Water and sanitation urban service supply chains – links to small entrepreneurs
When considering the set of actions needed to promote water sanitation, especially in urbanized areas, it is important to realize that the needs go far beyond the problem of providing sanitary services in homes. Human activities take place within a larger context of the whole environment, so that a number of interrelated phenomena must be included. In this short article it is only possible to illustrate the most important of these. To illustrate the nature of the problem, we have chosen to use examples from the United States. In one sense, this may be misleading, because U.S. examples may be hard to apply to other parts of the world. In another sense, the examples show that there are important goals that other nations should strive to attain. It is hard to escape the notion that water problems in the U.S. are of quite a different nature than those faced by nations that must rely on bottled water for simple safety. Therefore, the examples may be helpful in working toward a desired goal.
Content Table
Plumbing
To begin at a familiar point, the map in Figure 1 shows the percentage of U.S. households lacking complete plumbing. While all the percentages are small, it can be seen that the states that are more rural have the greatest needs in this category.
Figure 1: Percent of the Population Lacking Complete Plumbing by State; (Source: Rural Community Assistance Partnership; 2004; Still Living without the Basics in the 21st Century. http://www.rcap.org/resources/basics.html)
Drinking Water
Figure 2 shows a graph of unregulated chemicals in tap water. These stem from all major water-polluting sources. In a highly developed nation like the U.S., it is not surprising that the major tap water contaminants are industrial in origin. In another nation agricultural sources may be much more important. The point is that data of this kind is needed to know what problems are facing those attempting to provide safe drinking water, a major element of sanitation.
Figure 2: Source: Environmental Working Group analysis of water utility test data for 1998-2003, compiled and provided by state drinking water offices; National Tap Water Quality Data Base, http://www.ewg.org
Water Use by Category
Figure 3 shows how water withdrawals in the U.S. are allocated among the major uses. Even in this highly developed nation, one of the major uses is agricultural irrigation. The important point is that public supply for drinking water must be known as a separate number. One of the major problems in some nations is conjunctive use of water sources for all purposes. This can lead to pathways for bacterial and chemical contamination. Creating a separate public water supply is essential for good sanitation.
Figure 3: Trends in Total Water Withdrawals by Water Use Category, 1950-2005.
Kenney, Joan et al, “Estimated Use of Water in the United States in 2005,”
USGS Circular 1344, 2009. See http://water.usgs.gov/watuse/
Ambient Water Quality Impairment
Even with these precautions in place, it is necessary to determine the degree of impairment of water sources. Figure 4 shows the status of U.S. rivers and streams as an example, as determined by the U.S. Environmental Protection Agency. Major programs are in place to alleviate contamination caused by wastewater treatment plants. Agricultural non-point sources continue to be an important problem area, especially for sediment, pesticide, and nutrient runoff.
Figure 4: EPA 305(b) results for Rivers and Streams.
Waterborne Disease
The result of comprehensive sanitation programs should be the reduction of waterborne disease. Figure 5 shows the pattern of outbreaks in the U.S. for many years. If sanitation programs are to be successful, they should show a declining occurrence of outbreaks over time. The argument is again for a data collection program that can document progress as it occurs.
Figure 5: Reported Incidence of Waterborne Disease: Number of outbreaks, etiologic agent, and source of waterborne exposure—1971-1998; Adapted From: Surveillance for Waterborne Disease Outbreaks - US, 1997-1998 (UNICEF, State of the World’s Children).
Accessible at: http://www.cdc.gov/mmwr/preview/mmwrhtml/ss4904a1.htm
A Frontier of Research
Although the field is still developing, mention should be made of the concept whereby wastewater can be used to produce biofuels. The Water Environment Federation (WEF) has been instrumental in promoting this idea, and all the information here can be found on the WEF web site at
http://www.wef.org/AWK/page.aspx?id=2191
In this section we will briefly mention this ongoing effort. The work is now being carried forward by WEF, and may be expected to produce specialty conferences and papers in the future.
In the last few years there has been movement that includes some 50 small companies supported by the Department of Energy (DOE), the Defense Advanced Research Projects Agency (DARPA), venture capital and private investors using algae to produce biodiesel. In addition, both large and small universities and companies are pursuing this opportunity. The potential impacts are great. Many of these companies use strategies that utilize brackish water or wastewater as a feed. However, many problems remain to be addressed, and opportunities may have been influences by over-optimistic press releases. In the 1970s work in this field was conducted in Israel, and at the DOE National Renewable Energy Laboratory in the 1980s-1990s. Present work builds on this foundation.
Hightower (2008) presented background in the Energy-Water Nexus discussion. For example, a number of different water sources can be used for algae production. This includes brackish and saline ground water, produced water from oil and gas wells, desalination concentrate, geothermal water, and wastewater from agricultural, industrial, and municipal sources. Production of biofuels can be carried out at algal photo-bioreactor or pond systems, or from wastewater treatment plants.
Yoshitani (2008) pointed out that although the efficacy of algae for nutrient removal has been known for many years, there is now renewed interest based on biofuel feedstock, CO2 sequestration, and other potential benefits. The main challenge is scalability to economic magnitude. There is significant economic potential in this technology, but full utilization would require a more concentrated R&D effort. Even with the current state of the art, certain benefits of algae can be realized today if goals are clearly defined.
One example that shows what can be done now was provided by Tabor (2008). The Old Dominion University / Virginia Coastal Energy Research Consortium have developed a pilot plant that uses municipal and industrial wastewater. This study is focused on algal biodiesel fuel production coupled to wastewater effluent nutrient reduction and appears to meet its goals.
What are the roadblocks to employing this kind of technology? Ghylin (2008) has described several. First, algae biodiesel technology is on the fringe of the water-environment industry. It is not well known, and would require significant effort if WEF, for example, were to take algae biodiesel from the fringe to a main topic in the water environment dialogue. Second, there is a lack of information, for example published data regarding algae biodiesel production at wastewater treatment plants. This includes both economic feasibility and process design. Third, there is now mostly non-collaborative and unfocused research. Most research takes place in the private sector. There is no central authority that could organize research or influence the distribution of research funds. The potential thus exists for much duplication of effort and wasted money.
This work presents an important connection between water sanitation and energy. Even with advanced wastewater technology, factors like nutrients from treatment plants and agricultural runoff have led to impairment due to algal blooms and hypoxic conditions. This research offers the possibility of capturing the algae before it enters the ambient environment, and in fact turning it into an energy source. The combination of improved water quality and a new energy source would be attractive to many nations. Current research has that aim.
References
Ghylin, T. (2008). What are the roadblocks to producing algae biodiesel at WWTPs right now, WEFTEC’08 Special Session on “Algae - Uses for Wastewater Treatment and Production of Biofuels”, October 18-22, 2008, Chicago, IL.
Hightower, M. (2008). Overview of Biofuels from the Energy-Water Nexus Perspective and the Promise and Challenge of Algae as Biofuel Feedstock, WEFTEC’08 Special Session on “Algae - Uses for Wastewater Treatment and Production of Biofuels”, October 18-22, 2008, Chicago, IL.
Tabor, C. (2008). Algal Biodiesel Fuel Production Coupled to Wastewater Effluent Nutrient Reduction, WEFTEC’08 Special Session on “Algae - Uses for Wastewater Treatment and Production of Biofuels”, October 18-22, 2008, Chicago, IL.
Yoshitani, J. (2008). Intersection of Wastewater and Algae, WEFTEC’08 Special Session on “Algae - Uses for Wastewater Treatment and Production of Biofuels”, October 18-22, 2008, Chicago, IL.
Resources
This article was authored by
Dr. Tim Smith and Dr, Harry Zhang
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