OFFICE OF THE MAYOR                               CITY AND COUNTY OF HONOLULU                                   530 SOUTH ...
Alternative Technologies for theBeneficial Reuse of Sewage SludgeResponse to Resolution 11-182Oahu, HawaiiFinalOctober 201...
Alternative Technologies for the Beneficial Reuse of Sewage SludgeResponse to Resolution 11-182October 2011               ...
Alternative Technologies for the Beneficial Reuse of Sewage SludgeResponse to Resolution 11-182October 2011        3.5.4  ...
Alternative Technologies for the Beneficial Reuse of Sewage SludgeResponse to Resolution 11-182October 20116.1   Supplemen...
Alternative Technologies for the Beneficial Reuse of Sewage SludgeResponse to Resolution 11-182October 2011               ...
Alternative Technologies for the Beneficial Reuse of Sewage SludgeResponse to Resolution 11-182October 2011               ...
Alternative Technologies for the Beneficial Reuse of Sewage SludgeResponse to Resolution 11-182October 2011PEM            ...
Alternative Technologies for the Beneficial Reuse of Sewage SludgeResponse to Resolution 11-182October 2011               ...
Alternative Technologies for the Beneficial Reuse of Sewage SludgeResponse to Resolution 11-182October 2011        expedit...
Alternative Technologies for the Beneficial Reuse of Sewage SludgeResponse to Resolution 11-182October 2011It should be no...
Alternative Technologies for the Beneficial Reuse of Sewage SludgeResponse to Resolution 11-182October 2011Insert Figure 1...
Alternative Technologies for the Beneficial Reuse of Sewage SludgeResponse to Resolution 11-182October 2011Identification ...
Alternative Technologies for the Beneficial Reuse of Sewage SludgeResponse to Resolution 11-182October 2011    2. Emerging...
Alternative Technologies for the Beneficial Reuse of Sewage SludgeResponse to Resolution 11-182October 2011        O&M Cos...
Alternative Technologies for the Beneficial Reuse of Sewage SludgeResponse to Resolution 11-182October 2011Insert Table 2 ...
Alternative Technologies for the Beneficial Reuse of Sewage SludgeResponse to Resolution 11-182October 2011Insert Table 2 ...
Alternative Technologies for the Beneficial Reuse of Sewage SludgeResponse to Resolution 11-182October 2011SELECTION AND I...
Alternative Technologies for the Beneficial Reuse of Sewage SludgeResponse to Resolution 11-182October 2011the Honouliuli,...
Alternative Technologies for the Beneficial Reuse of Sewage SludgeResponse to Resolution 11-182October 20111.0         INT...
Alternative Technologies for the Beneficial Reuse of Sewage SludgeResponse to Resolution 11-182October 20111.2     Purpose...
Alternative Technologies for the Beneficial Reuse of Sewage SludgeResponse to Resolution 11-182October 2011redundancy plan...
Alternative Technologies for the Beneficial Reuse of Sewage SludgeResponse to Resolution 11-182October 20112.0     OVERVIE...
Alternative Technologies for the Beneficial Reuse of Sewage SludgeResponse to Resolution 11-182October 2011           In-v...
Alternative Technologies for the Beneficial Reuse of Sewage SludgeResponse to Resolution 11-182October 2011to what is requ...
Alternative Technologies for the Beneficial Reuse of Sewage SludgeResponse to Resolution 11-182October 2011               ...
Alternative Technologies for the Beneficial Reuse of Sewage SludgeResponse to Resolution 11-182October 2011           Figu...
Alternative Technologies for the Beneficial Reuse of Sewage SludgeResponse to Resolution 11-182October 2011Under normal op...
Alternative Technologies for the Beneficial Reuse of Sewage SludgeResponse to Resolution 11-182October 20112.4     Treatme...
Alternative Technologies for the Beneficial Reuse of Sewage SludgeResponse to Resolution 11-182October 2011of solids to be...
Alternative Technologies for the Beneficial Reuse of Sewage SludgeResponse to Resolution 11-182October 2011bulking agent t...
Alternative Technologies for the Beneficial Reuse of Sewage SludgeResponse to Resolution 11-182October 2011There are poten...
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Mayor's Message 152

  1. 1. OFFICE OF THE MAYOR CITY AND COUNTY OF HONOLULU 530 SOUTH KING STREET, ROOM 300 * HONOLULU, HAWAII 96813 PHONE: (808) 768-4141 * FAX: (808) 768-4242 * INTERNET: wwwbo~~~uaovPETER B. CARLISLE DOUGLAS S. CHIN MAYOR MANAGING DIRECTOR CHRYSTN K. A. EADS DEPUTY MANAGING DIRECTOR c-) October 28, 2011 The Honorable Ernest Y. Martin, Chair and Councilmembers Honolulu City Council 530 South King Street, Room 202 Honolulu, Hawaii 96813 Subject: Resolution 11-1 82 Alternative Technologies for the Beneficial Reuse of Sewage Sludge Dear Chair Martin and Councilmembers: We are pleased to provide the enclosed report in response to the investigation requested in Resolution 1 1-182: 1. Nine (9) hard copies of the AECOM Report: Alternative Technologies for the Beneficial Reuse of Sewage Sludge, October 2011; and 2. Two (2) hard copies of the CD disk with PDF files of the report. In order to include a broader range of the alternatives and impacts of wastewater treatment issues, information on technologies not specifically covered by the scope of Resolution 11-182 will be included in a supplemental report that will be available prior to the November 1 6th Public Works and Sustainability Committee hearing. We are looking forward to working with the council to develop a viable solids handling program at Sand Island Wastewater Treatment Plant that will be financially beneficial to the community while resolving our two primary concerns: overcapacity of the current system, and a back-up in the event of a catastrophic failure or upset of the current single system. Should you have any questions or concerns, please contact Deputy Director Ross Tanimoto of the Department of Environmental Services, at 768-3482. Very truly yours, 7~~A (~ Peter B. Carlisle Mayor Enclosures cc: Tim Steinberger, Director/ENV Douglas S. Chin, Managing Director MAYOR’S MESSAGE 152 (JI)
  2. 2. Alternative Technologies for theBeneficial Reuse of Sewage SludgeResponse to Resolution 11-182Oahu, HawaiiFinalOctober 2011Prepared for:City & County of HonoluluDepartment of Environmental Services1000 Uluohia Street Suite 308Kapolei, Hawaii 96707Prepared by:1001 Bishop Street, Suite 1600Honolulu, Hawaii 96813
  3. 3. Alternative Technologies for the Beneficial Reuse of Sewage SludgeResponse to Resolution 11-182October 2011 CONTENTSEXECUTIVE SUMMARY .......................................................................................................... vii1.0 INTRODUCTION AND OVERVIEW ................................................................................11.1 Background .....................................................................................................................11.2 Purpose ...........................................................................................................................21.3 Objectives .......................................................................................................................21.4 Methodology ....................................................................................................................32.0 OVERVIEW OF SOLIDS TREATMENT AND PROCESSING ..........................................42.1 Terminology.....................................................................................................................42.2 Regulatory Background ...................................................................................................5 2.2.1 Land Application................................................................................................5 2.2.2 Emissions for Sewage Sludge Incineration (SSI)...............................................62.3 Current CCH Treatment and Processing Operations .......................................................62.4 Treatment and Processing Technology Classification....................................................10 2.4.1 Digestion .........................................................................................................10 2.4.2 Composting .....................................................................................................11 2.4.3 Heat Drying Only .............................................................................................12 2.4.4 Incineration .....................................................................................................13 2.4.5 Gasification and Pyrolysis ...............................................................................14 2.4.6 Alternative Combustion ...................................................................................15 2.4.7 Alternative “Smokeless” Sludge Oxidation.......................................................15 2.4.8 Fuel Production ...............................................................................................16 2.4.9 Other Solids Technologies ..............................................................................16 2.4.10 Non-Solids Technologies ................................................................................16 2.4.11 Unknown Technologies ...................................................................................162.5 Technology Development Status ...................................................................................162.6 Consideration of Sludge Characteristics ........................................................................163.0 POTENTIAL TECHNOLOGIES AND VENDORS...........................................................183.1 Digestion Technologies .................................................................................................18 3.1.1 Omnivore ........................................................................................................18 3.1.2 Thermal Hydrolysis (TH) .................................................................................18 3.1.3 VERTAD .........................................................................................................183.2 Composting ...................................................................................................................18 3.2.1 Biozyme ..........................................................................................................18 3.2.2 Solorganics .....................................................................................................183.3 Heat Drying ...................................................................................................................18 3.3.1 Conventional Heat Drying ...............................................................................18 3.3.2 VitAg ...............................................................................................................193.4 Incineration ....................................................................................................................19 3.4.1 Fluid Bed Incineration (FBI).............................................................................193.5 Gasification and Pyrolysis (Closed-Coupled) .................................................................19 3.5.1 Kruger BioCon + Energy Recovery System (ERS) ..........................................20 3.5.2 MaxWest .........................................................................................................20 3.5.3 Nexterra ..........................................................................................................20 Page i of xvii
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Alternative Technologies for the Beneficial Reuse of Sewage SludgeResponse to Resolution 11-182October 2011 3.5.4 Prime Energy Gasification ...............................................................................21 3.5.5 Pyrobuster.......................................................................................................213.6 Gasification and Pyrolysis (Two Stage) .........................................................................21 3.6.1 Ascent BioEnergy............................................................................................22 3.6.2 Carbon BioEngineers Inc. ...............................................................................22 3.6.3 D4 ...................................................................................................................22 3.6.4 HGE – Korea (a KBI Group) High Temperature Conversion of Waste (HTCW) ........................................................................................................................22 3.6.5 Integrated Environmental Technologies LLC – S4 Energy Solution.................23 3.6.6 Intellergy .........................................................................................................23 3.6.7 Kopf ................................................................................................................23 3.6.8 Kore Process (G2E! Green Earth Energy).......................................................23 3.6.9 Nexterra ..........................................................................................................233.7 Alternative Combustion .................................................................................................23 3.7.1 Fabgroups Technologies – Plasma Assisted Sludge Oxidation (PASO) ..........23 3.7.2 Kunmin ............................................................................................................233.8 Alternative “Smokeless” Sludge Oxidation .....................................................................24 3.8.1 ATHOS Wet Air Oxidation (WAO) ...................................................................24 3.8.2 Sci-Fi SuperCritical Water Oxidation (SCWO) – AquaCritox™ ........................243.9 Fuel Production .............................................................................................................24 3.9.1 Enertech SlurryCarb™ ....................................................................................24 3.9.2 N-Viro International .........................................................................................24 3.9.3 Panatech .........................................................................................................243.10 Other Solids Technologies.............................................................................................24 3.10.1 Astec Thermal Remediation ............................................................................24 3.10.2 BioRenewables – Applied Filter Technologies.................................................24 3.10.3 HydroCell Dewatering .....................................................................................25 3.10.4 Ledcor .............................................................................................................25 3.10.5 PyroBioMethane™ ..........................................................................................253.11 Non-Solids Technologies ...............................................................................................25 3.11.1 Beneficial Active Microorganisms (BAM) .........................................................25 3.11.2 BioCleaner ......................................................................................................25 3.11.3 ECO-H2O ........................................................................................................25 3.11.4 Global Environmental Technology Services (GETS) .......................................26 3.11.5 SunPower .......................................................................................................263.12 Unknown Technologies .................................................................................................26 3.12.1 Ebara ..............................................................................................................26 3.12.2 Waste to Energy..............................................................................................264.0 EVALUATION CRITERIA ..............................................................................................274.1 Intent of the Resolution ..................................................................................................274.2 Onsite vs. Offsite Technologies .....................................................................................274.3 List of Criteria ................................................................................................................274.4 “Fatal Flaw” ...................................................................................................................284.5 Technology Development Status and Piloting................................................................294.6 Risks of Unknown Technologies ....................................................................................305.0 TECHNOLOGIES FOR FUTURE CONSIDERATION ....................................................336.0 SELECTION AND IMPLEMENTATION .........................................................................34 Page ii of xvii
  5. 5. Alternative Technologies for the Beneficial Reuse of Sewage SludgeResponse to Resolution 11-182October 20116.1 Supplemental Report for Resolution 11-182: Alternative Technologies for the Treatmentand Minimization of Sewage Sludge .........................................................................................346.2 Island-wide Solids Master Plan......................................................................................34 6.2.1 Island-wide Solids Quantity and Quality ..........................................................34 6.2.2 Solids Reduction at Smaller WWTPs (< 5 mgd) ..............................................34 6.2.3 Island-wide Transportation, Treatment, and Disposal ......................................34 6.2.4 Redundancy and Reliability for Processing and Disposal ................................35 6.2.5 Island-wide Solids Processing and Disposal Plan ...........................................356.3 Life-Cycle Cost Analysis ................................................................................................356.4 Schedule and Implementation .......................................................................................36 6.4.1 Pilot Testing ....................................................................................................36 6.4.2 Master Plan Timeline.......................................................................................36 6.4.3 Design and Construction .................................................................................36 6.4.4 Honouliuli and Sand Island Secondary Treatment ...........................................36 6.4.5 Facilities Planning for Kailua, Honouliuli, Sand Island, and Waianae WWTPs.36 TABLESTable 2-1. Island-wide Solids Production ....................................................................................9Table 2-2. Characteristics of Different Thermal Processing Technologies .................................14Table 4-1. Technology Comparison ..........................................................................................31 FIGURESFigure 2-1. Location of WWTPs and Waimanalo Gulch Landfill ..................................................7Figure 2-2. Honouliuli, Kailua, and Sand Island Process Flow Diagrams.....................................8Figure 2-3. Anaerobic Digester Schematic ................................................................................11Figure 3-1. Close-Coupled Gasification System for Energy Recovery .......................................20Figure 3-2. Two Stage Gasification System for Energy Recovery .............................................22 APPENDICESAppendix A – Resolution 11-182Appendix B – RFIAppendix C – Technology Fact Sheets Page iii of xvii
  6. 6. Alternative Technologies for the Beneficial Reuse of Sewage SludgeResponse to Resolution 11-182October 2011 WORKS CITEDAECOM. (2011). Technical Memorandum Work Task 11.C: Solids Processing Technology.Metcalf & Eddy. (2003). Wastewater Engineering Treatment and Reuse. 4th Edition.US EPA. (1994). A Plain English Guide to the EPA Part 503 Biosolids Rule, EPA/832/R-93/003.Chapter 4 – Incineration of Biosolids.US EPA. (2006). Emerging Technologies for Biosolids Management, EPA 832-R-06-005.US EPA. (2011). “Standards of Performance for New Stationary Sources and EmissionGuidelines for Existing Sources: Sewage Sludge Incineration Units,” Federal Register / Vol. 76,No. 54, pp. 15372-15454, 40 CFR Part 60.Water Environment Federation (WEF) Website. Glossary of Terms(http://www.wef.org/AWK/page.aspx?id=1951). Page iv of xvii
  7. 7. Alternative Technologies for the Beneficial Reuse of Sewage SludgeResponse to Resolution 11-182October 2011 ACRONYMS/ ABBREVIATIONSATAD Autothermal Thermophilic Aerobic DigestionBAM Beneficial Active MicroorganismsBioconversion Facility In-vessel Bioconversion FacilityBOD Biological Oxygen DemandBTU British Thermal UnitsCCH City and County of HonoluluCEM Continuous Emission MonitoringCFR Code of Federal RegulationsCH4 MethaneCHP Combined Heat and PowerCO Carbon MonoxideCO2 Carbon Dioxidecu. ft. cubic feetcu. yd. cubic yardDB Design and BuildDBB Design, Bid, and BuildDBO Design, Build, and OperateDBOM Design, Build, Operate, and MaintainDBOOF Design, Build, Own, Operate, and FinanceDS Dry Solidsdtpd dry tons per dayENV Department of Environmental ServicesEPA Environmental Protection AgencyERS Energy Recovery SystemESPC Energy Savings Performance ContractFBI Fluid Bed IncinerationFOG Fats, Oils and GreaseG2E! Green Earth EnergyGE General ElectricGETS Global Environmental Technology ServicesH2 HydrogenH2O WaterIATS Innovative Anaerobic Treatment SystemIC Internal CombustionHER Hawaiian Earth Recycling, LLCHTCW High Temperature Conversion of Wastelb poundMABA Mid-Atlantic Biosolids AssociationMBR Membrane Bioreactormgd million gallons per dayMHI Multiple Hearth IncinerationMSAP Modified Static Aerobic PileMW e Mega Watt equivalentNBP National Biosolids PartnershipNEBRA North East Biosolids and Residuals AssociationO&M Operation & MaintenanceORC Organic Rankine CyclePASO Plasma Assisted Sludge Oxidation Page v of xvii
  8. 8. Alternative Technologies for the Beneficial Reuse of Sewage SludgeResponse to Resolution 11-182October 2011PEM Plasma Enhanced MelterPFRP Processes to Further Reduce Pathogenspsig pounds per square inch gaugePSRP Process to Significantly Reduce PathogensResolution Resolution 11-182RFI Request for InformationSCWO Supercritical Water OxidationSEP Supplemental Environmental ProjectsSOUR Specific Oxygen Uptake RateSPV Special Purpose VehicleSSI Sewage Sludge IncinerationSynagro Synagro WWT, IncTCOM Thermal Conversion of Organic MaterialTH Thermal HydrolysisTS Total SolidsTSK Tsukishima KikaiVS Volatile SolidsWAO Wet Air OxidationWEF Water Environment FederationWWTP Wastewater Treatment Plant Page vi of xvii
  9. 9. Alternative Technologies for the Beneficial Reuse of Sewage SludgeResponse to Resolution 11-182October 2011 EXECUTIVE SUMMARYINTRODUCTIONBackgroundThe City and County of Honolulu (CCH) entered into the 1995 Consent Decree (Civil No. 94-00765DAE) with the State of Hawaii and the Environmental Protection Agency (EPA). As partof the 1995 Consent Decree, CCH committed to Supplemental Environmental Projects (SEPs)which included spending at least $10 million on beneficial sludge reuse. The result of the 1995Consent Decree was a contract in 2004 between CCH and Synagro WWT, Inc. (Synagro) inwhich Synagro would design/build/operate an In-vessel Bioconversion Facility (BioconversionFacility) at the Sand Island Wastewater Treatment Plant (WWTP) to convert the sludge into apellet fertilizer. The main components of the Synagro In-vessel Bioconversion Facility are anegg-shaped digester for anaerobic digestion, two centrifuges for dewatering, and a dryer forpelletizing.The 2010 Consent Decree between CCH, State of Hawaii, and EPA included the upgrade of theSand Island and Honouliuli WWTPs to full secondary treatment. In addition, CCH is evaluatingalternatives to the Waimanalo Gulch Landfill by conducting an Island-wide Biosolids MasterPlan.Currently the egg shaped digester at Sand Island WWTP is at full capacity resulting in the needto consider either expansion of existing operations or alternative technologies for processingand treatment. On June 28, 2011, the City Council signed Resolution 11-182 (herein referred toas the Resolution), which stated concerns about the current bioconversion facility including: (1) Public health and safety (2) Impact to businesses and residents (3) Visual blight and impacts to tourism (4) Marketability of fertilizer pellets (5) Reputation and credibility (6) The cost to construct the existing bioconversion facility was over $40 million, including cost overruns exceeding $7 million, and the projected cost of the second facility was budgeted at $26 millionAs part of an ongoing contract with ENV, AECOM began work in August 2010 on a LeewardRegion Solids Master Plan. In June 2011 ENV requested AECOM expand the effort to preparean Island-Wide Solids Master Plan. The Island-wide Solids Master Plan is evaluating theexisting solids treatment and disposal at all the CCH operated WWTPs with the goal ofrecommending improvements or upgrades at these WWTPs. On July 1, 2011 AECOM wasfurther tasked by ENV to investigate and prepare a report in response to Resolution 11-182,which requested the administration to: “...investigate alternative technologies for the beneficial reuse of sewage sludge other than the technology used at the Sand Island WWTP’s bioconversion facility that will be sustainable and less harmful to the environment, including technologies successfully used in Europe, Asia and North America by companies with good reputations for credibility... to the end that the Council [would] work with the City administration Page vii of xvii
  10. 10. Alternative Technologies for the Beneficial Reuse of Sewage SludgeResponse to Resolution 11-182October 2011 expeditiously to implement a safe and healthful alternative to the Synagro technology so as to ensure that any necessary construction may commence as soon as possible.”Overview of Solids Handling OperationsCCH currently operates nine WWTPs on Oahu including Honouliuli, Kahuku, Kailua, Laie,Paalaa Kai, Sand Island, Wahiawa, Waianae, and Waimanalo WWTP. Currently, Honouliuli,Kailua, and Waianae WWTPs’ sludge goes through anaerobic digestion for stabilization andcentrifuges for dewatering. The biosolids are then hauled to Waimanalo Gulch Landfill fordisposal. Synagro Bioconversion Facility at Sand Island WWTP also has anaerobic digestionfor stabilization, followed by dewatering, and drying for pelletization. The pellets produced atSynagro Bioconversion Facility have been used as a fertilizer at agricultural farms, golf courses,and parks. The dried product from the Synagro facility is either beneficially reused as a fertilizerproduct for land application or hauled to Waimanalo Gulch Landfill for disposal. Synagroindicated that currently most of their generated product is being beneficially used withoutrevenue. The Kahuku, Paalaa Kai, Wahiawa, and Waimanalo WWTPs haul liquid waste to thelarge facilities for further treatment. The Laie WWTP has an onsite composting facility that isoperated by CCH staff. The compost that has been approved for distribution is used by theMormon Church that owns the WWTP for agricultural purposes and the compost that is notapproved for distribution (mostly due to metal content) is disposed of at the Waimanalo GulchLandfill. Figure 1 shows the location of the existing WWTPs, currently available solids outletsand transfer of solids between the various facilities.Table 1 provides an estimate of solids production at each of the WWTPs as well as some keyaspects associated with treatment and disposal at each.Purpose and ObjectivesThe purpose of this report is to respond to the Resolution by identifying potential alternativesludge processing technologies for the beneficial reuse of sewage sludge other than thetechnology used at Sand Island WWTP. Some of the technologies included in this report arefrom vendors that responded to a Request for Information, were known by AECOM or hadapproached the CCH and/or the City Council directly.The outcome of this report is a list of technologies meeting the requirements of the Resolutionfor consideration as part of the ongoing island-wide solids planning effort. The intent of thistechnology listing is to have appropriate technologies to evaluate in considering island-widesludge management needs. This report is not intended to be a decision making document thatrecommends a best solution. Some additional factors that will need to be determined as part ofany evaluation and selection process would likely include: An assessment of a particular alternative technology specific to the WWTP with respect to the facilities already existing there. Capital and O&M costs specific to the WWTP in which it is being evaluated for. Implementation timeline for planning, design, permitting, procurement, construction and startup. Compatibility of technology with overall Island-wide Solids Master Plan New development and increased future capacity needs Planned upgrades at the existing WWTPs (i.e. upgrade to secondary treatment) Page viii of xvii
  11. 11. Alternative Technologies for the Beneficial Reuse of Sewage SludgeResponse to Resolution 11-182October 2011It should be noted that technology and process selection for implementation at any of the nineWWTPs will need to be looked at from an island-wide perspective due to the issues ofcombining/transportation of solids between WWTPs as well as the identified end user needsand beneficial use limitations. Other key elements that were considered include reliability andredundancy planning in the event that a WWTP treatment unit (i.e. centrifuge or digester) orsolids outlet (i.e. landfill or composting facility) is temporarily out of service. Table 1 - Island-Wide Solids Production Average Solids State of Dewatering Solids WWTP Flow1 Stabilization Production2 Solids Method Distribution (mgd) (dtpd) Waimanalo Anaerobic Honouliuli 25.92 7.28 Cake Centrifuge Gulch Landfill Digester (~7 mi) Aerobic Kailua Regional Kahuku 0.19 0.26 Liquid None Digester WWTP (~34 mi) Waimanalo Kailua Anaerobic 11.49 2.65 Cake Centrifuge Gulch Landfill Regional Digester (~32 mi) Mormon Church/ Laie 0.46 Clarigester ---3 Compost Composting Waimanalo Gulch Landfill Aerobic Honouliuli Paalaa Kai 0.09 0.05 Liquid None Digester WWTP (~21 mi) Class A Fertilizer Pellets Anaerobic Reuse/ Sand Island 61.29 9.21 Dried Pellets Centrifuge/Dryer Digester Waimanalo Gulch Landfill (~23 mi) Honouliuli Wahiawa4 1.64 Not Stabilized 2.00 Liquid None WWTP (~17 mi) Waimanalo Anaerobic Waianae 3.31 0.44 Cake Centrifuge Gulch Landfill Digester (~8 mi) Anaerobic Kailua Regional Waimanalo 0.55 0.26 Liquid None Digester WWTP (~33 mi)1 Source: City and County of Honolulu, Dept of Environmental Services, Wastewater Management website (FY 2011). Million gallons per day (mgd)2 Source: Annual Biosolids Production Reports – January 1 to December 31, 2010, Division of Wastewater Treatment and Disposal, ENV. Dry tons per day (dtpd)3 Dry weight is not available (no percent solids data). Laie WRF produced a total of 1,056 cu. yd. of compost that was disposed at the landfill. This is approximately 727.6 wettons (based on a measured unit weight of 51 lbs/cu. ft.) Source: Note 8, Annual Biosolids Production Reports – January 1 to December 31, 2010, Division of WastewaterTreatment and Disposal, ENV4 Wahiawa is currently being upgraded to an MBR facility, so solids characteristics will change when the new processes are in operation. Page ix of xvii
  12. 12. Alternative Technologies for the Beneficial Reuse of Sewage SludgeResponse to Resolution 11-182October 2011Insert Figure 1 - Location of WWTPs and Waimanalo Gulch Landfill Page x of xvii
  13. 13. Alternative Technologies for the Beneficial Reuse of Sewage SludgeResponse to Resolution 11-182October 2011Identification and Classification of TechnologyPotential technologies and technology vendors were identified by several methods. The initiallisting of technologies was developed using known technologies and technology vendors thatare currently active within the municipal wastewater industry. This includes technologies andvendors identified as part of the ongoing island-wide solids master planning effort that could beimplemented at large (>5 mgd) WWTPs. Additional technologies and vendors were obtainedthrough a formal Request for Information (RFI) and solicitation process through variousprofessional organizations. Technology vendors that had previously contacted the CCH weresent the RFI to provide key information required for evaluation.Technology ClassificationThe identified vendors and their technologies covered a wide range of treatment and processingtypes. In order to facilitate an organized approach to determining applicability many of thevendors were organized by the general classification or technology category which bestdescribed the process using standard industry terminology as described in the followingparagraphs. It should be noted that some solution providers responding to the RFI were notactually equipment manufacturers or suppliers. These solution providers were often systemintegrators that provided an alternative means of financing, often involving a rate paybacksystem or power purchase agreement to recuperate initial construction costs. As discussedfurther in the report the economics and life-cycle cost comparison of the various alternatives willbe conducted as part of the Island-wide Solids Master Plan and as such only the specifictechnologies proposed by any respective vendor are considered, irrespective of financingmethodology.The categories used for technology classification are identified below and described in detail inthe following report. In some instances an entire technology category was not considered forfuture consideration since the category itself did not meet the defined requirements. Thetechnology classifications are as follows with the more established technologies listed first,followed by the newer and innovative processes: Digestion Composting Heat Drying Only Incineration Gasification and Pyrolysis (Closed-Coupled) Gasification and Pyrolysis (Two Stage) Alternative Combustion Alternative “Smokeless” Sludge Oxidation Fuel Production Other TechnologiesTechnology Development StatusThe processes are generally classified in the industry based on the stage of development. Inthis report, the technologies are classified either as either “concept”, “emerging”,“demonstration”, or “established” technology as defined below: 1. Concept technologies are ones that are not proven at pilot and/or small scales. Page xi of xvii
  14. 14. Alternative Technologies for the Beneficial Reuse of Sewage SludgeResponse to Resolution 11-182October 2011 2. Emerging technologies are proven at pilot/small scale but are not proven at a full scale installation. 3. Demonstration technologies are proven at one to three full scale installations. 4. Established technologies are proven at more than three sites.“Concept” technologies are not considered further in this evaluation unless the vendor wouldlike to conduct pilot testing at one of the WWTPs at no expense to CCH. Pilot testing will notguarantee that the technology would be chosen; however, a successful demonstration wouldreclassify the development status from “Concept” to “Emerging”.TECHNOLOGY EVALUATIONAs stated in the Resolution, this report “…investigate[d] alternative technologies for thebeneficial reuse of sewage sludge other than the technology used at the Sand Island WWTP’sbioconversion facility that will be sustainable and less harmful to the environment, includingtechnologies successfully used in Europe, Asia and North America by companies with goodreputations for credibility...” As such, technologies other than anaerobic digestion, drying only,and pelletization are considered if the byproducts are beneficially reused or energy is beinggenerated for on-site use.The beneficial reuse technologies considered are focused on the on-site treatment of solids atthe larger facilities (Honouliuli, Kailua, and Sand Island WWTPs). Although composting isconsidered a beneficial reuse, the product may be considered a soil amendment or fertilizer andthe Resolution states that “…uses of sewage sludge byproducts for purposes other thanfertilizer should be explored...” The offsite incineration at H-power may be considered abeneficial reuse of the sludge; however, the energy produced would not be beneficial to theWWTP. Therefore, offsite technologies including composting by HER and incineration at H-Power are considered in the Supplemental Report for Resolution 11-182: AlternativeTechnologies for the Treatment and Minimization of Sewage Sludge.Evaluation CriteriaThe evaluation criteria for the technologies are as follows: Is it a Solids Handling Process? Process Input Requirement Responded to RFI? Status of Technology Development Ease of Operation Regulatory and Permitting Impact Footprint Ability and Willingness of Vendor to Pilot Is Upstream Anaerobic Digestion Required or Desired for Energy Production? End Product Ability to Produce Electricity Beneficial Byproducts Other Materials That Can Be Accepted Is Existing or Different Drying Required? Consumables Capital Cost for 25 dtpd Facility (Vendor Provided) Page xii of xvii
  15. 15. Alternative Technologies for the Beneficial Reuse of Sewage SludgeResponse to Resolution 11-182October 2011 O&M Cost (Vendor Provided) Does Capital and O&M estimate include upstream processing required such as drying?It should be noted that capital and O&M costs presented are unverified vendor estimates andmay not include or take into account site requirements, ancillary items, and cost of installation inHawai‘i. In addition, some of the vendors do not have full scale installations.In order to further consider appropriate technologies for solids processing, technologies withone or more of the listed “fatal flaws” below were not considered appropriate for futureconsideration. Technologies that are not considered “solids processing based” Technologies unable to process the 25 dtpd minimum amount of sludge Technologies where the main product is material that requires land application Technologies that are currently at the conceptual level Technologies where the vendor actively declined to respond to the RFI. Technologies where the providing vendor did not acknowledge or respond to the RFI.Table 2 presents all technologies that were evaluated in this report, with the technologiesrecommended for future consideration highlighted. The listed and evaluated technologiesexclude those used at the Synagro Bioconversion Facility. As the table shows, there is a widerange of technologies included. The list and development status of technologies/vendors will becontinually updated during the island-wide master planning process.Risks of Unknown TechnologiesAs many of the “appropriate” technologies considered are not “established” and there are limitedinstallations world-wide, the risk of unknown information is high. There may be unknowndisadvantages and unknown costs for the newer technologies. For “concept” technologies, theunknowns include unknown results of a pilot test and unknown costs and it may be difficult toprove the claims of the vendor. For “emerging” technologies, there is the unknown of upsizingto a full scale installation for both results and costs. For “demonstration” technologies, theunknown is if the results from the full scale installation can be reproduced. Page xiii of xvii
  16. 16. Alternative Technologies for the Beneficial Reuse of Sewage SludgeResponse to Resolution 11-182October 2011Insert Table 2 Screened Technologies Page 1 Page xiv of xvii
  17. 17. Alternative Technologies for the Beneficial Reuse of Sewage SludgeResponse to Resolution 11-182October 2011Insert Table 2 Screened Technologies Page 2 Page xv of xvii
  18. 18. Alternative Technologies for the Beneficial Reuse of Sewage SludgeResponse to Resolution 11-182October 2011SELECTION AND IMPLEMENTATIONSupplemental Report of Additional TechnologiesIn addition to this document, the Supplemental Report for Resolution 11-182: AlternativeTechnologies for the Treatment and Minimization of Sewage Sludge will be completed byNovember 11, 2011 to identify other solids technologies that may be appropriate for solidstreatment but may not directly meet the Resolution requirements. These technologies may beapplicable to both the small and large WWTPs. Similar to this report, the Supplemental Reportfor Resolution 11-182: Alternative Technologies for the Treatment and Minimization of SewageSludge will list technologies to consider for further evaluation during the master planningprocess.Further Evaluation and Life-Cycle Cost AnalysisFor each technology classification a single technology/vendor will be used as a representativefor comparison purposes during the island-wide planning effort. This evaluation should not beviewed as selecting the vendor for CCH rather selecting the category that best suits CCHcurrent and future needs. The ultimate selection of the vendor/technology would be based oncompetitive bidding by the appropriate method such as design, bid and build (DBB), design andbuild (DB), design, build and operate (DBO), design, build, operate and maintain (DBOM), anddesign, bid, own, operate and finance (DBOOF).Further evaluation of technologies will be qualitatively conducted during the island-wide studyevaluation using the criteria listed below in order to arrive at a group of technologies that aremost appropriate for solids processing. Expected capital cost Expected O&M cost Ease of operation and maintenance Energy producing potential Sustainable technology (measured as CO2e potential) Public perception of the facilityAlthough some of the information above is presented in the current comparison tables, it shouldbe noted that the values listed are for a “generic” plant that produces 25 DT/day and not aspecific WWTP operated by CCH. A more detailed evaluation and check should be performedto ensure that comparable scope items are included in the capital and O&M costs and that the“cost” factors are the same for all options based on the local island costs. For example,Nexterra provided a capital and O&M cost for their gasification systems but did not include thedrying component as a part of the cost. In addition, the scope boundary for an O&M estimateshould be thoroughly checked in the detailed evaluation to ensure that any comparison madefor further screening is based on an “apples to apples” comparison. Moreover, inclusion of anyboundaries set for labor and hauling costs should be the same for all screened technologies.This type of thorough check has not been completed at this time and will be included in theIsland-Wide Solids Master Planning for the “short-listed” technologies.Island-wide Solids Master PlanningCCH is currently underway with an Island-wide Solids Master Plan to evaluate the existingsolids treatment and disposal at all the CCH operated WWTPs. The goal of this master plan isto recommend improvements or upgrades at these WWTPs. The solids recommendations from Page xvi of xvii
  19. 19. Alternative Technologies for the Beneficial Reuse of Sewage SludgeResponse to Resolution 11-182October 2011the Honouliuli, Kailua, and Sand Island facilities plans will be incorporated into the Island-wideSolids Master Plan. Key elements of the master planning effort are outlined below: Island-wide Solids Quantity and Quality Estimates - Determine existing and project future solids quantity and quality at each WWTP. Solids Reduction at Smaller WWTPs (< 5 mgd) - Determine the cost effectiveness of onsite solids reduction treatment to reduce hauling, offsite treatment, and/or disposal costs for the smaller WWTPs, especially the WWTPs that haul liquid waste to the larger facilities. Island-wide Transportation, Treatment, and Disposal - Evaluate the cost effectiveness of transportation, treatment, and disposal options for all nine CCH operated WWTPs. Redundancy and Reliability for Processing and Disposal - Determine the reliability and back-up options for the planned solids processing and disposal in the event that one option is unavailable due to mechanical failure or other causes. Island-wide Solids Processing and Disposal Plan - Incorporate the findings of the previous reports to recommend upgrades to the existing solids processing and disposal at each WWTP.Schedule and Implementation Pilot Testing – If conducted, pilot testing of technologies is anticipated to take at least 18 to 24 months. This includes 12 months of data collection once the pilot testing facility is in operation. Master Plan Timeline - The master plan timeline is as follows: o Complete Sampling and Testing - January 2012 o Island-wide Solids Quantity and Quality Estimates – April 2012 o Solids Reduction at Smaller WWTPs – May 2012 o Island-wide Transportation, Treatment, and Disposal – May 2012 o Redundancy and Reliability for Processing and Disposal – August 2012 o Island-wide Solids Processing and Disposal Plan – December 2012 Design and Construction - Design and construction scheduling depends on the construction and phasing recommendations in the Island-wide Solids Processing and Disposal Plan. It is anticipated that design for each project would take one year and procurement and construction would take two to three years. It is assumed that some projects may run concurrently. Honouliuli and Sand Island Secondary Treatment - The Honouliuli and Sand Island WWTPs are anticipated to begin full secondary treatment by 2024 and 2035, respectively, in accordance with the 2010 Consent Decree. The solids quantity is expected to increase substantially when these WWTPs become secondary WWTPs. Master planning efforts along with any near term design and construction will take into consideration the timing and future anticipated needs at both facilities. Facilities Planning for Kailua, Honouliuli, Sand Island, and Waianae WWTPs – The net outcome of Facilities Plans and Island-wide Solids Master Plan will be coordinated to be in agreement regarding the proposed solids handling facilities at the referenced WWTPs Page xvii of xvii
  20. 20. Alternative Technologies for the Beneficial Reuse of Sewage SludgeResponse to Resolution 11-182October 20111.0 INTRODUCTION AND OVERVIEW1.1 BackgroundThe City and County of Honolulu (CCH) entered into the 1995 Consent Decree (Civil No. 94-00765DAE) with the State of Hawaii and the Environmental Protection Agency (EPA). As partof the 1995 Consent Decree, CCH committed to Supplemental Environmental Projects (SEPs)which included spending at least $10 million on beneficial sludge reuse. The result of the 1995Consent Decree was a contract in 2004 between CCH and Synagro WWT, Inc. (Synagro) inwhich Synagro would design/build/operate an In-vessel Bioconversion Facility (BioconversionFacility) at the Sand Island Wastewater Treatment Plant (WWTP) to convert the sludge into apellet fertilizer. The main components of the Synagro In-vessel Bioconversion Facility are anegg-shaped digester for anaerobic digestion, two centrifuges for dewatering, and a dryer forpelletizing.The 2010 Consent Decree between CCH, State of Hawaii, and EPA included the upgrade of theSand Island and Honouliuli WWTPs to full secondary treatment. In addition, CCH is evaluatingalternatives to the Waimanalo Gulch Landfill by conducting an Island-wide Biosolids MasterPlan.Currently, the egg shaped digester at Sand Island WWTP is at full capacity resulting in the needto consider either expansion of existing operations or alternative technologies for processingand treatment. On June 28, 2011, the City Council signed Resolution 11-182 (herein referred toas the Resolution and provided in Appendix A), which stated concerns about the currentbioconversion facility including: (1) Public health and safety (2) Impact to businesses and residents (3) Visual blight and impacts to tourism (4) Marketability of fertilizer pellets (5) Reputation and credibility (6) The cost to construct the existing bioconversion facility was over $40 million, including cost overruns exceeding $7 million, and the projected cost of the second facility was budgeted at $26 millionAs part of an ongoing contract with ENV, AECOM began work in August 2010 on a LeewardRegion Solids Master Plan. In June 2011 ENV requested AECOM expand the effort to preparean Island-Wide Solids Master Plan. The Island-wide Solids Master Plan is evaluating theexisting solids treatment and disposal at all the CCH operated WWTPs with the goal ofrecommending improvements or upgrades at these WWTPs. On July 1, 2011 AECOM wasfurther tasked by ENV to investigate and prepare a report in response to Resolution 11-182,which requested the administration to: “...investigate alternative technologies for the beneficial reuse of sewage sludge other than the technology used at the Sand Island WWTP’s bioconversion facility that will be sustainable and less harmful to the environment, including technologies successfully used in Europe, Asia and North America by companies with good reputations for credibility... to the end that the Council [would] work with the City administration expeditiously to implement a safe and healthful alternative to the Synagro technology so as to ensure that any necessary construction may commence as soon as possible.” Page 1 of 36
  21. 21. Alternative Technologies for the Beneficial Reuse of Sewage SludgeResponse to Resolution 11-182October 20111.2 PurposeThe purpose of this report is to respond to the Resolution by identifying potential alternativesludge processing technologies for the beneficial reuse of sewage sludge other than thetechnology used at Sand Island WWTP. Some of the technologies included in this report arefrom vendors that responded to a Request for Information (RFI), were known by AECOM or hadapproached the CCH and/or the City Council directly. It should be noted that this report is notintended to be a decision making document and it is only intended to identify appropriatetechnologies to consider moving forward and provide a high level comparison. A more detailedand thorough analysis will be conducted with the island-wide study.1.3 ObjectivesThe objectives of this report include: Assemble a formal RFI, provided in Appendix B, for a generic WWTP that produces 25 dry tons per day (dtpd) of solids but does not use the treatment process currently at Sand Island WWTP. Submit the RFI to the National Biosolids Partnership (NBP), the Mid Atlantic Biosolids Association (MABA), and the North East Biosolids and Residuals Association (NEBRA) to post on their websites and pass on to their respective members to allow experts in the field to comment and provide information about innovative and emerging technologies. Submit the RFI to various technology vendors that directly contacted CCH or City Council. Compile a list of technologies or vendors and information that was received from the RFI process. Compile a list of criteria to evaluate the technologies or vendors. Compile a list of technologies that should be further evaluated in the upcoming Island- wide Solids Master Planning.The outcome of this report is a list of technologies meeting the requirements of the Resolutionfor consideration as part of the ongoing island-wide solids planning effort. The intent of thistechnology listing is to have appropriate technologies to evaluate in considering island-widesludge management needs. This report is not intended to be a decision making document thatrecommends a best solution. Some additional factors that will need to be determined as part ofany evaluation and selection process would likely include: An assessment of a particular alternative technology specific to the WWTP with respect to the facilities already existing there. Capital and O&M costs specific to the WWTP in which it is being evaluated for. Implementation timeline for planning, design, permitting, procurement, construction and startup. Compatibility of technology with overall Island-wide Solids Master Plan New development and increased future capacity needs Planned upgrades at the existing WWTPs (i.e. upgrade to secondary treatment)It should be noted that technology and process selection for implementation at any of the nineWWTPs will need to be looked at from an island-wide perspective due to the issues ofcombining/transportation of solids between WWTPs as well as the identified end user needsand beneficial use limitations. Other key elements that were considered include reliability and Page 2 of 36
  22. 22. Alternative Technologies for the Beneficial Reuse of Sewage SludgeResponse to Resolution 11-182October 2011redundancy planning in the event that a WWTP treatment unit (i.e. centrifuge or digester) orsolids outlet (i.e. landfill or composting facility) is temporarily out of service.1.4 MethodologyThe vendors contacted during the compilation of technologies for this report includedtechnologies known by AECOM, technologies included in Work Task 11.C – Solids ProcessingTechnology (April 2011), technologies from vendors that contacted CCH and City Councildirectly, and vendors that responded to the posting on NBP, MABA, and NEBRA websites. Thevendors were sent and asked to respond to the RFI. The information collected from the RFIwas compiled and screening criteria were developed to determine technologies and vendorsthat may be applicable for beneficial reuse of sewage sludge at the larger WWTPs. Page 3 of 36
  23. 23. Alternative Technologies for the Beneficial Reuse of Sewage SludgeResponse to Resolution 11-182October 20112.0 OVERVIEW OF SOLIDS TREATMENT AND PROCESSINGThe following section provides background information that was taken into account whenevaluating the different technology vendors. This section discusses common industryterminology, provides some regulatory background and summarizes the islands currentbiosolids plan. This section also provides background on the technology classification used tocategorize the vendors as well as a summary of how the technology development was ratedand the impact of site specific sludge characteristics.2.1 TerminologyThis section defines terminology used in this report. Aerobic – Describes a condition where bacteria are living or occurring in the presence of oxygen. Many secondary treatment processes occur aerobically and sewage sludge can be digested under aerobic conditions to stabilize sewage sludge and generate biosolids. Anaerobic – Describes a condition where bacteria are living or occurring in the absence of oxygen. Many WWTPs digest their sludge anaerobically for stabilization, generating biosolids. Anaerobic process also produces methane (CH4) as a byproduct that can be beneficially used for energy production. Biosolids – Describes Solid materials resulting from wastewater treatment that meets government criteria for beneficial use, such as for fertilizer. To be classified as biosolids the sewage sludge must have undergone additional stabilization such as digestion, composting, drying or alkaline stabilization to meet federal and state standards for beneficial use. The stabilization requirements to convert sewage sludge to Biosolids are defined by the EPA under 40 CFR (Code of Federal Regulations) Part 503 Cake – Informal term used to describe dewatered sludge or dewatered biosolids coming off of a dewatering device such as a belt filter press or centrifuge. Class A Biosolids – Describes biosolids that are processed to the requirements defined by the EPA under 40 CFR, Part 503 with regards to pathogen and vector attraction reduction requirements. The goal of developing class A standards was to provide a quality of biosolids where pathogens in sewage sludge (including enteric viruses, pathogenic bacteria and viable helminth ova) were below detectable limits as defined in the 1992 regulation. Class B Biosolids – Describes biosolids that are processed to the requirements defined by the EPA under 40 CFR, Part 503 with regards to pathogen and vector attraction reduction requirements. The goal of developing class B standards was to provide a quality of biosolids where pathogens were below levels considered likely to pose a threat to public health and the environment under the specific use conditions. Applying Class B sludge involves site use restrictions to minimize the potential for human or animal exposure to Class B solids for a set period of time. Dewatering – The process of extracting or removing water from sludge or slurry Drying – To remove water through the means of evaporation Dry Tons – A unit of measurement representing only the dry mass of a substance. One dry ton is equal to 2,000 dry pounds (lbs) (Example: 10.0 dry tons at 35% solids 28.6 wet tons) In-vessel Bioconversion Facility – A term used by Synagro to describe the full sludge processing system at Sand Island including digestion, dewatering and drying. The process as installed converts thickened sewage sludge to a dry pelletized biosolids product that meets Class A requirements and can be marketed as a fertilizer product. Page 4 of 36
  24. 24. Alternative Technologies for the Beneficial Reuse of Sewage SludgeResponse to Resolution 11-182October 2011 In-vessel Composting Facility – A composting system with integral materials handling and in-vessel mixing and aeration. Solids Minimization – Process that reduces the mass and volume of sludge for further processing, beneficial reuse or disposition Pelletizing – A process that generates a uniform round or cylindrical dry biosolids product (a pellet). Some dryers are designed with back mixing, screening or other mechanisms to produce pellets at the dryer’s outlet. A second process can also be added to convert a non-uniform dried material to pellets. Percent Solids – The percentage of a sludge or biosolids total mass that is solid material. The percent water fraction is equal to one minus the percent solids Sludge - Solid matter that settles to the bottom of septic tanks or WWTP sedimentation; must be disposed of by bacterial digestion or other methods of stabilization. Sludge can also be pumped out for land disposal or incineration. Stabilization – A process that is applied to sludge for the purpose of reducing pathogens, eliminating offensive odors, and inhibiting, reducing or eliminating the potential for putrefication (EPA’s 503 documents). Volatile Solids (VS) - Materials, generally organic, that can be driven off from a sample by heating, usually to 550 °C (1022 °F); nonvolatile inorganic solids (ash) remain1. Wet Tons - A unit of measurement representing only the total mass of a substance including the mass of water. One wet ton is equal to 2,000 wet lbs (example: 10.0 wet tons 3.5 dry tons at 35% solids)2.2 Regulatory Background2.2.1 Land ApplicationFor Land Application under EPA Federal Regulations (Under 40 CFR Part 503), processedresiduals to produce biosolids are grouped into two categories depending on pathogenreduction: Class A and Class B. Class A biosolids that meet metal contamination limits aredeemed Exceptional Quality. Class A biosolids are treated to reduce the presence of pathogensto very low levels and can be used without any pathogen related restrictions. Class B biosolidsare also treated to reduce pathogens but to levels that are not as low as Class A biosolids. Tocompensate, there are a number of site restrictions for land application of Class B biosolidsincluding buffer zones and restrictions to public access which are intended to safeguard publichealth. Class B beneficial reuse is effectively restricted to agricultural applications. Sewagesludge that is not processed to either Class A or Class B standards is not considered biosolids.To meet Class A requirements a process must be used to reduce pathogen levels to certaincriteria. The process must also include a vector attraction reduction step either before or co-current with the pathogen reduction step which is meant to stabilize the biosolids. Currently theEPA defines six alternatives to meet Class A pathogen requirements. The objective of the sixalternatives is to reduce pathogen densities below detectable limits as defined when theregulations were written. Class A pathogen requirements are met by Alternative 1 through hightemperature treatments based on set time and temperature curves. Alternative 2 requires highpH and high temperature processes (alkaline treatment) for producing class A. A process thatdoes not meet one of the specific alternatives can achieve Class A through extensive pathogen,enteric virus and helminth ova testing through Alternative 3. Alternative 4 also allows for ClassA of biosolids that are treated in an unknown process through extensive pathogen testing similar1 Water Environment Federation (WEF) Website. Glossary of Terms (http://www.wef.org/AWK/page.aspx?id=1951). Page 5 of 36
  25. 25. Alternative Technologies for the Beneficial Reuse of Sewage SludgeResponse to Resolution 11-182October 2011to what is required in Alternative 3. Alternative 4 is mainly targeted for solids that are stockpiledor stored for extended periods in lagoons. Alternative 5 defines several Processes to FurtherReduce Pathogens (PFRP) which include processes such as heat drying, composting, and pre-pasteurization among others. Alternative 6 allows for other processes to be classified as beingequivalent to an existing PRFP defined in Alternative 5.To meet Class B requirements, a process must be used to reduce pathogen levels but not toquite as low of a level as it required for Class A. The EPA currently defines three alternatives tomeet Class B. Alternative 1 is to perform fecal coliform testing to ensure it is below the definedthreshold. Alternative 2 is to use a Process to Significantly Reduce Pathogens (PSRP) such asaerobic digestion, air drying, anaerobic digestion, composting, or lime stabilization. Biosolidscan also be classified as Class B by proving that a process is equivalent to a PSRP.Vector attraction reduction is also an important component of both Class A and Class Brequirements. A vector is defined by the EPA as “any living organism capable of transmitting apathogen from one organism to another either mechanically (by simply transporting thepathogen) or biologically by playing a specific role in the life cycle of the pathogen.” Vectors forsewage sludge pathogens include insects, rodents, and birds. There are several definedmethods for meeting vector attraction reduction. The vector attraction reduction methods aregenerally related to VS destruction, specific oxygen uptake rate (SOUR) tests, aerobicrequirements, pH requirements, percent dryness, or through a method of applying the biosolidsto the land where it would prevent the attraction of vectors.2.2.2 Emissions for Sewage Sludge Incineration (SSI)A major concern for any SSI technology is the impact of the process on air quality andpotentially rigorous air permitting requirements. In March 2011, New Sewage SludgeIncinerators Rules regulated under 40 CFR, Part 60 and Section 129 of the Clean Air Act wereenacted. From the new rules, all sewage sludge incinerators will now require a Title V airpermit. The ruling requires stricter air permitting and monitoring requirements than waspreviously required under the previous rules which were regulated under Section 112 of theClean Air Act. The new regulations are specific for Multiple Hearth Incineration (MHI) and FluidBed Incineration (FBI); however, they may also impact the gasification technologies discussedherein. It is expected that two stage gasification technologies may be exempt from the rulingsince the process includes syngas cleaning. However, there is not a biosolids gasificationsystem installed in the US that has been permitted since the new rules were enacted so there isnot currently a precedent set to know exactly how concept and emerging combustion orgasification technologies will be regulated.2.3 Current CCH Treatment and Processing OperationsCCH currently operates nine WWTPs on Oahu including Honouliuli, Kahuku, Kailua, Laie,Paalaa Kai, Sand Island, Wahiawa, Waianae, and Waimanalo WWTP. Figure 2-1 shows thelocations of the WWTPs along with the location of the Waimanalo Gulch Landfill. Figure 2-2shows the process flow for the CCH’s three largest WWTPs; Kailua, Honouliuli, and Sand IslandWWTPs. Page 6 of 36
  26. 26. Alternative Technologies for the Beneficial Reuse of Sewage SludgeResponse to Resolution 11-182October 2011 Figure 2-1. Location of WWTPs and Waimanalo Gulch Landfill Page 7 of 36
  27. 27. Alternative Technologies for the Beneficial Reuse of Sewage SludgeResponse to Resolution 11-182October 2011 Figure 2-2. Honouliuli, Kailua, and Sand Island Process Flow Diagrams Page 8 of 36
  28. 28. Alternative Technologies for the Beneficial Reuse of Sewage SludgeResponse to Resolution 11-182October 2011Under normal operating conditions, all WWTPs except for Wahiawa WWTP stabilize their solidsvia aerobic or anaerobic digestion. Currently, Honouliuli, Kailua, and Waianae WWTPs sludgegoes through anaerobic digestion for stabilization and centrifuges for dewatering. The biosolidsare then hauled to Waimanalo Gulch Landfill for disposal. The Synagro Bioconversion Facilityat Sand Island WWTP also has anaerobic digestion for stabilization, followed by dewatering,and drying for pelletization. The pellets produced at the Synagro Bioconversion Facility havebeen used as a fertilizer at agricultural farms, golf courses, and parks. The pellets that do notmeet the specifications or cannot be marketed are hauled to Waimanalo Gulch Landfill fordisposal. The Kahuku and Waimanalo WWTPs haul liquid waste to Kailua WWTP and PaalaaKai and Wahiawa WWTPs haul liquid waste to Honouliuli WWTP for further treatment. TheWahiawa WWTP is currently being upgraded with membrane bioreactors (MBRs); the solidsquality and quantity will differ once the MBRs are in service. The Laie WWTP has an onsitewindrow composting facility that is operated by CCH staff but owned by the Mormon Church.The compost that has been approved for distribution is used by the Mormon Church foragricultural purposes and the compost that is not approved for distribution (mainly due to metalcontent) is disposed of at the Waimanalo Gulch Landfill. Table 2-1 presents information on theIsland-wide Solids Production. Table 2-1. Island-wide Solids Production Average Solids State of Dewatering Solids WWTP Flow1 Stabilization Production2 Solids Method Distribution (mgd) (dtpd) Waimanalo Anaerobic Honouliuli 25.92 7.28 Cake Centrifuge Gulch Landfill Digester (~7 mi) Aerobic Kailua Regional Kahuku 0.19 0.26 Liquid None Digester WWTP (~34 mi) Waimanalo Kailua Anaerobic 11.49 2.65 Cake Centrifuge Gulch Landfill Regional Digester (~32 mi) Mormon Church/ Laie 0.46 Composting ---3 Compost Belt Filter Press Waimanalo Gulch Landfill Aerobic Honouliuli Paalaa Kai 0.09 0.05 Liquid None Digester WWTP (~21 mi) Class A Fertilizer Pellets Anaerobic Reuse/ Sand Island 61.29 Digester/Drye 9.21 Dried Pellets Centrifuge/Dryer Waimanalo r Gulch Landfill (~23 mi) Honouliuli Wahiawa4 1.64 Not Stabilized 2.00 Liquid None WWTP (~17 mi) Waimanalo Anaerobic Waianae 3.31 0.44 Cake Centrifuge Gulch Landfill Digester (~8 mi) Anaerobic Kailua Regional Waimanalo 0.55 0.26 Liquid None Digester WWTP (~33 mi)1 Source: City and County of Honolulu, Dept of Environmental Services, Wastewater Management website (FY 2011)2 Source: Annual Biosolids Production Reports – January 1 to December 31, 2010, Division of Wastewater Treatment and Disposal, ENV3 Dry weight is not available (no percent solids data). Laie WRF produced a total of 1,056 cu. yd. of compost that was disposed at the landfill. This is approximately 727.6 wettons (based on a measured unit weight of 51 lbs/cu. ft.) Source: Note 8, Annual Biosolids Production Reports – January 1 to December 31, 2010, Division of WastewaterTreatment and Disposal, ENV4 Wahiawa WWTP is currently being upgraded to an MBR facility, so solids characteristics may change when the new processes are in operation. Page 9 of 36
  29. 29. Alternative Technologies for the Beneficial Reuse of Sewage SludgeResponse to Resolution 11-182October 20112.4 Treatment and Processing Technology ClassificationThe identified vendors and their technologies covered a wide range of treatment and processingtypes. In order to facilitate an organized approach to determining applicability many of thevendors were organized by the general classification or technology category which bestdescribed the process using standard industry terminology as described in the followingparagraphs. It should be noted that some solution providers responding to the RFI were notactually equipment manufacturers or suppliers. These solution providers were often systemintegrators that provided an alternative means of financing, often involving a rate paybacksystem or power purchase agreement to recuperate initial construction costs. As discussedfurther in the report, the economics and life-cycle cost comparison of the various alternatives willbe conducted as part of the Island-wide Solids Master Plan and as such only the specifictechnologies proposed by any respective vendor are considered, irrespective of financingmethodology.The technology classifications are presented with the more established technologies listed first,followed by the newer and innovative processes. This section summarizes the technologyclassifications. Additional information is provided in Appendix C.2.4.1 DigestionDigestion is decomposition of organic matter in sewage treatment. There are two main types ofdigestion; aerobic digestion (with air) or anaerobic digestion (without air). Both aerobic andanaerobic digestion are well established technologies that have been used throughout theworld. CCH currently has two facilities that include aerobic digestion and five facilities that useanaerobic digestion.Aerobic digestion is a well proven process and is similar to activated sludge processes used insecondary treatment. Aerobic digestion uses aerobic microbes to decompose organic matter,stabilize sewage sludge and generate biosolids. Aerobic digestion is most commonly practicedat plants less than 5 mgd. Aerobic digestion typically yields high VS destruction, has a lowbiological oxygen demand (BOD) concentration in the side streams from dewatering, producesa relatively odorless stable end product, maintains a high nutrient value in the biosolids, issimple to operate and involves relatively low capital costs. The aerobic process, however,requires a lot of air input which requires a high electrical consumption. The resulting liquidbiosolids are typically difficult to dewater. The process is also very dependent on operatingconditions and does not produce a useful energy producing byproduct (CH4). ConventionalAerobic digestion produces Class B biosolids. A system can also be designed as anAutothermal Thermophilic Aerobic Digestion (ATAD) process which uses the exothermic energyin the biological process to heat the reactor to thermophilic conditions generating Class Abiosolids. Since Aerobic Digestion is energy intensive and not suitable for large plants, it is notconsidered an appropriate solution for CCH’s larger plants and will not be discussed further inthis report.Anaerobic digestion is another well proven process that involves the decomposition of organicmatter and inorganic matter in the absence of oxygen. The decomposition process produces adigester gas that consists of mostly CH4 (~65%) and carbon dioxide (CO2) (~35%). Anaerobicdigestion of municipal wastewater solids can, in many cases, produce sufficient digester gas tomeet the energy requirements of digestion and other plant operations. Therefore, due to theemphasis on energy conservation and recovery, the process continues to be advantageous forstabilizing sewage sludge. In principle, the conversion of organic matter to CO2 and CH4reduces biological solids leaving the digestion process. Digestion can reduce the total volume Page 10 of 36
  30. 30. Alternative Technologies for the Beneficial Reuse of Sewage SludgeResponse to Resolution 11-182October 2011of solids to be dewatered and the polymer cost for dewatering. There are a number of digestiondesigns which can produce Class A and Class B biosolids, allowing for flexibility with reuseoptions, by meeting the requirements of EPA’s Part 503 Rule. Anaerobic digestion doeshowever, require a relatively large footprint when compared to alternative technologies and canhave a high capital cost. Also since anaerobic digestion is a biological process, it slowlyrecovers from an upsets. The process may also accumulate with scum and grit which could bedifficult to clean and foaming may be problematic as well. Downstream dewatering centratemay also be high in ammonia and could require separate treatment if there are tight nitrogenlimits. The process may also be susceptible to struvite formation which can cause operation andmaintenance issues with scaling in pipes, heat exchangers, valves and other equipment.Figure 2-3 shows the anaerobic digester schematic. Figure 2-3. Anaerobic Digester Schematic (Figure from www. meniscus.co.uk)The biogas produced can be captured and treated for various energy recovery uses includingheat and electrical power in combined heat and power (CHP) system. CCH currently operatesanaerobic digesters at the Kailua, Honouliuli, Sand Island, and Waianae WWTPs and CCH isevaluating CHP options at these WWTPs in upcoming Energy Savings Performance Contracts(ESPCs).2.4.2 CompostingComposting is a well-established process in which biodegradable material is decomposed byaerobic microorganisms in a controlled environment. The heat generated in compostingpasteurizes the product and significantly reduces pathogens. The heat generated also drives offwater vapor, further dewatering the product and reducing reuse volume. Composting that isperformed according to regulatory guidelines produces Class A Biosolids. Composting that isperformed properly can produce a nuisance-free humus-like material. The three differentmethods of composting typically used for wastewater sludge are aerated static pile, windrowand in-vessel composting.Composting is a relatively simple process to operate and all composting processes generallyinclude common basic steps. First, the dewatered sludge is mixed with an amendment and/or Page 11 of 36
  31. 31. Alternative Technologies for the Beneficial Reuse of Sewage SludgeResponse to Resolution 11-182October 2011bulking agent to increase porosity of the mixture and provide a carbon source to improve thedegradability of the compost. A rule of thumb for composting is to have a 25:1 to 35:1 ratio ofcarbon to nitrogen (mass basis). The resulting mixture is piled or placed in a vessel wheremicrobial activity causes the temperature to rise starting the “active composting” period. Thedesired temperature required for optimal operation and end quality vary based on the method ofcomposting and desired use of the end product. The key is to keep the material aerated to allowaerobic bacteria to work. After the “active composting” period is complete, the material is curedand distributed. Static pile and windrow composting are generally manual in operation and canbe operator intensive. In-vessel composting is generally a proprietary process provided by avendor or solution provider and is typically more automated and sophisticated than othercomposting methods.Composting is an established technology with more than 300 installations nationwide. CCHcurrently operates the Laie WWTP which has an onsite composting facility. Due to the largefootprint requirements required for composting, CCH may not be able to implement an onsitecomposting facility at any other WWTP, however, off-site composting such as the systemproposed by Hawaiian Earth Recycling, LLC (HER) may be a feasible alternative. It would bethe responsibility of the composting company to market and distribute the product.2.4.3 Heat Drying OnlyDryers come in several types, all of which operate with the goal of decreasing water content inwastewater sludge. Drying is typically used in the last stage of solids processing and is done incombination with a dewatering process. Dryers are typically fed with dewatered sludge atapproximately 15-35% dry solids (DS) and dry the biosolids to 90-95% DS. Sludge fed to dryerscan be either undigested or digested dewatered sludge, although some vendors haverestrictions with handling undigested primary sludge. As a general rule upstream digestion istypically recommended for primary sludge due to potential for odors in the final product. Dryersare able to produce Class A biosolids which can be beneficially used. Even if beneficial use isnot the desired option, the drying process greatly reduces the storage, transportation anddisposal cost since it significantly lowers the water content and reduces the weight.Dryers are classified into three categories: 1) direct (convective) dryers, 2) indirect (conductive)dryers, and 3) combination direct/indirect dryers. Direct dryers use a drying medium such as hotair, which comes in direct contact with the sludge to increase the sludge temperature throughconvective heat transfer and evaporate the water in the sludge. Indirect dryers use a mediumsuch as hot oil or steam that heats the sludge through a conducting surface, so that the heatingmedium does not come in direct contact with the sludge. Combination dryers use two mediums,one which comes in direct contact with the sludge and one which heats the sludge through amembrane.Most dryers are flexible and able to use most fuel sources such as natural gas, propane, dieselfuel or fuel oil. The dryers can also be equipped with burners that can directly use digester orother biogas sources, although there typically needs to be a supplemental or standby fuel inaddition. Some dryers use the fuel to directly heat hot air for drying while others may use a heattransfer fluid such as thermal oil, steam or hot water to provide heat to the dryer. The ability touse waste heat from other processes, such as a CHP system, depends on the specific dryerdesign and operating temperature. Lower temperature dryers that utilize a heat transfer fluidare generally better suited for low temperature waste heat recovery applications. Unless wasteheat or fuel that results as a byproduct from another process (i.e. CH4) is used, the operatingcost of drying can be high due to the cost of consuming a large amount of fossil fuels. Page 12 of 36
  32. 32. Alternative Technologies for the Beneficial Reuse of Sewage SludgeResponse to Resolution 11-182October 2011There are potential risks and safety concerns with dryers related to fire and explosion potentialdue to combustible gases and dust. Safety systems such as a sprinkler system or water delugesystem are typically incorporated in the event an emergency condition such as high temperatureor carbon monoxide (CO) level is detected. Some dryers may also contain fugitive dustmonitoring, explosion relief panels and nitrogen purge systems. The safety system incorporatedtypically depends on the type of dryer used and designed operating conditions. The dry productcan also be a risk for fires and explosions if large amounts of product are stored in a storagevessel or silo. Specific safety precautions such as temperature and CO or CO2 monitoring, andinert air (nitrogen) blankets are typically required.Drying is an established technology that requires a relatively small footprint and does notgenerally require chemical additives. CCH currently has a third party operated direct rotarydrum dryer at the Sand Island WWTP that produces class A pellets that are marketed forbeneficial reuse. The pellets are currently beneficially reused for agricultural purposes althoughthey can also be beneficially reused for energy production. Dryers can be capital cost intensiveand are more complicated to operate than other stabilization technologies.2.4.4 IncinerationIncineration or advanced thermal oxidation is a combustion reaction that occurs in the presenceof excess oxygen. Incineration is the most commonly used thermal conversion processpracticed for sewage sludge today. FBI and MHI are established technologies and are the mostcommon types of incineration used for sewage sludge. MHI is now considered an outdatedtechnology and very few if any new systems are being constructed.Since MHIs and FBIs are mature technologies, there is extensive experience with bothoperation and applying air emission control technologies. With a full array of 204 incinerationinstallations (144 MHIs and 60 FBIs) in operation throughout the country, there is a substantialdatabase of background data available with which owners, vendors, and regulators are able topredict the expected performance of any proposed incinerator. With the future implementationof new EPA emission limits and standards for MHIs and FBIs, it would take some time for allparties to recalibrate their design guidelines to the stringent new standards. However, ingeneral, vendors and engineers would be able to provide system guarantees to meet theemission limits.Incineration achieves significant volume reduction and produces a byproduct that is inert, sterileand free of pathogen and toxic organic compounds. Incineration can also be equipped withprovisions for energy recovery and electrical generation. Incineration systems do not requireprior stabilization and raw dewatered sludge feed is typically preferred since it has a higher heatvalue than digested biosolids. Incinerators also require a relatively small footprint. The Airpermitting of a new incineration system, however, can be tedious and difficult especially with thenew SSI rules and may not be feasible for a nonattainment2 area. Incinerators have a highcapital cost and may require supplemental fossil fuel consumption if the feed is low in heat valueor the moisture content is too high. The process can also be very complicated requiring asophisticated operating staff and high operation and maintenance costs. The new SSI rulesalso require a continuous emission monitoring (CEM) for multiple pollutants. Besides tedious airpermitting and monitoring requirements, incineration is not popular in many places and may besubject to public opposition. Furthermore the ash product residual from incineration many times2 Nonattainment area per the EPA’s website is defined as “Any area that does not meet (or that contributes to ambient air quality ina nearby area that does not meet) the national primary or secondary ambient air quality standard for the pollutant.” Page 13 of 36

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