Isothermal drying kinetics of sewage sludge using weathered coal fly ash as adjuvant for agronomic application

Gomes, Luciano A.; Santos, Andreia F.; Lopes, Rui J. A.; Góis, José C.; Quina, Margarida J.

doi:10.1080/09593330.2019.1700311

Cited by 6 publications

(3 citation statements)

References 36 publications

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“…This contamination is due to the fact that this WWTP receives an industrial effluent from a metalworking industry with high concentrations of these refractory elements to biological processes. Overall, the PTM concentration is not a hampering factor to valorize Portuguese SS on the soil, which is in agreement with other reports in the literature [25,27]. Figure 1 summarizes the E. coli and Salmonella spp.…”

Section: Physical and Chemical Properties Of The Sewage Sludgesupporting

confidence: 90%

“…Subsequently, the temperature becomes constant and equal to the wet-bulb temperature. In the end, the temperature inside the sample rises until it reaches the chamber temperature [25,30]. According to the temperature profile in Figure 4a, it is possible to notice that at 70 • C, the temperature inside the solid was about 44 • C until moisture reached 50% and then rose to 65 • C when 30% of moisture had been reached.…”

Section: Sanitation Effect Of Thermal Treatmentmentioning

confidence: 96%

“…The SS samples (UM4, AD1.3, and AD1.4) were dried at 70, 100, and 130 • C until 50% and 30% moisture to evaluate the effect of the temperature on E. coli enumeration. Based on previous studies [25], about 40 g of SS were shaped in small cylinders (5 mm diameter and 30 mm length) and dried in a Moisture Analyzer, Precisa XM50. The weight was recorded until achieving the required moisture.…”

Section: Thermal Treatmentmentioning

confidence: 99%

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Effect of Thermal Drying and Chemical Treatments with Wastes on Microbiological Contamination Indicators in Sewage Sludge

Santos

Matos

et al. 2020

Microorganisms

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This work aims to evaluate the microbiological contamination of sewage sludge (SS) collected in urban wastewater treatment plants (WWTP) from Portugal. Two types of SS were considered: urban mixed (UM) and from anaerobic digestion (AD). The two types of samples were characterized in relation to the main physical and chemical parameters, as well as the microbiological contamination (Escherichia coli and Salmonella spp). Then, sanitation tests were conducted through thermal drying and chemical treatments. Towards a circular economy, industrial alkaline wastes (green liquor dregs -GLD, lime mud, coal fly ash, eggshell) were tested as alternatives to lime. Only six out of nineteen samples complied with the legal limits for both microorganisms. However, drying at 130 • C sanitized selected samples below the E. coli limit, regardless of the initial moisture or contamination. Additionally, CaO (obtained from eggshell) led to the complete elimination of E. coli at any dosage studied (0.05-0.15 g/g SS wet basis ). GLD evidenced the ability to reduce E. coli contamination at room temperature, but not enough to comply with the legal limit. In general, this work highlights the need to sanitize the SS before its application to the soil, and the positive role of some wastes on this goal.