J.I Oragui

Vibrio cholerae O1 (El Tor) removal in waste stabilization ponds in northeast Brazil

Abstract A series of ten waste stabilization ponds (a 1-d anaerobic pond followed by nine 2-d ponds) was monitored for the removal of Vibrio cholerae O1. The anaerobic pond reduced the mean number of V. cholerae from 485 per litre of raw wastewater to 28, and there was then a very gradual removal in the next five ponds, after a cumulative retention time of only 11 d, to zero.

Rotavirus removal in experimental waste stabilization pond systems with different geometries and configurations

Rotavirus removal in waste stabilization ponds is a relatively slow process: in a series of ten ponds (a 1-d anaerobic pond followed by nine 2-d ponds) its numbers were reduced from 1.4 × 105 per litre to zero, and in an “innovative” series (a 1-day anaerobic pond, 3-d facultative pond, 3.8-d, 3-d and 5-d maturation ponds) from 5.1 × 104 per litre to <5 per litre. Faecal coliforms were better indicators of rotaviruses than was Clostridium perfringens .

Enumeration of salmonellae in wastewater by the MPN technique

Abstract A comparative study of the use of double and single strength RV enrichment media for the enumeration of salmonellae by the MPN method was carried out. Of 53 samples of raw municipal wastewater and waste stabilization pond effluents examined 83% yielded higher numbers of positive tubes when the various volumes of the samples utilized for the estimations were inoculated into single strength RV enrichment medium than when inoculated into double strength medium. Extending the incubation period of the XLD agar plates from 24h to 48h at 37°C increased the number of confirmed positive tubes by 1–9% with a mean value of 3%. The effect of the strength of the enrichment medium used on the MPN values is discussed.