Enhanced virus recovery front municipal sewage sludge with a combination of enzyme and cation exchange resin

There is a great difficulty in virus enumeration in sewage sludge because v iruses in sludge are firmly captured by sludge solids. In order to determin e the precise number of viruses in sludge, an enhanced virus recovery metho d with a combination of an enzyme and a cation exchange resin (CER) was dev eloped. Test viruses were seeded to a sample sludge obtained from a municip al wastewater treatment plant, and the sludge were incubated with various e luents. The quantity of eluted viruses in the liquid phase was then measure d by the plaque assay technique. Using the eluent containing only water, CE R, and CER with enzyme exhibited 0 %, 19 % and 39 % of virus recovery, resp ectively. While the conventional USEPA method exhibited a virus recovery of 21 %. Furthermore, viruses eluted by the eluent containing the CER and the lysozyme included not only surface-attached viruses but also solids-embedd ed viruses.