Azura-Edo Independent Power Plant Environmental Impact ... - IFC

Liquid Effluents
Both oily water and chemical waste water effluents will be generated by the
power plant operations. Effluents generated will include backwash effluent
from pressure filters, regeneration effluent from the demineralisation plant as
well as other chemical laboratory wastes, battery waste water, gas turbine
compressor wash water and sludge. Further details of the effluents generated
are provided in Table 3.3 below.
Table 3.3
Details of Effluent Generated
SI.
No
Waste
Water
Source
1. Chemicals Bulk chemical
drains in
water
treatment
plant
Characteristics\
Contaminants
Various
chemicals
Disposal Method
Fed into the neutralisation pit, treated with
acid/alkali and transferred to the central
monitoring basin.
Effluent (containing detergent, dirt and oil)
from the gas turbine compressor on-line and
off line wash and exhaust plenum drain will
be fed to the wash water recovery pit. It
will then be passed through the oil water
separator and disposed by pumping to
tankers.
2. Oil in
water
Lube oil and
transformer
oil mixed
with water
from
transformer
yard, gas
turbine water
wash drain,
diesel fuel
from oil tank,
oil water run
off and drains
Oil contents: 500
– 10000 ppm (in
case of fire),
pH:5-9,
Suspended
solids:0-30 ppm
This will be collected into an oily water
capture basin and pumped into tankers for
disposal offsite and the water effluent will
be pumped into an oil water separation tank
for secondary treatment.
The oil separation tank will collect oil by an
oil skimmer, which will then run into the oil
holding tank and will be transferred to a
tank truck for final disposal offsite. The oily
wastes will be disposed of at a registered
waste disposal facility. Heavier suspended
solids will settle at the bottom of the
separation tank and this sludge will be
removed via the sludge tank and disposed
to sludge drying beds. The treated effluent
from this oil separation tank will be led to
the central waste water monitoring basin
before final discharge. Effluent discharge
will be as per Nigerian and World Bank
requirements.
The oil removal from the catch basin, sludge
disposal, gas turbine wash water and lube
oil drain disposal shall be done manually by
using portable sump pumps.
AZURA EDO IPP
3-13
DRAFT EIA REPORT