The HCSP is giving its opinion after a referral on 26 July 2022 from four central administration directorates on the existence of scientific and technical elements justifying the continuation of additional treatments applied to wastewater treatment plant sludge and the maintenance of restrictions on the spreading of this sludge during the Covid-19 period. These treatments were introduced in 2020 in response to concerns about the presence of the infectious virus SARS-CoV-2 in wastewater and sewage sludge.

Given the knowledge available at the date of this opinion, although there is no formal method for isolating SARS-CoV-2 from environmental media, the epidemiological, virological and technical data do not support the continued viability of SARS-CoV-2 in faeces, urban wastewater (or mixed urban and industrial effluents) and sewage plant sludge.

The HCSP recommends reconsidering the additional hygienisation treatments of wastewater treatment plant sludge related to SARS-CoV-2 and not maintaining the restrictive sludge spreading measures currently in force. The development of viral analysis methods (virus isolation and viability methods) in complex environments must be continued, as well as the reflections and work on the evolution of the regulations relating to the health and environmental risks associated with the spreading of sludge from wastewater treatment plants.