Nickel-chromium plating wastes treatment

It is important to note that all flotation clarifiers63,64 may be used for treatment of nickel-chromium plating wastes regardless of their shapes (rectangular or circular) or manufacturers. A filtration unit is an optional step for final polishing. The treatment efficiency of separate flotation and filtration units65 will be similar to that of a combined flotation-filtration unit (Figure 6.8). 

Chapter 6 Treatment of Nickel-Chromium Plating Wastes. 231... 

Applicable local, state, and federal environmental laws require that the waste generated by the nickel-chromium plating process be pretreated to provide a discharge acceptable to the public wastewater treatment system. 

The specific purpose of this chapter is to describe the chemical and physical pretreatment methods required for nickel-chromium plating wastewater, to describe the upgrades needed by a municipal wastewater treatment system to manage this waste, and to relate the methods and upgrades to the operation of the total treatment system. Special emphasis is placed on presentation of the following ... 

Initially the nickel-chromium plating process is designed to minimize the liquid loading to the waste treatment system. Counterflow rinsing, spray rinsing, and stagnant rinse recovery methods are employed in order to minimize the amount of wastes to be treated and allow as much treatment or retention time in the waste treatment system as is possible. 

The advantages of electroless nickel over hard chromium include safety of use, ease of waste treatment, plating rates of as much as 40 p.m/h, low porosity films, and the ability to uniformly coat any geometric shape without burning or using special anodes. Increased chemical safety is another... 

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