81    METAL FINISHING WASTEWATER TREATMENT
INCORPORATING MATERIALS RECOVERY AND LOW
TEMPERATURE EVAPORATION
Ernest R. Ramirez, Director of Environmental Engineering
Richard C. Ropp, Vice President of Technology
Ramirez Associates, Inc.
Far Hills, New Jersey 07931
INTRODUCTION
The electroplating and metal finishing industries traditionally are operations that have low profit
margins. This is especially true in the case of job shop operations where competitive bidding leads to
minimized earnings. In order to keep capital costs down, many plants still operate electroplating
equipment that is ten and even thirty years old. In general, innovation in this industry is not extensive
because this involves capital funds which electroplaters usually do not have.
While Federal EPA Effluent Limitations Guidelines for (non-integrated) Electroplating Point
Source Category has mandated that this industry be in compliance by April 27, 1984, there is still a
large number (perhaps 40%) of job shop operations which do not meet the USEPA Effluent Limitations Guidelines for Electroplating Point Source Category.
The conventional heavy metal precipitation and cyanide destruction will cost (capital) a metal plater
no less than $250,000 (installed), will occupy no less than 800 ft? of area, and last, but not least, will
generate a sludge that must be manifested (expensive). Additionally, operating costs for the above
wastewater treatment facility will vary annually from $25,000 to $50,000. There is no surprise that in
view of the above, many metal platers are not in compliance with the effluent discharge limitations.
This paper is a case study involving the design and engineering of a plating operation discharging
14,000 gpd. Metals involved are: chromium, nickel, copper and the cyanide ion.
NEW WASTEWATER TREATMENT CONCEPT WHICH LOWERS PLANT OPERATING
COSTS
The new concept of wastewater treatment involves the operations of material recovery and low
temperature evaporation. In reality these methodologies have been used and are still used by precious
metal platers where materials recovery is paramount to their staying in business. This paper refers to
the technology as new simply because platers have been unaware of its effectiveness, low capital costs
and its overall contribution to reduced operating costs when chemical dragout volumes are large. This
is typical in the barrel plating operations. Also, plating parts with blind holes will markedly lower
operating costs due to the value of the recovered chemicals. In these two cases wastewater pretreatment would actually lower overall costs and raise profits, contrary to the metal finisher's normal
perception.
CONCEPT-MATERIALS RECOVERY WITH LOW TEMPERATURE EVAPORATION
Materials Recovery
The guiding principles in materials recovery are straightforward and simply entail the following
concepts:
• Contains all (99%) chemicals that leave the electroplating tank on the plated part.
• Use still (non-flowing) dragout tanks directly in series with the electroplating tank.
• The size and the number of dragout tanks will be determined by an engineering material
balance encompassing the factors of: 1) parts plating load; and 2) the desired percentage
of recovery (often set at 99%).
• Each working day, the dragout tanks are pumped out once, as follows: 1) 1st dragout
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