Volume 9, Issue 2, December 2009
Comming up in this edition:
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6. Feedback |
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Since its first application in wastewater treatment plants (WWTP) over three decades
ago, bioaugmentation --the application of selected, adapted microorganisms to speed
biodegradation and minimize the effect of toxic or inhibitory compounds in the waste stream--
has proven a cost-effective way to improve plant operation.
Initially, its primary saving was avoidance of fines for exceeding state and federal
permit limitations on BOD, COD or toxic compounds in the effluent. Recently, it enabled a
food processing plant to avoid a shut-down when its primary treatment system failed to meet
the requirements of the receiving municipal WWTP.
As plant operators became familiar with the technique, and more biological products for
specific applications became commercially available, other savings became evident:
In regard to the final category, bioaugmentation is at the heart of a plant under construction in Portugal that will accept agricultural waste and use aerobic and anaerobic digestion with commercially available bacterial strains to convert it to organic fertilizer, methane and reusable water. Wastewater treatment plants in the U.S. already use biological methods to provide millions of gallons of contaminant-free water suitable for re-use in agriculture. |
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Lower Maintenance Costs A municipal lift station required vacuum pumping two to three times a month, plus frequent maintenance of pumps and floats due to fat, oil and grease (FOG) deposits. Complaints about odor were common. A blend of FOG-liquefying microorganisms, plus enzymes and other ingredients (Microcat®-DNTRF Drain and Trap Bioformula) was added to sewer lines above the lift station to alleviate these problems. The savings over 6 months, after deducting the cost of the bioformula, were slightly less than $17,000, and odor complaints vanished. |
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Sludge Reduction and Water Re-use Many WWTPs now use biological methods to alleviate FOG problems such as foaming and poor sludge settling caused by filamentous bacteria, primarily Nocardia. Effluent FOG is a serious drawback because considerable amounts of treated water are now used for irrigation. One 10 MGD treatment plant in Florida began to investigate bioaugmentation in 2006 because of large amounts of stable foam in the aeration basin, poor settling of biomass in the clarifier and high levels of FOG in the effluent. Microscopic examination showed excessive amounts of Nocardia in the mixed liquor, concentrated in the foam. A treatment program utilizing an oil and grease degrading bio-formula was begun in May, 2006. The sludge volume index declined rapidly from an average of 168 mL/g in April (average of three aeration tanks) to 90 mL/g in early May, 72 mL/g in the second two weeks of May, and 72 mL/g for the month of June. Effluent FOG decreased from an average of 5.13 mg/L prior to bioaugmentation to an average of 4.53 mg/L during May and June. Stability increased, as measured by the standard deviation of the results. Considerable savings have been realized in sludge disposal costs and in the water re-use program. |
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Water Re-use In a state that leads the nation in water reuse, the City of Apopka, Florida, near Orlando, is in a class by itself. Its 4.5 million-gallon per day (MGD) Water Reclamation Facility,supplies 6.4 MGD to golf courses, recreation facilities, agricultural irrigation and over 4,000 residents. Two years ago, infestation with Nocardia and other filamentous bacteria, due to FOG, resulted in poor sludge settling, FOG increases operating costs by necessitating frequent cleaning of sewer lines and lift stations. The use of biological methods at the Apopka facility began in the Spring of 2007 with a search for an environmentally friendly way to reduce waste sludge, disposal of which was a major cost. Bioscience recommended a sludge reducing formulation, Microcat®-SR, and a filament controlling formulation. The filament controlling product, Microcat-XF, is a dry powder containing a combination of aerobic and facultative anaerobic microorganisms selected from nature for their ability to break down a broad range of substances, including FOG. It also contains natural enzymes and other ingredients that reduce the length of filaments and restore a balance of filaments and single-celled floc formers. Bioaugmentation began in the summer of 2007. The filament controlling formulation improved settling and reduced sludge volume so well--over 20 percent-- that it was decided to use it instead of the sludge reducer. The facility now produces little foam, and odors due to dried-on foam in the clarifiers have been eliminated. Bioaugmentation has paid for itself many times over in sludge reduction-- and plant operators are now focused on reduction of TSS, foaming and odor by control of filamentous infestations. |
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Lower Energy Costs Methane gas generation from anaerobic digestion has already been mentioned as a potential energy saver for wastewater treatment plants. Microcat®-AD improves anaerobic digester conversion of biomass to methane, which can be burned for plant heating or converted to electricity. Microcat®-UASB can be used to improve stability and conversion of BOD to methane in UASB plants which are often used in developing countries for primary or sole treatment of wastewater, eliminating the need for electricity for aeration. |
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Better PR One of the most important savings of bioaugmentation is also the most intangible--maintaining good public relations by eliminating odors, back-ups, unsightly conditions or poor effluent quality. The process has an excellent track record in reducing or eliminating both sulfur and ammonia-based odors, reducing foaming or sewer line blockage and enabling plant operators to keep well within permit limits, without the costs and environmental drawbacks of chemical treatments. |
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BioPOPS for Drain and Sewer Maintenance Bioscience has introduced a new line
of Microcat® products for reduction of FOG deposits in traps, pump stations and sewer lines.
The Microcat®-BioPOP Series consists of compact netting-covered cylinders that slowly dissolve in water.
releasing microbes and enzymes that reduce odor and improve FOG degradation. They are designed to be suspended in a grease trap,
lift station or holding tank on the end of a tether for easy placement and retrieval. BioPOPs contain the same environmentally
safe, naturally occurring microbes and enzyme combinations that have proven successful in alleviating sewer line problems in
municipalities throughout the country. The microbes are selected for their ability to break down organic contaminants common in food
processing wastewaters and domestic sewage. | ||||||||||
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The new BioPOP cylinders, colored red for easy identification, provide convenient, longer lasting biological control of odors and
FOG deposits, in areas where water collects and also in downstream sewer lines. | ||||||||||
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| Bulletin on Treating Endocrine Disrupting Compounds (EDC) | ||||||||||
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Endocrine disrupting compounds (EDC) often appear in WWTP effluent
and can have significant biological effects (such as fish feminization) even in
concentrations as low as parts per billion or trillion.
They can be degraded in a WWTP by longer sludge retention times
(SRT) but longer SRTs may lead to poor settling due to filamentous growth.
A new Bioscience technical services bulletin describes strategies for
optimum treatment of these compounds.
For a copy e-mail us at
info@qmes.nl |
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