SURVIVAL AND DISINFECTION OF SARS-COV-2 IN ENVIRONMENT AND CONTAMINATED SURFACE

The detection of SARS-Cov-2 in the sewage and water resources has increased the awareness among the people about the possibility survival of SARS-Cov-2 in the environment and the potential to transmit into the human through food chain or water resources. Moreover, the surface contaminated by the virus need to be disinfected frequently by using an effective disinfectant, the current chapter discussed the efficiency of the most traditional treatment process of the sewage and wastewater, and their role in the elimination of the virus as well as the sterility assurance level concept. Moreover, the chemical disinfectant used currently and their temporary efficiency has been reviewed.

transmission route through the respiratory droplets as well as survive for more than one day in the environment. It is hypothesized that there is a risk exposure of the virus to environmental surface, which has not yet identified. In a comparison to SARS-and MERS-CoV pandemic which has associated with super spreading (R is 3.5).
Therefore, the indoor and outdoor surface should be disinfected frequently [4,5]. This chapter aimed to review the environmental aspects for SARS-CoV -2. The presence of SARS-CoV -2 in the hospital wastewater and the suggested treatment of these wastes are discussed. Moreover, the disinfection of the virus contaminated surface was also discussed in this chapter.

SARS-COV-2 IN THE ENVIRONMENT
Hospital wastewater contains heavily load of pathogenic bacteria and viruses. However, SARS-COV-2 which is transmitting through fecal-oral route is the most concern associated with the disposal of hospital wastewater into the environment. It has been indicated by the researchers in the literature review that the pathogenicity and virulence factors of the infectious agents lie in the ability to survive in the environment as well as the high potential to transmit into the human and animals without a host cell [6]. Based on abovementioned, the hospital effluents should be subjected for an efficient disinfection process before the final disposal into the environment. However, there are two factors should be considered for any disinfection process, these factors are biological indicators Preprints (www.preprints.org) | NOT PEER-REVIEWED | Posted: 21 June 2020 doi:10 and the assessment procedure for the disinfection process. The selection of indicator for evaluating the efficiency of disinfection process is depending on the nature of inactivation process such as chemical or physical process. The response of indicator organisms reflects the behaviour of infectious agents. Therefore, bacteriophages are used as indicator for human viral pathogens [7].
Although, the absence scientific reports for the presence of SARS-COV-2 in sewage a number of studies have shown high levels of viral shedding in faecal samples from SARS-COV -2 patients [8,9]. Besides, some of the news reports in France and Netherland indicated to presence of Gene fragments of SARS-COV -2 in the sewage and water surface.

TREATMENT OF HOSPITAL WASTEWATER
Many of the treatment process used for wastewater treatment focus mainly on inactivating pathogenic bacteria that are harmful to aquatic life. However, recent studies revealed that detectable amounts of pathogens remain in effluents, even after sewage treatment [10]. The most common disinfectants is the chlorine, but chlorination has a side effect on the environment and might be harmful to aquatic organisms in streams that receive the effluent.
Chlorine also may lead to the production of nitrosodimethylamine (NDMA) that is known to be carcinogenic to humans. The chlorination process can react with organic matter, forming another carcinogenic compound called trihalometanes (THMs) [11].
Preprints (www.preprints.org) | NOT PEER-REVIEWED | Posted: 21 June 2020 doi:10 Moreover, conventional filtration in wastewater is not efficient for the removal of micropollutant such as viruses. However, microbial is found to be resistance to chemical materials among different types of microorganisms. In addition to occurrence of bacterial regrowth after the treatment by these techniques has been reported by Al-Gheethi et al. [12].
The use of solar disinfection (SODIS) based technologies is a promising approach to the disinfection of water and wastewater because of the high availability of solar radiation as well as the low cost and sustainable nature of these water treatment methods [13]. In contrast, the application of nanotechnology in the wastewater treatment has been reported in the literature [14]. Noman et al. [15] investigated the inactivation of antibiotic-resistant Escherichia coli Sterility assurance level (SAL) (term use to describe the killing efficiency of a treatment process, where treatment process is very effective if SAL was very low as described by ISO 13408-1 [18]and log reduction (accepted by USEPA) terms are the most common used for assessing the efficiency of disinfection processes.
SAL is normally expressed as 10 -n with historically, a 10 -3 or a 10 -6 value being used most frequently for sterilization dependent on the initial concentrations of the pathogens. Log reduction is calculated as (10 −1 ) represents for 90% of the reduction in the microbial population. The disinfection process with "6-log reduction" (10 −6 ) indicate that the microbial population reduced from a million (10 6 ) to very close to zero or 99.9999%. A kill rate of 99.99 %, is expressed in terms as a 4 log reduction.
Moreover, in order to confirm the safe disposal of the against the risk of subsequent microbial contamination after treatment [20]. The diluted chlorine also has an efficient for inactivation of virus. However, the diluted chlorine should be prepared daily, because the solution reacts with the light and lost the activity [21]. Hence, the residual chlorine is not available for surface disinfection. Therefore, the outdoor surfaces such as in the transportation, and public place should be disinfected frequently.
For this reason, there is an urgent to find a disinfectant has more activity stability under the environmental conditions to be active against frequently surface contamination.
SARS-COV -2 has the ability to survival for long periods (might reach to 24 hrs), while the chemical disinfectants spread on the contaminated surface has short stability in their activity. In this matter, the nanoparticles which also have antiviral activity against H1N1 has a longer stability under different environmental conditions [17]. The biosynthesis of NPs represents the alternative for chemical and physical synthesis process. For instance, fungi contain proteins, enzymes and reducing components on its cell surface and produce reducing agents such as napthoquinones and anthraquinones [22]. Therefore utilizing fungi as the stabilizing/reducing agent is very effective in producing NPs with well-defined morphologies as they produce different types of intracellular enzymes for the development of metal and metal oxide NPs. Since fungi have high binding capacity, tolerance and metal bio-accumulation ability and the intracellular intake they are utilized to synthesize metallic NPs. Synthesis of NPs by fungi is more Preprints (www.preprints.org) | NOT PEER-REVIEWED | Posted: 21 June 2020 doi:10 beneficial compared to other microorganisms as fungi are easy to isolate and culture grow faster than bacteria and easy to handle and produce in the laboratory [15].
Thematically the ZnO-NPs with size less than 100 nm have high potential to penetrate the SARS-COV -2 virus with size of 400nm and breakdown the virus genome physically. Besides, ZnO-NPs play dual role such as anti-adhesive and antimicrobial agent simultaneously and has the ability to be stable on the surface under different environmental conditions such has humidity and temperature [23]. However, SARS-COV -2 has a high risk and therefore, the current project aim to investigate the effectiveness of bio ZnO-NPs as a nano-disinfectant against a bacteriophage virus as a model.

CONCLUSION
It can be concluded that the presence of SARS-Cov-2 in the water and wastewater represent an indication for the distribution of the virus in the surrounding community. There is no evidence for the pathogenicity of the detected DNA fragments in the wastewater.
Moreover, the survival of the virus on the surface needs an effective disinfectant to confirm the inactivation of the virus activity.