COVID-19: Weak liquid waste management can worsen spread

Liquid waste generated from healthcare facilities should be disinfected at source

The coronavirus might get transmitted to those operating sewage treatment plants

With the novel coronavirus disease (COVID-19) pandemic raging, it is important to pay attention to processing of liquid waste generated during diagnosis, treatment, and quarantine of patients to curb the spread of the disease. Studies by World Health Organisation (WHO) and Central Pollution Control Board (CPCB) suggest that presence of virus fragments in excreta increases the possibility of the infection reaching wastewater or liquid waste.

Lack of an efficient wastewater treatment system can worsen the impact of COVID-19 outbreak which has brought to the fore the need for assured access to safe water and sanitation as described through the Global Water Security & Sanitation Partnership (GWSP). 

The infected COVID-19 liquid waste mainly consists of wastewater generated during diagnosis, treatment and quarantine of patients. The liquid waste generated from healthcare and quarantine facilities must be managed as per the prevailing norms to prevent contamination of sewers and water bodies.

The risk of transmission of COVID-19 virus through sewerage systems is low. However, the virus might be transmitted to the people operating sewage treatment plants (STP), although there is no such evidence yet.

India has specific guidelines recommended for healthcare facilities and operators. The agencies responsible for managing COVID-19 infected liquid waste are healthcare facilities, isolation wards and operators of terminal or STPs.  Healthcare facilities and the agencies operating STPs should continue to ensure the disinfection of treated wastewater as per prevailing practices to inactivate COVID-19 viruses.

Operators involved with discharge from healthcare facilities and isolation wards should adopt standard operational practices, follow basic hygiene precautions, and wear personal protective equipment (PPE) like goggles, face mask, liquid repellent coveralls, waterproof gloves and rubber boots prescribed for the operation of STPs.

Liquid waste generated from healthcare facilities should have an effluent treatment plant to disinfect at the source, thereby eliminating the chance of untreated liquid waste mixing with the general sewerage system. This ensures the separation of suspended solids and helps to remove the viruses present in the suspended solids.

Once suspended solids are separated in the form of sludge, chlorine disinfection is most appropriate, coupled with many other secondary treatments. Storing wastewater for a longer period of time also destroys viruses. Once the pathogens have been inactivated, wastewater can be safely released into a common sewage pipeline.

Utilisation of treated wastewater within healthcare facilities may be avoided. Bio-toilets or bio-digesters based low-cost and low-maintenance toilets can be used in healthcare facilities and quarantine places to prevent the virus from reaching the existing sewerage system. 

The genome of COVID-19 is phylogenetically closest to SARS-CoV-1, the virus that causes Severe Acute Respiratory Syndrome (SARS), and so, the disinfection methods used for SARS-CoV-1 can act as a satisfactory reference for COVID-19 inactivation. According to a report published in Elsevier, the SARS-CoV-1 virus was completely inactivated after 30 minutes of disinfection with over 10 milligram per litre chlorine.

Chlorine disinfection depends on pH, temperature, concentration, and contact time. Nevertheless, with the increasing number of COVID-19 patients, research needs to be done to find the best way to keep the virus out of the water cycle. Continuous monitoring and testing of the common sewerage system of infected areas can indicate the scale of the problem.

Views expressed are the authors' own and don’t necessarily reflect those of Down To Earth

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