110
T.G. Metcalf, C. Wallis and J.L. Melnick
necessary.
Virus concentrating apparatus. A portable apparatus described previously (Wallis,
Homma and Melnick, 1972 b) was used for both laboratory and field studies. A gasoline
powered electric generator and deep well pump were used in field studies. A small tank of
nitrogen provided the source of positive pressure in laboratory studies. Virus recovery
from filters was effected by elution using a calcium, magnesium-free phosphate buffered
saline solution at pH 11.5. The eluate was immediately neutralized with a phosphate
buffered saline solution, pH 2.O.
Virus challenge to determine presence of MCC. Adsorbent filters through which
seawater had been passed were tested to determine whether substances occurred in this
seawater which were left on the filters, and which competed with virus for reactive sites
necessary for adsorption. The virus challenge represented a known amount of virus
suspended in 1 gallon of water, which was passed through a filter to be tested. Filtrate
assay indicated whether virus was retained or passed freely through a filter.
Virus challenge to determine impairment of virus-passing quality of filters. Clarifying
filters receiving depositions of marine sediment and debris from seawater passed through
them were tested to determine whether these deposits inhibited free passage of virus.
Virus challenge was carried out with known amounts of virus in 1 gallon volumes of water
which were passed through a filter to be tested. Filtrate assays indicated whether
retention or free passage of virus had occurred.
Virus and virus assays. A plaque-purified line of type 1 poliovirus (strain LSc) was used
throughout the study. Virus assays were made by the plaque-forming unit (PFU) method,
using primary monkey kidney monolayers prepared from immature vervet monkeys.
RESULTS
Virus removal from salt water by natural and synthetic textile filters.
Virus was added to artificial seawater and 5 gallon samples passed through various
filters housed in the virus concentrating apparatus at flow rates of approximately 300
GPH. Virus samples before and after passage through a filter were assayed and the
presence or absence of virus in the filtrates determined. The results of a series of
experiments are summarized in Table 1. Orion, polyester, and polypropylene filters
removed the least virus and were selected as the best for clarification purposes. These
filters permitted 80 to 90 percent of virus in seawater to pass into the effluent. By
contrast, fiberglass, dynel and cellulose acetate filters allowed the least virus to pass.
These filters were considered excellent candidates for use as virus concentrators. Viscose
and cotton filters retained too little virus to serve efficiently as adsorbents, and too much
virus to be considered for use as clarifiers. The results of these experiments indicated
clarification of seawater could be carried out with orlon, polypropylene or polyester
filters. Cellulose acetate, fiberglass or dyn«l appeared promising for subsequent collection
of virus.
Concentration of virus from salt water.
The ability of selected filters to clarify seawater without removing virus, combined
with an enhanced virus adsorption to other filters due to the high salt concentration of
seawater, was applied experimentally. Five gallons of artificial seawater containing virus
was passed first through a 1 μ orlon filter for simulated clarification, then through 1 μ
T.G. Metcalf, C. Wallis and J.L. Melnick
necessary.
Virus concentrating apparatus. A portable apparatus described previously (Wallis,
Homma and Melnick, 1972 b) was used for both laboratory and field studies. A gasoline
powered electric generator and deep well pump were used in field studies. A small tank of
nitrogen provided the source of positive pressure in laboratory studies. Virus recovery
from filters was effected by elution using a calcium, magnesium-free phosphate buffered
saline solution at pH 11.5. The eluate was immediately neutralized with a phosphate
buffered saline solution, pH 2.O.
Virus challenge to determine presence of MCC. Adsorbent filters through which
seawater had been passed were tested to determine whether substances occurred in this
seawater which were left on the filters, and which competed with virus for reactive sites
necessary for adsorption. The virus challenge represented a known amount of virus
suspended in 1 gallon of water, which was passed through a filter to be tested. Filtrate
assay indicated whether virus was retained or passed freely through a filter.
Virus challenge to determine impairment of virus-passing quality of filters. Clarifying
filters receiving depositions of marine sediment and debris from seawater passed through
them were tested to determine whether these deposits inhibited free passage of virus.
Virus challenge was carried out with known amounts of virus in 1 gallon volumes of water
which were passed through a filter to be tested. Filtrate assays indicated whether
retention or free passage of virus had occurred.
Virus and virus assays. A plaque-purified line of type 1 poliovirus (strain LSc) was used
throughout the study. Virus assays were made by the plaque-forming unit (PFU) method,
using primary monkey kidney monolayers prepared from immature vervet monkeys.
RESULTS
Virus removal from salt water by natural and synthetic textile filters.
Virus was added to artificial seawater and 5 gallon samples passed through various
filters housed in the virus concentrating apparatus at flow rates of approximately 300
GPH. Virus samples before and after passage through a filter were assayed and the
presence or absence of virus in the filtrates determined. The results of a series of
experiments are summarized in Table 1. Orion, polyester, and polypropylene filters
removed the least virus and were selected as the best for clarification purposes. These
filters permitted 80 to 90 percent of virus in seawater to pass into the effluent. By
contrast, fiberglass, dynel and cellulose acetate filters allowed the least virus to pass.
These filters were considered excellent candidates for use as virus concentrators. Viscose
and cotton filters retained too little virus to serve efficiently as adsorbents, and too much
virus to be considered for use as clarifiers. The results of these experiments indicated
clarification of seawater could be carried out with orlon, polypropylene or polyester
filters. Cellulose acetate, fiberglass or dyn«l appeared promising for subsequent collection
of virus.
Concentration of virus from salt water.
The ability of selected filters to clarify seawater without removing virus, combined
with an enhanced virus adsorption to other filters due to the high salt concentration of
seawater, was applied experimentally. Five gallons of artificial seawater containing virus
was passed first through a 1 μ orlon filter for simulated clarification, then through 1 μ