Sludge management arises as a relevant problem after being accumulated in primary ponds of septage treatment plants. One of the most attractive options for sludge disposal is its use in agriculture and then specific guidelines regarding hygienic quality must be fulfilled. This study aimed at evaluating the storage time needed to inactivate Ascaris eggs and Salmonella in sludge accumulated in a primary pond treating septage. Raw septage exhibited very low concentrations of viable Ascaris eggs, thus experiments with Ascaris suum eggs spiking were conducted. The concentration of Ascaris eggs in the solids accumulated at the bottom of the pond was 20 eggs/g of total solids (g TS) at the time of pond closure. Although it decreased, some eggs remained viable (0.59 mean viable eggs/g TS) up to 20 months of in-pond storage of the biosolids. Salmonella survival was studied after developing an analytical method that inhibited the native flora. Sludge was seeded with Salmonella enteritidis. An equation adequately describing Salmonella die-off in biosolids subjected to 115 days of in-pond storage/dewatering, was found to be represented by the regression: y = log MPN Salmonella/g TS = 6.67 x t(-0.086), with t = storage time elapsed in days. The initial concentration was 7.0 x 10(6) MPN/g TS and the removal efficiency was 99%.
During 2017, we studied knowledge, perceptions, and attitudes towards brown bears by extensive mountain sheep farmers in the Western Pyrenees, using a structured questionnaire, specifically, whether the scarce bear presence, or the administrative region, was influential. Livestock raising practices are mainly family properties and have suffered a strong decline in the last decades. Despite its low abundance (only 2 bear individuals during the study period in the area), there was a generalized negative attitude towards the presence of bears. Farmers considered bear presence as incompatible with sheep mountain herding. One third of them have experienced bear damages, although this was not the main difficulty for the viability of farming practices. They were able to change husbandry practices after wildlife and dog’s damages, increasing vigilance, hiring shepherds, and using livestock guarding dogs, whose work is perceived as satisfactory. Farmers considered that information available about bear and compensation systems for damages was insufficient, and should be improved.
Waste stabilization ponds (WSP) are an often-used option to treat faecal sludges collected from on-site sanitation systems. Since agricultural use is one of the most attractive options for sludge disposal, specific guidelines on the hygienic sludge quality must be fulfilled, such as for viable helminth eggs and Salmonella sp. Although Salmonella isolation methods are well known for other types of samples, they are not suitable for faecal sludge. The reason can be attributed to the co-existence of a native bacterial sludge flora masking Salmonella development, especially if this bacteria is present at low concentrations. In order to select the best methodology for Salmonella recovery from septage sludge, different culture media were assayed at different incubation periods and temperatures. The proposed methodology for Salmonella recovery from sludge can be summarised as follows: (1) enrichment in Rappaport-Vassiliadis broth at 43 degrees C, 48 hours, and (2) isolation in XLD agar at 40 degrees C, 24 hours. Identification of suspected colonies by biochemical tests: TSI, LIA, urease and serological confirmation with Group O Antigen.
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