Taking advantage of storm and waste water retention basins as part of water use minimization in industrial sites

A methodology for water use minimization has been developed by the Clean Technology Network of Bahia over a 10 year period in joint cooperative programs with the chemical, petrochemical and copper metallurgy industries located in the largest Industrial Complex in Latin America, in Camaçari, Bahia, Brazil. The methodology comprises a set of tools including reconciled aqueous stream balances, database of aqueous streams; large scale training leading to the identification of water minimization alternatives in the processes, water reuse optimization approaches; geographical information systems as well as, consideration of the region's hydro and hydro-geological characteristics. The results of a study carried out to assess the possibility of using storm and wastewaters for industrial use is presented in this paper. The inorganic system is composed by three water reservoirs (basins) receiving stormwater contaminated with inorganic effluents, and occasionally with organics. These basins have been operated to control water flow inputs according to the capacity of the pumping outlet systems before their discharge to a submarine outfall. A mass balance was performed with historical updated data to assess water availability from the basins based on the daily volume variation and flow rate of inorganic effluent from 2001 to 2007. The study identified the possibility of recovering about 1140 m3/h of the overall 5400 m3/h consumed by the Industrial Complex at the moment. Organizational changes in the present effluent disposal and stormwater harvest systems will be required in order to maximize water recovery for industrial use.