An innovative way to treat acidic wastewater
By Paul Chapple, Green Turtle Technologies
Industrial wastewater with a low pH is acidic wastewater, a common problem for many industries. Increasingly stringent environmental regulations require that pH, among other contaminants, be controlled to certain levels before they are discharged to a natural body of water or municipal sewer system. Unlike contaminants that can be surcharged, such as Biochemical Oxygen Demand (BOD), total suspended solids (TSS), or solvent extractable matter of animal or vegetable origin (grease and oil), pH cannot be surcharged, and, therefore, must be treated before it is released.
The ranges in acceptable pH discharge levels are usually from 5.5 to 10.5, but the actual levels are given in each region or city sewer discharge by-law. For example, the Region of Peel, Ontario, by-law for discharges to sanitary sewers gives the pH limit range as 5.5 to 9.5. Any corporation that is found to have pH discharge levels below 5.5 or above 9.5 can be charged $50,000 for the first offence, and $100,000 for any subsequent conviction.
The treatment of acidic wastewater has traditionally been done with multiple large collection tanks, mixers, injectors, pH controllers, and the addition of one of many caustic chemicals. This traditional system, though effective, has many problems associated with its use, including size of equipment, large footprint, complicated PLC configurations, maintenance issues, probe calibration, employee time, and the need for and storage of hazardous caustic chemicals.
A new technology has been developed to treat acidic wastewater that combats the problems associated with current treatment systems. Known as PHIX, it is designed to treat acidic wastewater in process and/or prior to discharge into a water body or municipal sewer system. The pH is effectively and efficiently adjusted to within by-law limits, or specific levels if required, resulting in by-law compliant sewer discharges.
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