

@article {4310,
	title = {{Elimination of micro-organisms from wastewater by tertiary precipitation and simultaneous precipitation followed by filtration}},
	journal = {Water Research},
	volume = {22},
	number = {11},
	year = {1988},
	month = {nov},
	pages = {1389{\textendash}1397},
	abstract = {The removal of micro-organisms from wastewater by activated sludge and precipitation processes was studied in two parallel pilot plants (4{\textendash}7m3 h-1). Activated sludge treatment removed vegetative bacteria (E. coli, faecal streptococci) by 96{\textendash}97{\%} (1.4{\textendash}1.5 log10 units), bacterial spores (sulphite reducing clostridia) by 75{\%} (0.6 log10 units), bacteriophages (somatic coliphages and F-specific phages) by 94{\textendash}98{\%} (1.2{\textendash}1.8 log10 units) and enteroviruses by 94 (1.2 log10 units). Simultaneous precipitation [25 gFe m-3 as iron(III)chloride] had no added effect on the removal of micro-organisms. Filtration of the effluent of the simultaneous precipitation process highly improved the removal of micro-organisms, in particular when 3{\textendash}7 gFe m-3 was added before filtration. Tertiary precipitation (25 gFe m-3) also resulted in improved removal of all micro-organisms. Addition of an anionic flocculation aid did further improve this effect for vegetative bacteria and bacterial spores, but not for bacteriophages (viruses not tested). On average, both complete treatment processes (activated sludge with post-precipitation using a flocculation aid or simultaneous precipitation with post-filtration using iron addition) removed vegetative bacteria, bacterial spores, bacteriophages and enteroviruses by 99.9, 99.8, 99.6 and 99.85{\%} (3.0, 2.7, 2.4 and 2.8 log10 units), respectively. The effects of precipitation processes were equal to or better than those of marginal chlorination of the activated sludge effluent of the same pilot plant. After the full treatment, both effluents had almost the same physico-chemical quality with BOD 3{\textendash}5 g m-3, total phosphate 0.06-0.4 gP m-3, suspended solids 5{\textendash}7 gm-3 and turbidity 1.4{\textendash}2.0 FTU.},
	keywords = {Bacteriophages, Disinfection, enterovirusses, Filtration, micro-organism removal, phosphate removal, simultaneous precipitation, tertiary precipitation, Wastewater treatment},
	issn = {00431354},
	doi = {10.1016/0043-1354(88)90095-4},
	url = {http://www.sciencedirect.com/science/article/pii/0043135488900954},
	author = {Nieuwstad, Th.J. and Mulder, E.P. and Havelaar, A.H. and Van Olphen, M.}
}
