Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) started in Wuhan, China, in December 2019 and became a global pandemic [1]. By 26 April 2020, more than 2.9 million people were infected by SARS-CoV-2 and over 203 thousand people lost their life globally. By 26 April 2020, 107773 confirmed cases were reported in Turkey with 2706 deaths. Majority of the cases in Turkey has been observed in Istanbul. In the world, the duration of availability of SARS-CoV-2 was found to be significantly longer in stool samples than in respiratory and serum samples [2]. SARS-CoV-2 was detected in wastewaters in Australia [3], Netherlands [4], USA [5], France [6], Spain [7] and USA [8] by using different virus concentration techniques. In this work, Istanbul metropole with 65 % of Covid-19 cases was chosen as the pilot city. On the 21st of April 2020, 24-hr composite samples were collected from the Ambarli, Pasakoy and Kadikoy wastewater treatment plants (WWTP). On the 25 th of April 2020, more wastewater samples were taken from Terkos, Buyukcekmece, Baltalimani and Tuzla WWTPs. These wastewater treatment plants were selected among 81 plants in Istanbul in order to take representative samples from 4 different districts of Istanbul according to the severity of Covid-19 cases, like very serious, serious, moderate and mild. Grab samples were also collected from Bagcilar and Kartal manholes located nearby the pandemic All rights reserved. No reuse allowed without permission.was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.

No abstract

In this study, the activity and diversity of nitrogen converters, ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB), ammonia-oxidizing archaea (AOA) and Anammox bacteria in a pilot-scale membrane bioreactor (MBR) were investigated and monitored using amoA and 16S rDNA-based molecular tools. The pilot-scale MBR (100 m(3)/day) was located inside the full-scale Pasakoy Advanced Wastewater Treatment Plant (WWTP), and operated for approximately 5 months without sludge purge. During 148 days of operation, volatile suspended solids (VSS) concentration increased from 2,454 mg/L to 10,855 mg/L and the average organic carbon and ammonia nitrogen removal rates were 92% and 99%, respectively. Real-time PCR results indicated that the fraction of AOB increased from 2.94% to 4.05% when VSS concentration reached to 3,750 mg/L throughout 148 days of operation. At higher VSS concentrations, the fraction of AOB declined gradually to 1.15% while the fraction of Nitrospira population was varied between 8.23 and 13.01%. However, significant change or any positive and negative correlations between VSS concentration and Nitrospira population were not observed in this period. The phylogenetic analysis revealed that MBR harbored diverse AOB community which was related to the Nitrosomonas and Nitrosospira lineage. Candidatus Nitrospira defluvii was the only detected NOB in this study.

In this study ultrafiltration has been used for the fractionation of humic acid samples. Humic acids were treated in a sequential oxidation system in which ozonation was followed by photocatalytic oxidation using TiO2. Evaluation of the spectroscopic characteristics of the oxidized and fractionated humic acid samples have shown that molecular size distribution ranges shift to lower molecular sizes depending on the oxidation stages. Applied ozone dosage and irradiation time during the photocatalysis stage are the factors affecting the molecular size distribution in the treated humic acid samples. Formation of lower molecular weight compounds during the ozonation stage resulted in increased degradation rates during the photocatalysis stage.

In this study, characterization and anaerobic treatability of leachate from Komurcuoda Sanitary Landfill located on the Asian part of Istanbul were investigated. Time based fluctuations in characteristics of leachate were monitored for an 8 month period. Samples were taken from a 200 m3 holding tank located at the lowest elevation of the landfill. COD concentrations have ranged between 18,800 and 47,800 mg/l while BOD5 between 6820 and 38,500 mg/L. COD and BOD5 values were higher in summer and lower in winter due to dilution by precipitation. On the other hand, it was quite interesting that such a dilution effect was not observed for ammonia. The highest ammonia concentration, 2690 mg/L was in November 1998. BOD5/COD ratio was larger than 0.7 for most samples indicating high biodegradability, and acidic phase of decomposition in the landfill. For anaerobic treatability, three different reactors, namely an upflow anaerobic sludge bed reactor, an anaerobic upflow filter and a hybrid bed reactor, were used. The anaerobic reactors were operated for more than 230 days and were continuing operation when this paper was prepared. Organic loading was increased gradually from 1.3 kg COD/m3.day to 8.2 kg COD/m3.day while hydraulic retention time was reduced from 2.4 days to 2.0 days. All the reactors showed similar performances against organic loadings with efficiencies between 80% and 90%. However the reactors have experienced high ammonia concentrations several times throughout the experimental period, and showed different inhibition levels. Anaerobic filter was the least affected reactor while UASB was the most. Hybrid bed reactor has exhibited a similar performance to anaerobic filter although not to the same degree.