API Publ 4665:1998 pdf download

API Publ 4665:1998 pdf download.Analysis and Reduction of Toxicity in Biologically Treated Petroleum Product Terminal Tank Bottoms Water.
As will be evident in the following discussion, this study involved the development of nonstandard approaches to obtaining meaningful data on the nature and removal of toxicity. This section provides an overview of what was done in the study, how it was done, and why the particular methods were chosen.
OBJECTIVES
The objectives of the study were to identify the degree and chemical nature of effluent toxicity in a variety of biologically treated petroleum product terminal tank bottoms water effluents and to explore techniques for cost-effectively removing the toxicity.
DISCUSSION
Water Source. Petroleum product terminal wastewaters can come from a variet
of sources within the terminal (6), but the only source considered in this study was
product tank bottoms water. That was done for the following reasons:
• Tank bottoms water is the major source of organic material in petroleum product terminal wastewaters, and is probably the major source of effluent toxicity.
• tank bottoms water is the only petroleum product terminal wastewater stream inherent to the function of the facility (storage of petroleum products). Other wastewater streams are incidental.
• The flow of many other petroleum product terminal wastewater streams, particularly those derived from storm water (general runoff and loading rack water) are highly variable. Since toxicity is concentration-dependent, dilution by these variable flows will affect combined effluent toxicity. The study was limited to tank bottoms water to eliminate this source of variability.
• The other major source of organic material and toxicity in petroleum product terminals is detergents, which are commonly used on truck loading racks. Since detergent usage is not inherent to petroleum product terminals, it was decided to eliminate this stream from the water being tested. (It should be noted, however, that a facility which has effluent toxicity problems should examine its use of detergents.)
Normalization. All of the tank bottoms waters which were used in the fmal testing were normalized by diluting their COD levels to 4000 mgfL prior to treatment. The reasons for this are as follows:
• The various tank bottoms water samples varied considerably in strength and thus in their inherent toxicity (since toxicity is concentration-dependent). This fact, along with the fact that tank bottoms waters are normally diluted with other terminal waste streams, implies that comparison of the toxicity of various samples is best done on the common basis of wastewater strength.