THE VIRUS PROBLEM IN THE
WINDHOEK WASTE WATER
RECLAMATION PROJECT
ETHEL M. NUPEN and G.J. STANDER
National Institute for Water Reseach of the C.S.I.R.,
PO Box 395, Pretoria, Republic of South Africa
INTRODUCTION
After the initial virological studies (Cillie et al 1961, Nupen 1970) which were run
before and at the commissioning of the Windhoek Waste Water Reclamation Plant (van
Vuuren et al 1970) an intensive plan for the monitoring and control of the plant was
deemed necessary. This monitoring included the virological testing of the settled sewage
entering the Gammams Sewage Purification Works and the final maturation pond effluent
from the works which constituted the intake to the Windhoek Waste Water Reclamation
Plant. Together with plant monitoring, all other sources of water supplied to the area
were routinely checked for virus and faecal contamination. Epidemiological data is also
being accumulated for correlation with the distribution of water supplies and the virus
loading at the sewage works.
Further techniques for the better evaluation of virus from larger volumes of water
were also investigated, and used during this monitoring period. In this paper the findings
from the above programme are discussed in relation to the problems of virus removal in
waste water purification processes.
MATERIALS AND METHODS
Viruses and Virus Quantification
Viruses used, methods of quantification and transportation of samples were as
previously described (Nupen 1970).
Virus Identification
All positive tubes were identified by their cytopathic effects on stained coverslips and
where necessary seriologically confirmed.
Concentration Methods
The two-phase polymer concentration method used was as previously reported.
An ultrafiltration (UF) method of concentration was also used. This process is a
method of selective molecular separation, it employs membranes which pass solvent and
solutes of low molecular weight, retaining solutes and colloidal matter of larger molecular
dimensions. Ten litres or more of a sample are pressurized in a stirred ultrafiltration cell
(Amicon high performance cell model 2000) and pass through a suitably supported
membrane. The thin skin of the non-cellulosic membrane produces a combination of
selectivity, high throughput and resistance to clogging because substances are rejected at
the surface. The diaflo P.M. 30 membrane was selected for experimental purposes as it is
autoclavable, and has a "cut-off or capability to retain larger molecules than those of
pore diameter well below the molecular weight of viruses and approximately the
133
WINDHOEK WASTE WATER
RECLAMATION PROJECT
ETHEL M. NUPEN and G.J. STANDER
National Institute for Water Reseach of the C.S.I.R.,
PO Box 395, Pretoria, Republic of South Africa
INTRODUCTION
After the initial virological studies (Cillie et al 1961, Nupen 1970) which were run
before and at the commissioning of the Windhoek Waste Water Reclamation Plant (van
Vuuren et al 1970) an intensive plan for the monitoring and control of the plant was
deemed necessary. This monitoring included the virological testing of the settled sewage
entering the Gammams Sewage Purification Works and the final maturation pond effluent
from the works which constituted the intake to the Windhoek Waste Water Reclamation
Plant. Together with plant monitoring, all other sources of water supplied to the area
were routinely checked for virus and faecal contamination. Epidemiological data is also
being accumulated for correlation with the distribution of water supplies and the virus
loading at the sewage works.
Further techniques for the better evaluation of virus from larger volumes of water
were also investigated, and used during this monitoring period. In this paper the findings
from the above programme are discussed in relation to the problems of virus removal in
waste water purification processes.
MATERIALS AND METHODS
Viruses and Virus Quantification
Viruses used, methods of quantification and transportation of samples were as
previously described (Nupen 1970).
Virus Identification
All positive tubes were identified by their cytopathic effects on stained coverslips and
where necessary seriologically confirmed.
Concentration Methods
The two-phase polymer concentration method used was as previously reported.
An ultrafiltration (UF) method of concentration was also used. This process is a
method of selective molecular separation, it employs membranes which pass solvent and
solutes of low molecular weight, retaining solutes and colloidal matter of larger molecular
dimensions. Ten litres or more of a sample are pressurized in a stirred ultrafiltration cell
(Amicon high performance cell model 2000) and pass through a suitably supported
membrane. The thin skin of the non-cellulosic membrane produces a combination of
selectivity, high throughput and resistance to clogging because substances are rejected at
the surface. The diaflo P.M. 30 membrane was selected for experimental purposes as it is
autoclavable, and has a "cut-off or capability to retain larger molecules than those of
pore diameter well below the molecular weight of viruses and approximately the
133