| a bacteriological and helminthological investigation of a sewage-irrigated area in a beijing suburb. | the municipal sewage and raw sludge removed from a sewage treatment plant were the main sources of pollution by pathogenic bacteria and helminthic eggs in land utilization. the level of pollution in the sewage-irrigated areas was as high as that in the areas using fresh night soil. the survival time of salmonella and ascaris ova in soil irrigated with sewage was relatively long. the soil had a definite natural capacity for purifying pathogenic bacteria. because of the different ways of watering, ... | 1988 | 3270523 |