R E G U L A T I O N S & S O L U T I O N S

Because of tightening regulations and the high cost of waste hauling, disposal of wastewater can be a problem for companies that routinely use penetrant NDT inspections.

Understanding the regulations and dealing with disposal problems can be very confusing for penetrant users. Federal law prohibits direct discharge into the environment, requiring wastewater to be "as clean as the body of water into which it is discharged." Locally, the specific discharge regulations established by Publicly Owned Treatment Works (POTW's) are vague and vary widely (see chart)

City                     FOG                Color

Boston, Ma         100                 Excessive

Chicago, IL         250                 Excessive

Ft. Worth, TX    200                 Objectionable

Montreal, CN       30                 15 Color Units

Omaha, NE         100                 Significant

St. Louis, MO     200                 Highly Colored

San Francisco, CA 100              Not Specified

While the specific discharge limits differ from city to city, the most important considerations are FOG (fat, oil, and grease content) and color.

Penetrant color is likely to be the first thing that draws the attention of your local POTW. FOG limits present obvious problems for oil-based penetrants, but even surfactant-based products that are supposedly oil free have FOG values that exceed most POTW limits.

Almost everything is biodegradable over time, but POTW's usually have less than 24 hours to remove color and contamination to meet EPA standards. In most cases, POTW's cannot meet the standards without penetrant pre-treatment.

U L T R A F I L T E R (UF), N A N O (NF) A N D R E V E R S E O S M O S I S (RO) F E A T U R E S

Environmental Hydrotech, Inc., (EHI) offers a complete line of Ultrafilters, Nano Filters and Reverse Osmosis Membranes with daily capacities from 50-1,000,000 gallons. They work on the same principle and share many common features.

Reduce hauling costs without discharging to a POTW and support a sound waste minimization program of recycling rinse water.

F I L T R A T I O N / R E C Y C L I N G  I S  T H E

There are many treatment alternatives, but most of them have significant disadvantages. For example, chemical treatment creates solid waste that is difficult to dispose of and residual floc contaminates the filtrate such that it is unusable. Evaporators are slow and consume a lot of energy. Carbon treatment requires frequent material changes and does not reduce the chloride level in the water.

Ultrafiltration in combination with Nano-Filtration or Reverse Osmosis for the treatment of penetrant wastewater will reduce 80-90% of the waste stream by recycling ultrapure water as rinsewater for reuse.

EHI equips systems with membrane products designed for long life. The Ultrafiltration system component followed by carbon filtration can generally reduce FOG's to as low as 10 ppm. Post treatment polishing with Nano-Filtration or Reverse Osmosis will eliminate FOG and reduce dissolved solids up to 99% depending on membrane selection.