Stormwater and Heavy Metals

April 7, 2009

Waste Treatment-Metals

Even with the most sophisticated and rigorous best management practices (BMPs), some heavy metals are invariably transported into storm water collection systems.

Storm water discharges into adjacent receiving waters are facing increasing regulatory compliance requirements which include not only additional BMPs, but chemical monitoring programs.

In addition to material selection, placement of the porous adsorber within the storm water system must be given careful consideration.

The engineering literature provides no details on the specific configurations of storm water collection systems typically encountered at a large commercial or Naval shipyard, however, a mix of combined sewers, sanitary sewers and separate storm water sewers would be expected.

Under the NPDES program a permit would be issued to a facility specifying effluent limits, actions to be taken to meet the limits, and monitoring and self reporting requirements for those limits.

The final sections of this report focus on the evaluation and testing of adsorbent materials for the removal of heavy metals from a synthetic saline storm water.

where M is the metal sorbate, S is the solid sorbent and MS is the metal-solid sorbent complex.

For the sorption of metals to the carbonaceous adsorbents we tested, physical entrapment of the metal into internal pores was probably the dominant sorption mechanism (i.e., physisorption).

This capacity is determined by generating an equilibrium sorption isotherm, which is a plot of the equilibrium aqueous concentration (Ceq – mass sorbate/volume of solution) versus the corresponding sorbed concentration (Csorb – mass sorbate/mass sorbent).

Batch adsorption isotherms were determined for Cu2+ with both adsorbents in a synthetic storm water solution of 100 mM NaCl adjusted to pH 6.3± 0.2 with 100 mM Na(HCO3)2.

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