Metals & Finishing Industrial Wastewater Treatment

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Courtesy of Integrated Engineers Inc.

Industrial Wastewater Treatment Success Stories

Metals and Finishing Industrial Wastewater Treatment

Aircraft Components - 80% Cost Reduction

Aircraft Engine Industrial Wastewater Jar Test for Treatability

A major manufacturer of aircraft engine components was having difficulty meeting their effluent limits for COD (limit 235 ppm) and Zinc (limit 1.0 ppm). The source of the wastewater came from these processes:

  • Mop water with alkaline cleaner
  • Petroleum based machining coolant
  • Floor scrubber water
  • Wet dust collectors
  • Vibratory finishing
  • Emulsified oils/surfactants
  • Non-destructive dye penetrants

Their chemistry to treat 3,000 gal/day wastewater was sulfuric acid/caustic to adjust the pH to 9.0, aluminum chloride (Al2Cl3), an anionic flocculant, and to pre-coat the plate and frame press with filter aid.

The facility tested the Floccin-I and found that it eliminated the Al2Cl3, the anionic flocculant, and the press pre-coat. The treatment costs were 80% less than their previous levels and the effluent now meets their discharge limits (see the comparison below).

Constituent Old Chemistry Floccin-I
COD 450 ppm 180 ppm
Oil & Grease 18.6 ppm <1.0 ppm
TSS 25 ppm 5 ppm
Zinc 3.2 ppm <1.0 ppm


Iron Foundry - $15k per month savings

The foundry recycles engine blocks to make iron pipe. They have a 350-gpm closed loop water reuse system that is used to cool the molds as part of the manufacturing process. The facility was using a coagulant and a flocculant to try and reduce the solids carryover from their clarifier. The solids in the reuse water were building up in their system filters causing intermittent downtime (downtime in a foundry of this size is in the range of $10,000/hour in lost production, salaries, etc.). The coagulant/flocculant program was costing $3,600.00/month and was not capable of generating a sludge that could be dewatered on their belt press. This caused the solids to be returned to the main sump and back to the reuse loop.

The operation of the reuse system required full time attendance on both shifts to keep the solids carryover to a minimum. The reuse process included a cooling tower after the clarifier to cool the water prior to reuse in the plant. The cooling tower builds up with solids that carryover from the clarifier requiring 8 man-hours/week to clean every Friday.


Industrial Wastewater Treatment for a Foundry

The objective of the trial was to reduce the solids carryover in the clarifier and from the belt press. To do this, the solids needed to settle in the clarifier and the sludge needed to have the consistency to dewater on the belt press. This would provide clear water for cooling of the molds with no downtime.

The trial involved the use of Floccin-D to replace the coagulant and flocculant. The water cleared up within 30 minutes and the belt press started generating a sludge cake as the solids were removed from the system. The effluent water from the clarifier was very clear (low solids, see picture right) with turbidity similar to tap water (see the photo). The usage rate of the Floccin-D was 15 lbs/hour or 15 lbs/21,000 gallons (0.71 lbs/1,000 gallons).



The facility now makes a sludge that can dewater on their press reducing the solids in the system. The Floccin-D eliminated the need for the coagulant and the flocculant. The cooling tower no longer needs to be cleaned on Fridays. The pre-filters need a minimal of cleaning and there has been no production downtime due to solids buildup in the water reuse system. The operators now spend 20% of the time watching over the system.

The Floccin-D has proven to save this facility an average of $15,000/month in labor, chemical costs, and plant downtime (lost production) due to water reuse quality.

Ceramic Polishing Media - 40% Cost Reduction

A company was using several chemistries to remove the total suspended solids (TSS) from their wastewater. The facility manufactures stainless steel surgical instruments. The wastewater is generated from the polishing/deburring of these instruments using an aluminum/ceramic polishing media.

Ceramic Polishing Media Wastewater Treatment Test using Flocculating Agents Floccin™

The jar tests shown are from the addition of the Floccin-H to the wastewater and moderate mixing. The TSS before ranged from 300-700 ppm and treated TSS was less than 10 ppm, well below their discharge permit. Costs for the Floccin™ H was 40% less than their previous chemistries and required less operator time and labor.

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