Effects of Waste Activated Sludge Extracellular Polymeric Substances on Biosorption
Extracellular polymeric substances (EPS) reportedly make up approximately half of the organic matter in activated sludge (AS), and therefore strongly influence AS properties. This study evaluated the component fractions of EPS normalized to volatile suspended solids (VSS) in waste activated sludge (...
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MDPI AG
2022-01-01
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| Series: | Water |
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| Online Access: | https://www.mdpi.com/2073-4441/14/2/218 |
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| author | Tiow Ping Wong Roger W. Babcock Theodore Uekawa Joachim Schneider Bing Hu |
| author_facet | Tiow Ping Wong Roger W. Babcock Theodore Uekawa Joachim Schneider Bing Hu |
| author_sort | Tiow Ping Wong |
| collection | DOAJ |
| description | Extracellular polymeric substances (EPS) reportedly make up approximately half of the organic matter in activated sludge (AS), and therefore strongly influence AS properties. This study evaluated the component fractions of EPS normalized to volatile suspended solids (VSS) in waste activated sludge (WAS) from a trickling-filter-solids contact process (TF/SC) and its ability to biosorb organic matter from raw wastewater with 30 min of contact time. Biosorption is the process in which organic matter (carbohydrates, proteins, humic acids, DNA, uronic acids, and lipids) in a sorbate, such as raw wastewater, sorbs onto a sorbent such as WAS. A statistically significant correlation was found between both the total concentration of EPS and the proteins component of the EPS and the biosorption removal of soluble chemical oxygen demand (sCOD) and truly soluble COD (ffCOD). Thus, the biosorption of soluble forms of COD can accurately be predicted by quantifying just the amount of proteins in WAS-associated EPS. No significant correlations were found for the biosorption of colloidal COD (cCOD). WAS biosorbed 45–75 mg L<sup>−1</sup> of COD in 30 min. WAS absorbed or stored the proteins fraction of the soluble microbial products (SMP) during the biosorption process. Higher concentrations of humic acids were found in the biosorption process effluent than in the untreated wastewater, which warrants further study. Longer cation exchange resin (CER) extraction times yielded more total EPS from the sludge: 90 ± 9, 158 ± 3, and 316 ± 44 mg g<sup>−1</sup> VSS, for 45-min, 4-h, and 24-h extraction times, respectively. Thus, EPS extracted represented only 9%, 15.8%, and 31.6% of the VSS, respectively, raising questions about whether the accurate characterization of EPS can be performed using the typical extraction time of 45 min due to different extraction rates for different components. It was found that the humic acids fraction was extracted much more slowly than the other fractions. |
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| last_indexed | 2024-03-10T00:19:39Z |
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| spelling | doaj.art-33e0b76aff16416db738bf2da4ce1b9a2023-11-23T15:44:46ZengMDPI AGWater2073-44412022-01-0114221810.3390/w14020218Effects of Waste Activated Sludge Extracellular Polymeric Substances on BiosorptionTiow Ping Wong0Roger W. Babcock1Theodore Uekawa2Joachim Schneider3Bing Hu4Department of Civil and Environmental Engineering, University of Hawaiʻi at Mānoa, Honolulu, HI 96822, USADepartment of Civil and Environmental Engineering, University of Hawaiʻi at Mānoa, Honolulu, HI 96822, USADepartment of Civil and Environmental Engineering, University of Hawaiʻi at Mānoa, Honolulu, HI 96822, USADepartment of Civil and Environmental Engineering, University of Hawaiʻi at Mānoa, Honolulu, HI 96822, USADepartment of Civil and Environmental Engineering, University of Hawaiʻi at Mānoa, Honolulu, HI 96822, USAExtracellular polymeric substances (EPS) reportedly make up approximately half of the organic matter in activated sludge (AS), and therefore strongly influence AS properties. This study evaluated the component fractions of EPS normalized to volatile suspended solids (VSS) in waste activated sludge (WAS) from a trickling-filter-solids contact process (TF/SC) and its ability to biosorb organic matter from raw wastewater with 30 min of contact time. Biosorption is the process in which organic matter (carbohydrates, proteins, humic acids, DNA, uronic acids, and lipids) in a sorbate, such as raw wastewater, sorbs onto a sorbent such as WAS. A statistically significant correlation was found between both the total concentration of EPS and the proteins component of the EPS and the biosorption removal of soluble chemical oxygen demand (sCOD) and truly soluble COD (ffCOD). Thus, the biosorption of soluble forms of COD can accurately be predicted by quantifying just the amount of proteins in WAS-associated EPS. No significant correlations were found for the biosorption of colloidal COD (cCOD). WAS biosorbed 45–75 mg L<sup>−1</sup> of COD in 30 min. WAS absorbed or stored the proteins fraction of the soluble microbial products (SMP) during the biosorption process. Higher concentrations of humic acids were found in the biosorption process effluent than in the untreated wastewater, which warrants further study. Longer cation exchange resin (CER) extraction times yielded more total EPS from the sludge: 90 ± 9, 158 ± 3, and 316 ± 44 mg g<sup>−1</sup> VSS, for 45-min, 4-h, and 24-h extraction times, respectively. Thus, EPS extracted represented only 9%, 15.8%, and 31.6% of the VSS, respectively, raising questions about whether the accurate characterization of EPS can be performed using the typical extraction time of 45 min due to different extraction rates for different components. It was found that the humic acids fraction was extracted much more slowly than the other fractions.https://www.mdpi.com/2073-4441/14/2/218biosorptionextracellular polymeric substancescation exchange resinbiofilmhigh-rate biological contactorprimary wastewater treatment |
| spellingShingle | Tiow Ping Wong Roger W. Babcock Theodore Uekawa Joachim Schneider Bing Hu Effects of Waste Activated Sludge Extracellular Polymeric Substances on Biosorption Water biosorption extracellular polymeric substances cation exchange resin biofilm high-rate biological contactor primary wastewater treatment |
| title | Effects of Waste Activated Sludge Extracellular Polymeric Substances on Biosorption |
| title_full | Effects of Waste Activated Sludge Extracellular Polymeric Substances on Biosorption |
| title_fullStr | Effects of Waste Activated Sludge Extracellular Polymeric Substances on Biosorption |
| title_full_unstemmed | Effects of Waste Activated Sludge Extracellular Polymeric Substances on Biosorption |
| title_short | Effects of Waste Activated Sludge Extracellular Polymeric Substances on Biosorption |
| title_sort | effects of waste activated sludge extracellular polymeric substances on biosorption |
| topic | biosorption extracellular polymeric substances cation exchange resin biofilm high-rate biological contactor primary wastewater treatment |
| url | https://www.mdpi.com/2073-4441/14/2/218 |
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