Appropriate water supply and sanitation technology for developing countries in tropical monsoon climates

Summary In the past, the water supply and sewage services for the urban regions of developing countries have been provided, in the main, only for the more affluent areas of these cities. This paper, dealing especially with those countries with tropical monsoon climates, advocates the construction of more comprehensive systems.Experience drawn from a wide range of projects and a review of the relevant literature provokes the authors to emphasise the need for suitable manuals of appropriate technology for use in these developing countries. These manuals should provide a full set of environmental guidelines for the design of water supply and sewage/sanitation systems for use in these countries.Dr Harvey F. Ludwig is Chairman and Greg Browder is Environmental Engineer for SEATEC International Consulting Engineers, Bangkok, Thailand.     

The Truth about Public Health Protection and Community Sewerage and Water Supply Sanitation in Developing Countries

Since the establishment, following World War II, of the World System, by which the affluent industrialized countries established various international assistance agencies (including the multilateral development banks, UN affiliates, and Bilaterals), these assistance agencies have invested very large sums in helping finance planning and construction of community sewerage and water supply facilities in the developing countries. However, much of this large investment has been ineffective and wasted, primarily because of the lack of understanding by the staff of the assistance agencies that the design criteria for the facilities must be modified to suit the socio-economic status of the developing country. The developing countries are relatively very poor in terms of available finances, hence cannot afford to emulate Western environmental standards and design practices, especially as related to operation and maintenance, hence much simpler approaches must be used. Experiences in several Asian countries are discussed, and a recommendation is made on how to go about resolving this problem.     

Modelling the resilience of Australian savanna systems to grazing impacts.

Savannas occur across all of northern Australia and are extensively used as rangelands. A recent surge in live cattle exports to Southeast Asia has caused excessive grazing impacts in some areas, especially near watering points. An important ecological and management question is "how resilient are savanna ecosystems to grazing disturbances?" Resilience refers to the ability of an ecosystem to remain in its current state (resist change) and return to this state (recover) if disturbed. Resilience responses can be measured using field data. These responses can then be modelled to predict the likely resistance and recovery of savannas to grazing impacts occurring under different climatic conditions. Two approaches were used to model resilience responses. First, a relatively simple mathematical model based on a sigmoid response function was used. This model proved useful for comparing the relative resilience of different savanna ecosystems, but was limited to ecosystems and conditions for which data were available. Second, a complex process model, SAVANNA, was parameterised to simulate the structure and function of Australian savannas. Simulations were run for 50 years at two levels of grazing to evaluate resistance and then for another 50 years with no grazing to evaluate recovery. These runs predicted that savanna grasslands were more resistant to grazing (changed less) than red-loam woodlands, which recovered relatively slowly from grazing impacts. The SAVANNA model also predicted that these woodlands would recover slightly slower under the climate change scenario projected for northern Australia.     

Umweltindikatoren für Immissionswirkungen

“In contrast to other fields of politics, a few, minor measurements (indicators) are still lacking in the environmental policies which enable one to evaluate the environmental situation and to consequently take over a major role in political discussions” (BMU 1998). There are a multitude of suggestions for such environmental indicators on both a national and an international level. To date, however, there are still no indicators through which the ecological effects of biosphere pollution can be evaluated. This work provides two examples how biomonitoring data can be connected to environmental indicators. Based on the background concentrations of a multitude of heavy metals and dioxins/furans in two individual bioindicators (standardized grass and kale cultures), which have been combined to act as indicators for the topic in question, indices have been calculated through the determination of reference values. The results are indicators for the pollution effects of traffic-related emissions, the pollution effects from the emissions of fossil fuels and the pollution effects of dioxins and furanes. These indicators may still be combined further through the methods of calculation which are described. The further, methodical development of bioindicators, however, turned out to be problematic. Only data whose survey methods have been standardized to such an extent that the results are comparable with each other over longer periods of time can be combined to represent indicators: an inalienable requirement for the presentation of trends.     

Biomonitoring verkehrsbedingter Platin-Immissionen

Traffic related platinum deposits on, or near to, the roads. Platinum accumulation was studied using the method of standardised culture of grass (Lolium multiflorum) at locations with different traffic exposure in the region of Munich. Grass cultures from 6 locations with high traffic exposure, and 3 reference locations far away from traffic emissions, were analysed in 1992 and 1993. The results show a good indication of the platinum emissions byLolium multiflorum. The platinum concentrations rose with the increasing traffic. They diminished with growing distance from the verge of the road. The highest average platinum concentrations were measured at locations close to highly frequented urban roads, in the range 0.8 to 2.9 μg/kg dm. The average platinum concentration at locations far from emissions was found in the range of 0.17 to 0.51 μg/kg dm in 1992 and 1993. The good correlation between the platinum concentrations in grass cultures and the concentrations of other traffic-related elements, like antimony, chromium and lead, verifies the dependence of platinum accumulation from traffic.     

Empfehlung des Länder-Arbeitskreises “Bioindikation/Wirkungsermittlung” für die landesweite Erhebung von Immissionswirkungen mit Bioindikatoren

The working group on “boindication/assessment of effects” is made up of specialists active in the fields of bioindication and emission ecology for the German Federal administrative offices concerned with the protection of the environment and for the Geman Environmental Protection Agency. In April 1996, this working group adopted the recommendation for a “countrywide survey on the effects of emissions using bioindicatiors”. The goal of this national survey is to determine the geographic distribution and the development over time of such emissions, as well as to document the effects of background emissions. In order to achieve these goals, the development of national measuring networks and permanent observation stations is mandatory. A minimal demand of investigations and of investigative procedures is required in order to compare the results of the individual Federal States and to consequently combine these findings as an overall picture for the entire Federal Republic of Germany. Mosses and lichens are recommended for passive biological monitoring, while standardized grass cultures, kale, stinging nettle and tobacco are suggested for active biomonitoring. In addition, detailed methodical recommendations concerning the use of standardized grass cultures and kale are discussed.