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

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...

Full description

Saved in:
Bibliographic Details
Published in:Microorganisms (Basel) 2020-03, Vol.8 (3), p.376
Main Authors: F Santos, Andreia, P Santos, Cátia, M Matos, Ana, Cardoso, Olga, J Quina, Margarida
Format: Article
Language:English
Subjects:
Agriculture
Alkaline wastes
Anaerobic digestion
Chemical treatment
Circular economy
Coal
Composting
Contamination
Drying
E coli
Egg shells
Fly ash
Landfill
Microbial contamination
Microorganisms
organic wastes
pathogenic contamination
Phosphorus
Pollutants
Room temperature
Salmonella
Sanitation
Sewage sludge
soil application
Soil contamination
Soil lime
Wastes
Wastewater treatment
Wastewater treatment plants
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary: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 ( and 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 limit, regardless of the initial moisture or contamination. Additionally, CaO (obtained from eggshell) led to the complete elimination of at any dosage studied (0.05-0.15 g/g SS ). GLD evidenced the ability to reduce 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.
ISSN:2076-2607
2076-2607
DOI:10.3390/microorganisms8030376