Efficiency of chitosan as a coagulant in the after-treatment of effluents from a pig slaughter plant

Los efluentes provenientes del sacrificio de cerdos son una fuente de contaminación debido a las altas concentraciones de materia orgánica, nitrógeno, fósforo, grasas, sólidos totales y coliformes fecales. En esta investigación se evaluó la efectividad del quitosano como coagulante en el postratamiento de efluentes porcícolas provenientes de un reactor discontinuo secuencial, con el fin de remover las fracciones no biodegradables remanentes del proceso biológico. El tratamiento terciario consistió en la coagulación, floculación y sedimentación. Se caracterizó el efluente tratado biológicamente mediante los siguientes parámetros: pH, DQO, turbidez, color, sólidos totales (ST), nitrógeno total Kjeldahl (NTK), nitrito, nitrato, fosforo total (PT) y alcalinidad total (AT). El tratamiento fisicoquímico se llevó a cabo mediante el uso de la prueba de Jarra a través de corridas exploratorias con dosis entre 50 y 800 mg/L de quitosano disuelto en ácido acético. Se comparó la efectividad del quitosano (700 mg/l) con sulfato de aluminio (430mg/l) y poliacrilamida (90 mg/l), los cuales son utilizados como coagulantes de uso convencional en el tratamiento de aguas residuales. El experimento se condujo mediante un diseño completamente al azar con un total de tres tratamientos (quitosano, sulfato de aluminio y poliacrilamida) y tres repeticiones cada uno. La dosis de quitosano (700 mg/l) permitió obtener porcentajes de reducción de turbidez de 83.1%, color de 64.7%, DQO de 84.6%, y 78.2% de NT para valores iniciales de 15.6 NTU, 26 UC Pt-Co, 865 mg DQO/L y 89 mg NT/L. Se encontraron diferencias significativas (P≤0.05) entre la dosis quitosano (700 mg/l) y los coagulantes convencionales (430 mg/l de sulfato de aluminio y 90 mg/l de poliacrilamida) en la reducción de NT, siendo el tratamiento con quitosano el coagulante con las mayores eficiencias de reducción. El tratamiento con quitosano con una dosis de 700 mg/l representó una opción viable para el tratamiento terciario de los efluentes proveniente del proceso de sacrificio de cerdos tratados biológicamente.Effluents from pig slaughter are a source of contamination due to high concentrations of organic matter, nitrogen, phosphorus, fats, total solids and fecal coliforms. This research evaluated the effectiveness of chitosan as a coagulant in the post-treatment of wastewater from the slaughter of pigs, in order to remove the remaining recalcitrant fractions from the biological process in a sequential batch reactor. The tertiary treatment consisted of coagulation, flocculation and sedimentation. The effluent was characterized by the parameters: pH, COD, turbidity, color, total solids (ST), Kjeldahl total nitrogen (NTK), nitrite, nitrate, total phosphorus (PT) and total alkalinity (AT). The treatment was carried out by using the jar test through exploratory runs with doses between 50 and 800 mg/L of chitosan dissolved in acetic acid. The effectiveness of chitosan with conventional coagulants in the treatment of wastewater, such as aluminum sulphate and polyacrylamide, was compared. The experiment was conducted using a completely randomized design with a total of three treatments and three replicates each. The evaluated range of doses of chitosan allowed to obtain percentages of turbidity removal of 83.1%, color of 64.7%, COD of 84.6%, and 78.2% NT for initial values of 15,6 NTU, 26 UC, 865 mg COD/L and 89 mg NT/L, using as optimal dose 700 mg chitosan /L. Significant differences (P≤0.05) were found between chitosan and conventional coagulants in NT removal, with chitosan being the coagulant with the highest removal efficiencies. The treatment with chitosan represents a viable option for the tertiary treatment of the effluents coming from the slaughter of pigs

Continuous Cultivation of Microalgae in Cattle Slaughterhouse Wastewater Treated with Hydrodynamic Cavitation

Cattle slaughtering produce large amounts of wastewater containing high concentrations of organic matter and nutrients and requires significant treatment before disposal or reutilization. However, the nutrients contained can be valued as a medium for microalgal biomass generation. In this work, hydrodynamic cavitation (HC) followed by membrane filtration or biological (microalgae cultivation) treatment in continuous mode were performed. From cattle slaughterhouse wastewater (CSW), by the effect of HC treatment with air injection in batch mode, more than 20% of the chemical oxygen demand (COD) was removed. In a continuous HC process, the COD content in output was 324 mg O2/L, which is 68% lower than the supplied CSW. After that, 76% of residual COD was removed by filtration through a tubular alumina membrane (600 nm). Finally, 85% of residual COD after HC treatment in 24 h in a batch mode was removed by microalgae. On the other hand, the COD concentration in the output was around 59 mg O2/L in continuous mode, which represents 85–93% COD removal. The process involving HC and microalgae growing looks promising since in addition to water treatment, the microalgae produced could be valued in a biorefinery concept

Continuous Cultivation of Microalgae in Cattle Slaughterhouse Wastewater Treated with Hydrodynamic Cavitation

Cattle slaughtering produce large amounts of wastewater containing high concentrations of organic matter and nutrients and requires significant treatment before disposal or reutilization. However, the nutrients contained can be valued as a medium for microalgal biomass generation. In this work, hydrodynamic cavitation (HC) followed by membrane filtration or biological (microalgae cultivation) treatment in continuous mode were performed. From cattle slaughterhouse wastewater (CSW), by the effect of HC treatment with air injection in batch mode, more than 20% of the chemical oxygen demand (COD) was removed. In a continuous HC process, the COD content in output was 324 mg O2/L, which is 68% lower than the supplied CSW. After that, 76% of residual COD was removed by filtration through a tubular alumina membrane (600 nm). Finally, 85% of residual COD after HC treatment in 24 h in a batch mode was removed by microalgae. On the other hand, the COD concentration in the output was around 59 mg O2/L in continuous mode, which represents 85–93% COD removal. The process involving HC and microalgae growing looks promising since in addition to water treatment, the microalgae produced could be valued in a biorefinery concept

Promising physicochemical technologies for poultry slaughterhouse wastewater treatment: A critical review

Poultry slaughterhouse wastewater (PSWW) is a serious concern mainly due to the huge generation and associated characteristics of high organic matter and nutrients (N, P) that this contains. Therefore, an understanding development and adaption of an apposite wastewater treatment option focused specifically on PSWW is an absolute need. Recently, innovative physicochemical-based technologies, such as; acid precipitation, electrochemical advanced oxidation, cavitation-based processes and even nanotechnology assisted processes have been reported as prominent alternatives for wastewater treatment. In this article, we performed a systematic literature review and a comprehensive discussion about these technologies, aiming to show them as alternatives for PSWW treatment. Among all discussed technologies, hydrodynamic cavitation (HC) was observed as an interesting possibility that can be implemented in combination with other processes for efficient pollutant degradation. It could be, e.g., associated with nanoparticles, nanocomposites and nanobubbles, which are also an interesting alternative to be associated with membranes, generating turbulence, and mitigating problems as fouling. Finally, the wide knowledge about such treatment technologies can offer a more cost-effective PSWW management, thus, allowing an adequate implementation from technical and economical viewpoints

Efficient Dye Removal from Real Textile Wastewater Using Orange Seed Powder as Suitable Bio-Adsorbent and Membrane Technology

Textile wastewater is widely produced and its discharge without treatment contributes to environmental pollution. The adsorption process is a suitable and eco-friendly process due to its low initial cost, no formation of degradation products, operation simplicity, insensitivity to toxic compounds, and the possibility of removal from greatly diluted solutions. Orange seed (OS) powder, from which lipids were removed by hexane extraction, was evaluated as a bio-adsorbent to remove dyes from real textile wastewater. In the screening step, pH was a more significant variable (p-value < 0.05) than bio-adsorbent dosage, temperature, stirring speed, and process time. Moreover, under optimized conditions (pH = 2.6, 0.58 g/L from OS powder and 26 °C), more than 95% of the dye was removed from real textile wastewater. Additionally, the dye removal percentage was reduced by only 4% when the volume of textile wastewater was increased from 0.05 L to 10 L. Then, 96% turbidity was removed using a 3 µm tubular ceramic membrane at a pH of 11. Furthermore, the permeate flux through the membrane was kept constant for longer than was observed at low pH (<11). Therefore, the proposed process is an interesting option, due to the fact that orange seeds are currently not valorized and, combined with the membrane process, this could prove a suitable option for the treatment of real textile wastewater

Enhanced Removal of Bordeaux B and Red G Dyes Used in Alpaca Wool Dying from Water Using Iron-Modified Activated Carbon

The aim of this research was to explore the removal of Red G and Bordeaux B dyes from water using a packed bed column with conventional carbon (C-conv) and iron-modified activated carbon (C-FeCl3). The bands increased in C-FeCl3, corresponding to groups already existing in C-conv, such as C = C and C-C, and the appearance of new groups, such as C-O, C-Cl, Fe-Cl and Fe-O. The total ash content (CT) was CT = (10.53 ± 0.12 and 8.98 ± 0.21)% for C-conv and C-FeCl3, respectively. A molecular structure in the shape of a cross was noticed in Bordeaux B, which was less complex and smaller than the one in Red G. For fixed-bed columns, the carbon fraction was (0.43 and 0.85) mm. The pH of the adsorbents was 8.55 for C-conv and 4.14 for C-FeCl3. Breakthrough curves were obtained and the Thomas model (TM) and Yoon–Nelson model (YNM) were applied. The sorption capacity of Bordeaux B on C-conv and C-FeCl3 was qTH: (237.88 and 216.21) mg/g, respectively, but the one of Red G was qTH: (338.46 and 329.42) mg/g. The dye removal (RT) was over 55%

Enhanced Removal of Bordeaux B and Red G Dyes Used in Alpaca Wool Dying from Water Using Iron-Modified Activated Carbon

The aim of this research was to explore the removal of Red G and Bordeaux B dyes from water using a packed bed column with conventional carbon (C-conv) and iron-modified activated carbon (C-FeCl3). The bands increased in C-FeCl3, corresponding to groups already existing in C-conv, such as C = C and C-C, and the appearance of new groups, such as C-O, C-Cl, Fe-Cl and Fe-O. The total ash content (CT) was CT = (10.53 ± 0.12 and 8.98 ± 0.21)% for C-conv and C-FeCl3, respectively. A molecular structure in the shape of a cross was noticed in Bordeaux B, which was less complex and smaller than the one in Red G. For fixed-bed columns, the carbon fraction was (0.43 and 0.85) mm. The pH of the adsorbents was 8.55 for C-conv and 4.14 for C-FeCl3. Breakthrough curves were obtained and the Thomas model (TM) and Yoon–Nelson model (YNM) were applied. The sorption capacity of Bordeaux B on C-conv and C-FeCl3 was qTH: (237.88 and 216.21) mg/g, respectively, but the one of Red G was qTH: (338.46 and 329.42) mg/g. The dye removal (RT) was over 55%