SARS-CoV-2 Detection in Istanbul Wastewater Treatment Plant Sludges

Abstract

Following the announcement of SARS-CoV-2 worldwide pandemic spread by WHO on March 11, 2020, wastewater based epidemiology received great attention in several countries: The Netherlands [Medama et al., 2020; K-Lodder et al., 2020], USA [Wu et al., 2020; Memudryi et al., 2020], Australia [Ahmed et al., 2020], France [Wurtzer et al., 2020], China [Wang et al., 2020], Spain [Randazzo et al., 2020; Walter et al., 2020], Italy (La Rosa et al., 2020; Rimoldi et al., 2020) and Israel [Or et al., 2020], performed analysis in wastewaters by using different virus concentration techniques. Turkey took its place among these countries on 7th of May, 2020 by reporting SARS-CoV-2 RT-qPCR levels at the inlet of seven (7) major municipal wastewater treatment plants (WWTPs) of Istanbul [Alpaslan Kocamemi et al., 2020], which is a metropole with 15.5 million inhabitants and a very high population density (2987 persons/km2) and having about 65 % of Covid-19 cases in Turkey. Sludges that are produced in WWTPs should be expected to contain SARS-CoV-2 virus as well. There has not yet been any study for the fate of SAR-CoV-2 in sludges generated from WWTPs. Knowledge about the existing of SARS-CoV-2 in sludge may be useful for handling the sludge during its dewatering, stabilizing and disposal processes. This information will also be valuable in case of sludges that are used as soil conditioners in agriculture or sent to landfill disposal. In wastewater treatment plants, generally two different types of sludges are generated; primary sludge (PS) and waste activated sludge (WAS). PS forms during the settling of wastewater by gravity in the primary settling tanks. Little decomposition occurs during primary sludge formation. Since most of the inorganic part of the wastewater is removed in the earlier grit removal process, the PS consists of mainly organic material that settles. The PS is about 1-2 % solids by weight. In the biological treatment part of the WWTPs, the biomass that forms in the anaerobic, anoxic and oxic zones of the process is settled in final clarifiers by gravity and returned to the beginning of the biological process so that it is not washed off. The waste activated sludge (WAS) is the excess part of the biomass that grows in this secondary treatment process. It has to be removed from the process not to increase the mixed liquor suspended solids concentration (bacteria concentration) in the secondary process more than a fixed value. The WAS is about 0.6 - 0.9 % solids by weight. This work aims to find whether SARS-CoV-19 is present in the PS and WAS before it is dewatered and sent to anaerobic or aerobic digester processes or to thermal drying operations. For this purpose, on the 7th of May 2020, two (2) PS samples were collected from Ambarlı and Tuzla WWTPs, seven (7) WAS samples were collected from Terkos, Ambarlı, Atakoy I & II, Pasakoy II, Buyukcekmece and Tuzla I WWTPs. Polyethylene glycol 8000 (PEG 8000) adsorption [Wu et al., 2020] SARS-Cov-2 concentration method was used for SARS-CoV-2 concentration after optimization. [Alpaslan Kocamemi et al., 2020]. Real time RT-PCR diagnostic panel validated by US was used to quantify SARS-CoV-2 RNA in primary and waste activated sludge samples taken from WWTPs in Istanbul. All samples were tested positive. Titers of SARS-CoV-2 have been detected ranging copies between 1.17E4 to 4.02x104 per liter.

Fecal Shedding of SARS-CoV-2 and Its Potential Role in Person-To-Person Transmission and the Environment-Based Spread of COVID-19

“…Wang et al, 2020). This is consistent with studies showing a 2 to 3 log10 removal efficiency in viral RNA abundance when comparing viral levels in influent and effluent (S Wurtzer et al, 2020) and the accumulation of SARS-CoV-2 in the sludge fraction (Peccia et al, 2020)(Alpaslan Kocamemi et al, 2020. If the sludge (biosolids) fraction is treated (e.g.…”

Fate of COVID-19 Occurrences in Wastewater Systems: Emerging Detection and Treatment Technologies—A Review

“…SARS-COV-2 RNA in wastewater from 19 communities in Australia, a median range of 171 to 1090 infected people were identified in the communities [19]. In the same study, they further stated that the viral RNA copies were enumerated using the reverse transcriptase quantitative polymerase chain reaction (RT-qPCR), resulting in two positive detections within a six-day period from the WWTPs [20][21][22][23][24].…”

“…Wastewater-based epidemiology (WBE) is a promising approach to better understand the occurrence of viruses in WWTP catchment population since the WW contains viruses excreted from symptomatic and asymptomatic individuals in a particular location under study [25]. Wastewater monitoring has a greater potential to provide early warning signs on how broadly SARS-CoV-2 is circulating in the community especially in the case of individuals showing mild symptoms or no symptoms at all [23,24]. Despite the applications of WBE in monitoring the outbreaks of enteric viruses such as norovirus, hepatitis virus, and poliovirus for public health interventions [25], there are still few studies documented on the concentration and detection of SARS-CoV-2 in wastewater settings [26].…”

“…The mandate and necessity for the use of biosensors for rapid analysis with cost-effectiveness require bio-fabrication that will pave the way to identify cellular to whole organism activity with a detection limit of high accuracy for single molecules [43]. Previous studies have reported that the rapid diagnosis of infectious diseases and apt initiation of appropriate treatment are typically assigned as determinants for the promotion of optimal clinical outcomes and that of the health of the public [7,20,23]. Other studies have reported that the conventional in vitro diagnostics for infectious diseases are time-consuming, requiring centralized laboratories, experienced personnel, and bulky equipment [32].…”

COVID 19: challenges for virologists in the food industry

“…A preprint report describes the quantification of SARS‐CoV‐2 RNA in primary and waste activated sludge samples taken from major municipal wastewater treatment plants in Istanbul. All samples tested positive with titres of SARS‐CoV‐2 ranging between 1 × 10 4 to 4 × 10 4 RNA genome copies per litre (Alpaslan Kocamemi et al ., 2020). It is currently not possible to precisely define an acceptable level of contamination for untreated sludge, or to specify a storage period beyond which the virus is inactivated.…”