✦ LIBER ✦

Control of filamentous organisms in food-processing wastewater treatment by intermittent aeration and selectors

✍ Scribed by George Nakhla; Andrew Lugowski

Publisher: Wiley (John Wiley & Sons)
Year: 2003
Tongue: English
Weight: 408 KB
Volume: 78
Category: Article
ISSN: 0268-2575
DOI: 10.1002/jctb.750

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✦ Synopsis

Abstract

Various measures were tested at a full‐scale wastewater treatment plant to control sludge bulking by type 0041 and 0675 filamentous microorganisms, instigated by highly variable wastewater loadings from a food‐processing facility. Intermittent aeration on a 1‐h on 1‐h off basis was found to effect a marginal improvement in sludge settling characteristics, as reflected by about an 11–36% reduction in the Sludge Volume Index (SVI) to 118 cm^−3^ g^−1^. At BOD loadings of 1500 kg d^−1^ which marginally exceeded the design capacity of the plant of 1200 kg d^−1^, SVI rose sharply to 230 cm^−3^ g^−1^ in less than a week. The anoxic selector effected a reduction in SVI to 170 cm^−3^ g^−1^ within 3 weeks of operation at temperatures of 8–12 °C. The aerobic selector was most effective, reducing SVIs further to 79 cm^−3^ g^−1^ in 2 weeks. Sludge settleablity was found to be inversely proportional to the aerobic selector food‐to‐microorganism ratio. The optimum aerobic selector loading was found to be 1.8–2.7 kgBOD~5~ kgMLVSS d^−1^, with corresponding SVIs in the range of 80–120 cm^−3^ g^−1^.