Effluent characteristics of domestic sewage oxidation ponds and their potential impacts on rivers

The performance of two sea outfalls that have been in operation off the coast of Durban for over 10 years has been monitored for effects on the marine environment and public health. The discharge has been a mixture of domestic sewage and industrial waste from which a large proportion of the sludge has been removed but a 2-year research project, in which the balance of the sludge is also being discharged, has commenced. Performance of the outfalls and details of the monitoring programme are reviewed.

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Wastewater Lagoons in a Cold Climate

Water Science & Technology ◽

10.2166/wst.1987.0125 ◽

1987 ◽

Vol 19 (12) ◽

pp. 47-53 ◽

Cited By ~ 4

Author(s):

J. A. Oleszkiewicz ◽

A. B. Sparling

Keyword(s):

Control Mechanism ◽

Maximum Load ◽

Domestic Sewage ◽

Full Scale ◽

Cold Climate ◽

Odor Control ◽

Intermittent Rivers ◽

In Series ◽

Break Up ◽

Lagoon Systems

Severe climate, intermittent rivers and availability of land make facultative lagoon systems the method of choice in treating primarily domestic sewage from smaller municipalities. The lagoons are designed on a recommended maximum load of 55 kgBOD5/ha d to first cell, while the second cell provides storage. The discharge is twice annually and the occurrence of the spring ice break-up odor period is one of the primary criteria limiting this load. Based on full scale performance data, it is demonstrated that, from the standpoint of odor nuisance, the load to the first cell should be kept equal to or less than 35 kg/ha d. Full scale studies of an overloaded lagoon system show the futility of under-ice aeration for odor control. Mechanism of natural odor control during ice break up is elucidated. Upgrading of the overloaded systems or lagoons receiving significant industrial contribution is best achieved by construction of a 3–5 m deep aerated lagoon preceding the two or more facultative cells in series.

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Behaviour of Coli Phages in Oxidation Ponds

Water Science & Technology ◽

10.2166/wst.1985.0113 ◽

1985 ◽

Vol 17 (10) ◽

pp. 219-227 ◽

Cited By ~ 9

Author(s):

T. Omura ◽

H. K. Shin ◽

A. Ketratanakul

Keyword(s):

Laboratory Experiments ◽

Field Investigation ◽

Host Cells ◽

Coliform Bacteria ◽

Alkaline Ph ◽

Viral Inactivation ◽

Effects Of Temperature ◽

Oxidation Ponds ◽

Incubation Temperatures ◽

Inactivation Efficiency

Coliphages are among the most promising indicators of viral inactivation efficiency of wastewater treatment. Therefore, it is important to investigate the behaviour of coliphages in oxidation ponds from the viewpoint of predicting the inactivation of infectious viruses. In this study, numbers of coliphages were measured in oxidation ponds consisting of a series of facultative and maturation ponds. In parallel with this investigation, the effects of temperature and pH on the behaviour of coliphages were examined in the laboratory, employing three species of coliform bacteria as host cells. The field investigation showed that there was positive correlation between counts of coliphages and those of coliform bacteria, and that more than 99% of coliphages were inactivated. The inactivation efficiency of coliphages in the facultative pond was much higher than in the maturation pond. The results of the laboratory experiments indicated that at 30°C more than 99% of the coliform group were destroyed in 7 days of incubation and that coliphages counts increased from 105/100 ml to 107/100 ml with a lag time of 3 days. Greater reduction of the coliform count was obtained at higher incubation temperatures. It was observed that the coliphages possessed greater ability to attack coliform bacteria at acidic rather than alkaline pH.

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Experimental Investigations into the Use of Emergent Plants to Treat Sewage in South Africa

Water Science & Technology ◽

10.2166/wst.1987.0097 ◽

1987 ◽

Vol 19 (10) ◽

pp. 51-59 ◽

Cited By ~ 2

Author(s):

W. V. Alexander ◽

A. Wood

Keyword(s):

South Africa ◽

Rural Communities ◽

Experimental Investigations ◽

Artificial Wetlands ◽

E Coli ◽

Effluent Quality ◽

Emergent Plants ◽

Treatment Facilities ◽

High Standards ◽

Oxidation Ponds

South Africa is a relatively water-short country which has many rural communities with water-borne sewage infrastructures requiring low technology treatment facilities. In order to protect the water resources of the country the authorities have set high standards for effluent quality (COD < 75 mg/l, NH3 < 10 mg/l, E. coli < 1000 and in some areas P < 1 mg/l). Traditionally, oxidation ponds have been used in these applications but have not been able to consistently meet the required standards and recently interest has been shown in artificial wetlands as a low technology means of solving the problem. As a result several experimental projects are at present being initiated in South Africa, both as primary and secondary treatment for domestic sewage and also as a tertiary treatment to remove nitrogen, phosphorus and E. coli from conventional sewage plant effluents. The designs of these experimental projects are described in the paper and it is hoped that data will be available for presentation at the seminar.

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