Wastewater Sources

Point Source & Nonpoint Sources of Water Pollution

Eco-efficiency Photo courtesy of SiemensOpens in new window

Introduced by the World Business Council for Sustainable Development (WBCSD, 2000)Opens in new window, Eco-efficiency is essentially oriented towards creating more goods and services while using fewer resources and creating less waste and environmental pollution.

Point Source

Point source water pollution refers to contaminants that enter a waterway from a single, identifiable source, such as a pipe or ditch. Examples of sources in this category include discharges from a factory, a sewage treatment plant or a publicly owned treatjent works (POTWs), or a city storm drain. The US Clean Water Act (CWA) defines point source for regulatory enforcement purposes (United States Code Clean Water Act Section 502(14) 33 U.S.S 1362(14) 1999). The CWA definition of point source was amended in 1987 to include municipal storm sewer systems, as well as industrial storm water, such as from construction sites.

Nonpoint Source

Nonpoint source (NPS) pollution refers to diffuse contamination that does not originate from a single discrete source. NPS pollution is often the cumulative effect of small amounts of contaminants gathered from a large area. A common example is the leaching out of nitrogen compounds from fertilized agricultural lands (Moss 2008). Nutrient runoff in storm water “sheet flow” over an agricultural field or a forest is also cited as examples of NPS pollution.

Contaminated storm water washed off of parking lots, roads and highways, called urban runoff, is sometimes included under the category of NPS pollution. However, because this runoff is typically channeled into storm drain systems and discharged through pipes to local surface waters, it becomes a point source.

Fugitive emissions are also NPS pollution in that the emissions of gases or vapors take place from pressurized equipment due to leaks and other unintended or irregular releases of gases, mostly from industrial activities. As well as the economic cost of lost commodities, fugitive emissions contribute to air pollution and climate change.

Eco-efficiency is the business response to the challenge of sustainable development—that is, meeting “the needs of the present without jeopardizing the needs of future generations.” It is an environmental philosophy that stresses:

  • increasing resource productivity so that more is obtained from less energy and raw material input
  • creating new goods and services that increase customer value while maintaining or reducing environmental impacts.

Economic development is the best response to this challenge—but we need a new kind of development that follows the seven guidelines of eco-efficiency:

  • reduce material intensity of goods and services
  • reduce energy intensity of goods and services
  • reduce toxic dispersion
  • enhance material recyclability
  • maximize sustainable use of renewable resources
  • extend product durability
  • increase the service intensity of products.

Businesses that do this will create bottom line benefits from:

  • creating new products and services that meet the aspirations of most of the world’s consumers for prosperity and a clean and healthy environment.
  • reducing the costs and liability associated with resource consumption, waste, and end of pipe pollution control (which are likely to rise as a result of environmental taxes and other measures).

According to the World Business Council for Sustainable Development (WBCSD, 2000), eco-efficient materials are those materials that ensure the use of less material in a given application, ensure the use of less energy both in the production or transformation of the material (low embodied energy materials) and in the operation time within the application (low operational energy), are nontoxic and recyclable, and last more time within the application.

Similarly, eco-efficient systems are those that ensure a reduction in the material intensity of goods or services, a reduction in the energy intensity of goods or services, reduced dispersion of toxic materials, improved recyclability, maximum use of renewable resources, greater durability of products, and increased service intensity of goods and services.

What Is Special about Eco-efficiency?

Of course, many environmental concepts and initiatives emphasize the importance of resource productivity or doing more with less. It is central, for example, to the United Nations Environmental Programme’s concept of cleaner productionOpens in new window. There are also many proven approaches to achieving it, such as design for environment (DFE), pollution prevention, and product stewardship.

While eco-efficiency draws upon and has much in common with these and other approaches it has several distinctive features. These can be summarized as:

  1. an emphasis on value creation
  2. an emphasis on stretching, long-term, targets for improvement
  3. linking environmental excellence to business excellence; and
  4. considering sustainable consumption as well as sustainable production.
  1.     Value Creation

Eco-efficiency harnesses the business concept of creating value and links it with environmental concerns. The goal is to create value for society, and for the company, by doing more with less over the entire life cycleOpens in new window, that is, from creation of raw materials to disposal of products at the end of their life. The idea is captured in Procter & Gamble’s statement:

Our goal is to provide more consumer performance and value with the use of less resources, including energy, and the creation of less wate.Procter & Gamble's Mission Statement

By promoting change toward sustainable growthOpens in new window, eco-efficiency enables a company’s business to grow in a qualitative way (by adding value), while reducing adverse effects on the earth. It also signals a significant shift in focus to concentrate on real customer needs.

This emphasis on creating and adding value is clearly to society’s benefit. Further, it’s often in line with the changing dynamics of the marketplace. Consumers everywhere want higher performance and increased value, at lower cost.

  1.     Setting—and Meeting—Stretch Targets

Eco-efficiency asks companies to consider long-term trends and make ambitious long-term commitments in response. One way of making this concrete is by emulating the quality concept of zero defectsOpens in new window.

Although this was often not a practical target, it provided a concrete goal that created a constant dissatisfaction with the present. Over time, that dissatisfaction resulted in more and more improvements that were previously thought impossible.

The environmental equivalent of zero defects is zero emissions of hazardous or potentially hazardous substances from a facility or product. Although strictly speaking this is impossible—the laws of thermodynamics state that there must be some wastes from every process—in practice it provides a clear sense of direction. Monsanto and 3M are two companies that have introduced zero emissions as a long-term aspiration—and introduced medium-term stretch targets to move a long way toward it. Xerox Corporation too has set the goal of waste-free products from waste-free factories and introduced clear targets for reducing solid wastes, air emissions, hazardous wastes, wastewater discharges, lower energy usage, and the inclusion of 25% postconsumer recycled materials in parts and packaging. And Dow has recently announced aggressive 10-year reduction goals for environmental performance and resource conservation.

  1. Environmental Excellence Is Business Excellence

Eco-efficiency is a management philosophy that links environmental excellence to business excellence and is synergistic with general trends in leading edge businesses. For example:

  • More and more companies are seeing shared values and a common sense of purpose among their staff as a key success factor. Making an environmental and social contribution can be an important element of these.
  • Eco-efficiency has close affinities with total quality management— “zero defects,” as we have seen can be translated into “zero emissions.”
  • Eco-efficiency’s emphasis on collaboration with suppliers, customers, and stakeholder organizations provides a practical example of the strategic collaboration that many management theorists are now advocating.
  1. A Sense of Purpose

Almost all social forecasters agree that more and more people, especially in the developed world, are searching for meaning in their lives—something traditionally provided by established religion or traditional communities and families. For a growing number, helping to protect the environment for future generation is an important part of their “sense of purpose.” This will drive their purchases—and favor the businesses whose own behavior and values resonates with their own.

More and more companies too are realizing that the best performance comes from staff or associates who share and commit to common values. 3M, for example, bases its success on consistent application of four key values:

  • Satisfying customers with innovative products, superior quality, and value,
  • Providing investors with an attractive return,
  • Respecting the social and physical environment,
  • Beign a company employees are proud to be part of.

These values provide employees with a sense of business purpose, based on meeting the requirements of stakeholders and making a broader contribution to the communities and countries they operate in.

Eco-efficiency contributes to this sense of purpose by providing a transcendent goal—respecting nature and helping to create a fairer world—that is in harmony rather than in conflict with business objectives. This same combination of long-term purpose and practical focus on current requirements is also attuned to the needs of customers, who will increasingly want both rather than one or the other.

Of course, to be effective, the everyday manaifestations of core values must stand up to the test of reality. If an organization professes and emphasizes sustainable business practices, it must condut its business accordingly or risk a loss of credibility and stature with regard to all its values from internal and external constituencies alike. Eco-efficiency does not require organizations to be environmentally perfect—but it does require them to be honest about their achievements and aim for continuous improvement.

  1. Total Quality Management

Eco-efficiency has many affinities with total quality management (TQM). We have previously discussed how the idea of zero defects can easily be converted into one of zero emissions—a concept that, although impossible to achive in practice, can provide a clear sense of direction. An emphasis on pollution prevention is also an environmental application of the central total quality tenet of dealing with causes rather than symptoms of defects. Both approaches also place great emphasis on continous improvement and the value of measurement and targeting as means of achieving this. Eco-efficiency’s stress on the importance of stakeholders too can be seen as an application of the TQM view that every process has a customer whose needs must be satisfied. In this perspective, regulators, NGOs, and others are “customers” for a company’s environmental management and innovation processes. Finally, both approaches place great emphasis on the importance of cross-functional collaboration. This can identify opportunities for improvement and build information and commitment for effective implementation.

There are many examples of the successful application of quality approaches to the environment. Take, for example, Thomson Crown Wood Products, a small manufacturer of wood and wood-finished audio and television cabinets and storage units. The company employs about 700 people at its Mocksville, North Carolina, plant. In the early 1990s a number of teams within its overall quality initiative focused on environmental issues—and achieved considerable success. As is often the case these teams had frivolous nicknames but serious intent.

  • The “Hazardous Five” team analyzed the quantity and origin of liquid hazardous waste streams. They realized that the hazards were create by a relatively small amount of material that could be separated out. Doing this meant that 5.7 million liters of water a year was no longer contaminated and could be used for recycling. It also created annual savings of $100,000 a year at a cost of only $26,000.
  • The “Millroom Madness” team made a small process change so that a piece of fiberboard cut out of a speaker panel could be used as a shelf for the same cabinet, saving $15,000 a year at no cost.
  • The “OOC/Fineliners” team addressed and resolved the gluing problems that were resulting in about twenty-one finished panels being sent to landfill. This saved around $250,000 a year.
  • The “Mix-Ups” team researched coating guns and identified one that would meet its specifications and reduce waste. This reduced wastage of coatings by over 50,000 liters a year and had a two-month payback.

Total quality management has brought many benefits. But busness academic Richard Schonberger believes that there are many more still to be achieved. The barriers are continuing divides between internal functions and departments, and between companies and their suppliers and customers. He calls for much greater “strategic collaboration’ within and between companies to reduce these barriers and achieve even better customer service.

Once again eco-efiiciency is synergistic with this goal. It too seeks to reduce functional barriers by extending environmental initiatives into all areas of a company and to better integrate supply chains through life cycle management and design for environment.

  1. Sustainable Production and Consumption

Agenda 21—the blueprint for sustainable development that emerged from the 1992 Rio Earth Summit—states:

Achieving the goals of environmental quality and sustainable development will require efficiencies in production and changes in consumption patterns in order to emphasize optimization of resource use and minimization of wastes.

Dealing with the unresolved challenges of sustainability now means shifting the emphasis beyond sites to industrial systems and society as a whole. This involves a trasition from the site-based approaches of pollution control, process integration, and whole facility (multimedia) planning. The emphasis is shifting to integrating environment throughout product chains—through ideas such as life cycle management and industrial ecology (in which one company’s wastes are used as inputs by others)—and the development of sustainable communities, cities, and regions. This means environment is not just a challenge for producers but for consumers, too.

A recent report by the WBCSD argues that business can best respond to the challenges of sustainable production and consumption by:

  • Taking account of the entire life cycle of goods and services—design and engineering, purchasing and materials management, production, marketing, distribution, use, and waste management
  • Applying the principles of eco-efficiency to create increased value for customers through the sustainable use of resources
  • In its role as consumer, procuring and requesting products and services that have less environmental impact
  • Making accurate, scientifically sound environmental information available to customers and the public so that they can make informed decisions about purchasing, use, and disposal.

Contrasting Brown and Green Priorities

Both green and brown proponents have reason to criticize many existing approaches to urban environmental managementOpens in new window, even if their priorities differ. At a superficial level, the brown and green agendas are in direct opposition to each other.

For example, the brown agenda would seem to call for more water use, more sewage connections, more waste collection, more urban residential land and more fossil fuel use (to replace smoky biofuels).

By ways of contrast, the green agenda would seem to call for water conservation, less water-borne sewerage, less waste generation, less urban expansion and less fossil fuel use.

While these potential contradictions should not be ignored, a review of existing policy problems indicates that the trade-offs need not be as sharp as such generalizations seem to imply.

Water

Urban water supply planning has been preoccupied historically with how to increase supplies to meet growing demand, given the physical and financial constraints of the city. By and large, demand has been assumed to be beyond the influence of water sector policies.

For those households and businesses connected to piped water systems, water is generally provided far below its full cost. For example, there is little incentive for users to conserve or encouragement to the industries that are the largest water users to recycle waste water or seek less water-intensive systems of production.

In some of the wealthier cities, subsidized water supply systems have brought major benefits to most of their populations, including a high proportion of their lower income populations.

For instance, there has been a considerable expansion in the proportion of the population with piped water supplies in many of the wealthier Latin American cities. In cities such as Sao Paulo, Belo Horizonte, Curtiba and Porto Alegre, most of the population receives piped water supplies to their homes (Jacobi, 1994; Mueller, 1995).

However, the proponents of the green agenda can rightly point to the serious consequences this often brings. The emphasis on increasing supply and keeping the price of water ‘affordable’ has resulted in major cities throughout Africa, Asia and Latin America overexploiting local water resources. For instance, in many coastal cities local aquifers have been overpumped, resulting in saltwater intrusion.

Overexploitation of underground water has also caused serious problems of subsidence for many buildings and sewage and drainage pipes in many cities (Damian, 1992; Postel, 1992). As local ground and surface water sources are overused (or polluted), meeting rising city demands generally means having to draw on ever more distant and expensive water resources.

This can be to the detriment of the populations (and often ecosystems) in the areas from which the water is drawn and with the higher water costs rarely reflected in higher prices for the largest city water users.

Proponents of the brown agenda often share this green agenda concern for unrealistically low water prices.

They can point to how the discrepancy between water utilities’ costs and revenues (from water sales and public subsidies) often inhibit expansion to low income areas and help to ensure that high proportions of the population in most cities remain unconnected to piped water systems.

Indeed, a combination of price controls and very limited public funds is a recipe for intragenerational inequities, with the subsidies that do exist flowing, along with the water, to those who least need them. Even for those low income groups who have access to connections, water supplies are often irregular or of poor quality or difficult to access – for instance, as dozens of households share each standpipe.

At least 300 million urban dwellers in Africa, Asia and Latin America remain without piped water supplies (WHO/UNICEF 1993) and tens of millions of those whose governments include in their statistics as having access to piped supplies still face inadequate, irregular or unsafe supplies which are often difficult to obtain (Satterthwaite, 1995; WHO, 1996).

While the water-related priorities of the green and brown agendas are different, their goals are not inherently incompatible. The often unmet minimum daily needs for health (about 30 litres per capita) amounts to about two flushes of a conventional toilet or one slowly dripping faucet.

The international standard of 150 litres per capita per day is only a small fraction of the typical usage in affluent cities in the North. Providing sufficient water for health needs is not the reason that many cities are overtaxing their water supplies.

Indeed, in many cities programmes encouraging water conservation and ensuring the better management and repair of piped water systems can often free up sufficient new supplies to allow regular piped water supplies to be extended to unserved households with no overall increase in water use. Intragenerational water inequities need not be solved by creating intergenerational or transboundary water inequities or vice versa.

It is politics and policy instruments, not physical imperatives, that create a stark trade-off between environmental health and ecological sustainability. Moreover, for most cities it is relatively clear whether environmental health or ecological sustainability ought to be the more pressing concern.

Sanitation

Proponents of the green and brown agendas can also point to problems in provision for sanitation, although, as in water supplies, they emphasize different problems. Here the conventional approach has been to promote water-borne sanitation systems, or steps in that direction, with the ultimate aim of providing all households with a flush toilet connected to a sewer.

Again, households obtaining connections receive considerable benefits, often at subsidized prices. But in most urban centres, sewage systems are characterized by significant inequities, relevant to both the brown and green agendas.

There are some cities in Latin America, Asia and parts of Africa where most of the population is adequately served by sewers. These are also generally the cities with low infant mortality rates and high life expectancies. However, the (generally) high unit costs of such systems also means that these cities are in the minority and very few cities have sewerage systems that serve most of their residents.

In many cities, sewers only serve a small proportion of the population (generally those in the more centrally located and wealthier areas). Most small urban centres have no sewer systems at all.

Estimates suggest that close to one-half the urban population of Africa, Asia and Latin America lack adequate provision for sanitation. Tens of millions of urban dwellers have no access to any form of sanitation or have only such poor quality, overcroweded public facilities that they have to resort to defecation in the open.

Proponents of the green agenda point to the environmental costs that conventional sewer systems can bring, especially the large volumes of water used to flush toilets and the problem of disposing of large volumes of sewage.

In Latin America, Asia and Africa only a small proportion of sewage is treated before disposal (WHO/UNICEF, 1993; WHO, 1996; Bartone et al, 1994). Untreated sewage is a major contributor to highly polluted water bodies in most cities, although it is generally difficult to determine its contribution relative to that of untreated industrial wastes and storm and surface run-off.

Fisheries are often damaged or destroyed by liquid effluents arising from cities. Thousands of people may lose their livelihood as a result as some of the largest cities are close to some of the world’s most productive fishing grounds.

Sewage systems also require large volumes of water to function and, as such, help to build into city sanitation systems high water demands. And although there are many examples of cities where some of the sewage is used for crop or fish production, the proportion of sewage used in such a way is limited by the sheer volume of such wastes and the difficulties (and costs) of transporting them to areas where they can be used productively.

Proponents of the green agenda often point to alternative sanitation systems that do not require sewers. These include many that bring ecological advantages such as requiring no water at all and some that are designed to allow the conversion of human wastes into safe fertilizers, allowing the recycling of nutrients in the food system.

These limit water demand and remove the problem of sewage disposal. Simple sewerless sanitation systems are also generally much cheaper than sewered systems, especially when account is taken of the cost of sewage treatment.

But here there is a serious potential conflict between the brown and the green agenda. Proponents of the brown agenda can point to the hundreds of millions of urban dwellers who currently rely on sanitation systems that do not use water—for instance, pit latrines—which bring serious health risks and often contaminate groundwater.

They often contaminate piped water supplies too, as inadequate maintenance of the piped water network means many cracks and leaks and water pressure is not constant (many city water supply systems have irregular supplies, with water available in many districts for only a few hours a day), so sewage seeps into the pipes.

Pit latrinesOpens in new window can be particularly hazardous in areas that regularly face floods as the pits become flooded and spread human excreta everywhere. There is also the problem in many cities of the lack of services to empty them (or the high price that has to be paid for doing so), while space constraints inhibit provision for solutions which limit this problem — for instance, twin vault systems or larger pits.

There is also the question of cost; in many cities, even a good quality pit latrine within their home (or plot) is an unattainable luxury for many low income households. This includes the large proportion of low income groups who rent accommodation and for whom there is no rented accommodation that they can afford with adequate provision for sanitation.

A stress on sewerless latrines may mean that the importance of adequate water supplies are forgotten (the latrines may need no water, but the households who use them certainly do, including the water needed for washing and personal hygiene).

A stress on dry latrines may also mean that the problem of removing waste water is forgotten; one of the key advantages of a sewer system is that it also conveniently and hygienically removes waste water other than sewerage after its use for cooking, laundry or washing.

Brown agenda proponents can also point to instances where the unit cost of installing sewers was brought down to the point where they no longer far beyond the price that low income households could pay (Orangi, 1995) and to community level sewer systems that do not require high levels of water use and with local treatment which greatly reduceds the ecological impact of the effluents on water bodies.

In assuming that all waterborne sanitation systems have unacceptable ecological impacts, there is a danger of promoting alternative sanitation systems that bring inconvenience, higher maintenance costs and greater environmental risks to the users, or of simply producing latrines that the population do not use.

In short, an excessive reliance on conventional water-borne sewerage intensifies the discrepancies between the brown and green agenda: as a tool of urban environmental management it can reduce intragenerational inequities, but typically at the cost of transboundary and intergenerational inequities.

Undoubtedly there are many instances where extending water-borne sewerage systems is justified, especially in high-density residential areas. There are also the measures that can be taken to reduce greatly the ecological disadvantages of such systems, as noted above.

However, proponents of both the brown and the green agendas can take issue with measures that subsidize sewerage systems for relatively affluent urban dwellers, diverting public funds from low income dwellers and imposing environmental costs on those living downstream and even future generations.

  1. DeSimone, Livio D., and Frank Popoff, Eco-efficiency: The Business Link to Sustainable Development, The MIT Press, Cambridge, MA, 1997.
  2. Curran, Mary Ann, Ed., Environmental Life-Cycle Assessment, McGraw-Hill, New York, NY, 1997.
  3. Fiksel, Joseph, Ed., Design for Environment: Creating Eco-Efficient Products and Processes, McGraw-Hill, New York, NY, 1996.
  4. Leff, Enrique, Green Production: Toward an Environmental Rationality, Guilford Press, New York, NY, 1995.
  5. Peck, Steven, and Elaine Hardy, The Eco-Efficiency Resource Manual, Economic Developers Council of Ontario, Fergus, Ontario, Canada, 1997.
  6. Nemerow, Nelson, Zero Pollution for Industry: Waste Mimization Through Industrial Complexes, John Wiley & Sons, New York, NY, 1995.
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