State of Waste Management in South East Asia
The sources of industrial wastewater are mostly agro-based industries, including
animal farms, and the manufacturing industries. In many of the ASEAN countries,
this industrial wastewater may include domestic sewage.
Malaysia has identified 16 types of manufacturing processes that contribute
to industrial wastewater discharge. The main polluting sources are the food
and beverage industry (23.7 percent), followed by electric and electronic industry
(11.4 percent), chemical based industry (11.2 percent), paper (8.8 percent),
textile (7.4 percent), metal finishing & electroplating (5.3 percent),
crude palm oil mills (5.3 percent) and raw natural rubber factories (2 percent)
(Ref. Malaysian Department of Environment Environmental Quality Report, 2000).
In the absence of available specific data, it is fair to assume that there
would be different sources of wastewater in the other ASEAN countries based
on the types of industries present there. Unfortunately there are no databases
provided in most of the developing nations for identifying the main industrial
wastewater sources and quantities generated. Some countries include leachates
from landfills as industrial wastewater.
Discharges from industries are extremely variable in quantity and characteristics,
and have been largely contributed to substantial deterioration of water quality
in the rivers, lakes and other receiving water bodies, since there has been
little or no treatment of the wastewater at all. This situation is affecting
the availability of clean water supply whether from surface water or ground
Storm water quantities are generally estimated from the precipitation-evaporation
rates of each country. ASEAN countries lie in the tropics and generally experience
high rainfall compared with other regions in the world. However, there can
be wide variations depending on location. Mandalay in Burma experiences rainfall
of from 661mm to 1024 mm annually. Kuala Lumpur, Malaysia, has an average annual
rainfall of about 2500 mm.
Singapore has an estimated storm water runoff of 770 million cubic meters
annually (1990-2000 data). Malaysia has a total estimated average runoff of
566,000 million m3 annually (1997). From the precipitation-evaporation data
of each country it will be possible to estimate the respective quantities of
storm water runoffs.
Storm water could be collected from house roofs, paved areas and roads, and
could carry solids depending on how much debris and pollutants lie in the path
of the runoff. Storm water drainage in most urban areas would generally consist
of roadside drains leading ultimately to natural streams, rivers and other
bodies of water.
In most cases the pollutant load of storm water would be lower than that of
other types of wastewater. However, water in the drainage system may inevitably
be contaminated with fecal matter from latrines and coliform septic tank effluent,
presenting direct health risks. Poor drainage may result in flooding as well
as cause stagnant pools of water - both further contributing to health risks.
In Malaysia some of the problems encountered due to storm water runoffs include:
- Construction cavities and mud flows
- Flash flood
- Water pollution and ecological damage
- Urban slope failures
- Traffic disruption and accidents
- Surcharges and overflows from wastewater facilities
- Garbage and floating litter
These problems are particularly prevalent in major zones of urbanized and
urbanizing centers and new socio-economic growth areas.