Browse Prior Art Database

Waste Water Recycling Process

IP.com Disclosure Number: IPCOM000080860D
Original Publication Date: 1974-Feb-01
Included in the Prior Art Database: 2005-Feb-27
Document File: 3 page(s) / 43K

Publishing Venue

IBM

Related People

Brackett, DW: AUTHOR

Abstract

Waste water from metal plating and metal etching operations is treated for recovery of useful solid contents and to enable recycling of the water through the plant, without creating the sludge deposits that result from ordinary waste water treatment methods.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 52% of the total text.

Page 1 of 3

Waste Water Recycling Process

Waste water from metal plating and metal etching operations is treated for recovery of useful solid contents and to enable recycling of the water through the plant, without creating the sludge deposits that result from ordinary waste water treatment methods.

In the drawing, 1 and 2 represent streams of influent waste water entering the processing system, stream 1 being the water in which plated or etched articles have been rinsed, and stream 2 being the water from the plating or etching baths (the latter having much higher concentration of solids than the more dilute rinse waters). The process rinse waste 1 is held temporarily in an equalization tank 3 to minimize fluctuations of solid content and to facilitate pH adjustment, in the event it is desired to prevent the precipitation of calcium and magnesium salts.

From tank 3 the waste water passes through a filter 4 to a "stage 1" solids removal unit 5, comprising either a reverse osmosis unit or an electrodialysis unit. This type of solids removal method is effective to lower the dissolved solid content of the stream passing through it. Since the solid content of water entering unit 5 is low to begin with, stage 1 effects substantially complete purification of this water. The purified effluent from stage 1 flows through a conventional organic material removal unit 6, from whence it is returned to the plant for reuse. This step is necessary in order to remove low-molecular weight organics, which are not removed by any membrane processing.

The concentrated brine from the stage 1 solids removal unit 5 passes to an equalization tank 7, into which the concentrated process waste stream 2 also flows. From thence the concentrated waste water passes through a filter 8 to a "stage 2" solids removal unit 9, which is similar to unit 5. The partially purified effluent from stage 2 is returned to equalization tank 3, where it mixes with the incoming rinse water 1, and then undergoes filtration and stage 1 solids removal....