| dc.description.abstract | Untreated or improperly treated wastewater has often been cited as the primary
contamination source of groundwater. Decentralized wastewater treatment systems have
applicability around the world since it obviates the need for extensive infrastructure
development and expenditures. The use of a sand filter, a submerged flow constructed
wetland and an aerobic treatment unit to remove bacterial and viral pathogens from
wastewater streams was evaluated in this study. Salmonella sp. and a bacteriophages tracer
were used in conjunction with the conservative bromide tracer to understand the fate and
transport of these organisms in these treatment systems. Viral transport patterns in the sand
filter and constructed wetland had a correlation of 0.8 (P< 0.05). In the constructed wetland,
the virus exhibited almost a 3-log reduction, while in the sand-filter, the viruses exhibited a
2-log reduction. The bacterial tracers, however, did not exhibit similar reductions. Low
numbers of bacteria and viruses were still detectable in the effluent streams suggesting that
disinfection of the effluent is critical. The survival of the tracer bacteria and viruses were as
expected dependant on the biotic and abiotic conditions existing within the wastewater. The
results suggest that the microbial removal characteristics of decentralized wastewater
treatment systems can vary and depend on factors such as adsorption, desorption and
inactivation which in turn depend on the design specifics such as filter media characteristics
and local climatic conditions. | en |
