Assessment of Landfill Gas Potential: Phuoc Hiep Landfill, Cu Chi District Ho Chi Minh City, Vietnam FINAL

Transcription

1 Assessment of Landfill Gas Potential: Phuoc Hiep Landfill, Cu Chi District Ho Chi Minh City, Vietnam FINAL Prepared under: U.S. Environmental Protection Agency Landfill Methane Outreach Program Contract: EP-W By: Eastern Research Group, Inc. and Organic Waste Technologies (H.K.) Limited 07 September 2010

2 Status: Final Date: 07 September 2010 Revision: 0 TABLE OF CONTENTS 1. INTRODUCTION PROJECT LIMITATIONS LANDFILL GAS LANDFILL DATA SITE LOCATION AND OPERATION WASTE INPUTS WASTE COMPOSITION RECYCLING ACTIVITIES LANDFILL FIRES SITE CONSTRUCTION GENERAL OBSERVATIONS ENVIRONMENTAL DATA WASTE DEPTH WASTE PLACEMENT SLUDGE PLACEMENT BASE LINING CAPPING LAYER SURFACE WATER MANAGEMENT LEACHATE AND GAS LEACHATE GAS GAS MODELING EMISSION MODELING MODEL PARAMETERS BASELINE RESULTS OF GAS MODEL ANTICIPATED COLLECTION EFFICIENCY CALCULATED GAS AVAILABILITY OPTIONS FOR UTILIZATION THERMAL ENERGY ELECTRICAL ENERGY EMISSIONS TRADING CONCLUSION...23 REFERENCES...24 i

3 LIST OF TABLES & FIGURES TABLE 1 - WASTE INPUT TABLE 2 - ESTIMATED WASTE INPUT TABLE 3 - WASTE COMPOSITION...9 TABLE 4 - MODEL INPUT PARAMETERS...14 TABLE 5 - LANDFILL GAS MODEL RESULTS (LANDGEM CH 4 )...16 TABLE 6 ESTIMATED LANDFILL GAS RECOVERY AND AVAILABLE THERMAL ENERGY...17 TABLE 7 - ESTIMATED AVAILABLE EMISSION REDUCTIONS...21 FIGURE 1 - BASELINE LANDFILL GAS EMISSIONS...15 EQUATION 1 - FIRST ORDER DECAY MODEL...13 EQUATION 2 - BASELINE GHG EMISSIONS...14 EQUATION 3 - AVAILABLE EMISSION REDUCTIONS...20 EQUATION 4 - EMISSION REDUCTIONS FROM FOSSIL FUEL OFFSET DUE TO GENERATION OF ELECTRICITY...20 EQUATION 5 - EMISSION REDUCTIONS FROM FOSSIL FUEL OFFSET DUE TO DIRECT USE...21 APPENDICES Appendix I...Landfill Location Map Appendix II... Landfill Aerial Photographs Appendix III...Selected Photographs ii

4 EXECUTIVE SUMMARY The Phuoc Hiep Landfill is located within the North East Solid Waste Treatment Complex, Phuoc Hiep Commune, Cu Chi District, Ho Chi Minh City (HCMC), Vietnam. The landfill has been developed in three phases (Phase 1, Phase 1A and Phase 2). Phases 1 and 1A are owned by HCMC government and Phase 2 is currently under contract (concession) with CITENCO. All phases are operated and maintained by CITENCO with only Phase 2 currently accepting waste. Phases 1 and 1A were closed in May 2006 and February 2008, respectively. Under contract to the United States Environmental Protection Agency (U.S. EPA), Eastern Research Group, Inc. (ERG) and Organic Waste Technologies (H.K.) Limited (OWT) completed an initial assessment of the Phuoc Hiep Landfill s potential to generate methane. Analysis of the data provided by the landfill management company indicates that the operating landfill, Phase 2, is currently generating the least amount of landfill gas (LFG) of the three phases, at a rate of 1,795 standard cubic feet per minute (scfm) (or 3,049 m 3 /hr) containing 50% methane. Nevertheless, the rate will peak at approximately 3,689 scfm (6,268 m 3 /hr) in the year 2014, one year after the anticipated closure. The other two phases (1 and 1A) are currently generating LFG at respective rates of 2,532 and 2,710 scfm (4,278 and 4,580 m 3 /hr), but these rates have already peaked and are trending downward. It is expected that they will decrease to only half of their respective current generation rates by the year Since not all of this landfill gas will be available for utilization due to the construction and operational techniques employed, it is estimated the amount of recoverable LFG that could currently be beneficially used at Phase 2 is approximately 1,167 scfm (1,982 m 3 /hr) and will peak at 2,398 scfm (4,074 m 3 /hr) in The estimated amounts of recoverable LFG that could currently be beneficially used for Phase 1 and 1A, respectively, are 1,645 and 1,761 scfm (2,780 and 2,976 m 3 /hr). LFG generation is expected to decrease rapidly, to 272 and 291 scfm (460 and 491 m 3 /hr) respectively in the year This is intended to be a slightly conservative, yet realistic estimate of recoverable landfill gas. Evaluation of users of energy for various industrial processes is another option that could potentially be sited near or on the landfill site to utilize landfill gas-fueled heat or power. Currently, the only industrial process near the Phuoc Hiep site appeared to be the leachate treatment plant. It was also noted that high tension electrical power lines are located adjacent to the site, providing an option for exporting power to the grid. The introduction and implementation of proper solid waste management practices will improve gas collection efficiency. Internationally accepted solid waste management practices that promote landfill gas generation and collection typically include waste placement methods, compaction rates, daily, intermediate and final cover, proper grading and drainage, and effective leachate and gas management systems. To achieve reasonable levels of gas recovery necessary for a successful energy project, optimization of gas collection system efficiency requires not only a well designed, installed, and operated gas collection system; but also prevention of potential subsurface combustion. With a significant and relatively steady quantity of landfill gas available from the landfill and the presence of potential end users for the gas or electricity generated with the gas, either on or near the site (e.g., existing on-site facilities including the leachate treatment plant, materials recovery facility and recycling center, office buildings and maintenance facilities, or future industrial developments adjacent to the site), there appears to be a good opportunity for the development of both technically and financially feasible direct use and electricity generation projects using the Phuoc Hiep Landfill s gas. 3

5 Although it may be possible to beneficially utilize the LFG from Phases 1 and 1A, the rapid drop in LFG generation adds difficulty in sizing LFGE infrastructure, and will likely not lend itself to development of an LFGE project separately from Phase 2. Different ownership of the LFG rights for Phase 2 (CITENCO) and Phase 1 and 1A (HCMC) is also a key consideration in assessing the viability of the projects separately or in combination. Next steps towards LFGE project development include, Preparation of the LFGE system design and pre-feasibility analyses for recovery of LFG from each Landfill Phase,to evaluate the costs and benefits, and determine if the LFG from Phases 1 and 1A could stand alone as an LFGE projects or be used as supplemental fuel for an LFGE project at Phase 2. Although the economic outlook was not evaluated within this report; the project is theoretically enhanced by the ability to take advantage of renewable incentives and greenhouse gas (carbon) reduction incentives. An energy project at the Phuoc Hiep Landfill would likely qualify for emission reductions trading. The financial feasibility of an energy project increases moderately as the market value of emission reduction credits increases and/or period of time over which emission reduction credits are available increases. 4

6 1. INTRODUCTION The U.S. Environmental Protection Agency (U.S. EPA) is working in conjunction with Vietnam, a partner country to the Methane to Markets Partnership, on a global cooperative program to promote the beneficial use of landfill methane, while also reducing landfill methane emissions to the atmosphere. Some of the key activities of this cooperative program include identifying suitable landfills with sufficient quantities of high quality gas that can be used to meet local energy needs, preparing assessment reports, and possibly conducting training on landfill gas energy and the ways to develop landfill methane projects. To support these activities, the U.S. EPA has contracted with two companies, Eastern Research Group, Inc. (ERG) and Organic Waste Technologies (H.K.) Ltd. (OWT). An important part of identifying good candidate landfills for energy projects involves conducting site visits at landfills that have been pre-screened and identified as having the potential for energy project development. The Phuoc Hiep Landfill site was visited to collect information on landfill design, waste volume, waste composition and gas composition, and to make observations to assess its gas generation and recovery potential. Information was also collected, where available, on the local energy users that could potentially be interested in using the energy produced by the landfill. This assessment report summarizes and presents our observations and findings on the Phuoc Hiep Landfill in Cu Chi District, Ho Chi Minh City, Vietnam. This report includes a brief assessment of the gas production and recovery potential of the landfill and examines the opportunities that may exist for using the landfill gas to meet the energy needs of local utilities or industries. This report also includes technical information that will be helpful to potential project developers as they assess the potential of a landfill methane energy project at the site. The site visit included non-invasive analysis of the landfill gas, as well as a walk over inspection of the landfill, including observation of gas and leachate control measures, containment technology, topography and general condition / operation of the landfill. Physical investigatory work on the site was limited to site reconnaissance, and no monitoring of gas quality was performed. 2. PROJECT LIMITATIONS The information and predictions contained within this assessment report are based on the data provided by the site owners and operators. Neither the U.S. EPA nor its contractors can take responsibility for the accuracy of this data. Measurements, assessments, and predictions presented in this report are based on the data and physical conditions of the landfill observed at the time of the site visit. Note that landfill conditions will vary with changes in waste input, management practices, engineering practices, and environmental conditions (particularly rainfall and temperature). Therefore, the quantity and quality of landfill gas extracted from the landfill site in the future may vary from the values predicted in this report, which are based on conditions observed during the site visit. While all due care and attention has been given to development of this report, potential investors in landfill gas utilization projects at the Phuoc Hiep Landfill are advised to satisfy themselves as to the accuracy of the data and predictions contained in this report. 5

7 This report has been prepared for the U.S.EPA as part of the Methane to Markets Partnership program and is public information. 3. LANDFILL GAS Landfills produce biogas (normally called landfill gas) as organic materials decompose under anaerobic (without oxygen) conditions. Landfill gas is composed of approximately equal parts methane and carbon dioxide, with a smaller percentage of oxygen, nitrogen, and water vapor, as well as trace concentrations of volatile organic compounds (VOCs) and hazardous air pollutants (HAPs). Both of the two primary constituents of landfill gas (methane and carbon dioxide) are considered to be greenhouse gases, which contribute to global warming. However, the Intergovernmental Panel on Climate Change (IPCC) does not consider the carbon dioxide specifically present in raw landfill gas to be a greenhouse gas. IPCC considers the carbon dioxide in landfill gas to be biogenic and thus, part of the natural carbon cycle. As such, only the methane content of the gas is included in calculations of atmospheric greenhouse gas emissions. Methane is a more potent greenhouse gas than carbon dioxide (CO 2 ), with a global warming potential over 20 times that of CO 2. Therefore, the capture and combustion of methane (transforming it to carbon dioxide and water) in a flare, an engine generator, or other devices, result in a substantial net reduction of greenhouse gas emissions. Additional benefits beyond greenhouse gas emission reductions include the potential for improvement in local air quality through the destruction of HAPs and VOCs through landfill gas combustion. There are two natural pathways by which landfill gas can leave a landfill: by migration into the adjacent subsurface and by venting through the landfill cover system. In both cases, without capture and control, the landfill gas (containing methane) will ultimately reach the atmosphere. The volume and rate of methane emissions from a landfill are a function of the total quantity of organic material buried in the landfill, the material s age and moisture content, compaction techniques, temperature, and waste type and particle size. While the methane emission rate will decrease after a landfill is closed (as the organic fraction is depleted), a landfill will typically continue to emit methane for many (20 or more) years after its closure. A common method for controlling landfill gas emissions is to install a landfill gas collection system that extracts landfill gas under the influence of a small vacuum. Landfill gas control systems are typically equipped with a combustion (or other treatment) device designed to destroy methane, VOCs, and HAPs prior to their emission to the atmosphere. Good quality landfill gas (high methane content with low oxygen and nitrogen levels) can be utilized as a fuel to offset the use of conventional fossil fuels or other fuel types. The heating value typically ranges from 400 to 500 Btu per cubic feet (or 14.9 to 18.6 MJ per cubic meter), which is approximately one half the heating value of natural gas. Existing and potential uses of landfill gas generally fall into one of the following categories: electrical generation; direct use of the medium-btu gas for heating/ fuel for boilers, kilns, or furnaces; upgrade to high Btu gas; and other uses such as vehicle fuel. 6

8 This study focuses on evaluation of potential electrical generation using reciprocating engines and direct use projects at Phuoc Hiep Landfill. Other utilization options (e.g. turbines and CHP system) are also commercially available. However, observations made and constraints noted during the site visit appear to favor a limited number of utilization options for further assessment. 4. LANDFILL DATA A site visit was performed on 29 April Prior to the site visit, CITENCO was requested to provide information on the waste inputs, engineering details, and environmental conditions of the site via a questionnaire. Data provided by them has been edited into a standard format. Some data were verified or information adjusted based on the results of site specific observations made during the visit. The following paragraphs highlight the data obtained and analyzed for Phuoc Hiep Landfill Site Location and Operation The Phuoc Hiep Landfill is located in Cu Chi District, in northwest Ho Chi Minh City. The site is located in a remote area, with no other immediate domestic or industrial neighborhoods observed during the site visit. It was noted that high voltage transmission lines run adjacent to the landfill site Waste Inputs Site operation began in January 2003 and municipal solid waste from HCMC was placed in Phase 1 of the Phuoc Hiep Landfill. The phase was operational until May 2006 and from the extrapolated data indicated in the questionnaire, a total of 5.5 million tonnes of waste has been deposited at this Phase. Waste disposal at Phase 1A only started in February 2007 and lasted for 12 months, with a total waste intake of more than 1.7 million tonnes. Landfill operation at Phase 2 started subsequent to the closure of Phase 1A in February 2008 and waste in place has reached approximately 2 million tonnes by end of A weighbridge was located at the site entrance and trucks were weighed prior to entry. The total waste input from 2003 to 2009 is shown below in Table 1. Table 1 - Waste Input Year Phase 1 Phase 1A Phase ,333, ,368, ,199, ,653, ,785, , ,041,748 Subtotal 5,554,277 1,785,089 1,964,268 7

9 Projected waste intake of Phase 2 from 2010 to 2013 is listed in Table 2. The landfill questionnaire indicated that the future waste intake at Phase 2 ranges from 1,500 to 2,500 tpd. As 2009 waste intake is already 1,041,748 tonnes (2,854 tpd equivalent), a future waste intake of 2,500 tpd (upper bound of the future range) is adopted and considered realistic. The total waste in place at Phase 2 by the time of landfill closure will reach 5.6 million tonnes, which is also consistent with 5.5 million tonnes as provided in the landfill questionnaire. Table 2 - Estimated Waste Input Year Phase , , , ,500 Total Future 3,650,000 TOTAL (Phase 2 only) 5,614, WASTE COMPOSITION Table 3 below presents the information provided on the general composition of the waste deposited in the Phuoc Hiep Landfill. Waste samples collected at the active tipping face were categorized and weighed in both the wet and dry seasons. However, no sampling times and locations were indicated in the landfill questionnaire. 8

10 Table 3 - Waste Composition Waste Category Wet Season Dry Season Average Composition (%) Composition (%) Composition (%) Food Bamboo, rice hush Paper Carton Nylon Plastic Cloth Leather Wood Soft Rubber Glass Metal Cans Porcelain C&D Waste Ash Styrofoam Nappies Hazardous Waste Sum For gas modeling purpose, the average of the wet and dry season waste compositions was adopted. The provided waste composition reported an organic content of more than 92%, with more than 84% of waste reported as food remains. This is consistent with observations during the site visit. Moisture content of waste for wet and dry seasons are indicated at 53.7% and 50.6% respectively, and are close to the calculated value (53.1%) using IPCC methodology. 6. RECYCLING ACTIVITIES The landfill operator reported that there are no scavenging activities at the site, and none were observed during the site visit. Most of the recycling takes place at materials recovery facilities within the transfer stations. The recycled materials were reported to include mainly plastics, glass and metal cans. Planning is underway for a composting facility at the site. No details were available on the capacity of the facility; therefore no analysis was performed on the potential reduction of organic waste received in the landfill. In general, however, diversion of organics from the waste stream will typically reduce the LFG generation and recovery estimates. 9

11 7. LANDFILL FIRES No landfill fires or signs of subsurface combustion were either reported or observed during the site visit. 8. SITE CONSTRUCTION The general site conditions and engineering design features were examined during the site visit. Waste inflow and composition data were reviewed, and operational practices observed. No gas quality monitoring data were obtained during the visit. The subsequent sections describe the pertinent features observed at the site General Observations The Ho Chi Minh City Peoples Committee Department of Natural Resources and Environment have issued the technical procedures for the operation of the Landfill No. 2 (i.e., Phase 2). The design of the site is a mound fill bounded mainly by waterways and agricultural land. Based on the information provided by the site operator, the landfill comprises three waste mound deposit areas; Phases 1, 1A and 2, with footprint areas of 16 ha, 9.75 ha and 19.7 ha respectively. The bottom of the landfill slopes generally from west to east. The active tipping area was well managed with minimal area utilized for tipping. Other areas were covered with geo-membrane and soil as interim cover materials. LFG wells are installed as the fill progresses and can be brought on line relatively quickly, which helps improve overall collection efficiency. The site was reportedly lined with geo-synthetic lining system and containment design features interlocking sheet piles installed to retain waste placed along the perimeter of the landfill. Landfill gas and leachate management system infrastructure is installed and geo-membrane covers applied as interim cover. Leachate that drains from the waste is pumped from collection ponds to an on-site leachate treatment plant. A workshop/maintenance depot and a police guard post are located immediately west of the landfill. An area of approximately 5,000m 2 (50m 100m), adjacent to the guard post, has been considered as a potential future gas collection and LFGE equipment complex area Environmental Data According to available meteorological data, the average annual rainfall at the landfill is 4,160 mm, and the temperature ranges from 35 o C to 37 o C. The site is therefore categorized as wet and hot, potentially enhancing the rate of waste degradation Waste Depth The data provided in the questionnaire indicated that the current average waste depth at Phase 2 of the landfill is approximately 20 to 22m, and it is consistent with site observations during the site visit. Shallow waste (less than 5 m) was deposited in some areas of Phases 1 and 1A. 10

12 8.4. Waste Placement A weighbridge was located at the entrance to the landfill and most of the trucks were weighed before disposal at the active tipping area. Waste is brought to the site in closed vehicles, offloaded in the tipping area, spread and pushed to the edge of the leading waste slope by both wheeled and trackmounted dozers. It was reported that there are three trucks for cover soil transport, one compactor, one excavator, one loader and one water spraying vehicle; all machinery was observed in good conditions. Compactors were in operation at the time of the site visit, but the waste density was not reported Sludge Placement No sludge placement, past or present, was reported by the landfill management Base Lining It was reported that the landfill was constructed with a geo-composite base and side-slope lining system Capping Layer The landfill reported covering the waste on a weekly basis, interim cover (soil and geo-membrane) placement was observed during the site visit. Compaction of the soil cover appeared to be well performed, and no signs of surface water ponds or other signs of inadequate grading, or differential settlement was observed during the site visit Surface Water Management Diversion channels were observed around the waste disposal area to divert stormwater away from the waste mass in the same leachate drainage system. These appear to be somewhat effective in reducing the amount of rainwater entering the waste. However, the runoff is all directed to the LPTW for treatment. 9. LEACHATE AND GAS 9.1. Leachate Leachate is the liquid produced by contamination of water within the landfill site by a wide range of solutes resulting from the disposal and decomposition of waste (including organic and inorganic components) in landfills. The water content results from drainage of moisture from the original waste, water resulting from degradation, and infiltration of surface water (rainfall). Leachate can be highly contaminated and usually has a very low concentration of dissolved oxygen. 11

13 A leachate drainage system consisting of drainage channels that divert the leachate collection pipes was built at the base of the landfill during the landfill construction. The gravity drainage system was reported to send cubic meters per day of leachate to the leachate treatment plant located approximately 800m south of the landfill via underground HDPE pipes. The LPTW uses a variety of treatment technologies, including nitrification and de-nitrification using aerobic and anaerobic technologies including Fentons reagent to treat the effluent prior to discharge into a nearby river. Small amounts of leachate were observed seeping out of some of the freshly placed waste indicating elevated leachate levels. Also, no facilities existed for the measurement of leachate depth in the waste and no indication of leachate depth was provided by the landfill Gas Landfill gas was vented from the existing waste mass through approximately 30 passive vents. These passive vents were apparently constructed with perforated HDPE pipes and some of them were protected by an outer perforated pipe filled with gravel. Nevertheless, some vents were observed to be off vertical and it is believed that they may have been damaged by on site machinery operation (or landfill settlement). Some landfill gas was observed escaping through the pipes and also through the space between the concrete plates used for the landfill access road. Gas could be audibly detected, bubbling while walking along the concrete plate road system at the Phase 2 staging area. 12

14 10. GAS MODELING 10.1.Emission Modeling The estimation of emissions indicates the potential total landfill gas emissions from the site. This calculation should not be confused with the recoverable landfill gas which may be available for utilization. Recoverable landfill gas is estimated in the following section of this report. The baseline for the estimated amount of methane generated by the site has been calculated with the use of the U.S. EPA LandGEM landfill gas model based on first order decay mathematics. The U.S. EPA LandGEM model is based on the following equation (Eqn.1): Equation 1 - First Order Decay Model n 1 k ( t tlag ) Q = kml 0 % vol 0e Where: Q total quantity of landfill gas generated (normal cubic meters) n total number of years modeled t time in years since the waste was deposited t lag estimated lag time between deposition of waste and generation of methane. % vol estimated volumetric percentage of methane in landfill gas L 0 estimated volume of methane generated per tonne of solid waste k estimated rate of decay of organic waste M mass of waste in place at year t (tonnes) The dry organic fraction of waste (derived by subtracting the mass of water and inorganic waste components from the total mass) is used to calculate the quantity of landfill gas generated. For landfills where there is evidence of previous or on-going underground landfill fires, the gas producing potential of the waste may be further reduced to reflect losses in waste mass due to prior or anticipated future combustion. When the amount of landfill gas being generated by the site has been theoretically determined, the following equation (Eqn. 2) can be used to estimate the effective number of tonnes of carbon dioxide equivalent being emitted by the site. This factor of 21 is used to estimate the greenhouse gas potential, in tonnes of carbon dioxide equivalent, resulting from the emission of methane [1]. 13

15 Equation 2 - Baseline GHG Emissions T = % vol x 21 x Q ρch CO x 2 eq. Where: T CO2eq. Total tonnes of carbon dioxide equivalent generated % vol Estimated volumetric percentage of methane in landfill gas. Q Total quantity of landfill gas from Eqn. 1 (normal cubic meters) Density of Methane = tonnes / cubic meter ρ CH Model Parameters 4 The values of the model parameters Lo and k depend on the available organic fraction, the temperature, and moisture content of the waste. Values for these two variables are presented in Table 4. These values were based on previous experience with landfills in Southeast Asia and China. Table 4 - Model Input Parameters Parameter L 0 (Ultimate methane generation potential, in m 3 /tonne) k (Methane generation rate constant) % vol (Methane percentage volume) Value % v/v Methane Generation Potential (Lo) is one of the two key model constants for LFG modeling, and it represents the total amount of LFG potentially produced by a given amount of waste over its lifetime. For this assessment study where conservatism is desirable, a Lo value of 110 is selected, which is slightly lower than the value of 134 used in the Project Design Document (PDD) for the landfill [2]. Methane Generation Rate (k) is the other important model constant, determining the rate (speed) of biodegradation of organics, hence generation of LFG, from waste. A higher k value will yield a LFG projection increasing more rapidly prior to landfill closure, but decreasing more quickly as well after closure. The peak of the curve (i.e. maximum amount of LFG) will increase with higher k values. Given the high food fraction at the Phuoc Hiep Landfill and the observed method of landfill operations, the selected k value of 0.18 per year seems to be within the range of typical values used for other similar landfills in southeast Asia. 14

16 11. BASELINE RESULTS OF GAS MODEL Results of the U.S. EPA LandGEM LFG model for the three phases are given in the following graph (Figure 1) and expected gas production rates for the next 20 years in Table 5. Using the above values for k and L 0, the LandGEM model estimates that Phase 2 of the landfill is currently emitting least amount of landfill gas at 1,795 standard cubic feet per minute (scfm) (or 3,049 m 3 /hr) amongst the three phases, containing 50% methane. Nevertheless, the rate will reach peak of 3,689 scfm (6,268 m 3 /hr) in 2013, one year after the anticipated Phase 2 closure, The LandGEM model estimates that the other two phases (1 and 1A) are currently generating LFG at respective rates of 2,532 and 2,710 scfm (4,278 and 4,580 m 3 /hr). These rates have already peaked, however, and are rapidly trending downward. It is expected that they will decrease to only half of their respective current generation rates by the year ,000 Phuoc Hiep Landfill, Ho Chi Minh City, Vietnam LFG Generation Estimates 3,500 LFG Flow (scfm) 3,000 2,500 2,000 1,500 Phase 1 Phase 1A Phase 2 1, Year Figure 1 - Baseline Landfill Gas Emissions 15

17 Table 5 - Landfill Gas Model Results (LandGEM CH 4 ) Year Phase 1 LandGEM Estimate (scfm) Phase 1A LandGEM Estimate (scfm) Phase 2 LandGEM Estimate (scfm) ,532 2,710 1, ,115 2,264 2, ,766 1,891 2, ,475 1,579 3, ,232 1,319 3, ,029 1,102 3, , , , , , , ANTICIPATED COLLECTION EFFICIENCY The estimate of landfill gas generation from the site does not imply that all the gas can be collected for utilization or flaring. Many engineering issues and the continued waste management operations at the site must be taken into account to assess the actual amount of gas that could be collected. These issues include landfill phasing, waste compaction and cover placement, gas management, condensate management, leachate management, and stormwater management. For a well managed landfill, the phasing plan would allow the prompt installation of gas extraction systems to maximize gas collection, the waste would be compacted and covered in a timely manner to minimize air and water intrusion and to avoid aerobic decomposition of the waste, stormwater would be diverted away from the waste to minimize leachate generation, and generated leachate would be removed from the waste to promote gas generation and collection. Proper management of the gas and condensate collection system would optimize the amount of gas recovered. Typical landfill gas collection efficiencies could be as high as 80% or more for such a well-managed landfill; however, for a poorly managed site, it could be 20%, or less. 16

18 Information necessary for a detailed evaluation of the collection efficiency that can be anticipated or achieved at the Phuoc Hiep Landfill in the future was not available. However, if proper solid waste management practices are introduced and employed (if an energy project were to proceed at the site) it is reasonable to expect that a modest collection efficiency of 65% could be achieved. Optimization of collection efficiency requires implementation and adherence to internationally accepted standards for solid waste management practices, which promote landfill gas generation and collection. These practices typically include waste compaction, daily cover, improved intermediate and final covers, proper drainage, and a properly designed, installed, and operated gas collection system. 13. CALCULATED GAS AVAILABILITY Based on the above discussion, it is assumed for this assessment that approximately 65% of the landfill gas generated at the Phuoc Hiep Landfill could be recovered for utilization. Applying the 65% availability factor to the estimate for the three phases in Table 5 gives an estimated available gas flow shown in Table 6. Landfill methane has a calorific value of approximately 1,012 Btu/cf (or 37.7 MJ/m 3 ); however, because typical landfill gas contains approximately 50% combustible and 50% non-combustible compounds, the resultant thermal energy contained in landfill gas is approximately 506 Btu/cf (or 18.9 MJ/m 3 ). Table 6 also shows the estimated available thermal energy for the three landfill phases. Table 6 Estimated Landfill Gas Recovery and Available Thermal Energy Year Recoverable LFG Thermal Energy Thermal 50% CH 4 (scfm) (mmbtu/hr) (kw) Ph. 1 Ph. 1A Ph. 2 Ph. 1 Ph. 1A Ph. 2 Ph. 1 Ph. 1A Ph ,645 1,761 1, ,636 15,670 10, ,374 1,471 1, ,225 13,088 13, ,148 1,229 1, ,211 10,932 16, ,027 2, ,529 9,131 19, , ,124 7,627 21, , ,951 6,371 17, , ,970 5,321 14, , ,152 4,445 12, , ,468 3,713 10, ,897 3,101 8, ,419 2,590 7, ,021 2,163 6, ,688 1,807 5, ,410 1,509 4, ,178 1,261 3, ,053 2, ,460 17

19 Year Recoverable LFG Thermal Energy Thermal 50% CH 4 (scfm) (mmbtu/hr) (kw) , , , OPTIONS FOR UTILIZATION A number of options exist for the utilization of landfill gas for industrial and agricultural processes, as well as the generation of electrical energy. The methane content of landfill gas can also be separated from the other components and used to supplement natural gas supplies or, in certain circumstance, compressed for use as vehicle fuel. In addition, because methane from solid waste disposal on land is one of the major sources of anthropogenic greenhouse gas emissions, its capture and oxidation to carbon dioxide results in an environmental benefit. This benefit may be measured and traded under a number of different emission reduction trading schemes world wide Thermal Energy Landfill gas has been used in a number of industrial or agricultural processes that require thermal energy input. In circumstances where there is a direct use for heat within a reasonable distance from the site, a potential exists for low cost utilization of the landfill gas. Landfill gas has been used for projects including the firing of brick kilns or other ceramic manufacture, heating of greenhouses and other industrial spaces. It should be noted that the combustion products of landfill gas, without pretreatment, may contain compounds that are hazardous to health including dioxins and furans. Therefore, direct use of landfill gas in agricultural processes in a manner where the combustion device exhaust gas contacts the plants must be carefully controlled. However, using a boiler or other method of heat exchange to provide heat to a greenhouse and exhausting the gas to the outside atmosphere where it does not contact the plants in the greenhouse can avoid such health concerns. A direct use project could be economically feasible if an appropriate end user in the form of an existing industry can be found within a reasonable distance from the landfill; however, it will depend on several issues, including the cost of equipping the potential end user to allow it to use the gas, whether it can use all of the available gas, and how much it can save and/or earn from the arrangement. It may also be feasible to attract certain industries to establish industrial facilities near the landfill, such that those industries are able to utilize the landfill gas supply as a low cost energy source for heat or power in various industrial processes Electrical Energy Electrical energy can be produced with a variety of technologies. The majority of landfill gas to energy projects uses standard reciprocating internal combustion engine-generator sets of typically 800 kilowatt (kw) capacity or greater, while very large projects have used conventional gas turbines producing from 3 MW to upwards of 10 MW. Small reciprocating engine-generator sets can also be used for smaller project sized between 100 kw and 1 MW. 18

20 Microturbine technology, typically in the 30 kw to 750 kw range, has also been used on a number of smaller landfill gas projects because the technology offers low emissions and low maintenance costs. Microturbines, however, tend to operate at lower thermal efficiencies than reciprocating engines. From the predicted gas availability at the Phuoc Hiep Landfill, it appears that the landfill will have sufficient gas available to operate a standard reciprocating engine-generator. On the other hand, it may be advantageous to install a smaller generator or microturbine, which could be used either to supply power for on site consumption or to the local grid, in combination with direct use of some of the landfill gas. In the case of Phuoc Hiep Landfill, there are several potential options to utilize the landfill gas; such as generating electricity for the leachate treatment plant and general site use, and export the excess to the local grid.. Estimates of the electricity consumption at the LPTW were not available at the time of visit, but it was reported that other landfill facilities (i.e. site lighting, pumping, aerators, office, guard, weigh-bridge house and equipment depot) on-site are relatively small in size compared to the power consumption of the LPTW. 15. EMISSIONS TRADING It is possible to account for, and transfer, the reduction in greenhouse gas emissions (i.e., greenhouse gas credits) resulting from activities that reduce or capture any of the six main greenhouse gases. Because methane from solid waste disposal on land is one of the major sources of anthropogenic greenhouse gas emissions, its capture and oxidation to carbon dioxide results in an environmental benefit. This benefit may be measured and traded under a number of different emission reduction trading schemes world wide. Assuming the project is qualified for trading of emission reductions, the calculation of emission reductions is defined by methodologies relating to the particular trading mechanisms. As part of all methodologies, it must be proven that normal business practice does not alter the emissions of greenhouse gases. Examination of the Phuoc Hiep City Landfill indicates that none of the methane generated by the site has been combusted on the current site boundary. Therefore, in assessing the amount of emission reductions available from the site, there is no need to apply an adjustment factor. 19

21 The following Equation 3 estimates the number of emission reductions available in each year from the Phuoc Hiep Landfill as a result of direct methane reduction. Equation 3 - Available Emission Reductions T 2 eq. = (1 AF ) x % x 21 x Q x ρ Avail. CO vol Avail CH Where: T AvailCO2eq. Total emission reductions available in Tonnes of Carbon Dioxide Equivalent (tco2e) % vol Volumetric percentage of methane in landfill gas Q Avail Total quantity of landfill gas available AF Adjustment Factor (0%, assumed in this case) Density of Methane = tonnes / cubic meter ρ CH4 While flaring is the normal method for thermal oxidation of landfill gas, any process which prevents the emission of methane to the atmosphere also qualifies for tradable emission reductions. The carbon dioxide created by the thermal oxidation of methane is considered to be "short cycle" and a product of the normal carbon cycle, and therefore does not need to be accounted for under the current methodologies. If electrical energy production is also included, and that power is either exported to the local distribution network or used to displace other usage of electricity, it is possible to gain additional emission reductions as a result of the displacement of fossil fuel use. To calculate the amount of emission reductions available in each year from the export of electricity, the following equation is used: Equation 4 - Emission Reductions from Fossil Fuel Offset due to Generation of Electricity TCO eq = EFgrid x MWh 2. exported Where: T CO2eq. Total emission reduction in Tonnes of Carbon Dioxide Equivalent (tco 2 e) EF grid Grid emission factor ( tco 2 /MWh, also used in the landfill s Project Design Document [2]) Total number of MegaWatt hours exported to the grid. MWh exported Instead of electricity generation, the landfill gas could also be utilized in a direct use scheme at a facility on or close to the site (such as the medical waste incineration plant). In this case, it is also possible to gain additional emission reductions as a result of the displacement of fossil fuel use. Assuming the fossil fuel displaced is natural gas, the following equation can be used to calculate the number of emission reductions available in each year from direct use: 4 20

22 Equation 5 - Emission Reductions from Fossil Fuel Offset due to Direct Use T CO Where: = 2 eq. EF fossil _ fuel x % vol x H methane / H natural _ gas x Q direct _ use T CO2eq. EF fossil fuel Total emission reduction in Tonnes of Carbon Dioxide Equivalent (tco2e) Emission factor (54.71 tco 2 /mcf for natural gas) % vol Volumetric percentage of methane in landfill gas H methane Heat content of methane (1,012 Btu/cf) H natural gas Heat content of natural gas (1,050 Btu/cf) Total volume of landfill gas utilized in direct use (in million cubic feet, or mcf). Q direct use On the basis of the calculated availability of landfill gas at Phuoc Hiep Landfill, and assuming that all the methane is used for energy generation (electricity generation or direct use) and/or flaring, the possible amount of emission reductions generated for each phase in the next 20 years is shown in Table 7. Emission reductions produced by the electricity generation or direct use result from the displacement of the use of fossil fuels and are therefore additional to flaring activities. The estimates shown in Table 7 are based on the assumption that an enclosed flare is used to ensure a high combustion efficiency (>99%). The estimates in Table 7 assume that the efficiency of the electricity generator is approximately 36%. Year Table 7 - Estimated Available Emission Reductions CO 2 Equivalent Tonnes from Flaring Activities Additional CO 2 Equivalent Tonnes from Direct Use * Additional CO 2 Equivalent Tonnes from Electricity Generation * Ph. 1 Ph. 1A Ph. 2 Ph. 1 Ph. 1A Ph. 2 Ph. 1 Ph. 1A Ph , , ,695 28,790 30,822 20,413 22,802 24,412 16, , , ,971 24,047 25,745 27,328 19,046 20,390 21, , , ,954 20,086 21,504 33,104 15,908 17,031 26, , , ,844 16,777 17,961 37,929 13,288 14,226 30, ,722 96, ,646 14,013 15,003 41,959 11,099 11,882 33, ,942 80, ,392 11,705 12,531 35,047 9,271 9,925 27, ,597 67, ,428 9,777 10,467 29,274 7,743 8,290 23, ,286 55, ,553 8,166 8,743 24,451 6,468 6,924 19, ,673 46, ,764 6,821 7,303 20,424 5,402 5,784 16, ,478 39, ,223 5,697 6,100 17,059 4,512 4,831 13, ,469 32,620 91,231 4,759 5,095 14,249 3,769 4,035 11, ,450 27,247 76,202 3,975 4,256 11,902 3,148 3,370 9, ,258 22,758 63,650 3,320 3,555 9,941 2,630 2,815 7, ,756 19,009 53,165 2,773 2,969 8,304 2,196 2,352 6, ,831 15,878 44,407 2,316 2,480 6,936 1,835 1,964 5, ,388 13,262 37,092 1,935 2,071 5,793 1,532 1,641 4, ,347 11,078 30,982 1,616 1,730 4,839 1,280 1,370 3, ,643 9,253 25,878 1,350 1,445 4,042 1,069 1,145 3, ,219 7,729 21,615 1,128 1,207 3, ,674 21

23 Additional CO CO Year 2 Equivalent Tonnes Additional CO 2 Equivalent 2 Equivalent from Flaring Activities Tonnes from Direct Use * Tonnes from Electricity Generation * ,030 6,455 18, ,008 2, ,233 * Provided that the installed capacity of electricity generating or direct use equipment exceeds gas availability at all times. It should be noted that the quantity of emission reductions that will be realized will generally fall below the available estimates shown in Table 7. It will be affected by such factors as downtime of the landfill gas collection and utilization system, size and efficiency of the electricity generator or direct use equipment, destruction efficiency of the equipment (such as electrical generator), and parasitic losses. 22

24 16. CONCLUSION The analyses documented in this assessment report indicate that the Phuoc Hiep Landfill has the potential to produce a moderate and relatively steady amount of LFG, and that based on the preliminary results an LFGE project could be both technically and financially feasible. Consideration of current energy costs and emission reduction pricing appears to favor the direct use option for an energy recovery project at the Phuoc Hiep Landfill. However, to implement such a project, a viable end user within a reasonable distance from the site must be identified. Electrical power generation for on-site use is one potentially feasible option, increasing the capacity for sale of power to the grid is another option worth further consideration. Although Phase 2 (with current estimated recoverable LFG of 1,167 scfm (1,982 m 3 /hr) and a peak of 2,398 scfm (4,074 m 3 /hr) in 2014) appears to be the preferred site for development of an LFGE project, Phases 1 and 1 A are still able to produce significant amounts of gas for beneficial use. The estimated amount of recoverable LFG that could currently be beneficially used from Phases 1 and 1A is currently 1,645 and 1,761 scfm (2,780 and 2,976 m 3 /hr), with LFG generation rates expected to decrease rapidly, to 272 and 291 scfm (460 and 491 m 3 /hr) respectively in the year Although it is possible to beneficially utilize the LFG from Phases 1 and 1A, the rapid drop in LFG generation adds difficulty in sizing LFGE infrastructure, and will likely not lend itself to development of an LFGE project separately from Phase 2. Different ownership of the LFG rights for Phase 2 (CITENCO) and Phases 1 and 1A (HCMC) is also a key consideration in assessing the viability of the projects. Detailed economic analyses should be performed to evaluate the costs and benefits, and determine if the LFG from Phases 1 and 1A could stand alone as an LFGE project or be used as supplemental fuel for an LFGE project at Phase 2. Evaluation of users of energy for various industrial processes is another option that could potentially be sited near or on the landfill site to utilize landfill gas-fueled heat or power. Currently, the only industrial process near the Phuoc Hiep site appeared to be the LPTW. It was also noted that high tension electrical power lines are located adjacent to the site, providing an option for exporting power to the grid. Next steps towards LFGE project development may include preparation of the LFGE system design and pre-feasibility analyses for recovery of LFG from each Landfill Phase,to evaluate the costs and benefits, and determine if the LFG from Phases 1 and 1A could stand alone as an LFGE projects or be used as supplemental fuel for an LFGE project at Phase 2 at the Phuoc Hiep Landfill. In the interim, designing, installing, and operating the LFG collection and flaring system will reduce emissions and allow calibration of modeling results with actual site conditions to project long term sustainable gas flow rates. Although no preliminary financial assessment (of the most likely LFGE technology options using the USEPA LFGcost model) has been performed, it is envisaged that the financial feasibility is also contingent upon the implementation of improved solid waste management practices required to achieve a reasonable level of LFG production and collection efficiency. 23

25 REFERENCES 1. Revised 1996 IPCC Guidelines for National Greenhouse Gas Inventories. Paris: Intergovernmental Panel on Climate Change, United Nations Environment Programme, Organization for Economic Co-Operation and Development, International Energy Agency. 2. Ecoeye Co., Ltd., CDM PDD: Phuoc Hiep I Sanitary Landfill Gas CDM Project in Ho Chi Minh City, Version 09 dated 21 September

26 APPENDIX I LANDFILL LOCATION MAP

27 N National Road No. 22 Cu Chi District Center Phuoc Hiep Landfill Provincial Road No. 8 Landfill Location Map Source: Google TM Maps (

28 APPENDIX II LANDFILL AERIAL PHOTOGRAPHS

29 Aerial View of Phuoc Hiep Landfill (Photo date: February 2009) Source: Google TM Maps (

30 APPENDIX III SELECTED PHOTOGRAPHS

31 Photo 1 Site entrance and weighbridge Photo 2 Main haul road entering tipping area (also serving as drainage system)

32 Photo 3 Main method of disposal with focused tipping area Photo 4 Waste compaction and interim cover installation ongoing

33 Photo 5 Waste placement near LFG wells with interim soil cover installed Photo 6 Interim soil cover placement over geo-membrane cover materials

34 Photo 7 Active waste reception area at Phase 2 Photo 8 Sludge delivery truck at the active waste reception area at Phase 2

35 Photo 9 Leachate lagoon behind gas wells on back side of Phase 2 Photo 10 Staging area with lights for 24 hr truck arrival

36 Photo 11 Leachate drainage and pumping station Photo 12 Phase 2 - Drainage channel and geo-membrane cover

37 Photo 13 Phase 1A currently closed with geo-membrane cover Photo 14 Phase 1 and 1A (with gas vent / wells) in foreground; and Phase 2 in the distance

38 Photo 15 Gas bubbling between concrete / steel plates on haul road at Phase 2 Photo 16 Leachate lagoon between Phase 1 and 2

39 Photo 17 Leachate Pre Treatment Works (LPTW) Photo 18 Leachate Pre Treatment Works (LPTW) with landfill in background