Newsletter and Technical Publications
<International Source Book On Environmentally Sound Technologies
for Wastewater and Stormwater Management>
2.1 Wastewater characteristics (Topic a)
The characteristics and volume of wastewater in West Asia countries depends
upon the water supply coverage, availability and cost. Due to the shortage of
water, the volume of wastewater produced per person is smaller than that
produced in the European countries. Water consumption for most of the West Asia
is low and it is estimated to be around 100 liters per person per day. As a
result the concentration of the physical, chemical, and biological consistuents
will be higher, in cases where sewer systems are available. In rural and poor
areas the situation is completely different. The availability of minimum
sanitation facilities and very low water consumption rate coupled with the lack
of collection system affect to a great extent the wastewater characteristics.
The degree of urbanization and industrialization and the disposal of industrial
and stormwater to domestic sewer network will also affect the characteristics of
Wastewater production and characteristics vary from country to country, from
rural to urban areas and from city to city. The coverage of sanitation
facilities and sewage networks is greater in oil producing countries; and
greater still in major cities compared with secondary cities and rural areas. In
urban areas, the sanitation services cover more than 85% of the houses while in
rural area the coverage is only about 25% (Table 2.1).
Table 2.1: The population of West Asia countries, percent
of urban population, percent of population connected to sewer systems, domestic
and industrial water
supply, and volume of wastewater produced and portion used in irrigation
The organic, solids and nutrients loading of the wastewater in the West Asia
region vary from country to country and vary also according to location within
the country and with time. Table 2 shows typical wastewater characteristics
in some selected countries of the region. The 5- day biological oxygen demand
(BOD5) ranges from 280 to 570 mg/L with an average of 530mg/L; total
suspended solids (TSS) ranges from 300 to 700 mg/L with an average of 453 mg/L;
the ammonia - nitrogen (NH4- N) ranges from 45 to 110 with an average value
of 75 mg/L. These values are very high when compared with the average US concentrations.
It can be noted that a significant portion of the salinity loading in the wastewater
is associated with the background salinity in the water supply.
The high concentration of these pollutants characterize the sewage of high
strength wastewater which are typical of areas in which water use rates are
moderately low. Dividing the observed wastewater concentration by the per capita
water consumption rate (which is around 100 lpcd) gives typical loading for
organic, solids and nutrient composition of wastewater (Table 2.2).
In some locations (poor urban areas and refugee camps), the concentration of
pollutants is very high where TSS exceeds 3000 mg/L. The situation is also
different in areas that are not connected to the public sewage network or in
rural areas. Most of them use on-site sanitation technologies such as pit
latrines, pour flush toilets and septic tanks. The septic tank is the most
common method where a sealed concrete chamber receives all household wastewater.
Table 2.2: Wastewater characteristics and per capita loading of most
countries in the West Asia region
||Water consumption (Lpcd)
||Per capita Loading g/c-d
Special tanker trucks are available to empty and dispose the sludge to
wastewater treatment facilities or receiving points.
In practice these septic tanks are not completely sealed allowing more
infiltration into the ground, which produce a very high strength wastewater. The
black water that is disposed of in latrines is all allowed to decompose in the
pits. Usually, when these pits are filled, they are sealed and enclosed and new
pits will be dug.
Non sewered areas of Jordan, Lebanon, Syria, the Gulf States and partly Egypt
and Iraq use septic tanks or cesspool. The main risk in their use is the seepage
to groundwater, specially if the water table is shallow or these pools are
excavated in limestone formation.
The disposal of industrial wastewater to the public wastewater network is
very limited for two reasons. First; many countries like Jordan, Saudi Arabia,
Egypt, and UAE do not allow industries to dispose their wastes to public
wastewater network unless they comply with certain standards and must be
compatible with the sewage treatment system. Second, most of the West Asia
countries are considered non-industrialized countries with the exception of
Egypt, Iran, and Iraq. In addition, most of their industries are light and
concentrating on food processing, dairy products and soft drinks. Other
industries that produce material wastes such as paper, steel, cement, paint,
chemical, fertilizers, and plastic are not allowed to discharge their waste to
the municipal sewer. Instead they must have their own treatment plants and
recycle or reuse their wastewater on-site. Hazardous industries are encouraged
to treat and dispose their wastewater through evaporation, drying and
incineration. In some industrial areas near Amman (Jordan) and Damascus (Syria)
and Cairo (Egypt), the high concentration of TDS, COD, and BOD are the result of
a much higher fraction of industrial waste that are allowed to be discharged in
the waste stream. In Jordan, Saudi Arabia, Egypt, and UAE the dairy processing
and paper industry treat their wastewater on-site and recycle the effluent or
reuse it for agriculture.
In many countries, e.g. Egypt, Jordan, Saudi Arabia, Syria, and UAE, the new
planning policy is to confine industry to what is called industrial cities.
These cities are equipped with sewer pipeline networks and treatment facilities.
Depending on the type of effluent of each industry, a pre-treatment facility is
Not all major cities in the southern part of the region are equipped with stormwater
drainage systems because of rare rainfall events. One or two rainfall events
in Cairo do not justify construction of stormwater sewer networks. Only some
major and coastal cities in the region are provided with these networks. Where
such facilities exist they are separated from the wastewater sewer system except
Tehran (Iran) where both networks are connected. The Jordanian legislation does
not allow stormwater connection to the main sewer network.