regulations), • Ammonia (or urea) injection, where syngas is burned in a boiler, for NOX control, • Carbon injection into the gas stream after it exits the boiler area for mercury and trace metal control, • Hydrated lime slurry wet/dry scrubbers (or sodium bicarbonate dry/dry scrubbers) for acid gas control, and ■ Fabric filter baghouse for removal of particulates. Pyrolysis and gasification systems produce several residues including char, silica, slag, and ash. These residues are typically landfilled and are subject to the same tests to assure they are not hazardous waste as is ash produced from a WTE facility. Slag from a conventional gasification process can sometimes be used in the manufacture of asphalt and roofing tiles. Plasma arc technology produces an inert vitrified material that is well suited to landfill disposal. 3. Applicability to County of Hawaii WRF Project Volume Reduction As mentioned above, Thermal Gasification plants typically require pre-processing to remove large non-combustible materials and create a uniform feedstock. If little pre-processing is required by the specific technology selected, overall volume reduction can theoretically approach 90 percent, but this type of facility will be more susceptible to shutdowns due to operation problems, and maintenance of the equipment will be more costly. If more extensive pre- processing is required for the specific technology selected (as we would expect) and more materials are removed "upstream" of the gasification process, overall volume reduction is expected to be in the range of 65 to 85 percent (see Table 4). Operational Issues A Thermal Gasification facility with pre-processing would utilize the Reload Building tipping floor to remove appliances and bulky items but would also likely require about 10,000 to 12,000 12 R. W. Beck Revised Draft Technology Memo41406.doc4119106 REVISED DRAFT TECHNICAL MEMORANDUM square feet of additional space and pre-processing equipment such as screens, conveyors, and magnets. 4. Commercial Status To our knowledge there are currently very few vendors offering performance guarantees on Thermal Gasification systems using MSW as the primary feedstock. There are a limited number of plants in the demonstration phase however. Conventional gasification plants using MSW as a feedstock are operational in Europe. (For example, there are two demonstration units in Italy that were designed to use palletized RDF as a feedstock.) It is expected that a number of plants could be constructed there over the next several years, but it is not clear whether or not there would be commercially financed or partially funded through government grants. It also should be noted that source separation of materials is strongly mandated in Europe so the MSW feedstock would be more uniform than what would be expected in Hawaii County. There are a few Thermal Gasification units in Japan in the range of 6.25 tonnes/hr. There are two plasma arc units in Japan that in part use MSW and are approximately 20 tpd and 160 tpd in size. The 160 tpd facility is being developed by Hitachi Metals. The design uses pre-processed MSW and auto shredder waste. We attempted to obtain operating data from that plant as part of a previous project but were not provided the requested information. We, therefore, were unable to determine if acceptable performance criteria are being met at that facility. 5. Approximate Cost There is limited information available on the capital and operations costs of commercial scale Thermal Gasification facilities. Based on the best information available, capital cost for gasification facilities of the capacity expected for the Hawaii WRF is expected to range from about $42 to $54 million including pre-processing. Operation and maintenance costs are expected to range from about $45 to $55 per ton, resulting in a total cost (amortized capital plus O&M costs) of between about $91 and $114 per ton. See Table 4 for a summary of these costs. The average energy production for a Thermal Gasification plant could range from 60 to 120 net MWHr per day, depending on the technology and other factors. 6. Risks Technology • Contamination of feed stock - poor performance. • Mechanical failures/equipment malfunction. • Failure of design to provide required capacity and quality of syngas. • Scale -up problems (i.e. demonstration projects do not accurately predict full scale performance). Revised Draft Technology Memo41406.doe 4/18/06 R. W. Beck 13 REVISED DRAFT TECHNICAL MEMORANDUM Environmental ■ Odor from waste preprocessing activities. Financial Lack of financial performance guarantees. No market for syngas product. 14 R. W. Beck Revised Draft Technology Men,A14%doc 4/18/06 0 z 0 m w J Q V Z 2 U W F I. - LL. In W U) W w 00 F- Z Q OZ z O W ZZ LL_ U n I � A r e i _s n I REVISED DRAFT TECHNICAL MEMORANDUM Technology: Anaerobic Digestion 1. Overview Description Anaerobic Digestion is a biological process that entails microbial breakdown of large organic molecules into methane and carbon dioxide in the absence of oxygen. A useful product of Anaerobic Digestion is biogas (methane and carbon dioxide). In addition to generating gas, Anaerobic Digestion produces a residue that contains inorganics, non -degradable organics, and other materials. Following the digestion process, these solids may be cured in standard composting type systems. A typical Anaerobic Digestion system would include the following components: • Waste Pre-processing Area, to remove materials that cannot be anaerobically digested (such as metals, glass, and concrete) to pre-process the remaining materials into a uniform feedstock. Moisture is often added to this material to form a slurry in the digester. • Anaerobic Digester, where large organic compounds are broken down into smaller compounds in an airtight vessel, called a reactor or digester. The gas produced by Anaerobic Digestion can be used with minimal treatment in boilers to generate heat and in reciprocating engines or turbines to generate electricity. If the gas is purified, it can be used in place of natural gas or compressed natural gas as a vehicle fuel. • Gas Flaring, Steam and/or Power Generation using the digester as a fuel. • Emissions Control on units combusting the gas produced. • Disposal or Residue Composting and Beneficial Use. Several different types of digester reactors are available. Most common are cylindrical vessels with vertical or horizontal mixing. Mixing techniques may be mechanical (with a large impellor) or by circulation of pressurized gas or effluent. Material is fed into the reactor and allowed to process under controlled conditions of temperature and moisture content. Material within the digester is typically a liquid or semi-liquid slurry. Material leaving the reactor is then typically dewatered. Anaerobic Digestion has been used for decades to process solids removed during wastewater treatment. Certain characteristics of MSW make Anaerobic Digestion more problematic than for sewage biosolids. For example, inert materials in MSW, such as glass and plastic, are not degraded in the process and will therefore remain a solid byproduct, unless removed by pre- processing or screening. Certain inert materials can also damage the equipment in the digester. An illustration of a typical Anaerobic Digestion process is included at the end of this section. 2. Waste Products/Environmental Controls Since all gases are contained in the Anaerobic Digestion process itself, odors and other pollutants are not emitted directly into the atmosphere provided that proper gas piping and storage is 16 R. W. Beck Revised Dmft Technology Memo41406 doc 4/18/06 REVISED DRAFT TECHNICAL MEMORANDUM provided. If the gas produced by Anaerobic Digestion is subsequently flared or used in combustion to produce electricity, air emissions controls are required. The solids byproduct of Anaerobic Digestion can be processed into a marketable compost product. However, securing reliable long-term markets for the material is difficult due to contamination with plastics and other materials. Anaerobic Digestion may also produce wastewater requiring treatment. 3. Applicability to County of Hawai'i WRF Project Volume Reduction For the WRF Project, if a beneficial use could be found for the resulting digester residue, the overall reduction in the amount of material requiring landfilling would be approximately 60 percent. If uses for the digested residue are not available and/or if the material is contaminated and required to be landfilled, the expected volume reduction from Anaerobic Digestion would be on the order of 35 to 45 percent of the waste delivered to the Reload Building tipping floor. Currently operating Anaerobic Digestion facilities in Europe either process a waste stream with significant source separation (in which case they receive almost exclusively organics), or they have extensive pre-processing in the form of dirty MRFs on the front-end to remove non - organics. Most of this material is recycled and reused in some manner. In addition, the European programs are generally much more focused on keeping toxics out of the waste stream than those programs currently required by RCRA Subtitle D and used in the United States, including Hawai' i. Operational Issues It is expected that an Anaerobic Digestion facility would utilize the Reload Building tipping floor to remove appliances and bulky items but would also likely require an estimated 10,000 to 15,000 square feet of additional pre-processing space and other equipment such as screens, conveyors, and magnets to remove non -organics and plastics. 4. Commercial Status Anaerobic Digestion is fully commercialized in use for sewage sludge, livestock, or agricultural waste and, less commonly, for food waste. Approximately 130 Anaerobic Digestion plants were commercially operating world-wide in 2003 digesting the organic fraction of MSW and/or organic industrial wastes. More than 95 percent of these facilities were operating in Europe with a few in other locations, including Canada. However, Anaerobic Digestion of MSW is a relatively new application of the technology, and poses special challenges such as the removal of contaminants and extraneous materials, such as plastic, finding reliable long-term markets, and sizing equipment to meet peak load requirements. To our knowledge there are no Anaerobic Digestion facilities using MSW as feedstock in the U.S., except for a few pilot programs. We are not aware of any vendors offering performance guarantees on Anaerobic Digestion systems using MSW as the primary feedstock, and this particular application cannot be considered to be fully commercialized at this time. Revised Draft Technology Memo41406.doc 4/18/06 R. W. Beck 17 REVISED DRAFT TECHNICAL MEMORANDUM 5. Approximate Cost There is very little reliable data on the cost of construction and operation of commercial scale Anaerobic Digestion facilities using MSW as a feedstock. Total installed costs for operational facilities that use a portion of the MSW stream as a feedstock have had median installed costs of about $200 to $250 per ton per year for facilities constructed within the last five to seven years. Based on the best information available, capital cost for Anaerobic Digestion facilities of the capacity expected for the Hawaii WRF Project could be expected to range from about $26 to $29 million (see Table 4). Operating and maintenance costs are estimated at $50 to $60 per ton. Total cost per ton (amortized capital cost plus O&M costs) could range from about $79 to $92 per ton. These costs include the costs of pre-processing ("Dirty MRF"). 6. Risks The risks associated with Anaerobic Digestion of MSW include the following: Technology • Contamination of feed stock. • Poor digestion performance. Environmental • Odor from waste preprocessing and digestion activities. • Shutdown of system thus requiring us of an alternative disposal system. Financial • Lack of performance guarantees. • Energy price escalation. • Excess energy usage. No longer term market/use for products. 18 R. W. Beck Revised Draft Technology Memo41406 doc4/18/06 0 z O. m W J a U Z 2 V W F H LL 4 LU W N W w ¢lj m A �8 'K 0 0 ~ 'a InO flabLu $F E 41 REVISED DRAFT TECHNICAL MEMORANDUM Technology: Aerobic MSW Composting 1. Overview Description Aerobic Composting of MSW involves the decomposition of large organic molecules through the action of microorganisms in the presence of oxygen. Composting systems receive and process the organic fraction of MSW. This fraction can be delivered in different forms: • Un -segregated MSW, without any previous source separation of recyclable or undesirable materials (i.e. household hazardous wastes), • The wet (organic) fraction from a wet -dry collection system after source separation of recyclable or undesirable materials, or Source separated organics. The most compatible materials for MSW composting are food waste, green waste, woody material, paper, and other organics. The quality of the compost is sensitive to both the process and the degree to which undesirable material has been excluded from the waste. A typical MSW composting system would include the following components: • Waste Pre-processing Area, to remove materials that cannot compost (such as metals, glass, plastic, and concrete) and to pre-process the remaining materials to varying degrees. • Active Composting Area, where large organic compounds are broken down into smaller compounds. • Odor Control Systems, which, depending on location, can include fully enclosing the compost area and providing odor treatment. • Compost Storage/Disposal, Products of Aerobic Composting include primarily soil amendments used in agriculture or landscaping. Aerobic Composting includes a variety of technologies, both enclosed (in -vessel) and open systems. Open systems commonly use windrows that can either be static piles with forced aeration or piles that are turned with specialized equipment to expose the material to air. In - vessel systems, though higher in capital cost, provide the best control of the composting process including air supply and temperature. An illustration of a typical Aerobic MSW Composting process is included at the end of this section. 2. Waste Products/Environmental Controls The most significant emission from Aerobic Composting of MSW is odor. With diligent operations and proper odor control equipment, odors can be reduced; however most operating MSW composting facilities in the U.S. have experienced some degree of odor problems. In some instances, odor problems have been extreme, causing shutdown of the facility. The 20 R. W. Beck Revised Draft Technology Memo41406 doe 4/18/06 REVISED DRAFT TECHNICAL MEMORANDUM technologies associated with odor control have continued to evolve, but odor management continues to be the greatest challenge for most operating facilities. Marketability of the resulting compost product has also proven difficult due to visible contamination of the compost (i.e. with plastics) and public concerns about the safety of material produced from MSW. These problems have been considerably lessened when the "feedstock" is limited to source separated organics. 3. Applicability to County of Hawaii WRF Project Volume Reduction The overall volume reduction for an Aerobic Composting facility could be on the order of 50 to 60 percent (see Table 4) depending partly on if a beneficial use could be found for the compost product. If a beneficial use cannot be found volume reduction will be 35 to 45 percent. Operational Issues In an Aerobic Composting facility, some level of front-end processing would be preferable to ensure that non-organic materials were removed before the composting process. It may be desirable to remove compost contaminants from the final compost product in addition to, or in lieu of, the front-end processing. It is expected that an Aerobic Composting facility would utilize the Reload Building tipping floor for removal of appliances and bulky items but would likely require an estimated 10,000 to 20,000 square feet of additional space and other equipment such as screens, conveyors, and magnets to remove non -organics from the waste and prepare finished compost. 4. Commercial Status MSW composting has been widely implemented, especially in Europe. About one quarter of the U.S. MSW compost facilities were shut down between 1992 and 1995 due to public opposition and technical problems, especially with odor control. No new MSW composting facilities have been developed in the last five years. Commercial viability of MSW composting facilities is currently in question because most vendors are unwilling to provide performance guarantees, especially for odor control, if MSW is the primary feedstock. Most of the new composting facilities are using source separated organics from the residential and/or commercial solid waste streams for feedstock, as opposed to mixed MSW. 5. Approximate Cost Capital and operating and maintenance costs for Aerobic MSW Composting facilities vary widely depending on capacity, technology, and the degree of odor control employed. As can be seen in Table 4, estimates for capital cost range from $39 to $48 million for a facility of the size required for the Hawaii WRF Project. Estimates for operating and maintenance costs range from $65 to $85 per ton. These estimates result in a total estimated cost per ton (amortized capital cost plus O&M costs) ranging from $108 to $138 per ton (see Table 4). Revised Dfaft Technology Memo41406.doc 4/18/06 R. W. Beck 21 REVISED DRAFT TECHNICAL MEMORANDUM 111LIM 1 The risks associated with Aerobic Composting of MSW include the following: Technology • Poor performance. • Problems with mechanical separation of mixed MSW into organic and other streams. Environmental • Odor problems potentially leading directly to plant shutdown due to an inability to meet permit requirements or indirectly due to escalating costs associated with odor control. • Potential emission of airborne fungi. • Presence of metals in the compost product. • Problems with visible "contaminants" (i.e. plastic) in compost. Financial • Lack of performance guarantees. • Lack of a market for compost. • Plant shutdown due to odor problems or lack of markets. 22 R. W. Beck Revised Draft Technology Memo41406.doc 4/18/06 C3 Z 9 O c W J Q U Z S U W 9 0 G W N W w � t b I IC 2W CL a ¢0 pq R l 11 __w 417I� ! I o M N I REVISED DRAFT TECHNICAL MEMORANDUM Technology: Bio -Refining 1. Overview Description Bio -Refining involves the conversion of plant biomass into a number of products that can be used as transportation fuels, such as ethanol; food ingredients; pharmaceuticals; industrial fibers; and as feedstocks for the production of chemicals. Bio -Refining uses acidic or enzymatic hydrolysis to breakdown large organic molecules as well as distillation and fermentation processes. A commercial Bio -Refining system would typically consist of the following five basic components: • Feedstock Separation, which involves either collection of source separated biomass (Le. yard waste, agricultural residues such as rice hulls and straw or sugar cane baggasse; forest thinnings, paper wastes) or use of a Materials Recovery Facility to separate biomass from other waste materials. ■ Feedstock Pre-processing, which involves further sorting, preparation of uniform size material, and drying. Cellulose Breakdown, through treatment of the feedstock with heat and/or chemicals. Hydrolysis, with acids or enzymes to further breakdown biomass. • Fermentation and Distillation of the sugars to produce biofuels and chemicals. An illustration of a typical Bio -Refining process is included at the end of this section. 2. Waste Products/Environmental Controls Bio -refineries produce very few pollutants since most process chemicals are recovered and recycled and byproducts, such as lignin, can be sold. Fuels from bio -refineries are ultimately combusted, however, and are a source of air emissions. 3. Applicability to County of Hawaii WRF Project Volume Reduction Volume reduction from Bio -Refining would be on the order of 30 to 70 percent depending on the amount of material that is segregated out during preprocessing. Operational Issues The planned Reload Building could be used to remove certain items such as appliances and bulky items from the waste stream. In addition, a relatively large area would be required for processing waste to remove inorganic materials and plastics. 4. Commercial Status Bio -Refining for ethanol production is fairly wide -spread in the U.S., with most facilities using corn as feed stock to produce 99 percent pure ethanol. These same facilities typically produce 24 R. W. Beck Revised D®fl Technology W..41406.d. 4/18/06 REVISED DRAFT TECHNICAL MEMORANDUM wet or dry distiller's grain which is desirable to farmers/ranchers as dairy cow or cattle feed. Several bio -refineries that use agricultural wastes as feedstock are in various stages of development. These facilities use feedstocks such as sugar cane bagasse, rice straw and wood. On the other hand, Bio -Refining using MSW is still in the development phase, and we are not aware of any commercial scale Bio -refinery facilities that are using MSW as feed stock. Several of the obstacles to commercialization of Bio -Refining have been overcome (i.e. there are now better markets for ethanol and other bio -refined products, and the rising price of petroleum has improved the relative economics of bio -refined products). Nonetheless, the technology as applied to MSW still faces barriers to commercialization. The County's Solid Waste Management Plan referred to development of a combined MRF/ Bio - Refining plant in New York to process 230,000 tons/year of MSW and 49,000 tons/year of sewage sludge. This plant was proposed by Masada Resources Group over 10 years ago and has yet to be developed. 5. Approximate Cost There are no reliable cost data for commercial scale Bio -Refining facilities using MSW. 6. Risks The risks associated with bio -refining of MSW include: Technology • Poor performance of refining process/failure to provide expected amount of ethanol. • Volume reduction less than predicted. • Mechanical/process failures and equipment malfunction. Environmental • Disposal of refining byproducts. Financial • Lack of financial/ performance guarantees. • Problems during construction resulting in contractor claim. • Energy cost escalation. Revised Draft Technology Memo41406 doc 4/18/06 R. W. Beck 25 0 Z C0 L LU L J a U Z S U w I. - I -- LL 9 0 uj w w a ■ � � m LLI a k LU � 9 � � w § ()�) \ ±]q /\t CO j c >- >— .`»; \j2z / 9 § (9 \ gC ° 4 a° z u ( \r 00 �}\\ / \\0 0 §/«00 IO_ a /55� § \/j\u k k \ 0 )/\\\ \ a E W-2 »\22o CL 4> k CL &}(f�/ 0 7 k j f 2 -0 bb k _ /\ 2 } § J / 0. 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