CHAPTER 7 ENVIRONMENTAL PERFORMANCE EVALUATION

Transcription

1 CHAPTER 7 ENVIRONMENTAL PERFORMANCE EVALUATION

2 Ideas for the Chapter Variety of methodologies that may be employed at different design stages will be discussed in this chapter : Section A : Tier 1 Environmental Performance Tools Section B : Tier 2 Environmental Performance Tools Introduction to Tier 3 Environmental Performance Tools.

3 Environmental Performance Evaluation (EPE) Goals An internal management process that provides information to facilitate management decisions regarding an organization s environmental performance Supported by ISO Environmental management systems Specifications with guidance for use, 1996, By means of the tool ISO/TC 207/SC 4 - develops international guidance on EPE, and, ISO Environmental management Environmental performance evaluation Guidelines, 1999 ISO/TR Environmental management - Examples of EPE, 1999

4 The EPE in context of the ISO Series: Environmental Management ENVIRONMENTAL MANAGEMENT SYSTEMS ISO 14001/ 4 ENVIRONMENTAL AUDITING SERIES (19011) ENVIRONMENTAL PERFORMANCE EVALUATION SERIES FOCUS: Organizations LIFE CYCLE ASSESSMENT SÉRIES DESIGN FOR ENVIRONMENT TR FOCUS: Product ENVIROMENTAL LABELLING SERIES NEW ITEM: ENVIRONMENTAL COMMUNICATION( TR 14063)

5 Objectives and Benefits of an EPE Program Better understanding of an organization s impacts on the environment, Providing a basis for benchmarking management, operational and environmental performance, Identifying opportunities for improving efficiency of energy and resource usage, Determining whether environmental objectives and targets are being met, Demonstrating compliance with regulations, Determining proper allocation of resources, Increasing the awareness of employees, and, Improving community and customer relations

6 EPE Indicators Environmental performance indicators (EPIs) - Management performance indicators (MPIs): policy, people, planning activities, practice, procedures, decisions and actions in the organization - Operational performance indicators (OPIs): inputs, the supply of inputs, the design, installation, operation and maintenance of the physical facilities and equipment, outputs and their delivery Environmental condition indicators (ECIs) Provide information about the local, regional, national or global condition of the environment INTEREST: Help an organization to better understand the actual impact or potential impact of its environmental aspects and assist in the planning and implementation of the EPE

7 Plan-Do-Check-Act Model: ISO 14031

8 Plan-Do-Check-Act Model: ISO Plan Objective: Selection of indicators based on - significant environmental aspects - Environmental performance criteria (internal and regulatory) - Views of interested parties (business plan) Indicators: ECI, EPI, MPI and OPI (see table for examples) Do assessing performance - Collecting data -regulations, operating permits, EMS procedures and records, reports government agencies (production, process, monitoring), environmental budgets, chemical inventories, storage tanks and spill records. - Converting data to information - Evaluating the information - Communicating the results

9 Examples of performance indicators and metrics 1 OPI Raw material used per unit of product (Kg/unit) MPI Environmental costs or budget ($/yr) ECI Contaminant concentration in ambient air (µg/m 3 ) Energy used annually per unit of product (MJ/1000 L product) Energy conserved (MJ) Number of emergency events or unplanned shutdowns (#/yr) Average fuel consumption of vehicle fleet (L/100 Km) Hazardous waste generated per unit of product (Kg/unit) Emissions of specific pollutants to air (Ton CO 2 /yr) Wastewater discharged per unit of product (1000 L/unit) Air emissions were exceeded (days/yr) Percentage of environmental targets achieved (%) Number employees trained (% # trained/to be trained) Number of audit findings (#) Time spent to correct audit findings (person-hr) Time spent responding to environmental incidents (personhr/yr) Number of complaints from public or employees (#/yr) Number of suppliers contacted about environ. mngment. (#/yr) Management levels with specific environ responsabilities (#) Frequency of photochemical smog events (#/yr) Contaminant concentration in ground- or surface water (mg/l) Change in groundwater level (m) Contaminant concentration in surface soil (mg/kg) Concentration of a contaminant in the tissue of a specific local specie (µg/kg) Population of an specific species within a defined area (#/m 2 ) Fish deaths in a specific watercourse (#/yr) Employee blood lead levels (µg/100 ml)

10 Plan-Do-Check-Act Model: ISO Check and Act reviewing and improving performance Objective: To identify opportunities for improving environmental performance including - Program cost and benefit - Progress towards meeting environmental performance targets - How appropriate are the environmental performance criteria and indicators - Data quality and collection methods Case study 1 Implementation of EPE at Mother Dairy Fruit and Vegetable Ltd., New Delhi, India, 2001 Problem: the dairy was monitoring liquid fuel and electric power consumption together with the volume of wastewater processed in the effluent treatment system EPE strategy: all parameters were normalized using the volume of milk processed Results: the dairy increased the amount of milk processed per unit of electrical power (23%) an diesel fuel consumed (38%) and reductions of wastewater generated (20%)

11 Case Study: Mother Dairy Company - EPIs Objective Program Performance Indicators Indicator Type Well water conservation Rain water harvesting Static well water level Well water analysis ECI ECI Water use reduction Water audit Well water used per volume of milk processed (L water/l milk) OPI Wastewater treatment efficiency Microbiological analysis of sludge Effluent processed (L) OPI Use of improved microculture Energy consumed (MJ/L effluent) OPI Employee training and awareness Environmental awareness training # Employees trained MPI Green horticulture On and off-site gardening # Plantings OPI Biosludge composting by vermiculture Quantity of compost produced (Kg) OPI

12 Example of EPE s application: Measuring Environmental Performance of Industry (MEPI) Project in Europe MEPI s Objective: the improvement of internal and external transparency about the effects on the environment and responses to mitigate them MEPI s Tools: Environmental Performance Indicators physical, business and environmental impact MEPI s Focus: materials and energy use and waste emissions at the level of plant and firm

13 Tools (indicators) in the MEPI Project Business activity Physical indicators Business management indicators Impact indicators Value added (Sales Cost of materials) Sales Operating profit Number of employees Energy and water inputs Waste generation CO2, SO2, Nox and VOC s emissions to air COD/BOD, N, P, heavy metals emissions to water Certifications ISO and/or EMAS (yes / no) Disclosure of environmental investments (yes / no) Number of noncompliance events reported Emissions of ozone depleting substances to air MEPI s indicators include: generic (Table) and sector - specific

14 Most significant variables influencing environmental performance in the Paper, Fertiliser and Electricity Industry in European Countries Sector Waste emissiones Air emissions Water emissions Water consumptio n Energy consumption Paper N=270 Total solid waste(53) Recycled waste(71) CO2 (63) SO2 (44) COD (107) N (91) P (54) Total water consumption (120) Total energy input (39) Fertiliser N=91 Total solid waste (10) SO2 (13) NOx (15) COD (9); N (20); P (12); Heavy metals (17) Total water consumption (26) Total energy input (26) Electricity N=184 Total solid waste (75) CO2 (118) NOx (134) SO2 (135) No variables selected due to missing values Total fuel (16; total oil (78); Renewables (20); Total energy (10) Numbers in parenthesis indicate available cases of the total (n)

15 Environmental Performance Tools Section A Tier 1

16 Environmental Performance Main Tools Economic Criteria Environmental Criteria (Persistence and Bioaccumulation) Toxicity Criteria and Weighting Evaluating Alternative Synthetic Pathways

17 Design Synthesis Steps Input and Output Structures Known Chemical Structures are Known Many Alternative Pathways Exist

18 Economic Criteria Estimate the cost of raw materials versus the value and/or cost of byproducts and products. The cost of the various options can be estimated by: [ Cost ] i Stoichiome tric coefficien t Cost * = i This is more of a qualitative analysis because it does not take into account other potential costs associated with the production of the given substance (i.e. higher temperatures require more energy, etc).

19 Environmental Criteria It only takes into account the substances Persistent, Toxic and Bioaccumulating properties. Persistence and Bioaccumulation are easily estimated and a table shows rating index values on the following slide.

20 Rating Index (RI) Persistence Rapid Moderate Slow Very slow >60% degradation over 1 week >30% degradation over 28 days <30% degradation over 28 days <30% degradation over more than 28 days RI = 0 RI = 1 RI = 2 RI = 3 Bioaccumulation High Potential 8.0 > log K ow > 4.3 or BCF > 1000 Moderate Potential 4.3 > log K ow > 3.5 or 1000 > BCF > 250 RI = 3 RI = 2 Low Potential 3.5 > log K ow or 250 > BCF RI = 1 Source : Green Engineering text, Allen and Shonnard, pp. 204

21 Toxicity Evaluations Threshold Limit Values (TLVs) : Definition : Airborne concentration limit for individual exposures in a workplace environment. Established by : ACGIH - Permissible Exposure Limits (PELs) : Definition : similar to TLV ; represents the legal implications in defining workplace conditions. Established by : OSHA - Recommended Exposure Limits (RELs) : Definition : more current then PELs ; solely based on toxicity research. Established by : NIOSH -

22 Toxicity Index One Toxicity Index can be calculated using : Environmen tal Index = 1 ( TLV ) Source : Green Engineering, Allen and Shonnard, pp 205.

23 Toxicity Weighting Taking into account ingestion pathways : - Inhalation Reference Concentration - Oral Ingestion Slope Factor -Unit Risk - IRIS database is one source of data :

24 The toxic weighting factor (Ftox) represents the weight to be given to each substance to make possible the comparison of the discharges. The toxic weighting factor is defined as the inverse of the most stringent water quality criterion for each substance (MSCi): Ftox i = 1/MSCi MSCi = min (CTACi, CCOAi) This is a dimensionless number, and represents the toxic potential to be assigned to a given pollutant to evaluate its relative importance in the discharges. Source:

25 Evaluating Alternative Synthetic Pathways A general Composite Index of the overall input-output structure can be established with the substance s PBT properties and can also rely on the emission rates.

26 Methods of applying Weighting Factors : 1) Toxicity as Weighting Factor. 2) US EPA Toxicity Approach. 3) Using PBT Weighting Factors.

27 Environmental Performance Tools Section B Tier 2

28 Tier 2 :Environmental Performance Tools Topics covered in this section: Environmental Release Assessment Release Quantification Methods Modeled Release Estimates Release Characterization and Documentation Assessing Environmental Performance

29 Design Synthesis Steps Basic information needed Preliminary Process Flowsheets. Basic Knowledge of Unit Operations. Rough Estimate of Unit Operation Sizing.

30 Environmental Release Assessment Necessary Knowledge about Releases Environment includes : -Water -Air -Land Releases may include : Spilling - Leaking - Pumping Pouring - Emitting - Emptying Discharging - Injecting - Escaping Leaching - Dumping into the environment Disposing into the environment

31 Release Assessment Components Identify Purpose and Need for Release Assessment Obtain/Diagram A process Flowsheet Identify and List Waste and Emission Streams (WESs) Determine Additional WESs Determine best method for quantifying the release rate of each WES Determine data/info needed to use the methods determined Collect data + info to fill in the gaps Quantify chemical s release rates + frequencies + the media in which it is released Document release assessment; include characterization of estimate uncertainties

32 Process Analysis When analyzing flowsheets, account for missing releases that include : Fugitive Emissions (which include leaks). Venting of Equipment (including breathing and displacement losses). Periodic Equipment Cleaning (frequent and infrequent). Transport Container Residuals (including drums, totes, tank trucks, rail cars and barges). Incomplete Separations (including destilation, gravity phase separation and filtration).

33 Process Analysis... continues Determining the manner in which substances are released is crucial in assessing environmental impacts Releases can also occur on and off site, including : - Air : include primary and secondary emissions. - Water : transfers into streams or water bodies. - Underground Injection : generally into wells. - Land : within the boundaries of the facility.

34 Air: Primary Emissions Stacks Emissions There are different dispersion patterns to high-stack (over 75 meters), medium-stack (25 meters 75 meters) and low-stack sources (less than 25 meters). High-stack sources are synonymous with modern power plants; medium-stack sources with large industrial plants, district heating plants, and suboptimal power utilities; and low-stack, or low-level, sources with small industrial and commercial users, transport, and the domestic sector. Source:

35 Air: Secondary Emissions Fugitive Emissions The sources of fugitive emissions are categorized as (1) industrial processes, operations, activities, or materials that emit particulate or chemical pollutants or (2) activities or operations that create fugitive dust. Particulates that become airborne by wind and/or human activity are also referred to as fugitive dust. Source:

36 Release Quantification Methods 1. Measured release data for the chemical or indirectly measured release data using mass balance or stoichiometric ratios. 2. Release data for a surrogate chemical with similar releaseaffecting properties and used in the same (or very similar) process. Surrogate data may be measured, indirectly measured, modeled or some combination of these. Some emission factors would be considered to be surrogate data.

37 3. Modeled release estimates : a. Mathematically modeled (eg) release estimates for the chemical or by analogy to a surrogate chemical. b. Rule of thumb release estimates, or those being developed using engineering judgement.

38 Measured Release Data for the Chemical Usually only applicable for actual processes For a continuous process : release = [ ] * * ρreleasestream avg Q release stream avg Can also be estimated using the chemical s weight fraction and the mass flowrate of the release stream

39 Release Data for a Surrogate Chemical By using surrogate chemical data, it should be ensured that there exist similarities in some physical/chemical properties of the chemicals, unit ops and their operating conditions and quantities of chemical throughput.

40 Emission Factors - Usually only used for Air Emissions. - Many databases exist containing these factors.

41 A. Average Marginal CO 2 Emissions Factors for Electricity Generation by EPA Region (2000): Source:

42 B. CO 2 Emission Factors by Fuel Type per Unit Volume, Mass, and Energy: Source:

43 Emissions from Process Units and Fugitive Sources Equation for Rate of Emission : E = m voc EF Where : m voc is the mass fraction of the VOC in the stream or process unit, EF av is the average emissions factor ascribed to the stream or process unit (kg emitted/10 3 kg throughput), M is the mass flow rate through the unit (mass/time). See tables with lists of various factors examples. av M

44 Losses of Residuals from Cleaning of Drums and Tanks Nature of the cleaning process should be considered Capacities. Shapes. Materials of construction of the vessels to be cleaned. Cleaning schedule. The residual quantity of the chemical in the vessels. The type and amount of solvent used (aq. Vs. Organic). Solubility/miscibility of the chemical in the solvent. If applicable, treatment of wastewater containing the chemical.

45 Secondary Emissions from Utility Sources Utility use is extensive in causing environmental impact. Emission estimation equations : E ( kg / unti/ yr) 1 = ( ED)( EF)( FV) ( BE Where: ED is the energy demand of a process unit (energy demand/unit/yr). EF is the emission factor for the fuel type (kg/volume of fuel combusted). FV is the fuel value (energy/volume fuel combusted). BE is the boiler efficiency (unitless; typical values). ) 1

46 E ( kg / unit / yr) = ( ED)( EF)( ME) 1 Where: ED is the electricity demand of a process unit (energy demand/unit/yr). EF is the emission factor for the fuel type (kg/volume of fuel combusted). ME is the efficiency of the device.

47 Modeled Release Estimates Process design software account for some releases, but not all. The following slides will introduce information that allows the calculation of the missed releases : - Loading transport containers - Evaporative losses from static liquid pools - Storage tank working and breathing loss.

48 Loading Transport Containers Quantity of evaporative losses from a loading container is a function of : - Physical and chemical characteristics of the previous cargo - Method of unloading the previous cargo - Operations to transport the empty carrier to a loading terminal - Method of loading the new cargo - Physical and chemical characteristics of the new cargo

49 Evaporative Losses from Static Liquid Pools - Evaporation Rate : G 1 = M P AT ( DabvzΔz Where : G is the generation rate (lb/hr), M is the molecular weight (lb/lb mole), P is the vapor pressure (in Hg), A is the area (ft 2 ), D ab is the diffusion coefficient (ft 2 /s of a through b is air), V z is the air velocity (ft/min), T is the temperature (K), Δz is the pool lenght along flow direction (ft). 1 ) 0.5

50 - Diffusion Coefficient D = T (29 + M ) M Pt Where the units are : D ab (cm 2 /s), M (g/gmole), P t (atm), T (K).

51 Storage Tank Working and Breathing Loss Two types of losses exist : - Working Losses (originating from the raising and lowering of the liquid level in the tank as a result of raw material utilization and production of product) - Standing Losses (originating from daily temperature and ambient pressure fluctuations)

52 Release Characterization and Documentation The uncertainty depends on how well we know the process, how well we understand the estimation method and its data and parameters, and how well the method and parameters seem to match up with those expected for the actual process.

53 HIGH EFFICIENCY GENERATION OF HYDROGEN FUELS USING NUCLEAR POWER A thermochemical water-splitting cycle is a set of chemical reactions that sum to the decomposition of water into hydrogen. The Sulfur-Iodine cycle, an example of a pure thermochemical water-splitting cycle. The objective of this work is to define an economically feasible concept for the production of hydrogen, by nuclear means, using an advanced high temperature nuclear reactor as the energy source. Source: web.gat.com/hydrogen/images/pdf%20files/ brown_si_cycle.pdf

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55 Section 1 Chemical recycle and acid generation

56 Section 2 Sulfuric acid concentration and decomposition

57 Section 3 Hydrogen iodide concentration and decomposition

58 Assessing Environmental Performance Two types of overall assessments can be used : 1. Evaluates the treatablility or costs of treatment of the waste streams. 2. Evaluates a set of environmental performance indicators :

59 a. Energy consumed from all sources within the manufacturing or delivery process per unit of manufactured output. b. Total mass of materials used directly in the product, minus the mass of the product, per unit of manufactured output. c. Water consumption per unit of manufactured output. d. Emissions of targetted pollutants per unit of manufactured output. e. Total pollutantsper unit of manufactured output.

60 Environmental Performance Tools Introduction Tier 3

61 Introduction to Tier 3 Environmental Performance Tools Design synthesis steps. - Detailed process flowsheets. - Equipment specifications. - Energy specifications. Limited design alternatives to screen. More is known, therefore all knowledge should be incorporated into the evaluation.