Although common bean (Phaseolus vulgaris L.) has a good potential for N₂ fixation, poor nodulation following inoculation, principally under field conditions, has led to increased nitrogen (N) fertilizer use in this crop. In the face of the negative environmental effects of N fertilizer, alternative methods have been studied to minimize the amount to be applied. In this sense, foliar application of molybdenum (Mo) has been cited as a promising method. Several papers show that high bean yields (1,500–2,500 kg ha^‐1), may be obtained in the southeasten region of Brazil, when there is an application of N as side dressing or Mo spray 25 days after plant emergence. A field experiment was carried out to verify the effect of Mo foliar application on nitrogenase and nitrate reductase activities and on bean yield. Treatments included Rhizobium inoculation (with and without), foliar application of Mo (0 and 40 g ha^‐1), N at planting (0 and 20 kg ha^‐1) and N applied as side dressing (0 and 30 kg ha^‐1). Molybdenum and N as side dressing were used 25 days after plant emergence. Molybdenum increased greatly the nitrogenase activity and extended the period of high nitrate reductase activity, with a consequent increase in total shoot N. Increase of nitrogenase activity did not depend on inoculation, showing that soil native rhizobia may increase in effectiveness when appropriately handled. Bean yield did not differ significantly when fertilized with either Mo or N as side dressing.

Harvesting is a critical step in microalgal biomass production process for many reasons. Among the existing techniques available for harvesting and dewatering microalgal biomass, recovery from aqueous medium by coagulation-flocculation has been the most economically viable process, althoughit is highly dependent on pH. This study aims to assess alternative coagulants compared to the standard coagulant aluminum sulfate for microalgal biomass recovery from anaerobic effluent of domestic sewage treatment. The effluent quality was also analyzed after biomass recovery. Coagulants represented by modified tannin, cationic starch and aluminum sulfate recovered more than 90% of algae biomass, at concentrations greater than 80 mg/L, in the pH range 7-10. Cationic starch promoted higher microalgal biomass recovery with a wider pH range. Powdered seeds of Moringa oleifera and Hibiscus esculentus(okra) gum promoted biomass removal of 50%, only in the acidic range of pH. After sedimentation of the microalgal biomass, the effluents showed a removal of >80% for phosphorus and nitrogen values and >50% for BOD and COD when using aluminum sulfate, cationic starch and modified tannin as coagulants. Natural organic coagulants in a wide pH range can replace aluminum sulfate, a reference coagulant in microalgal biomass recovery, without decreasing microalgal biomass harvesting efficiency and the quality of the final effluent.

Sludge samples from an upflow anaerobic sludge blanket (UASB) reactor and four submerged aerated biofilters (BFs) of a wastewater treatment plant (1,000 inhab.) were processed at bench scale by alkaline and acid hydrolysis with the objective to evaluate the organic matter solubilization, volatile solids (VS) destruction and the effect of hydrolytic processes on the extracellular polymeric substances (EPS) fraction of the sludge samples. The results showed that alkaline hydrolysis of sludge samples treatment with 1.0% total solids (TS) using NaOH 20 meq L−1 was more efficient on organic matter solubilization and VS destruction than acid hydrolysis. The EPS sludge content was also affected by the alkaline treatment of anaerobic sludge samples. The EPS concentrations (mg EPS/gVSS) on the anaerobic sludge after the alkaline treatment were significantly lowered according to sample height in the UASB reactor. Data indicated that the EPS sludge fraction is the main component affected by the alkaline hydrolytic process of anaerobic sludge samples.

Mangroves are vital part of the local economy for some communities in the region of Vitória, Brazil. Oysters, mussels, and crabs, which are naturally abundant in the mangroves, are harvested and largely consumed in restaurants and by the population. In recent years, unusually high rates of annual gastroenteritis cases have been reported in the region suggesting an association between the consumption of contaminated shellfish and the development of gastrointestinal diseases. The objective of this study was to evaluate water samples and mussels collected in the mangrove region using bacterial indicator Escherichia coli and enteric viruses (adenovirus, rotavirus, and norovirus). Our results showed that the region of study is impacted by a continuous discharge of domestic sewage. Although E. coli was detected at low densities in water samples, mussels were shown to be 400 times more contaminated throughout the period of the study. Adenovirus and rotavirus genomes were detected by nested-polymerase chain reaction respectively in 76 and 88% of water samples and 100% of mussel samples. Norovirus was found in 4.8% of water samples and was not detected in the mussels. The screening of bivalves for the presence of health-significant enteric viruses can help in the prevention of outbreaks among shellfish consumers and contribute to improvement of the estuarine environment.