Soils, sludges and treated bio-wastes — Extraction of bacteriophages from sludge, soils and treated biowastes

Abstract

This document is developed in the framework of the project 'Horizontal'. It is the result of a critical review "Methods for bacteriophages (and viruses) to be monitored in EU in sludges, soils and treated biowastes" and aims at evaluation of the latest developments in assessing bacteriophages in sludge, soil and biowastes. After discussion with all parties concerned in CEN (European Committee for Standardization) and selection of a number of test methods described in this study the standard has been developed further as a modular horizontal method and was validated within the project ”Horizontal”. Sludges, soils and biowastes can contain pathogens such as Enteroviruses, Salmonella spp. Most occur in the intestinal tract of humans and animals and can be transmitted through faecal contamination. The use of such contaminated materials in agriculture may cause outbreaks of infection due to the production of contaminated food and animal foodstocks. They may also be transmitted to wild animals. There is a need to monitor the efficacy of storage and treatment processes to control pathogens, and application rates to land. Viruses had been described to have a tendency to adsorb to solids. There are some differences between different viruses regarding adsorption efficiency, solids to which they can be adsorbed better and conditions that favour adsorptions. Once they are adsorbed to solids, they persist longer than when they are free. Consequently, viruses are expected to concentrate in sludges, biowastes, sediments and soils, where they will persist longer that in the contaminated waters. This standardised protocol specifies a procedure for the elution of bacteriophages (as viral indicators) from sewage sludges, compost and biowaste samples. The user should, prior to analysis, validate the method for the particular type of sample they wish to analyse: sludges, soils and biowastes.