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Waste Water Treatment

Water Maze


This is a process in which contaminants in a waste stream are filtered or screened out. This method is effective in preventing particles, even very tiny ones like mud and sludge, from moving downstream. The downside is that solids build up on the filtering media and restrict the water flow requiring some type of maintenance, such as purging or backwashing. Also, mechanical filtration is not an effective method for dealing with emulsified oils.

There are three main types of filtration methods—(1) indexing paper filters, (2) cartridge filters and (3) media filters. A description of each along with the Pro and Con are listed below:


  • Indexing Paper Filters A very fine paper filter continuously unrolls while the waste stream flows through the paper filter
    • Pro: Very effective when there’s not a lot of dirt or solids in the waste stream. 
    • Con: Solids plug up the paper quickly requiring you to use (buy) a lot of paper; plus you have to find a way to dispose of the contaminated paper safely. 

  • Cartridge Filters per filter is placed inside a canister or enclosed tank. 
    • Pro: Provides excellent filtration even down to 5 microns in size. 
    • Con: As with indexing paper filters, they can plug quickly and, depending on the dirt load, must be removed often to clean or replace.

  • Media Filters Other media, like sand or carbon, are used to filter contaminants in the water. 
    • Pro: It provides reasonable removal of solids without plugging up. 
    • Con: It requires regular maintenance such as backwashing.

Like a pan of water on the stove, wastewater subjected to heat is evaporated leaving the pollutants to be skimmed off or disposed of as sludge. It short, wastewater evaporators safely and naturally eliminates the water portion of a waste stream leaving behind only the gunk—usually about 5%-10% of the total volume—to dispose of.

The technology use in wastewater evaporators is typically either through immersion heating (pan on a stove) or submerged combustion (sending the heat into a tube immersed in water). Water Maze has systems with both technologies.

  • Pro: It effectively minimizes the wastewater so there’s only a fraction left to dispose of. 

  • Con: It still requires disposal of hazardous wastes plus heating fuel costs can be expensive.

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If you're reading this page right now, chances are you have a wastewater disposal issue. Don't touch that mouse -- you've come to the right place. HPI processing has been helping our customers solve their water treatment problems for years. Let's face it, disposing of materials in a hazardous form is costly and inconvenient. On-site water treatment is much easier and surprisingly affordable, given the rising cost of hazardous waste disposal. E-Mail us with your individual needs and we'll show you how we can save you money. Plus you'll enjoy the added benefit of knowing that you're "doing the right thing" environmentally. Here's how we helped some of our customers solve their problems...

Case #1: Customer's manufacturing process involves the use of a chromate dip tank to etch metal parts prior to a painting operation. Needs to find a way to safely and economically dispose of used etching solution.

Solution: HPI Processing  using "The ROC" system changed the chromate into hexavalent chromate. The water is subsequently treated for the removal of the hexavalent chromate, which puts it into a non-hazardous sludge cake. By passing the TCLP test, the cusomter can dispose of the sludge as non-hazardous and the recycled water can be discharged into the sewer or recycled. Thus, saving the customer money on water usage and the high costs of hazardous waste removal.


Case#2: Customer needs to remove Zinc from processing water that comes from zinc coating on utility trucks.

Solution: "The ROC" can remove zinc from 50 ppm to .02 ppm making it safe to discharge into the municpal sewer and putting the sludge into a non-hazardous waste.

Case #3: Customer wants to recycle truck engine wash water.

Solution: "The ROC" can remove suspended solids, emulsified oils, heavy metals and hydrocarbons putting them into a non-leachable solid sludge which will pass a TCLP test. This will allow the solid sludge to be disposed of via normal trash collection. The recycled water is fed back to the power washer for reuse. This in turn makes this a closed loop system. It is also beneficial when area water use is restricted because of serious drought conditions or due to local regulations.


Case #4: Customer operates a powder coating line. Metal items are cleaned with acids and caustic material leaving high amounts of oil and metals in the wash and rinse waters.

Solution: HPI Processing solved the problem by treating the wash and rinse waters for removal of the metals, oils and suspended solids. The removal of these contaminants allow the customer to recycle the water and put the sludge into a non-hazardous sludge cake.

How the ROC system works:

The following steps occur in a few moments in a mix tank. Typically, this is a one-step process. When dealing with more exotic waste streams, there may be some more steps involved. Each waste stream has its own unique characteristics and we always ask for a sample (usually 1 gal) for assessment before we make a recommendation as to the treatment method.

1. The pH of the wastewater is briefly reduced to a point where the oil emulsion breaks, becomes insoluble and is removed from the waste stream by being attracted to the cationic component of our reactant.

2. Suspended solids are also attracted to our reactant during this phase.

3. The pH is then elevated briefly for optimum precipitation of dissolved metals. These metals are immediately attracted to the anionic component of our reactant and removed from the waste stream.

4. Finally the pH of the waste stream should return to the neutral range. The cationic (positively charged) components and contaminants combine with the anionic (negatively charged) components and contaminants to form a floc. This final reaction allows micro-encapsulation of the contaminants to take place and generally produces a non-leachable solid waste or residue. The non-leachable of the solid waste can be substantiated by performing a TCLP (Toxic Characteristic Leachate Procedure).

5. The treated water or filtrate should be suitable for reuse or discharge. If discharging the water, then appropriate testing should be done to meet the parameters for discharge to the local POTW.



Types of Industry
  • Waste Streams

  • General metal working

  • Cutting and grinding oils,

  • Water soluble coolants.

  • Metal Finishing, Polishing

  • Burnishing, vibratory,

  • deburring effluent.

  • Metal Fabricators

  • Parts washer effluent.

  • Rental and Repair Centers

  • Steam cleaning,

  • pressure washer effluent.

  • General Industry

  • Mop water, compressor

  • condensate, oils, metals,

  • and suspended solids.

  • Printing, Screening,

  • Paint Coating

  • Inks, latex solutions.

  • Die Casting

  • Die lube, quench pits,

  • machine, run-off.

  • Plating,

  • General Manufacturing

  • Dissolved metals,

  • Emulsified oils.

  • Truck Wash Centers

  • Emulsified oil,

  • suspended solids.




System Overview

1) Wash pad. this should be about 5' wider than the largest piece of equipment to be washed. A lip is provided at the borders for containment. The pad slopes toward a collection pit or catch basin.

2) Equipment is driven onto the pad for washing and rinsing.

3) Pressure washer necessary for cleaning equipment.

4) Catch Basin. Installed below grade and plumbed adjacent to the location of the recycling machine. A grate strong enough to be driven over covers the catch basin. The grate acts as a screen for large sediment which can be cleared as needed. For smaller sediment such as grass clippings, etc., a finer mesh screen may be used on top of the grate.

5) Used wash water is pumped automatically from the catch basin to the recycling machine for cleaning.

6) Recycling Machine. The volume of wash water you generate determines the model to use. Water passes through the machine, contaminants are removed and the clean water is stored in a holding tank for reuse.

7) Separated contaminants are collected in either bag filters or on filter cloth which dumps the residue into a container for disposal. Clean water for reuse by the pressure washer for equipment cleaning.

Easy to maintain...
Environmentally friendly...


For more info contact us!

Water Maze & ROC Brochures
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