If oxygen levels are high, reduce them to around 3 ppm. If oxygen levels are extremely low, bordering on anaerobic, increase them to 2 to 3 ppm, to encourage predominance of floc-forming strains. At the same time, gradually increase wasting, to increase your F/M ratio. Try to keep the pH slightly acid, but not so acid that the desired floc formers are also inhibited. Make pH adjustments, slowly, to avoid upsetting the desirable strains already present in the system. Shorten the sludge age and compensate for the reduced total concentration of bacteria by augmenting with Alken Clear-Flo 7015[11]

Since most filamentous strains will "fix atmospheric nitrogen" if nitrogen is rate-limiting in the water-phase, they gain a competitive advantage in a system that is deficient in nitrogen, especially since most filamentous species prefer to utilize reduced forms of nitrogen. A savvy plant manager can switch the advantage to the preferred floc-forming strains by supplementing the system with sodium nitrate instead of the traditional ammonium chloride. Many filamentous strains ALSO require reduced forms of sulfur, such as hydrogen sulfide, mercaptans or thiosulfate. Alken-Murray advises clients to apply Alken 894, an aqueous chemical nutrient formula which contains 30% sodium nitrate, supplemented by 2.5% Alken 896 BioStimulant, providing supporting nutrients that are preferred by the floc-forming, FOG and fatty acid-degrading cultures, in Alken-Murray's municipal wastewater-treatment formulas.

Starkeya novella, an aerobic floc-forming, sulfide-oxidzing gram-negative species, included in Alken Clear-Flo 7015[11], rapidly targets a wide assortment of fatty-acids, but this facultative species is capable of using carbon dioxide as its sole carbon source, if desirable varieties of organic carbon are absent or limited. S. novella oxidizes hydrogen sulfide, mercaptans, thiosulfate, dimethyl sulfide and polythionate. S. novella aggressively oxidizes reduced sulfur compounds, while heterotrophically digesting FOG and a broad spectrum of fatty-acids, allowing this power-house to competitively starve aerobic, filamentous cultures of Beggiatoa alba and related strains causing bulking and foaming issues.

If the F/M ratio is seriously unbalanced, Alken-Murray has created a new nutrient blend, Alken Bio-Nutrient 10, specially formulated to deliver nutrients, while exerting a positive selection toward beneficial floc-forming probiotic and bioremediation cultures included in Alken Clear-Flo 7015[11], while inhibiting pathogenic and filamentous species. The organic carbon sources selected to deliver this performance were whey protein concentrates, maltodextrin, and a small amount of Yucca schidigera. Oxygenated forms of powdered nitrogen, like sodium nitrate, potassium nitrite, etc., cannot be SAFELY blended with the combustible powdered organic carbon compounds, milk whey protein concentrate, maltodextrin and Yucca schidigera. No phosphate nutrient sources were discovered which could exert positive selection toward probiotics and bioremediation, while inhibiting growth of pathogenic and filamentous species, we decided to include monosodium phosphate (MSP) and disodium phosphate (DSP), a pair of phosphates which can be used to balance the ratio of carbon to nitrogen to phosphate, with no other impact on any bacteria, fungi or algae in the wastewater system.

Alken Bio-Nutrient 10 was formulated with reduced oncentrations of both nitrogen and phosphate, so that a LIQUID source of oxygenated nitrogen, specifically Alken 894, can be applied to encourage system seeding with the consortium in Alken Clear-Flo 7015[11] and Alken Nu-Bind 1. [13] A plant manager or authorized Alken-Murray distributor can calculate whether or not any additional phosphate nutrients are necessay, applying Alken® Bio-Nutrient 6, as necessary to balance the ratio of organic carbon to nitrogen to phosphate to equal 100 to 6 to 1.2 for municipal wastewater.

 To rapidly knock down foam and restore flocculation, apply approximately 10 to 20 ppm of concentrated Alken Nu-Bind 1 [13] to the tank experiencing the bulking and foaming problem, using a large nozzle sprayer, to keep it from becoming clogged with the suspended matter in this formula. Apply continuously until the foam is completely dispersed and settling is apparently restored. This treatment delivers performance comparable to a combination of a chemical antifoam and a cationic polymer, providing the fastest elimination of foam with sludge settling. The non-pathogenic Bacillus, included in Alken Nu-Bind 1 [13], target FOG, fatty acids and reduced sulfur compounds, continuing the elimination of all advantages formerly enjoyed by the filamentous species.

Alken-Murray has devised a wastewater treatment maintenance product that specifically addresses the most serious problems caused by overgrowth of filamentous species in wastewater treatment plants, a product offered under the name Alken Clear-Flo 7015 [11], which is headlined by an exceptionally talented bacterial strain, Bacillus megaterium (strain AMC 300), which degrades cyanide, FOG (food Fats, Oils and Greases), a favorite diet of filamentous species and Trehalose, the primary biosurfactant produced by Nocardia amarae, the best known filamentous troublemaker in municipal wastewater treatment facilities, notorious for causing disruptive foaming, bulking and violation of NPDES discharge permits. Supporting this special star are three other strains that also digest "Trehalose"-based biosurfactants, specifically: Bacillus amyloliquefaciens (strain 843), Bacillus licheniformis (strain 406) and Bacillus megaterium (strain 112). One of the Trehalose-digesting Bacillus also digests both long and short-chain fatty acids, which assures that this strain will develop a large, healthy biomass that will continue to expand its population by competing with Nocardia amarae, and so on, to digest fatty acids present in the water body, until the concentration drops low enough that only the floc-formiers with wider dietary tastes, will continue to survive. To ensure that ALL surfactants/detergents present in a treatment system will be fully digested, the strains specializing in biosurfactants are supported by a pair of Pseudomonas putida (strains 151 & 483) that digest a variety of chemical surfactants, including nonylphenols, linear and branched ethoxylated alcohols and sulfonated surfactants. To deliver better protection from upsets caused by influent of phenolic sanitizers and related compounds, two strains of Pseudomonas putida (usually strains # 369 & # 800) were conscripted from our industrial phenol-degrading formula, Alken Clear-Flo 7002 [14] into this maintenance formula. To assure that our treatments will be comfortable in an environment that has been supporting growth of filamentous species in the system, the pH range of most strains selected for these formulas is broad enough to tolerate a somewhat acidic environment, while also tolerating a moderately alkaline environment, encouraging competition between the desired floc-forming and unwanted foam-producing, filamentous species. To bracket the pH range possible, we included a soil-isolated Bacillus laevolacticus (strain 494) to digest proteins and amino acids through excursions down to pH 3, along with a grease-trap isolate of Sporosarcina pasteurii (strain 453), also known as Bacillus pasteurii, which can digests food-FOG up to pH 10. A dosage of 74 to 80 ppb of Yucca schidigera leaf extract mechanically/physically blocks the filamentous strains, especially Cyanobacteria, from fixing nitrogen from the atmosphere, while it also inhibits the urease enzyme from converting urea into ammonia, a form of nitrogen that is much more desirable for filamentous species. If filamentous strains can be consistently blocked from access to ammonia-nitrogen, they are forced to use much more energy to fix nitrogen from the atmosphere, to get their needed ammonia-nitrogen, for additional growth, all of which reduces their competitive advantage until they have none left.

After using Alken Nu-Bind 1 [13] and Alken 894 to rapidly gain control of bulking and foaming, Alken Clear-Flo 7015 [11], should be applied to the last collection system lift station, prior to the main plant or to the primary clarifier. This treatment will keep a plant in compliance, while other conditions (F/M, oxygen level, etc. are adjusted to discourage the return of filamentous foam-causing strains. Alken Clear-Flo 7015 [11] contains a small supplement of Alken Bio-Nutrient 10 to provide nutrients, selected to provide positive nutritional selection for the commercial cultures in the product,without feeding the filamentous species in the system.

If high levels of foaming are present without concurrent food FOG wastes, bench testing should be performed by either the locally authorized Alken-Murray distributor or by the laboratory associated with the problem facility. We generally suggest bench-testing the following options, either as a single batch of testing, with each blend or single product tested in its own Erlenmeyer flask, against one untreated "control" and one "nutrient-augmentation ONLY control"

• A combination of Alken Clear-Flo 7008 [17] & Alken Enz-Odor 12 [21]. Although CF 7008 contains a single strain of filamentous Rhodococcus, which produces a small amount of Trehalose-based biosurfactant to help it digest alkanes, we believe that inclusion of a pair of Trehalose-digesting strains (one strain each of Bacillus licheniformis & Enterobacter cloacae) prevents foam development before it can begin. Many of Alken-Murray's refinery clients apply this pair of products, providing superb odor control and effluent wastewater sufficiently clean to allow reuse of system effluent as "industrial process water". This combination eliminates discharge fees, while reducing the quantity of process water that the plant needs to purchase.
• Alken Clear-Flo 7004 [15] This product was created to treat chemical detergents-surfactants, including nonylphenols, branched and linear alcohols, sulfonates, etc. and is especially useful when applied to Textile processing wastewater systems.
• a 50-50 blend of Alken Clear-Flo 7004 [15] & Alken Clear-Flo 7008 [17]. If the majority of foam present in the wastewater is confimed to be related to petroleum chemicals, instead of carbohydrate-based biosurfactants (primarily Trehalose, Glucose, Glycine Rhamnose and Ornithine), this blend should be compared with test results of performance of CF 7004 alone.
• Alken Clear-Flo 7015 [11] See the paragraph further up the page describing the formulation of this product for treatment of wastewater in which filamentous organisms rely on food FOG as thieir preferred organic carbon source, a very different adaptation than is taken up by filamentous organisms that select petroleum hydrocarbon related compounds as their preferred organic carbon source.