Persistence of pathogens and bacterial community dynamics in tropical soil after application of raw sewage.

The objective of this work was to evaluate the persistence of faecal indicators and pathogenic organisms (Salmonella spp., Escherichia coli and viable helminth eggs) and the structure/diversity of bacterial communities in soil receiving raw sewage (RS) for an extended period of application (3 uninterrupted years). In the experimental design, three treatments were defined: (1) Control soil, characterized by the analysis of a composite sample collected in an area of similar soil, but not a recipient of RS (TSC); (2) Soil receiving conventional mineral fertilization, and furrow irrigation with supply water (TW); and (3) Fertirrigated soil with RS applied by furrows (TF).

Macronutrient distribution in soil subjected to raw sanitary sewage application by closed-end furrows.

This work aimed to evsaluate the influence of raw sanitary sewage (RS) application in closed-end and level-bottom furrows on the distribution of macronutrients and sodium in the soil along its depth. The applied amount of RS was controlled due to the harmful effect of sodium, with a weekly application over three consecutive years. The experimental design consisted of two experimental plots receiving RS, one with alternating the site of effluent application (alternation of inlet and outlet-TFA) and the other without alternating the site of application (only inlet-TFN); and two experimental plots receiving conventional mineral fertilization, both irrigated with public water supply, where one alternated the site of water application (alternation of inlet and outlet-TWA) and the other without alternating the site of application (only inlet-TWN).

Influence of the sanitary sewage application method to closed-end furrows on the macronutrient extraction capacity and productivity of elephant grass.

The objective of this work was to evaluate the influence of the form of raw sanitary sewage (RS) application in closed-end and level-bottom furrows on the dry matter yield and macronutrient extraction capacity (extraction of nitrogen, phosphorus and potassium) by the aerial part (stem and leaves) of elephant grass. Fertigation of elephant grass with RS were conducted for 3 uninterrupted years, and the RS application dose was established as a function of the amount of sodium fed to the soil (300 kg ha year). In the experimental planning four treatments were established, where two experimental plots received RS and the water demand was complemented by treated water from the public supply network (TW), with and without alternation in the position of RS application in the furrows (TFA and TFN, respectively); and as a control there were two experimental plots in which the plants received conventional mineral fertilization, where the grass was irrigated with TW, with and without alternation in the position of water application in the furrows (TWA and TWN, respectively).