Hi Marcus, If you are ...
Published by Deepak Kharat (Dr), Technical Specialist - Flood & Water at Waterco Consultants, UK
Hi Marcus,
If you are referring to LFZDC's Lekki Free Trade Zone (SW Quadrant) then the area is 16,500 ha with 285 ha planed as waterbodies (canals) connected to the Lekki Lagoon. The planned waterbodies will divide the island into eight catchments.
In lieu of any WQ standards by the Nigerian Authorities, the planned waterbodies were proposed to comply:
a) The Water Framework Directive of the European Union (2000/60/EC) which provides guidelines on the minimum water quality standards required for the protection of aquatic ecology in all surface waters,
b) The Bathing Water Directive of the European Union (2006/7/EC) which provides guidelines on the microbiological standards for recreational waters, and
c) The World Health Organization (WHO) guidelines on the drinking water quality standards for the safety of human health.
Only one STP is planned. The following effluent characteristics were given.
Expected sewage treatment plant pollutant concentration values
Water quality parameter | Average values used at the sewage treatment plant |
DO (mg/l) | 1 |
BOD (mg/l) | 30 |
TDS (mg/l) | 200 |
Nitrates (mg/l) | 20 |
Ammonia (mg/l) | 0.6 |
Ortho-phosphates (mg/l) | 5 |
Faecal coliforms (no/100ml) | 400 |
Lead (mg/l) | 1 |
Copper (mg/l) | 1 |
Nickel (mg/l) | 1 |
Iron (mg/l) | 20 |
Manganese (mg/l) | 5 |
Zinc (mg/l) | 1 |
So you will have to find solutions to treat the industrial and domestic wastewaters to meet the above criteria as a minimum.
As regards to the water supply: Lekki Lagoon is a freshwater body and the water supply is expected to be sourced from this. So the treatment plant for water supply will be required to treat this water to potable standards. Saltwater intrusion was found not to be an issue.
I am posting the above as this will help others to help you find appropriate solutions. All the best.
1 Comment
The average values used at the sewage treatment plant you listed apart from Faecal coliforms (no/100ml) 400 and other metals concentration, is for potable/drinking water not for wastewater
Published by Ramsey Haddad, Director at Free Radicals TEchnology
1 Comment
These were the characteristics of the effluent given by the project authorities. If Marcus has been given a different set, he will have to check against your advice and see if it is a realistic target. WQ standards in Nigeria seem to be not agreed upon.
Published by Deepak Kharat (Dr), Technical Specialist - Flood & Water at Waterco Consultants, UK