From: Rethinking Sanitation: Panacea or Pandora=92s=20
Box Steven A. Esrey, Ph.D. sesrey@igc.apc.org International Conference on Water, Sanitation, and =
Health: resolving conflicts between drinking water demands and =
pressures from society=92s =
wastes November 24-28, 1998 Bad Elster, Germany
Sanitation solutions were designed and built on the = premises=20 that human excreta is a waste suitable only for disposal and that the=20 environment is capable of assimilating the waste. Times have changed, = the=20 premises are outdated, and current solutions contribute, either directly = or=20 indirectly, to many of the problems faced by society today: water = pollution,=20 scarcity of fresh water, food insecurity, destruction and loss of soil=20 fertility, and global warming. A common denominator of all these = problems is how=20 society deals with its wastes, specifically how it deals with human = excrement.=20 We have to rethink past premises, design and build new systems, and = contribute=20 to the solving of society=92s most pressing problems.
INTRODUCTION
Last century England and the West pioneered = waterborne sewerage=20 as a means to deal with human excrement. During much of the = 19th=20 century the miasma and filth theories of disease prevailed, so sewerage = was=20 designed to rid people=92s living spaces of organic matter that smelled, = particularly excreta. It was only at the end of the 19th = century that=20 the germ theory of disease began to take hold and influence medical = practice and=20 public health initiatives. At that time, waterborne sewerage was a = panacea to=20 the problem of human excrement and organic waste, and it turned out it = also=20 succeeded in reducing infectious diseases (McKinlay and McKinlay = 1977).
Despite these advances half of humanity live, work = and play on=20 a film of fecal contamination because they have no means of basic = sanitation.=20 Once pathogens get into the environment, some eventually find their way = into=20 drinking water supplies, hands and food. This is a life and death issue, = and=20 "those that survive are left underweight, stunted mentally and = physically,=20 vulnerable to even more deadly diseases - and too debilitated for the = primary=20 business of childhood: learning" (Bellamy 1997).
The other half of humanity attempts to keep pathogens = away from=20 people by depositing human excreta in pits or flushing them off-site. = These=20 solutions, thought to be a panacea for many years, has opened up a = pandora=92s box=20 by creating pollution elsewhere in the ecosystem, downstream from the = original=20 source of the pollution. Over 95% of sewage in developing countries is=20 discharged without any treatment into receiving bodies of water in the=20 environment (World Resources Institute 1998), and pit latrines leak for = a=20 variety of reasons with the contaminants finding their way into fresh = water=20 sources. Even in the West, we still have not solved the problem of = fecal-oral=20 infectious disease transmission.
The purpose of this paper is two-fold: 1) show the = links=20 between current sanitation approaches and many of society=92s problems, = starting=20 with drinking water sources, and 2) propose new ways of thinking about=20 sanitation solutions so that drinking water needs can be met. The paper = will=20 focus on water-borne sanitation, primarily sewerage, because it remains = the gold=20 standard that others want to achieve and emulate.
WHAT IS THE PROBLEM?
Drinking water quality:"Water quality is = deteriorating=20 due to pollution from almost all human activities" (Kuylenstierna et = al.,=20 1998) In 1996, the world=92s human population used an estimated 54% of = all=20 accessible freshwater contained in rivers, lakes and underground = aquifers=20 (Hinrichsen et al., 1998), and it is projected to be 70% by 2025. = This=20 increase only reflects population growth, not increases in per capita=20 consumption. If current trends continue, the world=92s entire stable = river flow=20 would be needed just for dilution and transport of pollutants (Food and=20 Agricultural Organization, 1990). Deteriorating water quality is not = surprising=20 when one considers that any and all chemicals generated from human = activity can=20 and will find their way into water supplies.
Drinking water can become contaminated in three ways: = the=20 source water is itself contaminated, contamination arises during = treatment, or=20 the materials that are used to convey water are contaminants and become = ingested=20 by consumers. The first two pose the largest risk and concern. Until = recently in=20 man=92s history, the pollution was comprised mostly of pathogens from = human and=20 animal wastes getting into source water. Today, the pollution of source = water=20 still includes pathogens from human and animal wastes, but it also = includes=20 industrial, agricultural and pharmaceutical contaminants most of which = did not=20 exist when the current sanitation solutions were developed and = refined.
Sanitation and pathogens: In the USA the = number of=20 water-borne outbreaks and cases per outbreak have been increasing since = 1940=20 (Hunter, 1997), and the causes have remained largely the same - = fecal-oral=20 infectious agents causing gastrointestinal illness, with the exception = of=20 typhoid which has been virtually eliminated. The immediate causes of = these=20 outbreaks were reported to be untreated and/or inadequate disinfection = of ground=20 or surface water. The problem is not confined to the USA. Coliform=20 concentrations in major rivers in Europe have also increased several = fold during=20 this same time. In 1920, the coliform concentration in the River Seine = was=20 <10/100 ml. In 1980 is was nearly 500/100 ml, with a steady increase = over=20 time (Meybeck et al., 1990). South America pollutes almost 11 = times more=20 fresh water per capita than Europe, largely from human waste (Joyce, = 1997). We=20 have failed in the West to keep our waters free of excrement.
Even if we could adequately treat surface or ground = water to=20 meet current water quality criteria, there is a chance that the level of = gastrointestinal illness would still be elevated relative to what could = be=20 prevented if the water was even purer. In a recent study in Qu=E9bec it = was=20 estimated that 35% of reported gastrointestinal illness among tap water = drinkers=20 was preventable if current water quality criteria were more stringent=20 (Payment et al., 1991).
Sanitation and pharmaceuticals: Drugs and = drug=20 metabolites have been found recently in drinking water supplies in = Europe=20 (Raloff, 1998). The only reasonable explanation for their appearance in = water=20 supplies is that they are excreted by humans as they have shown up in = ground=20 water beneath sewage treatment plants in countries that do not even = manufacture=20 the drugs. They have not been looked for yet in the USA or other parts = of the=20 world. The types of pharmaceuticals include lipid regulating drugs = (e.g.,=20 phenazone and fenofibrate), analgesics (e.g., ibuprofen and diclofenac), = chemotherapy drugs, antibiotics, hormones, antiseptics, beta-blocker = heart=20 drugs, epilepsy controlling drugs, and drugs for contrast during scans. = In some=20 cases 50%-90% of the administered drug may be excreted in a biologically = active=20 form, and partially degraded drugs may convert back into an active form = through=20 chemical reactions in the environment.
What do the presence of these drugs and their = metabolites mean?=20 Do they represent a health risk, acceleration of antibiotic resistance, = or=20 damage to ecosystems? These questions are hard to answer at this time, = but=20 recent reports suggest that water pollution from human sewage is = feminizing=20 animals throughout the world, largely through the hormones found in = effluent=20 (Cone, 1998). "Everyday concentrations of sewage effluent in rivers = appear to=20 contain estrogen-like chemicals potent enough to cause fish to be born=20 half-male, half-female" (Cone, 1998). In two of eight rivers downstream = from=20 sewage treatment plants in the UK, 100% of the male fish had feminized=20 reproductive tracts, ranging from severe to slight. The other six rivers = had=20 rates ranging from 20% to 80%. The levels of antibiotics found suggests = that=20 antibiotic resistance could occur (Raloff, 1998). The short term and = long term=20 health risks from this type of contamination remains unknown.
Sanitation and disinfection by-products: = Treatment of=20 drinking water to acceptable standards poses an additional health risk - = cancer.=20 A recent review of drinking water and cancer showed that chlorine = by-products,=20 used to reduce the risk of infectious disease, were associated with a=20 substantial portion of the cancer cases from drinking water supplies. = The=20 by-products of chlorine account for 5,000 cases of bladder cancer and = 8,000=20 cancers of rectal cancer each year in the US (Morris, 1995). There was = an=20 elevated risk with colorectal and liver cancer as well although the = number of=20 studies was small. In the mid-1970's it was discovered that chlorination = resulted in organohalide reactions, and these were suspected to be = carcinogenic.=20 Since then over 400 disinfection by-products have been discovered, and = very few=20 have been investigated for carcinogenicity (Reiff, 1996).
Sanitation and nitrates: Plants need = nutrients, healthy=20 soil, water and sun to grow. Excreta contains valuable nutrients, which = help=20 plants grow, and carbon, which increases water holding capacity and = nurtures=20 healthy soil. Failure to put these nutrients back onto the land has = resulted in=20 the production and use of artificial fertilizers, increased use of = pesticides=20 because we destroy healthy soil, and the need for more water. All of = these=20 nutrients and pesticides eventually find their way into drinking water. = One=20 nutrient in particular has proved detrimental to human health - = nitrates. It is=20 well know that methemoglobinemia occurs from nitrate pollution of = drinking=20 water. A recent investigation found that nitrate-contaminated ground = water may=20 also lead to spontaneous abortion in humans (Grant et al., 1996). = Excretion of=20 nitrate from urine and saliva were correlated positively with the level = of=20 nitrates in drinking water (van Maanen et al., 1996). In over 150 = countries nitrates from fertilizers have seeped into drinking water = (Maywald=20 et al., 1988).
Sanitation and dwindling supplies of fresh = water:=20 Water-borne sanitation requires huge supplies of freshwater to transport = human=20 waste to another location. As the quality and quantity of freshwater = supplies=20 dwindle, it will become increasing more expensive to access and provide = an=20 adequate supply of good quality water. In many parts of the world the = water does=20 not even exist to consider waterborne sewage. Currently, 8% (31 = countries) of=20 the world=92s population have chronic water shortages, and by 2025 there = will be=20 48 countries, or 35% of the world=92s population, experiencing chronic = water=20 shortages (Hinrichsen et al., 1998). Fifty-six countries do not = even meet=20 a minimum recommended daily water requirement of 50 liters per person = per day=20 (Gleick, 1996).
Yet, on average 50 to 100 liters of water are used = daily to=20 flush away 1-1.5 liters of human excreta, or nearly 20,000 to 40,000 = liters per=20 person annually (J=F6nsson, 1997; Van der Ryn, 1995). Most of the water = is used to=20 flush away urine, which is 90% of the waste, but for the most part urine = is=20 sterile. Feces, which poses the significant health risk, weighs 70-140 g = when=20 wet and about 35 g when dry. Effectively, we are using 50-100 liters of=20 freshwater each day to flush away 0.035 kg of dangerous material, a = ratio of=20 1,500 to 3,000 units of water to one unit of dangerous material. We will = be=20 confronted more and more with the choice: use fresh water to transport = excreta=20 away from people or grow food with it. By the middle of next century, = population=20 will increase by 100%, but freshwater supplies will increase by 0%.
Sanitation and food insecurity: One-third of = the world=20 is considered to be food insecure (Esrey, 1997) and nearly 1 billion = people are=20 engaged in urban agriculture, with 200 million producing food for = markets=20 (United Nations Development Programme, 1996). The practice of dumping = human=20 waste into water and off the land, not only depletes soils of valuable = nutrients=20 reducing food production, it also destroys marine life, reducing food = prospects=20 from the sea. Nitrogen loading in estuaries and coastal waters, causing = anoxia=20 or hypoxia in bottom waters, has resulted in significant losses of fish = and=20 shellfish in the Baltic Sea, the Black Sea, Chesapeake Bay, Long Island = Sound,=20 the North Sea and the Kattegat (Vitousek et al., 1998).
In the Czech Republic 70% of all surface waters are = heavily=20 polluted, mostly with municipal and industrial waste. Some 30% of the = country=92s=20 rivers are so foul with pollutants that no fish survive (Nash, 1993). In = England=20 in 1986, oxygen levels in the Thames declined so much from sewage = pollution that=20 oxygen was pumped into the river to prevent massive fish die-offs = (Rapaport,=20 1996). Starting next year, no sewage can be discharged into waters in = England=20 (Dillon, 1998). Half of the nutrients flowing into oceans are the result = of raw=20 or partially treated sewage or other failing technologies (Weber, 1993). = In some=20 regions, like the Pacific Islands, sewage is the single most significant = source=20 of marine pollution. All of the pollution results in nutrient overload, = toxic=20 algae blooms (e.g., red tides), and declining fish catches.
Sanitation and destruction and loss of soils: = By=20 failing to return natural fertilizers to the land, we are depleting = soils of=20 nutrients, ultimately diminishing food supply. In Southern Africa, 20% = of soils=20 need some degree of rehabilitation, and each hectare of cultivated land = loses an=20 average of 22 kg nitrogen, 28 kg of potassium, and 6 kg of phosphorous = annually=20 (Southern African Research & Documentation Center, 1994). This is = the=20 equivalent to the resource value of 30 people - 6 people to replace the=20 nitrogen, 30 to replace potassium, and 15 to replace phosphorous = (J=F6nsson,=20 1997). In addition, hauling manure away from feed lots is = cost-ineffective once=20 the distance exceeds 12 miles (Dr. R. Jackson, CDC/NCEH Director, = personal=20 communication). Of course, other problems specific to agricultural = practices=20 contribute to the loss and degradation of soils (e.g., tilling practices = and=20 density of vegetation), but the inability to utilize natural fertilizers = certainly contributes to the problem as well.
Sanitation and loss of biodiversity: Coastal = water and=20 coral reefs are fragile and are affected quickly by excess nutrients and = lack of=20 sunlight, the result of sewage contamination. Increased nitrates are = toxic to=20 corals, increased phosphates harm coral skeletal growth, and much of the = culprit=20 is human sewage (Hawkins and Roberts, 1994). Prospective anti-cancer = drugs=20 (e.g., Bryostatin 1) are derived from barnacles that grow on coral = reefs. Excess=20 nitrogen fertilization on land results in fewer species surviving as a = few=20 nitrogen-responsive grasses dominant (Vitousek et al., 1998). = Therefore,=20 destruction of one life form may affect the survival and utilization of = another.=20
Sanitation and global warming: At the same = time that=20 atmospheric levels of carbon are increasing, carbon levels in soils are=20 decreasing (Hodges, 1993). Currently, the net loss of carbon to the = atmosphere=20 exceeds the net intake of carbon on earth. Most of the attention has = focused on=20 fossil fuel burning and deforestation, with little attention given to = how human=20 waste is managed. The carbon content of food and fiber exported to urban = and=20 peri-urban areas is of the same order of magnitude as the global net = flow of=20 carbon to the atmosphere (Strong and Arrhenius 1993). A large amount of = this=20 carbon is released as sewage to the aquatic environment, as nearly half = of=20 humanity lives within 50 km of a coastline, and much of the sewage = eventually=20 finds its way into the atmosphere. The potential carbon-building effects = of=20 adding excreta to soils was demonstrated in a experiment begun in 1852, = in which=20 some fields were treated with manure while others were not. After 20 = years the=20 fields that received the manure showed an annual increase in carbon of = 45 g per=20 m2 to a depth of 23 cm, whereas the unmanured field showed a = net loss=20 of carbon. One hundred years later, the manured fields still had greater = soil=20 carbon levels (Jenkinson et al., 1987)
In summary, we divert excreta away from people before = it is=20 sanitized creating potential health hazards. It is transported away from = land=20 into water causing water pollution. Fresh water is used to convey it = consuming a=20 scarce and finite resource to do it. This results in water pollution, = and more=20 pollution is created in an attempt to control the original water = pollution. By=20 diverting nutrients away from land, artificial fertilizers are added to = land,=20 creating even more water pollution. In the end, loss of biodiversity, = global=20 warming and destruction of aquatic life occurs. We must find another = way.
WHAT IS THE SOLUTION?
The old premises must give way to new thinking. The = panacea of=20 the 19th century is turning out to be the pandora=92s box of = the=20 21st century. In the 19th century, there was no or = little=20 concern for the environment. Population growth and density were not a = concern;=20 there was no concept of limits to growth. In addition, people lived = mostly in=20 rural settings, not in crowded urban areas. All of this has changed. The = environment is a major concern all over the world today, water and other = resources are now recognized as being limited, and the majority of the = world=20 will be urbanized by the middle of next century, living within 50 km of = a=20 coastline. The premises have changed, and so must our attitude and = practices of=20 dealing with society=92s wastes.
Sanitation needs to be rethought, and three basic = issues that=20 should be reexamined: waste, pollution, and nutrient flows. There is a = universal=20 feeling that human excreta and products of human activities are wastes. = Human=20 excreta is a resource, not a waste. There is no such thing as a waste in = nature,=20 only in our minds. Waste is nothing more than a resource in the wrong = place. It=20 is not waste that we should dispose of, rather the concept of waste. All = of what=20 we conceive to be a waste, is a food for another process.
"... everything we have to work with is already here = - the=20 stones, the clay, the wood, the water, the air. All materials are given = to us by=20 nature are constantly returned to the earth, without even the concept of = waste=20 as we understand it. Everything is cycled constantly with all waste = equaling=20 food for other living systems" (McDonough and Hawken, 1993).
Our job is to assist this process by putting the = product of=20 human activity in a place and a form to be cycled. Currently, we try to = get=20 excreta as far away from us as possible, using valuable resources to do = this,=20 concentrating them, stockpiling them, and disposing of them in a place = where=20 nature cannot readily use it as food.
Human excrement contains valuable resources. We = produce 4.56 kg=20 nitrogen, 0.55 kg phosphorous, and 1.28 kg potassium per person per year = from=20 feces and urine (J=F6nsson, 1997). This is enough to produce wheat and = maize for=20 one person every year. Most of the plant nutrients in excreta are found = in urine=20 - 88% of the nitrogen, 67% of the phosphorous, and 71% of the potassium, = and=20 these are the major nutrients used in commercial fertilizer.
At the same time, as we rethink the concept of waste, = we will=20 move away from pollution and towards zero discharge. It is not how much = can we=20 discharge and the environment assimilate, but how little can we pollute. = If the=20 resources are put in appropriate places for nature to use them as food, = no or=20 little pollution will result. This aspect would go a long way toward = helping to=20 solve society=92s problems (e.g., loss of soil fertility, destruction of = marine=20 environments, global warming).
In today=92s world we have encountered other problems = for which=20 sanitation was never designed to handle. Sewerage systems were designed = to deal=20 with organic human excrement, but we must find a way to render drugs,=20 antibiotics, hormones and heavy metals innocuous and keep them separate = from=20 plant nutrients.
Nutrients flow in a circular, closed looped, system = in nature,=20 but we perceive of nutrients in a linear, open looped system. By = recycling plant=20 nutrients and putting resources back into the environment where they = serve as=20 food for other processes, we begin to close nutrient flows (Figure 1). = In its=20 simplest form plants, animals and humans exist in a closed loop cycle. = Plants=20 nourish animals and humans, which in turn nourish plants. When we open = these=20 loops, we require food (e.g., artificial fertilizers) from outside the = system,=20 thereby polluting the environment with natural food constituents. Once = one=20 closed loop system is opened, it may force open other closed looped = systems=20 elsewhere in the ecosystem.
=20
In summary,
Human [sanitation] absolutely needs a conceptual = framework ...=20 [Sanitation] does not come as a prepared kit, all cut up and ready to = process.=20 It comes in a flood of jumbled material that needs to be picked over and = sorted=20 out by endless imaginative work. Conceptual frameworks ... must be used = for this=20 ... The cure for bad concepts lies in thinking better, not in = suppressing=20 thought. This situation is similar to the one over censorship. There the = cure=20 for the danger of dangerous facts does not usually lie in concealing = them, but=20 in supplying more and better facts to balance them, and much the same = thing is=20 true of pernicious theories. They get accepted because their faults are = not=20 seen. In order to see them, people need to be exposed to other sorts of = theory,=20 and to learn to discriminate between them (Midgley, = 1991).
In the above quote the word life was replaced by=20 sanitation.
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