scholarly journals First comparison of conventional activated sludge versus root-zone treatment for SARS-CoV-2 RNA removal from wastewaters: statistical and temporal significance

2021 ◽  
Author(s):  
Manish Kumar ◽  
Madhvi Joshi ◽  
Keisuke Kuroda ◽  
Prosun Bhattacharya ◽  
Damia Barcello
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Root Zone ◽  
Genetic Material ◽  
Treatment Plant ◽  
Temporal Variations ◽  
Conventional Activated Sludge ◽  
Treatment Processes ◽  
Treatment Facilities ◽  
Respiratory Coronavirus

In the initial pandemic phase, effluents from wastewater treatment facilities were reported mostly free from Severe Acute Respiratory Coronavirus 2 (SARS-CoV-2) RNA, and thus conventional wastewater treatments were generally considered effective. However, there is a lack of first-hand data on i) comparative efficacy of various treatment processes for SARS-CoV-2 RNA removal; and ii) temporal variations in the removal efficacy of a given treatment process in the backdrop of active COVID-19 cases. This work provides a comparative account of the removal efficacy of conventional activated sludge (CAS) and root zone treatments (RZT) based on weekly wastewater surveillance data, consisting of forty-four samples, during a two-month period. The average genome concentration was higher in the inlets of CAS-based wastewater treatment plant in the Sargasan ward (1.25 x 103 copies/ L), than that of RZT plant (7.07 x 102 copies/ L) in an academic institution campus of Gandhinagar, Gujarat, India. ORF 1ab and S genes appeared to be more sensitive to treatment i.e., significantly reduced (p <0.05) than N genes (p>0.05). CAS treatment exhibited better RNA removal efficacy (p=0.014) than RZT (p=0.032). Multivariate analyses suggested that the effective genome concentration should be calculated based on the presence/absence of multiple genes. The present study stresses that treated effluents are not always free from SARS-CoV-2 RNA, and the removal efficacy of a given WWTPs is prone to exhibit temporal variability owing to variations in active COVID-19 cases in the vicinity and genetic material accumulation over the time. Disinfection seems less effective than the adsorption and coagulation processes for SARS-CoV-2 removal. Results stress the need for further research on mechanistic insight on SARS-CoV-2 removal through various treatment processes taking solid-liquid partitioning into account.

scholarly journals LCA of a Membrane Bioreactor Compared to Activated Sludge System for Municipal Wastewater Treatment

Membranes ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 421
Author(s):  
Dimitra C. Banti ◽  
Michail Tsangas ◽  
Petros Samaras ◽  
Antonis Zorpas
Keyword(s):  
Wastewater Treatment ◽  
Life Cycle ◽  
Activated Sludge ◽  
Membrane Bioreactor ◽  
Municipal Wastewater ◽  
Wastewater Treatment Plants ◽  
Treatment Plant ◽  
Real Data ◽  
Municipal Wastewater Treatment ◽  
Conventional Activated Sludge

Membrane bioreactor (MBR) systems are connected to several advantages compared to the conventional activated sludge (CAS) units. This work aims to the examination of the life cycle environmental impact of an MBR against a CAS unit when treating municipal wastewater with similar influent loading (BOD = 400 mg/L) and giving similar high-quality effluent (BOD < 5 mg/L). The MBR unit contained a denitrification, an aeration and a membrane tank, whereas the CAS unit included an equalization, a denitrification, a nitrification, a sedimentation, a mixing, a flocculation tank and a drum filter. Several impact categories factors were calculated by implementing the Life Cycle Assessment (LCA) methodology, including acidification potential, eutrophication potential, global warming potential (GWP), ozone depletion potential and photochemical ozone creation potential of the plants throughout their life cycle. Real data from two wastewater treatment plants were used. The research focused on two parameters which constitute the main differences between the two treatment plants: The excess sludge removal life cycle contribution—where GWPMBR = 0.50 kg CO2-eq*FU−1 and GWPCAS = 2.67 kg CO2-eq*FU−1 without sludge removal—and the wastewater treatment plant life cycle contribution—where GWPMBR = 0.002 kg CO2-eq*FU−1 and GWPCAS = 0.14 kg CO2-eq*FU−1 without land area contribution. Finally, in all the examined cases the environmental superiority of the MBR process was found.

Removal Characteristics of Human Antibiotics during Wastewater Treatment in Japan

2006 ◽  
Vol 1 (3) ◽  
Author(s):  
Y. Kobayashi ◽  
M. Yasojima ◽  
K. Komori ◽  
Y. Suzuki ◽  
H. Tanaka
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Wastewater Treatment Plants ◽  
Treatment Plant ◽  
Treatment Method ◽  
Batch Experiment ◽  
Aqueous Environment ◽  
Activated Sludge Process ◽  
Conventional Activated Sludge ◽  
Conventional Activated Sludge Process

Pharmaceuticals resident in sewage and in the aqueous environment has begun to attract attention. The objectives of this research were to clarify the behaviour of selected human antibiotics in wastewater treatment plants, namely levofloxacin (LVFX), clarithromycin (CAM) and azithromycin (AZM) which are much used in Japan. The concentrations in raw influent of LVFX, CAM, AZM were respectively 425~981ng/L, 340~573ng/L, ND(&lt;190 ng/L)~371ng/L. The averages of removal ratio were about 50 % for all selected antibiotics. It was suggested that selected antibiotics was not too much removed in the conventional creature processing like the conventional activated sludge process. The remarkable removals in activated sludge tank using high class treatment method were confirmed about all selected antibiotics. The rise of the concentrations of CAM and AZM was confirmed after the addition of chemical coagulants in one wastewater treatment plant. From the result of batch experiment with activated sludge, it was suggested that LVFX and AZM were removed from water mainly by the absorption to activated sludge. Also, in batch experiment with chemical coagulants, it was suggested that LVFX was removed from water and CAM, AZM were eluted a little in water by adding sulphuric acid band.

scholarly journals Aeration Process in Bioreactors as the Main Energy Consumer in a Wastewater Treatment Plant. Review of Solutions and Methods of Process Optimization

Processes ◽  
2019 ◽  
Vol 7 (5) ◽  
pp. 311 ◽  
Author(s):  
Jakub Drewnowski ◽  
Anna Remiszewska-Skwarek ◽  
Sylwia Duda ◽  
Grzegorz Łagód
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
High Efficiency ◽  
Good Condition ◽  
Treatment Plant ◽  
Treatment Technology ◽  
Conventional Activated Sludge ◽  
Smart Control ◽  
Biological Decomposition ◽  
Aeration Process

Due to the key role of the biological decomposition process of organic compounds in wastewater treatment, a very important thing is appropriate aeration of activated sludge, because microorganisms have to be supplied with an appropriate amount of oxygen. Aeration is one of the most energy-consuming processes in the conventional activated sludge systems of wastewater treatment technology (may consume from 50% to 90% of electricity used by a plant), which makes it the most cost-generating process incurred by treatment plants. The paper presents the construction of aeration systems, their classification as well as parameters and factors that significantly affect the aeration process e.g., oxygen transfer efficiency, diffuser fouling, methods of dealing with diffuser fouling, diffuser selection. Additionally, there are briefly presented “smart control” systems in wastewater treatment and effect of application control strategy based on Supervisory Control and Data Acquisition system connected with the decrease in the energy consumption for aeration of bioreactors with activated sludge. It is noted that before the process is optimized, the system should be equipped with suitable metering devices. Only when relevant data is available, the improvements can be carried out. However, it’s important, that the operator should regularly maintain good condition and high efficiency of diffusers.

scholarly journals Nitrification Processes in Tehran Wastewater Treatment Plant

2011 ◽  
Vol 2011 ◽  
pp. 1-9
Author(s):  
S. A. Sadrnejad
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Wastewater Treatment Plant ◽  
Treatment Plant ◽  
Primary Treatment ◽  
High Rate ◽  
Trickling Filter ◽  
Combined System ◽  
Conventional Activated Sludge ◽  
Balance Analysis

A wastewater treatment plant is designed to daily treat 450000 m3 of wastewater collected from the city of Tehran. The wastewater treatment plant is located at the south of Shahr-Ray in southern Tehran with the area of 110 hectares. The treatment plant effluent will be transferred to Varamin agricultural lands to be used for the irrigation of crops. A conventional activated sludge for carbon removal and a high-rate trickling filter for nitrification of ammonia to nitrate are designed and constructed. The treatment plant consists of inlet pumping station, primary treatment, primary sedimentation tanks, selector and aeration tanks, trickling filter, and sludge treatment units. A mass balance analysis method which is a new approach for optimum design is used to achieve cost saving for the construction of south Tehran wastewater treatment plant. The comparison between combined system of activated sludge with trickling filter and an activated sludge alone shows that the combined system is 20% less costly and more efficient for the treatment of Tehran wastewater, the system has low volume demand, maximum biogas yeild, and low process control and is less variable to pH and chemical effects and highly energy-efficient.

Survey on filamentous micro-organisms in activated sludge processes in Bangkok, Thailand

1995 ◽  
Vol 31 (9) ◽  
pp. 193-202 ◽  
Author(s):  
Takashi Mino
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Wastewater Treatment Plant ◽  
Treatment Plant ◽  
Brewery Wastewater ◽  
Tropical Zone ◽  
Milk Processing ◽  
Treatment Processes ◽  
Micro Organisms ◽  
Activated Sludge Processes

A survey to investigate the proliferation of filamentous micro-organisms, which cause filamentous bulking in activated sludge wastewater treatment processes, was conducted for the first time in the tropical zone. Activated sludge samples were collected from six wastewater treatment processes in Bangkok City, Thailand. The activated sludge plants investigated include those for 1) an industrial wastewater from an industrial estate, 2) a domestic wastewater from apartment houses, 3) a brewery wastewater, 4) a hotel wastewater, 5) a textile industry wastewater and 6) a milk processing wastewater. The identification of proliferating filamentous micro-organisms in the samples was attempted. Type 021N was exclusively dominant in the milk processing wastewater treatment plant. The characteristics of the 021N present were different from “typical” 021N. The most proliferating filament in the textile wastewater treatment plant was suspected to be Nostocoida limicola. There was a predominant filament in the brewery wastewater treatment plant, which is suspected to be a new type. Other major filaments proliferating include Eikelboom Type 021N, 1701, 0041 and 0092. Nocardia was also found in a few plants.

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