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Reduction in Generation In today's wastewater arena a major contributor to the local publicly owned treatment work (POTW) can be an industrial laundry. These facilities can be responsible for discharging up to 250,000 gallons per day to the sewer. The waste itself is the result of washing hundreds of thousands of pounds of uniforms, shop towels and food service items such as bar mops, aprons, and butcher coats. The waste influence can have a direct and major impact on the local POTW depending on the size of the receiving treatment plant. These factors can lead to local and state regulation of the industry through ordinances that demand compliance. When commercial laundries are required by local authorities to clean their wastewater before discharging it into the sewer, the traditional method has been to clarify the water with the use of Dissolved Air Floatation (DAF), Induced Air Floatation (IAF) or Settling Clarifiers coupled with a chemistry program consisting of some combination of organic and inorganic components. Typically, the wastewater generated through the laundering process is moved from the
washing machines to a holding area (pit or tank), it is then screened for debris and lint
and moved to another holding area to be equalized before being treated to remove the
contaminated components. Prior to the clarifying system, the contaminated particles are
agglomerated from a micro emulsion using a process of coagulation and then flocculation Traditionally in the world of commercial laundries, wastewater has been chemically
treated to alter the micro-emulsion bond between the water and soil by the use of high
sludge producing organic and inorganic chemicals. Especially high in sludge production Most chemical treatment programs rely on from three to six separate steps of injecting or adding chemicals (organic and inorganic) to treat the influent for compliance, and or, for the ability of the sludge to be dewatered in a press or rotary vacuum filter. The addition of these additives to the waste stream results in more sludge generated and increases the amount of solids thereby decreasing overall efficiency of the treatment unit. From a cost standpoint; the addition "extra" chemicals represents a potential for the cost of the treatment of the water to rise. The sludge that is being generated at the treatment unit must ultimately be disposed of in a landfill in so doing creating a greater burden on landfill space. The cost of wastewater treatment and sludge disposal negatively impacts the profitability of an industrial laundry in areas such as labor, sludge disposal, and chemical costs. In some cases the bottom line detractor can undermine the profitability of the individual business to the point of viability. In response, GenChemUSA began to research ways to reduce the amount of sludge being
generated, maintain effluent compliance, and to lower the cost of the chemical process.
With the assistance of a large commercial laundry, a 2-part chemical treatment program
was put into place that met these goals. The program consisted of a primary cationic
(positive) coagulant and dry anionic (negative) flocculent. No pH adjustment was
required to lower the alkaline nature of the wastewater. This eliminates the use of acid as
a pH reducer as a step in the wastewater treatment process, unless required by local
ordinace. A patent was applied for and granted to Stuart Davis and Robert Davis for this The achievement of effluent clarity and compliance was not the most daunting task
attempted by this program. One of the most difficult parts of the program was being able
to dewater the sludge for cake formation in the press. This required using the correct After initial success, the program was rolled out to other facilities, and is now in place in over 40 industrial laundries treating between 2 and 3 million gallons of wastewater per day to compliant standards and reuse quality. During the past three years over thirteen awards for compliance excellence have been awarded to facilities using GenChemUSA's Sludge Reduction Program. They range from silver and gold awards to industrial plant of the year. The typical reduction in sludge generation at an industrial laundry transitioning from a traditional wastewater treatment program to "GenChemUSA's Sludge Reduction Program" ranges from 30% to 80%. This correlates to an estimated 11 million pounds of sludge per year not being sent to landfills, thus relieving an already stressed landfill system. Extrapolating these numbers to the costs to process (labor to dewater and process the sludge), and the costs to haul and dispose of the sludge, one can begin to see a plant's advantage in using GenChemUSA's Sludge Reduction Program. The average savings for chemistry, labor, and sludge removal is estimated at over
$20,000.00 per plant. Table A contains the cost data for 6 facilities that have converted
to the patented sludge reduction treatment program. The table indicates savings in The true measure of the program's success is creating compliant effluent. Table B is the
data from a facility that had serious issues with compliance prior at the introduction of
the program. After its introduction the plant achieved not only compliance with absolute Case Studies
An industrial laundry with a typical product mix and with an average water flow of
70,000 gallons per day needed to inject as much as 600 pounds of bentonite clay slurry
into the waste stream as a coagulant aid and as a body feed for sludge dewatering. The Case Two An industrial laundry with a wash mix that is a majority of heavy soil products and with
an average water flow of 120,000 gallons per day treated their wastewater with separately
fed injections of pDADMAC (200-500 part per million, ppm) followed approximately 20 Case Three An industrial laundry with an average water flow of 80,000 gallons per day treated the wastewater with a pDADMAC coagulant blended with aluminum sulfate (Alum) (200- 400 ppm) injected prior to the transfer pump, followed by a bentonite clay injection (600-900 ppm) followed by an emulsion flocculent (7 ppm) 15 seconds down stream. The effluent was non-compliant, with a reading of four on a standard turbidity wedge. Sludge production for the facility was 560 gallons per day. Filter cakes were not forming inside the press, which necessitated hauling away liquid sludge. After replacement of the above-described and introduction of GenChemUSA's Sludge Reduction Program, the sludge was reduced to 325 gallons per day. The plant became compliant (with 21 out of 21 on a standard Triton turbidity wedge) and the cakes were well formed. Summary
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