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Big cities with little sanitation infrastructure can easily be
swamped by human waste. In Jakarta, with a population of
nine million people, less than three per cent of the 1.3 million
cubic meters (enough to fill more than 500 Olympic swim-
ming pools) of sewage generated each day reaches a treat-
ment plant – there is only the capacity to process 15 swimming
pools’ worth. Compare this to a city like Sydney, with a popula-
tion of four million, where 100 per cent of urban wastewater is
treated to some degree. Sewage treatment plants process 1.2
million cubic metres per day (each person in Sydney produces
nearly three times as much wastewater as a person in Jakarta).
In Jakarta there are more than one million septic tanks in the
city, but these are poorly maintained and have contaminated
the groundwater with faecal coliform bacteria. When tanks are
emptied their contents are often illegally dumped untreated
into waterways (Marshall, 2005). Jakarta has a network of ca-
nals, originally built to control flooding but these have been
partially filled with silt and garbage. This coupled with severe
subsidence due to groundwater water extraction (60 per cent
of residents are not connected to the water grid so rely on
wells), results in increasingly severe flooding. Flooding and
stagnant stormwater create conditions for mosquitoes and
the incidence of dengue fever and other water related diseases
such as diarrhoea and leptospirosis is increasing.
Sanitation in big cities
Figure 8:
Case study to compare two urban centres.
1.2 million
cubic metres
1.3 million
cubic metres
Sanitation sewage and treatment in big cities
Two study cases:
Jakarta
Sydney
1 million people
Portion of sewage that
reaches a treatment plant
Daily generated sewage
3%
Almost
100%
Sources: this report.