Newsletter and Technical Publications
<International Source Book On Environmentally Sound Technologies
for Wastewater and Stormwater Management>
2.2 Collection and transfer (Topic b)
The percentages of people that are connected to the public collection systems
in West Asia region based on 1997 data are presented in Table 2.1. In some
countries like Iran, Yemen, Oman, and the West Bank, only 10-30 % of the
population is connected to the public collection systems. The percentage of
population that is connected to public collection system in the oil producing
countries (Saudi Arabia, Bahrain, Qatar, Kuwait and UAE) ranges from 70-90%.
About 50% of population of the remaining countries (Syria, Egypt, Jordan, and
Iraq) are connected to public networks. The other collection system is septic
tank or cesspools. People in the rural areas and in the countryside use other
facilities such as latrine pit or small- bore sewer, which dispose their waste
into the ground. In some cases septic tanks are associated with field drains.
The transfer of wastewater is always associated with public connection
systems or conventional sewage system. Public authorities manage these kinds of
systems. In almost all West Asia countries, there are no specific national
standards for sewer design. The European and American design standards are
mostly being used. As a result of inadequate development of the wastewater
engineering discipline an ad hoc mix of technologies are used in the region.
Usually wastewater flows into sewer by gravity through different levels of sewer
lines with manholes and inspection stands. Where topography permits, the flow to
the main sewer is by gravity; otherwise wastewater will be discharged into the
pipeline under pressure by a number of pumps.
In Jordan, the collection system consists of sewer pipeline networks that
collect the domestic wastewater from individual household, business, and
industrial connections. The existing policy is that the storm drains should not
to be connected to the sanitary sewer lines. However, in the greater Amman area,
about one quarter of the buildings have storm drain connections to the sanitary
lines. Consequently manholes surcharge and raw sewage outflows in the streets
and basements of buildings during flood rainfall events. The overall hydraulic
capacity of greater Amman collection sewer system is adequate to carry the
wastewater flows for which it was designed. However, problems revealed by the
hydraulic analysis are silt/debris build up and stormwater inflow. For example,
field investigation revealed about 10% of all manholes inspected and 25% of all
pipes inspected contained significant debris build up. The impact of roof drain
connections is significant which will increase the amount of surcharged pipes
during wet weather. The impact of stormwater inflow is pertinent for the major
conveyance system, which is already at full capacity with dry weather flow.
In areas where septic tanks are used, the policy is to collect and discharge
sludge at septage receiving stations. Septage that is collected by tanker trucks
are taken directly to the treatment facilities or septage receiving points. This
policy includes additional cost of the septage to the receiving points. However,
the private users pay the cost of trucking septage. The percentage of septage
water to the total wastewater influent to the treatment plant is in the order of
5-10 %. The difference, which is 30-35%, is either lost from the cesspools
through seepage or being discharged into dump sites or wadis (dry streams) in
close proximity of the source of septage. In areas where treatment facilities
are not in the proximity or close-by, the septage of the cesspools are
discharged into leach fields which are associated with solid waste disposal
sites (dump sites). Examples of that can be seen in most villages and secondary
cities of Jordan, Yemen, and in Egypt to wadis. About 15-20% of the septage is
discharged to sewer or treatment facilities. In some countries, like Oman,
septage should be pre treated before mixing with collected domestic wastewater
but there are no such regulations in other countries. The pretreatment
facilities are in the form of settling tanks.
For industrial wastewater, the current regulations, in almost all countries,
require that industrial and commercial wastewater effluent discharged into the
sanitary sewer system should be protected. Implication of these regulations will
include establishment for pre-treatment standards and construction of
pre-treatment facilities. The construction of the treatment facilities will
require additional financial funding.
In Jordan all branches and sub-mains are made of concrete pipes whereas
pressure pipelines, siphon pipelines, and force mains are made of steel. In
Kuwait, Saudi Arabia, and UAE, sewer lines are made exclusively of asbestos
cement pipes ranging from 8 to 48 inches in diameters. The mains are receiving
sewage from branches and sub-mains and conveying wastewater to main pumping
station by means of gravity or lifting stations or screw conveyors. In cities
like Amman, where mountains and valleys are the main features, a siphon pipeline
and tunnels are used in sections of the mainline.
In areas that are not connected to water supply systems, such as: remote areas
and undeveloped town areas, the volume of water consumption is very little.
In these areas, pit latrines are used and greywater is disposed into the streets
where it forms clogged areas or it evaporates. These spots can be found in the
very poor undeveloped parts of major cities or in some of the refugees' camps
in Jordan or Lebanon. In some rural areas of Yemen, Egypt, Syria and Iran dry
latrines are used and water for other household use are limited resulting in
minimum wastewater disposal.
There is a major concern for wastewater collection and transfer for a large
number of holdings and housing complexes that are increasing near remote coastal
areas or near archeological sites. The efforts in Jordan and Egypt are to have
special collection and conveyance systems or to have for each holding a small
scale treatment plant. The newly developed tourist areas have to be equipped
with on site treatment facilities coupled with reuse systems.