1
|
Gemza N, Janiak K, Zięba B, Przyszlak J, Kuśnierz M. Long-term effects of hydrocyclone operation on activated sludge morphology and full-scale secondary settling tank wet-weather operation in long sludge age WWTP. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 845:157224. [PMID: 35835188 DOI: 10.1016/j.scitotenv.2022.157224] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Revised: 06/30/2022] [Accepted: 07/04/2022] [Indexed: 06/15/2023]
Abstract
This paper presents the study concerning long-term effects of a full scale hydrocyclone unit implemented in a continuous flow long sludge age system, on sedimentation, treatment efficiency and sludge morphology. The research concentrates on identifying the mechanisms of sludge behaviour within the system. The gravimetric selection of activated sludge via a hydrocyclone is a recent development for enhancing sludge separation, where heavier flocs are retained in the system, and lighter ones are discarded as waste sludge. The effects of implementing hydroclyclones were analysed with the use of SEM imagining and fractal dimensioning through the frequent assessment of sludge settling capabilities, effluent quality, and floc properties. Over the course of 60 weeks of hydrocyclone operation, sedimentation efficiency varied significantly. Sludge volume index values of 40 mL/g, achieved during the warm season, were not sustained when the temperature decreased and an overgrowth of filamentous bacteria occurred. Good settling efficiency was also observed in batch tests, where settling velocity of experimental sludge was app. 1 m/h higher than for the reference train at the same concentrations. This was confirmed during wet weather, as the experimental train sustained safe sludge blanket height in secondary clarifiers. SEM imaging and fractal dimension analysis revealed that the underflow that returned to the system had a more compact and spherical shape, which led to an increased content of granule-like particles in the reactor. The presence of flocs with a diameter exceeding 900 μm in the underflow, which is not observed in the feed, indicated agglomeration within the hydrocyclone. This is contradictory to most of the literature data coming from laboratory experiments. This phenomenon was attributed to differences in the size and geometry of the used hydrocyclones, and the potential process mechanism was presented.
Collapse
Affiliation(s)
- Natalia Gemza
- Faculty of Environmental Engineering, Wroclaw University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wroclaw, Poland; Wroclaw Municipal Water and Sewage Company, Na Grobli 19, 50-421 Wroclaw, Poland.
| | - Kamil Janiak
- Faculty of Environmental Engineering, Wroclaw University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wroclaw, Poland; Wroclaw Municipal Water and Sewage Company, Na Grobli 19, 50-421 Wroclaw, Poland
| | - Bartosz Zięba
- Faculty of Environmental Engineering, Wroclaw University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wroclaw, Poland
| | - Jacek Przyszlak
- Wroclaw Municipal Water and Sewage Company, Na Grobli 19, 50-421 Wroclaw, Poland
| | - Magdalena Kuśnierz
- The Faculty of Environmental Engineering and Geodesy, Wroclaw University of Environmental and Life Sciences, Norwida 25, 50-375 Wroclaw, Poland
| |
Collapse
|
2
|
Roman MD, Sava C, Iluțiu-Varvara DA, Mare R, Pruteanu LL, Pică EM, Jäntschi L. Biological Activated Sludge from Wastewater Treatment Plant before and during the COVID-19 Pandemic. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:11323. [PMID: 36141596 PMCID: PMC9517470 DOI: 10.3390/ijerph191811323] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Revised: 08/31/2022] [Accepted: 09/05/2022] [Indexed: 06/16/2023]
Abstract
The COVID-19 pandemic and the related measures brought a change in daily life that affected the characteristics of the municipal wastewater and further, of the biological activated sludge. The activated sludge process is the most widely used biological wastewater treatment process in developed areas. In this paper, we aim to show the situation of specific investigations concerning the variation of the physicochemical parameters and biological composition of the activated sludge from one conventional wastewater treatment plant from a metropolitan area. The investigations were carried out for three years: 2019, 2020 and 2021. The results showed the most representative taxa of microorganisms: Microtrix, Aspidisca cicada, Vorticella convallaria, Ciliata free of the unknown and Epistylis and Rotifers. Even if other microorganisms were found in the sludge flocs, their small presence did not influence in any way the quality of the activated sludge and of the wastewater treatment process. That is why we conclude that protozoa (especially Flagellates and Ciliates) and rotifers were the most important. Together with the values and variation of the physicochemical parameters, they indicated a good, healthy, and stable activated sludge, along with an efficient purifying treatment process, no matter the loading conditions.
Collapse
Affiliation(s)
- Marius-Daniel Roman
- Faculty of Building Services Engineering, Technical University of Cluj-Napoca, 28 Memorandumului Street, 400114 Cluj-Napoca, Romania
| | - Cornel Sava
- Faculty of Engineering Materials and the Environment, Technical University of Cluj-Napoca, 28 Memorandumului Street, 400114 Cluj-Napoca, Romania
| | - Dana-Adriana Iluțiu-Varvara
- Faculty of Building Services Engineering, Technical University of Cluj-Napoca, 28 Memorandumului Street, 400114 Cluj-Napoca, Romania
| | - Roxana Mare
- Faculty of Building Services Engineering, Technical University of Cluj-Napoca, 28 Memorandumului Street, 400114 Cluj-Napoca, Romania
| | - Lavinia-Lorena Pruteanu
- Department of Chemistry and Biology, North University Center at Baia Mare, Technical University of Cluj-Napoca, 76 Victoriei Street, 430122 Baia Mare, Romania
| | - Elena Maria Pică
- Faculty of Engineering Materials and the Environment, Technical University of Cluj-Napoca, 28 Memorandumului Street, 400114 Cluj-Napoca, Romania
| | - Lorentz Jäntschi
- Department of Physics and Chemistry, Technical University of Cluj-Napoca, 103-105 Bd. Muncii, 400641 Cluj-Napoca, Romania
- Institute for Doctoral Studies, Babes-Bolyai University, 1 M. Kogălniceanu Street, 400084 Cluj-Napoca, Romania
| |
Collapse
|
3
|
Li L, Mazurowski L, Dewan A, Carine M, Haak L, Guarin TC, Dastjerdi NG, Gerrity D, Mentzer C, Pagilla KR. Longitudinal monitoring of SARS-CoV-2 in wastewater using viral genetic markers and the estimation of unconfirmed COVID-19 cases. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 817:152958. [PMID: 35016937 PMCID: PMC8743272 DOI: 10.1016/j.scitotenv.2022.152958] [Citation(s) in RCA: 32] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Revised: 12/21/2021] [Accepted: 01/03/2022] [Indexed: 05/18/2023]
Abstract
In this study, wastewater-based surveillance was carried out to establish the correlation between SARS-CoV-2 viral RNA concentrations in wastewater and the incidence of corona virus disease 2019 (COVID-19) from clinical testing. The influent wastewater of three major water reclamation facilities (WRFs) in Northern Nevada, serving a population of 390,750, was monitored for SARS-CoV-2 viral RNA gene markers, N1 and N2, from June 2020 through September 2021. A total of 614 samples were collected and analyzed. The SARS-CoV-2 concentrations in wastewater were observed to peak twice during the study period. A moderate correlation trend between coronavirus disease 2019 (COVID-19) incidence data from clinical testing and SARS-CoV-2 viral RNA concentrations in wastewater was observed (Spearman r = 0.533). This correlation improved when using weekly average SARS-CoV-2 marker concentrations of wastewater and clinical case data (Spearman r = 0.790), presumably by mitigating the inherent variability of the environmental dataset and the effects of clinical testing artifacts (e.g., reporting lags). The research also demonstrated the value of wastewater-based surveillance as an early warning signal for early detection of trends in COVID-19 incidence. This was accomplished by identifying that the reported clinical cases had a stronger correlation to SARS-CoV-2 wastewater monitoring data when they were estimated to lag 7-days behind the wastewater data. The results aided local decision makers in developing strategies to manage COVID-19 in the region and provide a framework for how wastewater-based surveillance can be applied across localities to enhance the public health monitoring of the ongoing pandemic.
Collapse
Affiliation(s)
- Lin Li
- Department of Civil and Environmental Engineering, University of Nevada Reno, Reno, NV 89557, USA
| | - Lauren Mazurowski
- Department of Civil and Environmental Engineering, University of Nevada Reno, Reno, NV 89557, USA
| | - Aimee Dewan
- Department of Civil and Environmental Engineering, University of Nevada Reno, Reno, NV 89557, USA
| | - Madeline Carine
- Department of Civil and Environmental Engineering, University of Nevada Reno, Reno, NV 89557, USA
| | - Laura Haak
- Department of Civil and Environmental Engineering, University of Nevada Reno, Reno, NV 89557, USA
| | - Tatiana C Guarin
- Department of Civil and Environmental Engineering, University of Nevada Reno, Reno, NV 89557, USA
| | | | - Daniel Gerrity
- Southern Nevada Water Authority, P.O. Box 99954, Las Vegas, NV 89193, USA
| | - Casey Mentzer
- Truckee Meadows Water Reclamation Facility, Sparks, NV 89502, USA
| | - Krishna R Pagilla
- Department of Civil and Environmental Engineering, University of Nevada Reno, Reno, NV 89557, USA.
| |
Collapse
|
4
|
Haak L, Delic B, Li L, Guarin T, Mazurowski L, Dastjerdi NG, Dewan A, Pagilla K. Spatial and temporal variability and data bias in wastewater surveillance of SARS-CoV-2 in a sewer system. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 805:150390. [PMID: 34818797 PMCID: PMC8445773 DOI: 10.1016/j.scitotenv.2021.150390] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Revised: 08/31/2021] [Accepted: 09/13/2021] [Indexed: 05/04/2023]
Abstract
The response to disease outbreaks, such as SARS-CoV-2, can be constrained by a limited ability to measure disease prevalence early at a localized level. Wastewater based epidemiology is a powerful tool identifying disease spread from pooled community sewer networks or at influent to wastewater treatment plants. However, this approach is often not applied at a granular level that permits detection of local hot spots. This study examines the spatial patterns of SARS-CoV-2 in sewage through a spatial sampling strategy across neighborhood-scale sewershed catchments. Sampling was conducted across the Reno-Sparks metropolitan area from November to mid-December of 2020. This research utilized local spatial autocorrelation tests to identify the evolution of statistically significant neighborhood hot spots in sewershed sub-catchments that were identified to lead waves of infection, with adjacent neighborhoods observed to lag with increasing viral RNA concentrations over subsequent dates. The correlations between the sub-catchments over the sampling period were also characterized using principal component analysis. Results identified distinct time series patterns, with sewersheds in the urban center, outlying suburban areas, and outlying urbanized districts generally following unique trends over the sampling period. Several demographic parameters were identified as having important gradients across these areas, namely population density, poverty levels, household income, and age. These results provide a more strategic approach to identify disease outbreaks at the neighborhood level and characterized how sampling site selection could be designed based on the spatial and demographic characteristics of neighborhoods.
Collapse
Affiliation(s)
- Laura Haak
- Department of Civil and Environmental Engineering, University of Nevada, MS-0258, Reno, NV 89557-0258, USA
| | - Blaga Delic
- Department of Civil and Environmental Engineering, University of Nevada, MS-0258, Reno, NV 89557-0258, USA
| | - Lin Li
- Department of Civil and Environmental Engineering, University of Nevada, MS-0258, Reno, NV 89557-0258, USA
| | - Tatiana Guarin
- Department of Civil and Environmental Engineering, University of Nevada, MS-0258, Reno, NV 89557-0258, USA
| | - Lauren Mazurowski
- Department of Civil and Environmental Engineering, University of Nevada, MS-0258, Reno, NV 89557-0258, USA
| | - Niloufar Gharoon Dastjerdi
- Department of Civil and Environmental Engineering, University of Nevada, MS-0258, Reno, NV 89557-0258, USA
| | - Aimee Dewan
- Department of Civil and Environmental Engineering, University of Nevada, MS-0258, Reno, NV 89557-0258, USA
| | - Krishna Pagilla
- Department of Civil and Environmental Engineering, University of Nevada, MS-0258, Reno, NV 89557-0258, USA.
| |
Collapse
|
5
|
Gharoon N, Dewan A, Li L, Haak L, Mazurowski L, Guarin T, Pagilla K. Removal of SARS-CoV-2 viral markers through a water reclamation facility. WATER ENVIRONMENT RESEARCH : A RESEARCH PUBLICATION OF THE WATER ENVIRONMENT FEDERATION 2021; 93:2819-2827. [PMID: 34528319 PMCID: PMC8661921 DOI: 10.1002/wer.1641] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Revised: 09/08/2021] [Accepted: 09/10/2021] [Indexed: 05/09/2023]
Abstract
There have been multiple reports of COVID-19 virus, SARS-CoV-2 RNA presence in influent wastewater of water reclamation facilities (WRFs) across the world. In this study, the removal of SARS-CoV-2 RNA was investigated in a WRF by collecting samples from various stages relayed to hydraulic retention time (HRT) and analyzed for viral RNA (N1 and N2) gene markers and wastewater characteristics. SARS-CoV-2 RNA was detected in 28 out of 28 influent wastewater and primary effluent samples. Secondary effluent showed 4 out of 9 positive samples, and all tertiary and final effluent samples were below the detection limit for the viral markers. The reduction was significant (p value < 0.005, one-way analysis of variance [ANOVA] test) in secondary treatment, ranging from 1.4 to 2.0 log10 removal. Adjusted N1 viral marker had a positive correlation with total suspended solids, total Kjeldahl nitrogen, and ammonia concentrations (Spearman's ρ = 0.61, 0.67, and 0.53, respectively, p value < 0.05), while demonstrating a strongly negative correlation with HRT (Spearman's ρ = -0.58, p value < 0.01). PRACTITIONER POINTS: Viral RNA was present in all samples taken from influent and primary effluent of a WRF. SARS-CoV-2 gene marker was detected in secondary effluent in 4 out of 9 samples. Tertiary and final effluent samples tested nondetect for SARS-CoV-2 gene markers. Up to 0.5 and 2.0 log10 virus removal values were achieved by primary and secondary treatment, respectively.
Collapse
Affiliation(s)
- Niloufar Gharoon
- Department of Civil and Environmental EngineeringUniversity of Nevada RenoRenoNVUSA
| | - Aimee Dewan
- Department of Civil and Environmental EngineeringUniversity of Nevada RenoRenoNVUSA
| | - Lin Li
- Department of Civil and Environmental EngineeringUniversity of Nevada RenoRenoNVUSA
| | - Laura Haak
- Department of Civil and Environmental EngineeringUniversity of Nevada RenoRenoNVUSA
| | - Lauren Mazurowski
- Department of Civil and Environmental EngineeringUniversity of Nevada RenoRenoNVUSA
| | - Tatiana Guarin
- Department of Civil and Environmental EngineeringUniversity of Nevada RenoRenoNVUSA
| | - Krishna Pagilla
- Department of Civil and Environmental EngineeringUniversity of Nevada RenoRenoNVUSA
| |
Collapse
|