Showing papers by "Duncan Mara published in 1987"

TL;DR: In situ studies on waste stabilization ponds (in Portugal) showed that faecal coliform numbers were lowest at positions in the water column where pH, temperature, dissolved oxygen and algae were high as mentioned in this paper.

TL;DR: In this article, the minimum evaluation of the performance of existing full-scale waste stabilization ponds is presented for a 5-week period at the hottest and coldest periods of the year and analyzed for BOD, COD, SS, NH3N, NO3N and total P; faecal coliform numbers are determined on grab samples, and algal biomass estimated by measuring chlorophyll concentrations in samples of the pond water column.

TL;DR: All the algal species were sensitive to sulphide at µM concentrations in a tolerance sequence Chlamydomonas Chlorella Scenedesmus Euglena, and the effects are related to species dominance and pond performance.

TL;DR: The hydraulic regime in two Portuguese facultative waste stabilization ponds, a primary facultative pond receiving raw sewage (in Portimao) and a secondary pond receiving the effluent from an anaerobic pond (in Vidigueira) was studied by means of a fluorescent dye tracer technique, and results did not agree with those obtained from the available predictive equations.

TL;DR: In this paper, a diurnal series of samples of the effluent and the total in-pond water column of facultative and maturation ponds were analysed for COD, suspended solids, faecal coliforms, chlorophyll and ammonia with a view to finding the most efficient way of obtaining reliable mean daily effluent quality data.

TL;DR: In this article, the performance of a series of 2.2 m deep anaerobic, facultative and maturation ponds, which had an overall retention time of 25 days, and a mean mid-depth temperature of 25 ° C, was studied.

TL;DR: The forced aeration static pile composting system was used to compost mixtures of domestic refuse and sewage sludge Several different control methods have been evaluated over the past four years from simple, low cost fixed rate aeration timers to microcomputer based systems Their relative merits are considered as mentioned in this paper.

TL;DR: In this paper, waste stabilization ponds at Cajamarca (altitude: 2,675 metres) and Juliaca (3,827 metres) in Peru have shown that existing pond design equations can be confidently used for designing ponds for high Andean towns, even though there are large diurnal variations in air temperatures and high light intensity.