The results showed that both quick lime and urea gave a reduction of E.Coli, bacteriophages and Ascaris eggs in the sludge. The ordinary drying of the sludge also contributed to pathogen die-off, but not as efficient as with urea and lime. At the end of the field study, there were still measurable amounts of Ascaris eggs in the sludge. However, likely the reduction of Ascaris eggs would have continued if the storage time would have been longer.
Implementation of urea or lime treatment of faecal sludge is firstly limited by the costs. However, the urea treatment was shown to be significantly cheaper than treatment with lime. The study also indicated that lime treatment is more difficult to carry out in full-scale since it was difficult to mix the sludge with lime, especially when the sludge had quite low moisture content.
Emma Lindberg and Anna Rost have now finalized their studies and left Luleå University of Technology. Emma is now working at ÅF in Luleå and Anna at SWECO in Umeå.