COM 0212.453 1996-1998 - Laserfiche WebLink

Home

i simply getting rid of it; they fail to recognize the solid waste is not collected. This combination of waste as an economic asset. Because soil nutrients cazeless waste disposal and unprotected water for ate continuously exported from the fields where they drinking and bathing has deadly consequences. grow to the dinner tables ofcity-dwellers, farmers aze Even a small disparity between the amount of forced to rely on petroleum-based fertilizers to org<tic waste produced by a city and the amount / replenish them. However, these manufactured fertil- pruperly disposed of can nun into a disastrous back- t izers do not contain all the constiruents net?ssary for log. In the city of Surat in western India, the 2.2 mi~- healthy soil (they lack the organic natter and lion residents generate 1,250 metric tons of waste microorganisms provided by natural compost, for each day, but only about 1,000 tons of that is col- j example), and continued reliance on them ultimately lected. Every day, as a result, the amount of uncol- diminishes the soil's fertility. lected garbage piling up around the city increases by ~ Meanwhile, the prevailing means of "getting rid" another 250 tons. In September, 1994, Surat was struck by an epidemic of plague. Authorities found one cause of the our break to be the numerous heaps of r i ~ trash, which provided an ideal habitat for the rats that carry the plague infec- _ don. But even when wastes are collect ed, the likelihood is that they will be dumped without any sort of treatment, overwhelming the capacity of local ~ ecosystems to absorb them. In the _ ~ developing world, some 90 percent of '1r- ~~r all sewage is discharged-along with the fecal coliform bacteria that cause intestinal diseases-directly into rivers, lakes, and coastal waters. These conta- ~ / minants not only disrupt aquatic ~ ~ ecosystems, but can get into the food ~ chain and evenrually make their way ~ ' A ~ back to the people living in the city. i , I {vl The nutrient cycle, instead of becoming an ecologically closed loop, becomes a short-circuited one. In Hong Kong, for ~ example, raw sewage from the citt•'s 3.1 r"~r'~ million inhabitants flows directly into Victoria Harbor, causing shellfish cont- aminadon That led in 1988 to a hepati- tis epidemic afflicting nearly 1,400 peo- ple. It is possible, instead, to restore the of the wastes tends to concentrate them in ways that organic nutrients in urban wastes to their proper wreak havoc with local ecosystems. As urban popu- place-the soil-and continue to utilize them to pro- ladons expand faster than the support systems that duce the food needed for urban consumption. By make cities work, the unmanaged wastes also consti- reusing wastes for local agticulrural production, cities rute a growing threat to the residents themselves. An can become more sustainable, retaining their pro- ' estimated 70 to 95 percent of all new residents in the ductive capabilities without causing contamination of tides of the developing world are illegal squatters, nearby land, air, or water. the majority living in substandard housing without Reusing urban wastes can take a variery of forms. access to such basic necessities as water lines, sewage Human sewage, euphemistically called nightsoil, systems, and trash collection. According to the when treated becomes a rich fertilizer that can be World Resources Institute, in 1994 at least 220 mil- applied to agricultural fields. Using nightsoil as a fer- lion urban dwellers lacked a nearby source of potable tifizer is an important component of China's inte- water, while more than 420 million did not have grated urban agriculture system. For example, in access to even the simplest latrine. In the cities of the 1991, Shanghai was collecting 90 percent-about developing world, an estimated 20 to SO percent of 8,000 tons--of the city's human waste each day, i~a rid lPo¢h•NOVCmb<r/December ~