Newsletter and Technical Publications
<International Source Book On Environmentally Sound Technologies
for Wastewater and Stormwater Management>
1.5 Disposal (Topic e)
Only 5% of the inhabitants of Lagos Metropolis, Nigeria are connected to
water-borne system and associated sewerage treatment plants. The plants do not
treat the sewage to acceptable standards, and are poorly maintained and
operated. Open storm water drains are common and in many cases act as open
sewers, particularly for the conveyance of sullage water.
Most industrial wastewater was being discharged directly into water
courses/bodies without any form of treatment. Major stormwater drains are not
maintained. Both secondary and tertiary drains are also poorly maintained, hence
they fail to alleviate flooding. The bulk of wastewater is being discharged
directly and untreated into water courses or the Lagos Lagoon.
The Niger Delta is one of the world’s largest wetlands, encompassing over
20,000km2. The Niger Delta is relatively highly populated and urbanised, and has
serious problems not only with industrial and oil pollution, but with inadequate
domestic waste management. No municipal sewage treatment plants operate in the
Niger Delta. Households, commercial establishments and industries discharge
wastes directly into open drains. Many of the drains are unlined, blocked with
solid wastes, or broken. Untreated urban wastewater is transported via sewage
systems or drains emptying organic matter, including nutrients into receiving
In Port Harcourt (the Niger Delta, Nigeria), dissolved oxygen levels in some
rivers are very low and no longer able to support even herbivorous fish. High
density areas of the city also have elevated levels of total solids, chloride
and turbidity. Urban wastewater also contains industrial effluents, and
household pesticides released into common drainage or sewerage systems. Water
supplies are often degraded from the practice of laying water pipes in open
drains or near soakaway pits, and constructing shallow wells near poorly
maintained drains. Consequently, health risks associated with sewage
contaminated water are highly significant and affect a large proportion of the
urban population in the region, since there are no sewage treatment facilities.
Plans are afoot to remedy the anomalous situation in this oil producing region.
The average wastewater flow for Lagos metropolis is only 115 l/c/d (compared to
Cairo where it is 310 litres/day). In 1995 the total wastewater emptied into
Lagos Lagoon was 811,300 m3 per day, of which domestic wastewater accounted for
54%. The volume of wastewater generated is expected to increase to 1,663,090 m3
per day by 2010 (Harrington, 1996).