7.2.1 Total Cost Assessment of Pollution Control and Prevention Strategies

Traditional economic measure of engineering projects evaluate equipment, raw‐material, energy, operating, and maintenance costs. These evaluations generally overlook some of the costs of waste generation. A more complete accounting of environmental costs is referred to as total cost assessment. Four types of costs are identified, which are labeled as tier 0, tier 1, tier 2, and tier 3. Tier 0 costs are the “usual” costs that are included in a conventional analysis of a project. Tier 1 costs are included in a conventional analysis of a project. Tier 1 costs include permitting, reporting, monitoring, manifesting, and insurance costs and are often referred to as “hidden” costs because they are usually treated as overhead costs and are not directly charged to a project. Waste disposal costs are sometimes treated as overhead costs as well. Tier 2 costs include future liabilities, which are extremely difficult to accurately evaluate. Even more difficult to evaluate are tier 3 costs, which include consumer responses, employee relations, and public image. All four tiers of costs provide information for financial analysis methods, where measures such as ROR and payback periods (PPs) are evaluated.

7.2.2 Economics of Pollution Control Technology

In the present economic system, the goal of a sustainable development process is to maintain intergenerational equity by ensuring quality of life for future generations, which essentially requires the stopping of further damage to the environment. From this point of view the necessity of an integrated system consisting of modern manufacturing production and controlling technologies is being gradually recognized. To this end, various regulatory measures are being implemented, mainly in the industrial sector, which is the major contributor of pollution, for adopting such technologies.

7.3.1 Elements of Total Capital Investment

Total capital investment (TCI) includes all costs required to purchase equipment needed for the control system (purchased equipment costs), the costs of labor and materials for installing that equipment (direct installation costs), costs for site preparation and buildings, and certain other costs (indirect installation costs). TCI also includes costs for land, working capital, and off‐site facilities.

Direct installation costs include costs for foundations and supports, erecting and handling the equipment, electrical work, piping, insulation, and painting. Typical indirect installation costs are engineering costs, construction and field expenses (i.e. costs for construction supervisory personnel, office personnel, rental of temporary offices, etc.), contractor fees (for construction and engineering firms involved in the project), start‐up and performance test costs (to get the control system running and to verify that it meets performance guarantees), and associated costs with contingencies. “Contingencies” is a catch‐all category that covers unforeseen costs that may arise if, for example, it becomes necessary to redesign, modify equipment, to pay higher costs of equipment or field labor costs, or to compensate for delays in start‐up. Contingency costs are not the same as uncertainty and retrofit factor costs.

The elements of TCI are displayed in Figure 7.1. Note item “battery limits” cost, which is the sum of the purchased equipment cost, direct and indirect installation costs, and costs of site preparation and buildings. By definition, this is the total estimate for a specific job; any support facilities that may be needed (e.g. control systems) are assumed to already exist at the plant and are not included in the battery limits. For systems installed in new plants, off‐site facilities (special facilities for supporting the control system) also might be excluded from the battery limits. Off‐site facilities are exemplified by units to produce steam, electricity, and treated water; laboratory buildings; and railroad spurs, roads, and other transportation infrastructure items. Pollution control devices rarely consume enough energy to warrant dedicated off‐site capital units. However, it may be necessary – especially in the case of control systems installed in new or “grassroots” plants – to build extra capacity into the site's generating plant to service the system. (A Venturi scrubber, which often requires large amounts of electricity, is a good example.) Nevertheless, that the capital cost of a device does not include utility costs, even if the device were to require an offsite facility. Utility costs are charged to the project as operating costs at a rate that covers both the investment and operating and maintenance costs for the utility.

As Figure 7.1 shows, the installation of pollution control equipment may also require land, but since most add‐on control systems take up very little space (a quarter‐acre or less), this cost tends to be relatively small. Certain control systems, such as those used for flue‐gas desulfurization or selective catalytic reduction (SCR), require larger quantities of land for the equipment, chemicals storage, and waste disposal. In these cases, especially when a retrofit installation must be performed, space constraints can significantly influence the cost of installation, and the purchase of additional land may be a significant factor in the development of the project's capital costs. Land retains its value over time; however, land is not treated the same as other capital investments, retains its value over time, the purchase price of new land needed for sitting a pollution control device can be added to the TCI, but it must not be depreciated. Instead, if the firm plans to dismantle the device at some future time, either the land should be excluded from the analysis or its value included at the disposal point as an “income” to the project, to net it out of the cash flow (CF) analysis.

One might expect to include initial operational costs (the initial costs of fuel, chemicals, and other materials, as well as labor and maintenance related to start‐up) in the operating cost section of the cost analysis instead of in the capital component, but such an allocation would be inappropriate. Routine operation of the control does not begin until the system has been tested, balanced, and adjusted to work within its design parameters. Until then, all utilities consumed, all labor expended, and all maintenance and repairs performed are a part of the construction phase of the project and are included in the TCI in the “start‐up” component of the indirect installation costs.

7.3.2 Elements of Total Annual Cost

Total annual cost (TAC) has three elements: direct costs (DC), indirect costs (IC), and recovery credits (RC), which are related by the following equation:

(7.1)

Clearly, the basis of these costs is one year, a period that allows for seasonal variations in production (and emissions generation) and is directly usable in financial analyses. The various annual costs and their interrelationships are displayed in Figure 7.2.

DC are those that tend to be directly proportional (variable costs) or partially proportional (semi‐variable costs) to some measure of productivity – generally the company's productive output, but for purposes of pollution control, the proper metric may be the quantity of exhaust gas processed by the control system per unit time. Conceptually, a variable cost can be graphed in cost/output space as a positive sloped straight line that passes through the origin. The slope of the line is the factor by which output is multiplied to derive the total variable cost of the system. Semi‐variable costs can be graphed as a positive sloped straight line that passes through the cost axis at a value greater than zero – that value being the “fixed” portion of the semi‐variable cost and the slope of the line being analogous to that of the variable cost line discussed above.

7.5.1 Achieving a Responsible Balance

In the real worlds, taking socially desirable action for pollution prevention may not be in the best interest of an industry in the short run, since environmental protection costs money. The type of production, input used, technology employed, space used as well as plant size and the scale of production determine the nature and extent of pollution which, in turn, influence the abatement cost. Hence, the decisions of the profit maximizing private investor for implementation of pollution abatement measure are influenced by the benefit expected as a result of the investment required. On the other hand, the task of government planners and policy makers is to encourage industry to adopt modern production and pollution control technologies to provide a better environment for the society. In upgrading their facilities to meet the near antipollution regulations, industries turn for guidance to the principles of best available control technology (BACT).

7.6.1 Life Cycle Costing

While firms can use any of these factors, the importance of the LCC (for total cost analysis) makes the PV of net benefits the preferred method. Additional details of LCC and TCA follows.

LCC tool and the total cost assessment (TCA) tool are introduced as concept overviews. Both tools can be used to establish economic criteria to justify pollution prevention projects. TCA is often used to describe the internal costs and savings, including environmental criteria. LCC includes all internal costs plus external costs incurred throughout the entire life cycle of a process, product, or activity.

LCC has been used for many years by both public and private sector. It associates economic criteria and societal (external) costs with pollution prevention opportunities. The purpose of LCC is to quantify a series of time varying costs for a given opportunity over an extended time horizon, and to represent these costs as a single value. These time varying costs usually include the following:

1. Capital expenditures. Cost for large, infrequent investment with long economic lives (e.g. new structures, major renovation and equipment replacement).
2. Nonrecurring operations and maintenance (O&M). Costs reflecting items that occur on a less frequent than annual basis that are not capital expenditures (e.g. repair or replacement of parts in a solvent distillation unit).
3. Recurring O&M. Costs for items that occur on an annual or more frequent basis (e.g. oil and hydraulic fluid changes).
4. Energy. All energy or power generation related costs. Although energy costs can be included as a recurring O&M cost, they are usually itemized because of their economic magnitude and sensitivity to both market prices and building utilization.
5. Residual value. Costs reflecting the value of equipment at the end of the LCC analysis period. This considers the effects of depreciation and service improvements.

By considering all costs, a LCC analysis can quantify relationships that exist between cost categories. For example, certain types of capital improvements will reduce operations, maintenance, and energy costs while increasing the equipment's residual value at the end of the analysis period.

Societal (external) costs include those resulting from health and ecological damages, such as those related to unregulated emissions, wetland loss, or deforestation, can also be reflected in a LCC analysis either in a qualitative or in a quantitative manner. LCC includes the following cost components:

1. Extraction of natural resources. The costs of extracting the materials for use and any direct or indirect environmental cost for the process.
2. Production of raw materials. All of the costs of processing the raw materials.
3. Making the basic components and products. The total cost of material fabrication and product manufacturing.
4. Internal storage. The cost of packaging and storage of the product before it is shipped to distributors and/or retail stores.
5. Distribution and retail storage. The cost of distributing the products to retail stores including transportation costs, and the cost of retail storage before purchase by the consumers.
6. Product use. The cost of consumer use of the product. This could include any fuels, oils, maintenance, and repairs which must be made to the equipment.
7. Product disposal or reuse and/or recycling. The costs of disposal or recycling of the product.

7.6.2 Total Cost Assessment

The TCA tool is especially interesting because it usually employs both economic and environmental criteria. As with the LCC analysis, the TCA study is usually focused on a particular process as it affects the bottom‐line costs to the user. Environmental criteria are not explicit, i.e. success is not measured by waste reduction or resource conservation, but by cost savings. However, since the purpose of TCA is to change accounting practices by including environmental costs, environmental goals are met through cost reductions.

Because of its focus on cost and cost effectiveness, TCA shares many of the features of LCC analysis by tracking DC, such as capital expenditures and O&M expenses/revenues. However, TCA also includes IC, liability costs, and less tangible benefits – subjects that are not customarily included in both economic and environmental goals, because of its private‐sector orientation, as well as other economic computation methods.

7.6.3 Economic Consideration Associated with Pollution Prevention

The greatest driving force behind any pollution prevention (P²) plan is the promise of economic opportunities and cost savings over long‐term. Pollution prevention has been recognized as one of the lowest‐cost options for waste/pollutant management. Hence, an understanding of the economics involved in P² programs/options is important in making decisions at both the engineering and management levels. Every engineer should be able to exercise an economic evaluation of a proposed project. If the project cannot be justified economically after all factors – include those discussed earlier have been taken into account – it should obviously not be pursued. The earlier such a project is identified, the fewer resources will be wasted.

Before the true cost or profit of a P² program can be evaluated, the factors contributing to the economics must be recognized. As discussed earlier, there are two traditional contributing factors (capital costs, and operating and maintenance costs), but there are also other important costs and benefits associated with P² that need to be quantified if a meaningful economic analysis is going to be performed. The TCA aims to quantify not only the economic aspect of P² but also the social costs associated with the process, product, or a service from cradle‐to‐grave (i.e. life cycle). The TCA attempts to quantify less tangible benefits such as the reduced risk derived from not using a hazardous substance. The future is certain to see more emphasis placed on the TCA approach in any P² program. For example, a utility considering the option of converting from a gas‐fired boiler to coal‐firing is usually not concerned with the environmental effects and implications associated with such activities as mining, transporting, and storing the coal prior to its usage as an energy feedstock. Pollution prevention approaches will become more aware of this kind of need.

7.8.1 National Metal Finishing Strategic Goals Program

This was the first nationwide program initiated by the USEPA to build voluntary participation in a compliance program by providing incentives in return for a real commitment to reducing pollution to levels below those required for compliance. The SGP was created to address environmental problems and institutional barriers to achieving compliance in a number of industries. It was designed to provide a working relation that facilitates and encourages companies to go beyond environmental compliance to pollution prevention–based operations. SGP member companies were offered incentives, resources, and a means for removing regulatory and policy barriers as they work to achieve specific environmental goals.

The SGP program brought together stakeholders to identify important issues, conduct demonstration projects, and develop consensus policy recommendations that offered opportunities for reducing pollution. The stakeholders included industry, labor, environmental groups, state and local government, and other federal agencies. The metal‐finishing industry was represented by the National Association of Metal Finishers, American Electroplaters and Surface Finishers Society, Metal Finishing Suppliers Association, and Surface Finishing Industry Council. Through the SGP (USEPA 2001), the participants worked together to improve environmental performance and the bottom line.

Participation required top management commitment to the implementation and maintenance of an approved Environmental Management System (EMS). The EMS has caused management to take careful note of the true costs of pollution and institute policies and procedures to eliminate this waste at its source (USEPA 2003a). The results of these efforts have provided the first large‐scale quantification of the power of pollution prevention for achieving significant reductions in pollution and the resulting economic benefits in the metal‐finishing industry. The SGP program was designed to help a metal‐finishing company achieve its goals – both environmental and economic. A wide variety of state and local SGP resources (USEPA 2001) were available to provide a company with the tools need to get the job done. These include the following:

• Free, non‐regulatory environmental audits
• Funding for environmental technologies
• On‐site technical assistance in (evaluation and planning) achieving compliance and improving pollution prevention, safety, and health measures
• Free assistance from interns to help fill out the SGP data worksheets
• Free workshops on energy, water, and waste reduction
• Regulatory flexibility
• EMS training
• Public recognition

All parties benefited from the use of these tools. A few of the advantages listed in the project report are listed here.

• Companies received the incentives and resources needed to take the risk of going beyond compliance requirements.
• As the participating companies employ less‐polluting technologies, waste is reduced, less pollution is discharged to the environment, and the plant saves money, becoming more cost efficient and competitive.
• As the results demonstrated in the participating plants are employed by other plants to reduce pollution and improve competitiveness, the practices of pollution prevention are spread throughout the industry.
• The industry as a whole benefits from the positive action of SGP member companies.
• As the metal‐finishing industry becomes increasingly more self‐regulated, government regulators – from the EPA to the local publicly owned treatment works – save time and money.

The SGP has seven environmental performance goals (USEPA 2001) that form the core of the program (see Table 7.1). Through the end of 2000, many participants had already made significant progress toward meeting the goals, which translated into real environmental gains:

• 380 million gal of water conservation
• 120 million lb of hazardous waste not sent to landfills
• 665 000 lb of organic chemicals not released to the environment.

A comparison of the reductions achieved through 2000 and 2003 shows continuing and significant improvements in pollution prevention. This continued progress of the participants is a positive indicator of the benefits of a program driven by the employment of the EMS. The SGP participants were provided free, non‐regulatory environmental audits and access to technical support in achieving compliance and improving pollution prevention. Data like this readily demonstrates the power of the EMS management tool to reduce pollution. But to see how this progress was achieved, we must examine the role of pollution prevention (P²) technologies in enabling the reductions.

7.8.2 The Role of Pollution Prevention Technologies

7.8.2.5 Environmental Benefit

Two commercial processes, chromate conversion coating and zinc phosphatizing, were employed in the field tests as the experimental control baseline (Figures 7.3 and 7.4, respectively). Metal buildup in these conventional processes ruined the baths, and the baths had to be dumped. In the metal‐finishing sector, the discarding of such metal‐containing waste streams is a major contributor to pollution. The Picklex chemical used in the process tank is used up on the product; however, with filtering, the bath does not become contaminated. As a result, it is not necessary to dump the bath to control impurity buildup, and the chemical make‐up is simply added to the bath as needed. This process was demonstrated to have a strong potential as a leading technology for pollution prevention in surface preparation operations.

As can be seen in the comparison of the conventional practices to this emerging technology, the Picklex process eliminates up to eleven steps in metal‐finishing processes. The reductions of waste at the source were very significant. These reductions were accomplished by the elimination of the hexavalent chromium tank and subsequent rinsing operations; the elimination of the acid baths used for etching and cleaning along with subsequent rinsing operations; the elimination of the zinc phosphatizing baths and subsequent rinsing operations; and the elimination of the deoxidizing bath and subsequent rinses. All of the steps eliminated are steps that emit pollution. In addition, the Picklex process significantly reduces the pollution from the remaining steps. It does this while providing the same high‐quality finish and wear resistant capabilities as the conventional processes.

Although normally the Picklex bath does not need to be dumped, but, as part of the study, the bath was evaluated for waste treatment issues in the event of a spill or accidental contamination. Fresh, spent, and impurity‐spiked spent Picklex samples were treated using the conventional pH 9 precipitation industrial wastewater treatment method to produce samples for a waste disposal assessment for Picklex. The waste solids were assessed for toxic leachability. The treated water supernatants for discharge were also examined and found as most likely dischargeable. Waste treatment may not be frequent or necessary in many processes. Actual discharge limits from industrial waste treatment plant operations are site‐specific and are determined on a case‐by‐case basis with local, state (and federal only where necessary) regulatory agencies. Hence, no exact classification of these potential waste solutions is possible until a specific location is known. All leachates are passed with respect to the applicable federal regulations (USEPA 1995b). Therefore, Picklex does not appear to present unusual waste treatment issues.

7.8.3 Value‐Added Chemicals from Pulp Mill Waste Gases

Methanol, formed during the pulping of wood and is contaminated with reduced sulfur compounds and terpenes, is the largest single source of VOC emissions from kraft pulp mills, accounting for 70–80% of total emissions. The Cluster Rule (Cluster Rule Regulation: 40CFR Part 63 1998) limits methanol emissions for all pulp mills in the United States. Canada faces similar legislation (Das 1997, 1999a, b; Das and Houtman 2004; Das and Jain 2001).

Methanol emissions can be reduced by collecting condensate streams from the digesters, evaporators, and other sources in the mill. The collected condensate streams can then be steam‐stripped to concentrate the methanol for incineration. A few mills are “hard‐piped” to send this methanol‐laden stream to bio‐treatment plant, thus avoiding incineration.

Stripper overhead gas (SOG) contains roughly equal part of methanol and water (40–50 wt%) and roughly equal parts of TRS and terpenes (1–5 wt%).

In the United States, the SOG is likely to be burned in an incinerator, kiln, or boiler. Recently, some mills have found it advantageous to rectify the SOG to about 80% methanol and collect it as a liquid, which has a higher fuel value. With this concentrated (70–80%) methanol stream available, plants can cut down on the amount of natural gas that must be bought.

A process has been developed at Georgia‐Pacific that converts the methanol and TRS (mostly mercaptans) in the rectified SOG into formaldehyde. Based on work by Wachs (1999a, b), this patented catalytic process (Burgess et al. 2002) has achieved commercially viable yields of formaldehyde (70–80%) from a typical pulp mill SOG feedstock containing methanol, water, and TRS compounds.

The conversion of methanol and TRS to formaldehyde presents kraft mills with a more profitable alternative for SOG than incinerating the gas as a fuel. The formaldehyde produced can be used by resin manufacturers to produce thermosetting resins commonly used in plywood and other structural panels. A typical pulp mill of 2000 air‐dried tons per day (ADTPD) output may achieve a payout of 2–4 years, depending on the price of methanol and local economics.

The process also produces two levels of low‐pressure stream, 60 and 70 psig, usable within a paper mill, by reducing most of the methanol to formaldehyde, rather than CO₂. The reduction in CO₂ emissions is about 80–85% of the amount otherwise generated by incineration or by the bio‐treatment plant. For a 2000 APTDP mill, this equates to 28 T/Y of CO₂ emissions that are avoided.

A typical itemization of income, costs, and earnings is given in Table 7.4. For a 2000 ADTPD mill, a payout of 3–4 years is calculated based on formaldehyde prices of $0.06/lb (50%) basis. This assumes a customer‐shipping radius of 500 miles from the mill producing the formaldehyde. A heat value credit to the mill is included (equivalent of natural gas fuel) for the methanol that would otherwise have been incinerated and used to generate steam via heat recovery exchangers.

7.8.4 Recovery and Control of Sulfur Emissions

Sulfur is often considered one of the four basic raw materials in the chemical industry. It can be recovered as a by‐product from sulfur removal and recovery processes (Kirk and Othmer 2004). Historically, sulfur recovery processes focus on the removal and conversion of hydrogen sulfide (H₂S) and sulfur dioxide (SO₂) to elemental sulfur, as these species represent significant emission from pulping process. Various processes for the removal of SO₂ in the combustion gases are available. Direct catalytic oxidation of SO₂ to SO₃, and subsequent absorption of SO₃ in water to produce sulfuric acid, is an alternative method (Paik and Chung 1996). Total mill TRS emissions of 10–20% are contributed by vent streams from brownstock washers, foam tanks, black‐liquor filters, oxidation tanks, and storage tanks that are not typically collected in the noncondensable gas system (Pinkerton 1999). The emissions from these sources can be collected and combusted for energy recovery, reducing the atmospheric emissions of TRS and VOCs.

7.9.1 Introduction

Every day, water‐cooled thermoelectric power plants in the United States withdraw from 60 billion to 170 billion gal of freshwater from rivers, lakes, streams, and aquifers, and consumes from 2.8 billion to 5.9 billion gal of that water. Freshwater withdrawals for cooling in thermoelectric power production account for about 40% of all withdrawals, essentially the same amount as withdrawals for agricultural irrigation, as documented by the U.S. Geological Survey. Sustained droughts nationwide underscore the critical need to think about using treated municipal wastewater (MWW) for use in cooling in electric power generation. It needs a great deal of water for electric power production, to condense stream in the power plant stream cycle. Air cooling is possible, but it is more costly and less efficient. Water will continue to be the preferred coolant for new thermoelectric power plants (Dzombak 2013).

Motivation for the project: Increase in demand for electricity brings with it an increase in water needed for cooling. The cooling of thermoelectric power plants accounts for 41% of all freshwater withdrawal in the United States, i.e. approximately the same amount of water as is withdrawn for agricultural irrigation. Some areas of the United States have little or no freshwater available for use. Alternative sources of water are needed for new electric power production. The U.S. Department of Energy has been conducting and sponsoring research to investigate the feasibility and costs of using alternative sources of water for power plant cooling, especially in recirculating cooling systems which are required for most new power production in the United States.

Goals and highlights of the project: Treated MWW is a common, widely available alternative source of cooling water for thermoelectric power plants across the United States, as determined in a predecessor DOE project (2006–2009) by the project team. However, the biodegradable organic matter, ammonia–nitrogen, carbonate, and phosphates in the treated wastewater pose challenges with respect to enhanced biofouling, corrosion, and scaling, respectively. The overall objective of this study was to evaluate the benefits and LCC of implementing tertiary treatment of secondary treated MWW prior to use in recirculating cooling systems.

The study comprised bench‐and pilot‐scale experimental studies with three different tertiary treated MWWs, and LCC and environmental analyses of various tertiary treatment schemes. Sustainability factors and metrics for reuse of treated wastewater in power plant cooling systems were also evaluated. The three tertiary treated wastewaters studied were secondary treated MWW subjected to acid addition for pH control (MWW_pH); secondary treated MWW subjected to nitrification and sand filtration (MWW_SF); and secondary treated MWW subjected to nitrification, sand filtration, and GAC adsorption (MWW_NFG).

Tertiary treatment was determined to be essential to achieve appropriate corrosion, scaling, and biofouling control for use of secondary treated MWW in power plant cooling systems. The ability to control scaling, in particular, was found to be significantly enhanced with tertiary treated wastewater compared to secondary treated wastewater. MWW_pH treated water (adjustment to pH 7.8) was effective in reducing scale formation, but it increased corrosion and the amount of biocide required to achieve appropriate biofouling control. Corrosion could be adequately controlled with tolytriazole addition (4–5 ppm TTA), however, which was the case for all of the tertiary treated waters. For MWW_NF treated water, the removal of ammonia by nitrification helped to reduce the corrosivity and biocide demand. Additional GAC adsorption treatment, MWW_NFG, yielded no net benefit. For all of the tertiary treatments, biofouling control was achievable, and most effectively with preformed monochloramine (2–3 ppm) in comparison with NaOCl and ClO₂.

LCC analyses were performed for the tertiary treatment systems studied experimentally and for several other treatment options. A public domain conceptual costing tool (LC3 model) was developed for this purpose. MWW_SF (lime softening and sand filtration) and MWW_NF were the most cost‐effective treatment options among the tertiary treatment alternatives considered because of the higher effluent quality with moderate infrastructure costs and the relatively low doses of conditioning chemicals required (Dzombak 2013).

Life cycle inventory (LCI) analysis along with integration of external costs of emissions with DC was performed to evaluate relative emissions to the environment and external costs associated with construction and operation of tertiary treatment alternatives. Integrated LCI and LCC analysis indicated that MWW_NF and MWW_SF alternatives exhibited moderate external impact costs with moderate infrastructure and chemical conditioner dosing, which makes them (especially MWW_NF) better treatment alternatives from the environmental sustainability perspective since they exhibited minimal contribution to environmental damage from emissions (Dzombak 2013).

7.9.2 Key Points

1. This study undertook a comprehensive, integrated approach by looking at all aspects of the water quality control problem in a recirculating cooling system employing treated MWW as makeup water, and we determined optimal approaches for tertiary treatment considering both direct economic costs and environmental impacts of alternative water treatment/management approaches in an integrated manner.
2. The work included pilot‐scale demonstrations in the field, in addition to laboratory and modeling work, in partnership with a MWW treatment facility.
3. In regard to originality and innovation, this study was the first comprehensive research study in the public domain of the use of treated MWW as makeup water in recirculating cooling systems of electric power plants.
4. The challenges of using treated MWW in power plant cooling systems are many and include the technical challenges of controlling corrosion, scaling, and biofouling in a recirculating cooling system employing a low‐quality makeup water; the challenge of determining capital and operating costs in a complex operational environment in which the water is being concentrated four times or more in the recirculating cooling system; and the challenge of assessing environmental and social risks and benefits for use of treated wastewater as cooling system makeup water. It was a complex problem, and further complicated by the economic, social acceptance, and sustainability issues involved.
5. Alternative sources of water are needed for new power production in regions without new sources of freshwater available. Our research will help advance the use of treated MWW in electric power production and thus help contribute to economic development. Further, in this research they evaluated explicitly the relative sustainability of various water treatment/management alternatives by considering environmental impact and social acceptance factors in addition to direct economic costs of the alternatives.

7.9.3 The World's First Zero Effluent Pulp Mill at Meadow Lake: The Closed‐Loop Concept

The $250 million Millar Western Meadow Lake Mill is located on a 247‐acre site about 200 miles northwest of Saskatoon, Saskatchewan. It uses mechanical action supplemented by mild chemicals to turn aspen wood chips into bleached chemi‐thermomechanical pulp (BCTMP), about 240 000 MT/Y.² More efficient than the kraft process, this approach uses half the trees to make the same amount of pulp, producing almost one ton of pulp for each ton of wood on a water‐free basis. The Millar Western BCTMP process also eliminates chlorine compounds and odorous sulfur‐based impregnation chemicals. This environmentally friendly mill uses hydrogen peroxide to increase the brightness of the pulp, making it suitable for printing and writing grades of paper as well as for tissue and paper towels.

The plant is the first pulp mill in the world to operate a successful zero liquid discharge system. Effluent from the thermomechanical pulping process is concentrated from 2% solids to 35% solids by three falling film vapor compression evaporators, followed by two steam‐driven concentrators which further concentrate the effluent to about 70% solids. Of the 1760 gal/min of effluent sent to the system, 1720 is recovered as high‐purity water for reuse in the pulping process. Solids are burned in the boiler; the smelt is cast into ingots and stored on site for future chemical recovery.

In early1990s, when Millar Western Pulp (Meadow Lake) Ltd. announced plans to build a mill in northern Saskatchewan, the community was concerned about the pollution it would generate, especially effluent discharged to the Beaver River. Though a biological treatment system planned at the mill would have made the effluent cleaner than river water, Millar Western decided to go one step further and eliminate all effluent discharge from the pulp mill. The zero effluent system at Meadow Lake is the first of its kind in the world. The evaporator system, the key equipment in the water recovery process, was designed and supplied by Resources Conservation Company (Fosberg 1992). All effluent coming out of the mill is treated in the water recovery plant. As a result, the mill only needs about 300 gpm of makeup water to replace water lost to the atmosphere by evaporation. The same type of pulp mill without a water recovery plant would need about 2500 gpm of raw makeup water. The effluent treatment system started up in January 1992, when the mill went on line.

Millar Western's Meadow Lake BCTMP mill is an example of successful closure of the water cycle in a mechanical pulp mill. An earlier attempt in Canada to close a kraft mill by recycling bleach plant effluents through the kraft chemical recovery process had failed on account of the buildup of corrosive materials (Smook 1992). Thus, it is useful to study in detail the advanced system in place at Meadow Lake.

The effluent produced by the BCTMP process at Meadow Lake is discharged at a rate of almost 1800 gpm. It has a temperature of 150 °F, a pH of about 8 and contains about 20 000 ppm dissolved solids. Figure 7.5 shows a more detailed view of the water recovery portion of the system, consisting of five stages: clarification, evaporation, concentration, stripping, and incineration.

7.9.3.1 Clarification

The first unit operation to receive pulp mill wastewater is the floatation clarifiers. Since removal of fiber is very important to the performance of the evaporators, the mill decided to install two clarifiers instead of one. This allows for maximum removal efficiency and flexibility. Chemicals are added to aid in flocculation and floatation of the solids.

To ensure that upsets in the pulp mill do not directly affect the evaporators, an on‐line meter measures suspended solids in the clarifier accepts stream. When the suspended solids exceeds 900 ppm, the clarifier accepts are directed to the settling ponds. Clarifier accepts normally go directly to the evaporators in the winter to conserve heat. In the summer the accepts go preferentially to the settling pond to dump heat since the heat balance changes from season to season.

7.9.4 Successful Implementation of a Zero Discharge Program

In July 1996, a paper company located on the west bank of the Mississippi River undertook a program to eliminate the discharge of industrial wastewater to the river. A wastewater recycling system consisting of pumps, surge tank, and filtration system reduced discharges by 99%. The successful pollution prevention includes the annual elimination of 562 million gal of wastewater, 149 000 lb of total suspended solids, and 57 000 lb of biochemical oxygen demand. The plant primarily manufactures colored construction‐grade paper from a mixture of secondary fiber, stone ground‐wood pulp, and kraft pulp.

The company initiated a Zero Discharge program, described in detail by Klinker (1996), having two goals:

1. Eliminate the discharge of wastewater into the Mississippi River.
2. Improve the efficiency of water use in manufacturing to reduce the mill's dependence on river water.

Recycling treated wastewater into the mill's water supply system would accomplish these goals.

Besides the regulatory motivation for reusing wastewater, the company had concerns about periodic interruptions in the flow of water to the mill. A local power company's hydroelectric plant located immediately upstream caused these interruptions. On occasion, the utility lowered the river level by halting water flow through a canal that also feeds water from the Mississippi to the paper mill. When this occurred, the mill had to stop its manufacturing process until there was sufficient volume of water to run the mill. By reusing wastewater, the company could reduce its dependency on river water and avoid this disruption to production.

The nucleus of the Zero Discharge program, a closed‐loop wastewater recycling system in the mill, not only offers environmental benefits but also generates difficulties because of the increase in the volume of recycled wastewater used in manufacturing and the expenses associated with addressing these problems.

7.9.4.1 Closing the Loop

Figure 7.6 is a diagram of the company's closed‐loop wastewater recycling system. Before the Zero Discharge program began, the Mississippi River supplied all the process and cooling water for the mill. Freshwater from the river entered the mill, passed over a fine mesh screen, and entered a 2700‐gal freshwater tank. The house pump directed it to process and cooling water demand points in the mill.

The resulting process wastewater underwent treatment in the company‐owned, activated sludge, wastewater treatment plant. Discharge was through a process‐wastewater outfall designated outfall 01. Cooling wastewater discharge was at outfall 02. Wastewater sludge underwent dewatering on a belt filter press followed by land application on company owned agricultural land.

Before the Zero Discharge program, the plant discharged an average of 607 000 gal of process wastewater and 1.14 million gal of cooling wastewater into the river each day. By using the closed‐loop system to pump increased amounts of treated wastewater into the freshwater tank, the mill was able to state that its process and cooling water consisted of nearly 100% recycled wastewater. The total volume of wastewater discharged to the river decreased by 82% (Klinker 1996).

7.9.5 Conclusions

The US pulp and paper industry has made significant progress towards reducing water consumption and increased water recycling and reuse through innovative technologies and process modification. Some mills have implemented processes that “close the loop” and proved to be successful Zero Discharge bleach plant systems. The effects of the EPA's Cluster Rule, which became applicable on 15 April 2001, have yet to be fully felt. It is reasonable to expect, however, that the new linkage of federal regulations aimed at reducing air and water pollution will result in an even higher level of processed water recycling, reuse within the mills, as well as greater pollution prevention and Zero Discharge in water, air, and solid waste areas the next decade or two. As technologies to reduce facility water, chemical, and energy use have advanced, other chemical industries, like pulp and paper and power generating industry, have increasingly embraced the use of reclaimed water for a wide‐ranging suite of purposes: from process water, boiler feedwater, and cooling tower use to finishing toilets and site irrigation. Current technologies produce reclaimed water that can provide the same performance as more‐expensive potable water. As water resources become increasingly valued around the world, industrial water reuse is expected to expand (DaSilva and Goodman 2014).

7.10.1 Public Health

Nationwide, the report found nearly four in ten Americans live where pollution levels are often dangerous to breathe. But overall, the number of Americans exposed to unhealthy levels of air pollution dropped to about 125 million people, down from 166 million in last year's report (which covered the period from 2012 to 2014).

Air pollution can cause asthma attacks, heart attacks, lung cancer, reproductive harm, and premature death. Globally, the World Health Organization says three million people die prematurely each year from breathing polluted air, and children are especially at risk. Airborne mercury falls into the rivers and estuaries, contaminating freshwater and saltwater fish populations. Mercury compounds bioaccumulate in the food chain, making king mackerel, bass (in some areas), and bowfin unfit for human consumption by children and women of childbearing age.

7.10.2 Visibility

Visibility in the southeast has declined by 75% from natural levels. One should be able to see out 93 miles on an average day, but now air pollution has reduced this to an average of 20 miles. On any given summer day, due to regional haze in the regional, there is a good chance that views may be entirely obscured by pollution.

7.10.3 Ecosystems

Air pollution causes acid rain and nitrogen deposition, which make vegetation more susceptible to disease and pests, contributing to stunted growth and significant declines in populations of redwood, dogwood, spruce, fir, beech, and other tree species. Rainfall in the regions is more acidic than normal rainfall. In the west, airborne nitrogen adds to nutrient pollution in sensitive coastal watersheds, contributing to algal blooms and fish kills.

7.10.4 Economic Consequences

California's dirty air threatens the vitality of the state's economy. Dirty air is estimated to cost the state over $20.0 billion annually in morbidity and mortality costs. Ozone's effect on plants is “significant stress factor in agricultural production”. Air pollution reduces crop yields, which causes California farmers to lose estimated more than $300 million each year. Frequent smog alerts in ozone‐smog non‐attainment areas discourage hiking and other outdoor activities. The impairment of visibility undermines California's $10 billion tourism industry. The loss in economic activity in the state's National Parks is estimated to cost more than $500 million each year.

7.10.5 Global Climate Change

Carbon dioxide pollution from mobile and point sources is one of the primary pollutants that contributes to global warming, which over the next 30 years is expected to raise sea levels off the California coast lines.

7.10.6 Quality of Life

A loss of air quality clearly diminishes the quality of life for all Californians, but putting a price tag on it is difficult. Nonetheless, some indirect measures are possible. For example, quality of life has long been a major factor in persuading new businesses to locate in the state, which implies that as air quality declines, it will be harder for the state to attract new investment and jobs.

7.10.7 Costs–Benefits Analysis

Section 812 of the Clean Air Act Amendments of 1990 provides a case study of a status that requires a particularly detailed risk assessment (or cost–benefits). The goal of this section of the Clean Air Act is to assess the costs of the Clean Air Act. It requires the USEPA to estimate the hazardous associated with the air pollutants covered under the act (USEPA 2011).

The statistics just given are not comprehensive: the economic effects of acid rain, eutrophication, mercury exposure, and other environmental problems are not included. Thus, the actual costs of dirty air are much higher than those reflected by the dollar amounts cited. Nor can any no economic calculation quantify the pain experienced by a child who suffers from asthma or a grandparent with cardiopulmonary disease whose death is hastened by exposure to high levels of fine particulate matter.

7.11.1 Economic Performance Indicators

Costs associated with poor environmental and societal performance can be very large. Waste disposal feed, permitting costs, and liability costs can all be substantial. Wasted raw material, waste energy, and reduced manufacturing throughput are also consequences of wastes and emissions. Corporate image and relationships with workers and communities can suffer if performance is substandard. But how can these costs be quantified? This section will review the tools available for estimating environmental and societal costs and benefits. These include traditional concepts such as the time value of money, PV, PP, internal ROR, and other financial evaluation calculations. Nontraditional tools include methods for monetizing environmental costs that are hidden from normal accounting procedures. We'll also touch upon less tangible costs and benefits that can still be monetized.

In general, traditional accounting practices have acted as a barrier to implementation of sustainable engineering projects because they hide the costs of poor environmental and societal performance. Many organizations are now giving more consideration to all significant sources of environmental and societal costs. The principle is that if costs are properly accounted for, management practices that foster good economic and societal performance will also foster superior environmental and societal performance (USEPA 1995c).

7.11.2 Estimates of Environmental Costs

It is generally recognized that in environmental and societal cost accounting, words like full (e.g. full‐cost accounting), total (e.g. total cost assessment), true, and life cycle (e.g. life cycle costing) are used to indicate that not all costs are captured in traditional accounting and capital budgeting practices. Among the easiest environmental costs to track are the costs associated with treating emissions and disposing of wastes. DC of pollution abatement are tracked by the U.S. Census Bureau and have been increasing steadily. Expenditures in 1972 totaled $52 billion (in 1990 dollars) and were projected to grow to approximately $140 billion (in 1990 dollars), or 2.0–2.2% of gross national product, in the year 2000 (for a review and analysis of these data, see United State Congress 1994).

These expenditures are not distributed uniformly among industry sectors. As shown in Table 7.7, sectors such as petroleum refining and chemical manufacturing spend much higher fractions of their net sales and capital expenditures on pollution abatement than do other industrial sectors. Therefore, in these industrial sectors, minimizing costs by preventing wastes and emissions will be far more strategic an issue than in other sectors.

Pollution abatement costs reported by individual companies both reflect these general trends and provide more detail about the magnitude and the distribution of environmental expenditures. For example, Tables 7.8 and 7.9 show the distribution of environmental costs reported by the Amoco Yorktown refinery and DuPont's LaPorte chemical manufacturing facility (Heller et al. 1995; Shields et al. 1995). In the case of Amoco refinery only about a quarter of the quantified environmental costs are associated with waste treatment and disposal; the costs are summarized in Table 7.7 associated with removing sulfur from fuels, meeting other environmentally based fuel requirements, and maintaining environmental equipment were greater than the costs associated with waste treatment and disposal. This indicates that the magnitude of environmental costs is substantially greater than that reported in Table 7.7 and that these costs may be hard to identify.

7.11.3 Total Annualized Cost for BACT

In Chapter 6, top‐down BACT analyses for criteria pollutants were presented for a gas turbine facility (Section 6.6). As an example, here we present the TACs and costs per ton pollutant of particulate matter removed against exhaust gas rate and boiler steam capacity for four control options: (i) multi‐cyclones (MC), (ii) Venturi scrubber (VS), (iii) electrostatic precipitator (ESP), and (iv) fabric filter (FF). The TACs were computed using the EPA's air pollution control cost manual and the control‐cost spreadsheets (APTI 1995; USEPA 1996). The USEPA control‐cost spreadsheets consider most aspects of cost evaluation, using operating parameters, design parameters, capital costs, and annual cost. The TAC spreadsheets for control options, e.g. MC, FF, ESP, and VS, are given in the report by Das (2003).

The TAC for a chosen boiler exhaust flow rate at 18 685 dscfm (Table 7.10). Cost effectiveness, or dollar per ton of pollutant removal, is one of the key economic criterion used to determine if a control option is acceptable for permitting use. Cost effectiveness is calculated as the TAC of the control option being considered divided by the baseline emissions minus the control option emissions rate (Figures 7.7 and 7.8) (Das 2001, 2003; Peters et al. 2002).

7.11.4 Cost Per Ton (T) of Pollutant Removal

The following is the calculation of ton per year (T/Y) and dollar per ton ($/T) using Figure 7.7 for four control technologies (MS, VS, ESP, and) for particulate matter (PM) removal.

7.12.1 Equipment Costs

Process equipment costs can be correlated with size or capacity by the following relationship.

(7.5)

where

• capacity_B = equipment throughput, in standard units of cfm, gpm, etc.
• size_B = equipment size, in standard units of 2 ft², ft³, etc.
• b, b′ = constant

The exponents b and b′ vary from 0.5 to 0.8 and will average between 0.6 and 0.7 for many types of equipment. Typical exponent values for various types of air pollution control equipment are shown in Table 7.12.

7.13.1 Methods

7.13.2 Other Technologies

There are a number of other new and emerging technologies that are able to produce energy from waste and other fuels without direct combustion. Many of these technologies have the potential to produce more electric power from the same amount of fuel than would be possible by direct combustion. This is mainly due to the separation of corrosive components (ash) from the converted fuel, thereby allowing higher combustion temperatures in, e.g., boilers, gas turbines, internal combustion engines, and fuel cells. Some are able to efficiently convert the energy into liquid or gaseous fuels.

Thermal technologies:

• Gasification: produces combustible gas, hydrogen, synthetic fuels
• Thermal depolymerization: produces synthetic crude oil, which can be further refined
• Pyrolysis: produces combustible tar/bio‐oil and chars
• Plasma arc gasification or plasma gasification process (PGP): produces rich syngas including hydrogen and carbon monoxide usable for fuel cells or generating electricity to drive the plasma arch, usable vitrified silicate and metal ingots, salt, and sulfur

Non‐thermal technologies:

• Anaerobic digestion: biogas rich in methane
• Fermentation production: examples are ethanol, lactic acid, hydrogen
• Mechanical biological treatment (MBT)
  • MBT + anaerobic digestion
  • MBT to refuse derived fuel

7.13.3 Global Developments

During the 2001–2007 period, the WtE capacity increased by about 4 million MT/Y. Japan and China each built several plants based on direct smelting or on fluidized bed combustion of solid waste. Japan is the largest user in thermal treatment of MSW in the world, with 40 million T. Some of the newest plants use stoker technology and others use the advanced oxygen enrichment technology. There are also over one hundred thermal treatment plants using relatively novel processes such as direct smelting, the Ebara fluidization process, and the thermoselect JFE gasification and melting technology process. In India its first energy bio‐science center was developed to reduce the country's greenhouse gases and its dependency on fossil fuel. As of June 2014, Indonesia had a total of 93.5 MW installed capacity of WtE, with a pipeline of projects in different preparation phases together amounting to another 373 MW of capacity.

Biofuel Energy Corporation of Denver, CO, opened two new biofuel plants in Wood River, Nebraska, and Fairmont, Minnesota, in July 2008. These plants use distillation to make ethanol for use in motor vehicles and other engines. Both plants are currently reported to be working at over 90% capacity. Fulcrum BioEnergy Incorporation located in Pleasanton, California, is building a WtE plant near Reno, Nevada. The plant is scheduled to open in 2020. https://fulcrum‐bioenergy.com/facilities. BioEnergy Incorporation predicts that the plant will produce approximately 10.5 MG/year of ethanol from nearly 200 000 T/Y of MSW.

WtE technology includes fermentation, which can take biomass and create ethanol, using waste cellulosic or organic material. In the fermentation process, the sugar in the waste is changed to carbon dioxide and alcohol, in the same general process that is used to make wine. Normally, fermentation occurs with no air present. Esterification can also be done using WtE technologies, and the result of this process is biodiesel. The cost effectiveness of esterification will depend on the feedstock being used, and all the other relevant factors such as transportation distance, amount of oil present in the feedstock, and others. Gasification and pyrolysis by now can reach gross thermal conversion efficiencies (fuel to gas) up to 75%; however, a complete combustion is superior in terms of fuel conversion efficiency. Some pyrolysis processes need an outside heat source which may be supplied by the gasification process, making the combined process self‐sustaining.

7.13.4 Examples of WtE Plants

According to ISWA there are 431 WtE plants in Europe (2005) and 89 in the United States (2004). The following are some examples of WtE plants.

Waste incineration WtE plants:

• Lee County Solid Waste Resource Recovery Facility, Fort Myers, Florida, USA (1994)
• Montgomery County Resource Recovery Facility in Dickerson, Maryland, USA (1995)
• Essex County Resource Recovery Facility, Newark, New Jersey, USA (1996)
• Spokane Waste‐to‐Energy Facility, Washington, USA (1996)
• Spittelau (1971), and Flötzersteig Vienna, (Wien Energie), Austria (1963)
• SYSAV Waste‐to‐Energy Plant, Malmö, Sweden (2003 and 2008)
• Stoke Incinerator, Stoke‐on‐Trent, England, UK (1989)
• Teesside EfW plant near Middlesbrough, North East, England, UK (1998)
• Edmonton Incinerator in Greater London, England, UK (1974)
• Burnaby Waste‐to‐Energy Facility, Metro Vancouver, Canada (1988)
• Timarpur‐Okhla Waste to Energy Plant, New Delhi, India (2001)
• Algonquin Power, Brampton, Ontario, Canada (1990)

7.13.5 Case Study: Energy Recovery from Municipal Solid Waste: Profitable Pollution Prevention at the City of Spokane, Washington (see Appendix G)

7.14.1 What Is a Sustainable Economy?

An environmentally sustainable economy – an eco‐economy – requires that the principles of ecology be observed in establishing the framework for formulating economic policy and that economists understand that all economic activity, indeed all life, depends on the Earth's ecosystems – the complex of individual species living together, interacting with each other, and with their physical habitat. Millions of plant and animal species exist in an intricate balance, woven together along the food chain by nutrient cycles, the hydrological cycle, and global climate systems. Economists know how to translate goals into policy. Economists and ecologists, along with engineers, scientists, and policy makers, working together are being challenged to design and build an eco‐economy, one that can sustain progress (Brown 2001a, b; Western Governors' Association, 3 December 2004).

Through industrial ecology, eco‐industrial parks, eco‐efficiency, Zero Discharge manufacturing, and engineering new products from agricultural materials (biorenewable resources), an eco‐economy that facilitates sustainable economic progress offer the potential for the achievements, over the long‐term, of a sustainable economy and a healthy planet. Humankind has gone outside the biotic environment for the majority of its material needs only recently. Plant‐based resources were the predominant source of energy, organic chemicals, and fibers in the West as recently as 150 years ago, and they continue to play important roles in many developing countries.

The transition to nonbiological (or nonrenewable) sources of energy and materials was relatively swift and recent in the history of the world. Biorenewable resources are by definition sustainable natural resources; that is, they are self‐renewing at a rate that ensures their availability for use by future generations. Biorenewable resources can be converted into either bioenergy or biobased engineering products. Bioenergy, also known as biomass energy, is the result of the conversion of the chemical energy of a biorenewable resource into heat and stationary power. Biobased products include transportation fuels, chemicals, and natural fibers derived from biorenewable resources. Transportation fuels are generally liquid fuels, such as ethanol or biodiesel, but compressed hydrogen and methane have also been proposed and evaluated for use in vehicular propulsion.

Chemicals may include pharmaceuticals, nutraceuticals, and other fine chemicals, but the emphasis here is on commodity chemicals, which produce high demands for biorenewable resources. An example is polylactic acid, which is derived from the fermentation of sugars hydrolyzed from cornstarch and can be converted into biobased polymers used in a variety of consumer products such as carpets.

The cost of a biorenewable resource is related to the demand for the resource by a supply curve. Figure 7.9 is a generalized representation of a supply curve for the three kinds of biorenewable resources. The cost of biorenewable resources is highly variable and dependent on local conditions of supply and demand. This is particularly true for the costs involved in processing residue and wastes. Table 7.13 provides an estimate of the availability and cost of several kinds of residues and wastes along with a comparison of the costs of a few crop. The cultivation and harvesting of dedicated energy crops, on the other hand, is amenable to standardized cost estimating since information on “unit operation,” such as planting, fertilizing, and harvesting, can be readily obtained from knowledgeable sources (Brown 2001b).

7.14.2 Costs of Manufacturing Various Biobased Products and Energy

Over the next decades, a much larger fraction of fuels, chemicals, and materials will be produced from renewable plant materials. These biobased industrial products offer the potential for a much more sustainable economy based on environmentally superior products. This section briefly describes the associated costs of producing electricity, fuels, and chemicals from various feedstocks using biorenewable resources.