Questions for Thinking and Discussing

Go to the Web and develop a list of suppliers along with unit costs for some of the various types of flocculants described in this chapter. Also obtain the MSDS (Material Safety Data Sheets) for these chemicals. Once you have collected the information, develop a relative ranking of unit cost and health risk associated with each. For question 2 you will need information of recommended doses. 

For a 50,000 GPD filtration operation with an average loading 50 mg/L TSS (Total Suspended Solids) determine the optimum flocculant to use in order to achieve at least an 85 % reduction in solids. Assume that a rotary drum filter unit is used. 

For each of the chemicals selected in question 1, calculate the recommended dosage (As Lbs/gal. solution) for 25,0(X) gpd of waster treatment. 

Discuss the advantages and disadvantages of polyelectrolytes over other convention flocculants. 

Develop a list of the issues and parameters to examine when making a selection of the proper filter aid. 

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For newcomers to this subject, there is a section of general questions for thinking and discussing among your colleagues. These will help reinforce some of the general coneepts and principles covered in this first chapter, and help you to prepare for the more technical discussions that follow. 

As with other chapters, you will find a section at the end dealing with Questions for Thinking and Discussing. Some of the questions are problem-solving and rely on formulae and reference material provided to you in the last chapter. Remember to refer to the Glossary at the end of the book, if you mn across any terms that are unfamiliar to you. 

More reliable results can be obtained by assuming average conditions over divided parts of the compression zone. That is, the above expression can be applied to divisions of the compression zone and the total volume obtained by the sum of these calculations. Try some of the problems in the section on Questions for Thinking and Discussing to strengthen your understanding of the principles covered. 

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