Jerry L.Anderson, P.E.
CH2M HILL
Louisville, Kentucky

A principal issue in modern water treatment plant design is the decision of what chemicals are to be used for treatment processes, how they are to be shipped and stored, and what type of chemical feed equipment should be used. This chapter summarizes alternatives and issues associated with gaseous, dry, and liquid chemicals and the associated equipment and piping necessary for their use. Other issues for the designer to consider involve the many regulations that must be met and safety considerations in planning the chemical feed systems. Finally, the importance of securing and hardening of chemical handling facilities is a part of modern design.

Additional discussions of the theory of chemical treatment may be found in detail in Water Quality and Treatment. Details of specific chemicals commonly used in water treatment processes are provided in Appendix A.

RECEIVING AND STORING PROCESS CHEMICALS

Many alternatives are available for receiving and storing process chemicals, depending on plant size and location, treatment processes to be used, and many other factors.

Sizing Storage and Feed Systems

Sizing of storage and feed systems begins with an investigation of dosage requirements for each chemical used. Chemical feed rates (lb/day, ft ³/h, gal/day, kg/day, etc.) can be computed from dosages (mg/L) and plant flow rates [million gallons per day (mgd), ML per day]. For chemicals in dry form:

For chemicals in solution form:

Chemical storage or inventory requirements can be computed from feed rates and the number of...