Uncontaminated rainwater

Prevention of waste water from scrap storage The generation of waste water from the storage of contaminated scrap can be prevented by roofing the storage area. The run-off water is collected as uncontaminated rainwater. All techniques for storage are discussed in Section 4.1... 

The presence of SO2 in the atmosphere and the sulfuric acid that it produces result in the phenomenon of acid rain. (Nitrogen oxides, which form nitric acid, are also major contributors to acid rain.) Uncontaminated rainwater is naturally acidic and generally has a pH value of about 5.6. The primary source of this natural acidity is CO2, which reacts with water to form carbonic acid, H2CO3. Add rain, however, is more addic than normal rainwater and typically has a pH value of about 4. This addity has affected many lakes in northern Europe, northern United States, and Canada, reducing fish populations and affecting other parts of the ecological network within flie lakes and surrounding forests. 

If uncontaminated rainwater from diked areas drains into a storm drain or open watercourse the following procedures will be implemented at the facility [ 112.8(c)(3) and 112.12(c)(3)] Bypass valve is normally sealed closed Retained rainwater is inspected to ensure that its presence will not cause a discharge to navigable waters or adjoining shorelines B3 ass valve is opened and resealed under responsible supervision Adequate records of drainage are kept ... 

At tank batteries, separation and treating areas, drainage is closed and sealed except when draining uncontaminated rainwater. Accumulated oil on the rainwater is returned to storage or disposed of in accordance with legally approved methods. [ 112.9(b)(D] ... 

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