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United Nations Environment Programme
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Newsletter and Technical Publications
<International Source Book On Environmentally Sound Technologies
for Wastewater and Stormwater Management>

5. America (Central and South)

5.0 General introduction

This regional Overview covers the countries that comprise the South and Central America Region Country names and associated populations, in the year 1995, are given in table 5.1 as follows:

Table 5.1: Countries in South and Central America Region and Populations.
Country Population (in 1000’s)
  Total Urban Rural
Argentina

34,587

30,152

4,434

Bolivia

7,061

4,320

2,741

Brazil

161,790

126,190

35,594

Chile

13,951

11,823

2,128

Colombia

35,886

26,491

9,395

Costa Rica

3,330

1,441

1,859

Ecuador

11,460

6,944

4,516

El Salvador

5,310

2,685

2,625

Guatemala

10,621

4,108

6,513

Honduras

5,462

2,425

3,037

Mexico

91,606

66,396

25,210

Nicaragua

4,139

2,138

2,001

Panama

2,630

1,412

1,218

Paraguay

4,564

2,297

2,267

Peru

23,468

16,445

7,021

Suriname

410

263

147

Uruguay

3,129

2,820

309

Venezuela

21,844

18,656

3,168

Total

349,642

260.610

88.973

In general terms it may be stated that the difference between the wastewater sector in South and Central America (S&CA) and developed countries is somewhat proportional to differences observed in their economic (and perhaps, "pour cause" educational) capacities. However, digging a bit deeper, evidence would also suggest that the internal disparities and the enormous income concentrations existing in S&CA have produced a small core number of capital cities and other important cities bearing a reasonable wastewater collection infrastructure. Even so many of these cities do not possess treated wastewater outlets to the environment, or as the case may be, reasonably well operated marine outfalls.

Cities of developed countries take into consideration, for instance, the availability of infrastructure, wastewater collection facilities (and sludge hauling and soil infiltration in case of on-site options) included, as a given. The major problem in the developed world is how to optmize final destination, environmentally speaking, of wastewater and sludge. In turn, in S&CA most efforts are still concentrated, and in some cases yet to be concentrated, on the provision of wastewater collection systems. In other words, in the Region problems persist in relation to questions of public health and sanitary engineering rather than environmental engineering. The vast majority of the water utilities of S&CA are still investing and getting loans for increasing their water coverage or, at most, increasing their sewage collection rate, with likely heavy downstream environmental hazards in the future resulting from more wastewater discharged to the environment. It is fair to say that in S&CA, exceptions apart, adequate wastewater disposal still faces a significant leap from the good will and intentions and engineering plans of some to reality.

While questions relating to wastewater in S&CA are crucial, and some decision-makers and institutions are searching for tools to improve the situation, there are other factors which make the situation more complicated. Two main components include (i) plumbing facilities and (ii) stormwater collection and disposal. In the former case, a significant number of households in S&CA still do not possess an adequate bathroom, which can have a number of health and environmental implications. In the latter case, quite frequently the mere existence of drainage systems provided simultaneously with the street paving, thus being available prior to the wastewater infrastructure, can produce very negative health impacts. It will surely be used to carry clandestine sewage that can contribute to accelerated local oral-fecal transmission. Drainage has been carried by municipalities at no tariff or charge, with the negative foreseeable result, of an unmanageable sewage/storm water mixture producing enormous environmental hazards at the outlets and their surroundings.

It might also be important to establish the public health/sanitary and environment benefits associated with the list of recommended sanitation technologies. Very little has been written on the subject and many people still mix up the positive sanitary benefits of laying down sewer pipes for unserved communities and the concentrated pollution resulting from a single non-treated outlet to the receiving body. So, for non-used watertables the adoption of on-site sanitation may be stressed as not concentrating pollution though still concentrating sludge effluents for disposal. This is part of the effort required in the Region to educate decision makers and engineers.

Using developed world water and sewerage companies as a model; water and sanitation companies in the Region take their limit of work before the household as the pathway manhole. In the developed world this is quite right as it may be taken for granted that housing plumbing facilities exist and are in adequate condition. Furthermore, it is expected that housing connections are also workable. In parallel, it may also be stated that whenever septic tanks serve the developed world households it is expected that the sludge generated will be cleaned out into vacuum trucks and from them it will be pumped out into sewage treatment plants' anaerobic digesters.

In turn, let's assess what happens quite often in S&CA. In the affluent urban areas good plumbing facilities exist and the yards of households are usually adequately drained out. Septic tanks, when available, maybe well served at the household level, except for the fact that most of the times the servicing company does not provide a preventive care but attends an emergency call from the householder "because the septic tank is overflowing to the yard". This means that sludge has already left the septic tank and invaded the soakaway, clogged it and then overflown. At this point the soakaway’s life span will have been dramatically reduced. Doubts still remain about the sludge disposal point, quite frequently being a close, clandestine dumpsite. When the focus is on low-income settlements the typical case is as follows: toilets and plumbing facilities are inadequate or virtually non-existent; and when existent they leak out quite a lot, thus calling for immediate public health agency action. So this is why in the non-developed world the water and sanitation companies must be completely redesigned so as to encompass a frequent house assessment, perhaps to be made by the water meter reader (monthly visits) who may also check plumbing facilities.

Last decade, in Brazil the World Bank/UNDP Low-Cost sanitation Project through its Technology Advisory Group (TAG), led by a Consultant, worked with the private sector to make the so-called low-water volume toilets (VDR) available in the market. The major impetus for the marketing of the system included the development by the State of Săo Paulo Technology Research Institute (IPT) of a cistern tank VDR; insertion to the toilet design code of the characteristics of a VDR (maximum 5 litres per flush); and distribution to the market by three manufacturers of around 400.000 VDRs. At the same time in Colombia Messrs. Mancesa developed the pour-flush toilet type "taza campesina" which has served Colombia and Central American countries in various successful sanitation projects targeted at low income areas. Unfortunately given lack of Government’s support the manufacturing of VDRs in Brazil has been discontinued, a fact that may be reversed as a result of the recently-launched National Water-Saving Programme; in turn MANCESA have evolved the model for a design closer to the conventional toilet, though keeping its water-saving characteristics.

5.0.1 Health aspects

Given the above framework it is understandable that diahorrea in its various modes still afflicts S&CA. In one way or another the following transmission sources and associated diseases are noticeable, following PAHO reports:

  • Oro-fecal transmission: a wide range of diahorreas, that include (i) cholera, being noteworthy the recent outbursts occurred in Peru and Brazil, (ii) salmonelosis, (iii) diahorreas caused by giardia, escherichia coli, ameba and rotaviruses.
  • Caused by lack of water and poor hygiene practices: skin and eye infections, flee-transmitted typhoid fever.
  • Water-related diseases such as schistosomiasis and leptospirosis, the latter always occurring after seasonal floodings in low-lying areas, examples from recent floodings occurred in Central America countries.
  • Vector-transmitted diseases (vectors that either breed in water or attack near water bodies): malaria, filariosis, dengue (which has recently been recognized in almost the whole Region), leishmaniosis and yellow fever.

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