Virus exclusion and inactivation during water treatment by reverse osmosis

Hawkes, M.J., 1977. Virus exclusion and inactivation during water treatment by reverse osmosis. PhD, Nottingham Trent University.

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Abstract

A river survey was undertaken to ascertain the virus load expected to be received by an RO unit treating river water, and it was shown that Al(OH)3 flocculation, the concentration method originally employed, also concentrated heavy metals to levels toxic to assay cell lines.

Iron oxide adsorption was substituted, using a specially constructed electromagnet, and following a 1000 fold concentration of 20 litre water samples 87.46 % recovery of added viruses was achieved. With this method viruses were isolated at up to 2.4 pfu 1-1, with most isolations occuring during summer months. As a result a correlation between the number of virus isolations and improving water quality was established both between the sampling sites chosen, and during the course of the investigation.

Reverse osmosis, rising artificially high loadings of test viruses was shown to effectively separate viruses from river water and tertiary treated sewage effluent, with 99.999+ % exclusion under normal operational conditions. Penetration of the membrane was shown not to occur, except at elevated pressures. A correlation was noted between decreasing recirculation water pH and increasing virus LOI .

Viral LOI was also thought to occur with heavy metal cations concentrated within the units and a series of laboratory studies were undertaken to examine this further. It was shown that LOI was temperature, metal ion concentration and valency dependent for all cations tested. However, divalent mercury and lead, and trivalent cations were so effective as to totally inactivate the viruses at all ion concentrations examined. These studies also showed the presence of two virus sub-populations, one more sensitive to cationic action than the other.

Virus titre was partially recoverable by dialysis and electron microscopic examination revealed that viral aggregation was the main cause of LOI.

It was concluded that Enterovirus and MS 2 acted as hydrophilic colloids in water and that coat and A protein precipitation was the result of metal induced aggregation.

Item Type:	Thesis
Creators:	Hawkes, M.J.
Date:	1977
ISBN:	9781369313932
Identifiers:	Number Type PQ10183112 Other
Divisions:	Schools > School of Animal, Rural and Environmental Sciences
Record created by:	Jeremy Silvester
Date Added:	17 Sep 2020 13:56
Last Modified:	19 Jul 2023 09:52
URI:	https://irep.ntu.ac.uk/id/eprint/40762

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