Isolation of indigenous enteroviruses from chemically treated and dewatered sludge samples

Inactivation of indicator microorganisms and biological hazards by standard and/or alternative processing methods in Category 2 and 3 animal by-products and derived products to be used as organic fertilisers and/or soil improvers

The European Commission requested EFSA to assess if different thermal processes achieve a 5 log10 reduction in Enterococcus faecalis or Salmonella Senftenberg (775W) and (if relevant) a 3 log10 reduction in thermoresistant viruses (e.g. Parvovirus) as well as if different chemical processes achieve a 3 log10 reduction of eggs of Ascaris sp., in eight groups of Category 2 and 3 derived products and animal by-products (ABP). These included (1) ash derived from incineration, co-incineration and combustion; (2) glycerine derived from the production of biodiesel and renewable fuels; (3) other materials derived from the production of biodiesel and renewable fuels; (4) hides and skins; (5) wool and hair; (6) feathers and down; (7) pig bristles; and (8) horns, horn products, hooves and hoof products. Data on the presence of viral hazards and on thermal and chemical inactivation of the targeted indicator microorganisms and biological hazards under relevant processing conditions were extracted via extensive literature searches. The evidence was assessed via expert knowledge elicitation. The certainty that the required log10 reductions in the most resistant indicator microorganisms or biological hazards will be achieved for each of the eight groups of materials mentioned above by the thermal and/or chemical processes was (1) 99-100% for the two processes assessed; (2) 98-100% in Category 2 ABP, at least 90-99% in Category 3 ABP; (3) 90-99% in Category 2 ABP; at least 66-90% in Category 3 ABP; (4) 10-66% and 33-66%; (5) 1-33% and 10-50%; (6) 66-90%; (7) 33-66% and 50-95%; (8) 66-95%, respectively. Data generation on the occurrence and reduction of biological hazards by thermal and/or chemical methods in these materials and on the characterisation of the usage pathways of ABP as organic fertilisers/soil improvers is recommended.

Poliovirus retention in soil columns after application of chemical- and polyelectrolyte-conditioned dewatered sludges

The transport of poliovirus type 1 (strain LSc) was studied in Red Bay sandy loam columns that were treated with chemical- or polyelectrolyte-conditioned dewatered sludges and then leached with natural rainwater under saturated flow conditions. Poliovirus was concentrated in the alum and ferric chloride sludges that were produced following the flocculation of virus-seeded raw sewage. Virtually complete inactivation of the virus was observed following the flocculation of raw sewage or the stabilization of alum and ferric chloride sludges with lime at pH 11.5. Poliovirus was also concentrated in polyelectrolyte-conditioned dewatered sludge that was produced from virus-seeded, anaerobically digested sludge. Despite the saturated flow conditions for a sustained period, no viruses were detected in the leachates of the soil columns that were treated with these chemical and chemically treated sludges. Since the viruses were mostly associated with the solids in these sludge samples, it is believed that they were immobilized along with the sludge solids in the top portion of the soil columns.