Development of EPA's new methods to quantify vector attraction of wastewater sludges

Farrell, Jay A.; Bhide, V. V.; Smith, James E.

doi:10.2175/106143096x127721

Cited by 8 publications

(2 citation statements)

References 1 publication

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“…It is clear from Figure 2 that the initial hump of the fluorescence profile corresponds to the period of fast sludge digestion. From the regulatory point of view, the 1979 EPA regulation requires greater than 38% of VSS reduction, and one of the alternative tests added in 1993 was to attain SOUR <1.5 mg of O 2 (g of TS) −1 h −1 (13). As indicated in Figure 2, these criteria were met when the online fluorescence completed the initial hump.…”

Section: Resultsmentioning

confidence: 99%

On-line Fluorescence Profile of Aerobic Sludge Digestion

1999

Biotechnol. Prog.

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An online fluorometer designed for following intracellular NAD(P)H was used to monitor aerobic sludge digestion experiments. The fluorescence showed an initial rise to a high plateau, a sharp decline after staying at the plateau for 20-60 h, and a trailing very slow decrease. The characteristic fluorescence profile was shown to result mainly from the solids-associated fluorescence, after ruling out other factors such as pH, temperature, and supernatant fluorescence. The fluorescence profile was, however, not a mere result of the decreasing solids concentration. The varying sludge viability and population composition (e.g., the decay of heterotrophs and the increasing fraction of nitrifiers) played important roles. The fluorescence profile correlated well with the profile of the viable heterotrophic cell number concentration evaluated with TSB-agar plates. The initial increase of the number concentration was attributed to the growth of multiple small bacteria from the lysate of each large microorganism, which was demonstrated in the experiments with baker's yeast as the starting culture for digestion. The fluorescence profiles observed in the yeast experiments were similar to those in the sludge experiments. Responding to glucose additions and the switch from aerobic to anaerobic conditions, the yeast systems showed typical step increases of fluorescence as expected from the change of NAD(P)H level associated with heterotrophic metabolism. However, no such fluorescence responses were detectable in the sludge digestion systems. NAD(P)H were thus uncertain to be responsible for the online fluorescence observed. Nonetheless, the initial fluorescence plateau corresponded to the period of rapid digestion and, for the plant studied, the EPA regulation criteria of VSS reduction >38% and/or SOUR <1.5 mg of O(2) (g of TS)(-)(1) h(-)(1) were satisfied at the end of the plateau. The online fluorescence provides an effective means of monitoring the aerobic sludge digestion process.

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Section: Resultsmentioning

confidence: 99%

On-line Fluorescence Profile of Aerobic Sludge Digestion

1999

Biotechnol. Prog.

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“…Farrell et al (1996) reported that the coefficient of variation for total solids and volatile solids concentrations was 2.0%. Intrinsic data for both the %VSR and AVSR tests are based on data published in the White House Document.…”

Section: Weftec 2002mentioning

confidence: 99%

Developing Protocols for Measuring Biosolids Stability

Switzenbaum¹,

Pincince²,

Donovan³

et al. 2002

proc water environ fed

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A study was conducted to validate test protocols commonly used to assess the stability of various biosolids products and to specify a standard for each test method. A comprehensive and coordinated effort involving a literature review, a selected survey of practicing facilities, and a sampling and analysis program were performed. Information concerning stability testing protocols and data for each of the biosolids stabilization technologies evaluated (aerobic digestion and anaerobic digestion, alkaline stabilization, and composting) and testing methods (specific oxygen uptake rate, volatile solids reduction and additional volatile solids reduction; pH and changes in pH, and carbon dioxide evolution) were collected and evaluated.Specific protocols for each of the five testing methods are recommended. For each of the specific protocols, intrinsic precision data (that is related to the test) are presented. In addition, data are presented from facilities using each protocol to evaluate the collective degree of variability associated with each stabilization process. Using split -sample testing, interlaboratory data (variability among different laboratories) are presented. Issues associated with variability, sources of error, shortcomings and numerical criteria values are discussed for each method.

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Storage of Sewage Sludge and Biosolids

Shammas

Wang

2008

Biosolids Engineering and Management

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Development of EPA's new methods to quantify vector attraction of wastewater sludges

Cited by 8 publications

References 1 publication

On-line Fluorescence Profile of Aerobic Sludge Digestion

On-line Fluorescence Profile of Aerobic Sludge Digestion

Developing Protocols for Measuring Biosolids Stability

Storage of Sewage Sludge and Biosolids

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