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The aim of this research was to improve the removal of organic matter and nutrients from wastewater from pig farms in a combined batch reactor performed as anaerobic-aerobic sequential. For this purpose, it was suggested to include recirculation cycles of wastewater in a sequentially pulsed manner in the anaerobic treatment followed by intermittent aeration in the aerobic-anoxic treatment. This novelty implemented in both sequential reactors was studied under pilot scale conditions. The process of pulsed intermittent recirculation allowed better contact between the microorganisms and organic matter, and intermittent aeration improved the removal of nutrients, primarily nitrogen (nitrification and denitrification), total phosphorous and organic matter. The best configuration tested for the combined system was the one consisting of pulsed intermittent recirculation with 1 hour of recirculation and 3 hours rest in the anaerobic step and 2 hours of aeration and 1 hour without aeration cycle in the aerobic step. The removals achieved were 98 ± 1% of total organic matter, 86 ± 5% of soluble organic matter, 96 ± 1% of total phosphorus and 55 ± 18% of total nitrogen. Hence, it was demonstrated that a combined system with pulsed intermittent recirculation in the anaerobic stage and intermittent aeration in the aerobic stage could enhance the overall treatment of swine wastewater. [ABSTRACT FROM AUTHOR]

Microorganisms' role in pesticide degradation has been studied widely. Insitu treatments of effluents containing pesticides such as biological beds (biobeds) are efficient biological systems where biomixture (mixture of substrates) and microorganisms are the keys in pesticide treatment; however, microbial activity has been studied poorly, and its potential beyond biobeds has not been widely explored. In this study, the capacity of microbial consortium and bacteria-pure strains isolated from a biomixture (soil-straw; 1:1, v/v) used to treat agricultural effluents under real conditions were evaluated during a bioremediation process of five pesticides commonly used Yucatan Mexico. Atrazine, carbofuran, and glyphosate had the highest degradations (>90%) using the microbial consortium; 2,4-D and diazinon were the most persistent (DT 50 = 8.64 and 6.63 days). From the 21 identified bacteria species in the microbial consortium, Pseudomonas nitroreducens was the most abundant (52%) according to identified sequences. For the pure strains evaluation 2,4-D (DT 50 = 9.87 days), carbofuran (DT 50 = 8.27 days), diazinon (DT 50 = 8.80 days) and glyphosate (DT 50 = 8.59 days) were less persistent in the presence of the mixed consortium (Ochrobactrum sp. DGG-1-3, Ochrobactrum sp. Ge-14, Ochrobactrum sp. B18 and Pseudomonas citronellolis strain ADA-23B). Time, pesticide, and strain type were significant (P < 0.05) in pesticide degradation, so this process is multifactorial. Microbial consortium and pure strains can be used to increase the biobed efficiency by inoculation, even in the remediation of soil contaminated by pesticides in agricultural areas. Image 1 • Consortium isolated from biomixture was efficient in pesticide degradation. • Pseudomonas nitroreducens was the most abundant bacteria (21 identified bacteria). • DT 50 for 2,4-D, carbofuran & diazinon was lower in the mixed bacteria consortium. • Ochrobactrum sp. pure strain was better degrading atrazine & glyphosate. • Bacteria consortium showed a high potential in pesticide bioremediation process. [ABSTRACT FROM AUTHOR]