Integration of swine manure anaerobic digestion and digestate nutrients removal/recovery under a circular economy concept.

The application of the circular economy concept should utilize the cycles of nature to preserve materials, energy and nutrients for economic use. A full-scale pig farm plant was developed and validated, showing how it is possible to integrate a circular economy concept into a wastewater treatment system capable of recovering energy, nutrients and enabling water reuse. A low-cost swine wastewater treatment system consisting of several treatment modules such as solid-liquid separation, anaerobic digestion, biological nitrogen removal by nitrification/denitrification and physicochemical phosphorus removal and recovery was able to generate 1880.6 ± 1858.5 kWh d-1 of energy, remove 98.6% of nitrogen and 89.7% of phosphorus present in the swine manure. In addition, it was possible to produce enough fertilizer to fertilize 350 ha per year, considering phosphorus and potassium. In addition, the effluent after the chemical phosphorus removal can be safely used in farm cleaning processes or disposed of in water bodies. Thus, the proposed process has proven to be an environmentally superior swine waste management technology, with a positive impact on water quality and ensuring environmental sustainability in intensive swine production.

Organic carbon bioavailability: Is it a good driver to choose the best biological nitrogen removal process?

Organic carbon can affect the biological nitrogen removal process since the Anammox, heterotrophic and denitrifying bacteria have different affinities and feedback in relation to carbon/nitrogen ratio. Therefore, we reviewed the wastewater carbon concentration, its biodegradability and bioavailability to choose the appropriate nitrogen removal process between conventional (nitrification-denitrification) and Anammox-based process (i.e. integrated with the partial nitritation, nitritation, simultaneous partial nitrification and denitrification or partial-denitrification). This review will cover: (i) strategies to choose the best nitrogen removal route according to the wastewater characteristics in relation to the organic matter bioavailability and biodegradability; (ii) strategies to efficiently remove nitrogen and the remaining carbon from effluent in anammox-based process and its operating cost; (iii) an economic analysis to determine the operational costs of two-units Anammox-based process when compared with the commonly applied one-unit Anammox system (partial-nitritation-Anammox). On this review, a list of alternatives are summarized and explained for different nitrogen and biodegradable organic carbon concentrations, which are the main factors to determine the best treatment process, based on operational and economic terms. In summary, it depends on the wastewater carbon biodegradability, which implies in the wastewater treatment cost. Thus, to apply the conventional nitrification/denitrification process a CODb/N ratio higher than 3.5 is required to achieve full nitrogen removal efficiency. For an economic point of view, according to the analysis the minimum CODb/gN for successful nitrogen removal by nitrification/denitrification is 5.8 g. If ratios lower than 3.5 are applied, for successfully higher nitrogen removal rates and the economic feasibility of the treatment, Anammox-based routes can be applied to the wastewater treatment plant.

Corpo estranho intratorácico: achados radiológicos / Intrathoracic gossypiboma: imaging findings

Os autores relatam três casos de corpo estranho intratorácico, que é definido como uma massa de matriz de algodão, e geralmente se refere a compressa cirúrgica retida, uma rara complicação das cirurgias torácicas. Os pacientes foram examinados por radiografia de tórax e tomografia computadorizada,sendo os achados de imagem confirmados por toracotomia e estudo anatomopatológico. Os principais achados de imagem são de massas intratorácicas em pacientes com história de cirurgia prévia apresentando sintomas relacionados ao trato respiratório inferior em tempo variávelapós a intervenção cirúrgica. Foram analisados os principais achados de imagem dos três casos de corpo estranho intratorácico e correlacionados com revisão da literatura.

The authors report three cases of intrathoracic foreign body that is defined as a cotton matrix mass, mostly retained surgical sponge, a rare complication of a thoracic surgery. The patients wereevaluated by chest radiography and computed tomography with the imaging findings confirmed after thoracotomy and anatomopathological study. The mainly imaging findings consisted of intrathoracic masses in patients with previous thoracic surgery that return to hospital with lower respiratory tract symptoms in different period after surgery procedure. The three cases were related with a brief review of the literature.