Resumo Os efluentes dos sistemas de produção de animais confinados (SPACs), se não tratados adequadamente antes do descarte, podem interferir significativamente no balanço natural do nitrogênio no meio ambiente. Nesse trabalho, um sistema Lutzak-Ettinger modificado (MLE), consistindo de dois reatores sequenciais, um pré-desnitrificante (RD) e um nitrificante (RN), foi utilizado para determinar os efeitos da carga de alimentação e o tempo de retenção hidráulico (TRH), na remoção simultânea de nitrogênio total (NT) e carbono orgânico total (COT) de efluentes da suinocultura. O sistema MLE foi alimentado com efluente da suinocultura por 205 dias, usando diferentes razões de recirculação (Rr) e TRH. Foram obtidas eficiências de remoção de NT e COT (90,7% e 96,1%, respectivamente) com a recirculação do meio do RN (4.5:1) combinado com o lodo do decantador final (1:1). Essas eficiências foram obtidas com TRH de 3,5 dias e cargas de alimentação de 0,56 gNT L-1 d-1 e 2,15 g TOC L-1 d-1. Concluiu-se que o processo MLE se demonstrou robusto, resistindo a grandes variações na composição físico-química do efluente de alimentação e nas condições de operação, sem sofrer impacto importante nas eficiências de remoção de NT e COT.

Abstract Wastewater from confined animal feeding operations (CAFOs) can interfere significantly with the natural nitrogen and phosphorus balance in the environment if not treated adequately prior to disposal. In this work, a modified Lutzak-Ettinger (MLE) consisting of sequential pre-denitrification/ nitrification was used to determine the effects of nutrient loading rates and hydraulic retention times (HRT) on total nitrogen (TN) and organic carbon (TOC) removal from swine wastewater. MLE reactor was continuously fed swine wastewater for over 205 days using different recycle ratios (Rr) and HRT. Higher TN and TOC removal efficiencies (90.7% and 96.1%, respectively) were obtained when recycling effluent from the nitrification tank (4.5:1) combined with effluent from the final clarifier (1:1). Removal efficiencies of 96% for TOC and 90% for TN were obtained for the maximum loading rates of 0.56 gTN L-1 d-1 and 2.15 g TOC L-1 d-1, respectively. TN and TOC removal rates were achieved with HRT in as little as 3.5 days. Overall, MLE was a robust bioprocess withstanding variations in wastewater physical-chemical composition and/or changes in operational conditions without significant impairment of N and TOC removal efficiencies.

ABSTRACT The swine industry has been presented strong growth and thus is producing large volumes of effluents that must be correctly management. Nitritation/denitritation process can be used to improve system performance, saving the energy cost with aeration and with the external source of carbon due to the lower C/N requirement. The aim of this study was to evaluate swine wastewater Nitrification/Denitrification (NDF) and Nitritation/denitritation (NDT) processes at different C/N ratios, using the Modified Ludzack-Ettinger (MLE) process, in order to obtain a system with efficient nitrogen removal and low oxygen and carbon consumption. Four phases were conducted during the experiment: Phase I) DO between 2.0-3.0 mg L−1 of O2 and C/N 1.5 (NDF); Phase II) DO between 0.6-0.7 mg L−1 of O2 and C/N 1.5 (NDT); Phase III) DO between 0.6-0.7 mg L−1 of O2, C / N ratios of1.5, 0.9, 0.75 and 0.6 (NDT); Phase IV) DO between 2.0-3.0 mg L−1 of O2, C/N ratios of 1.5, 0.9, 0.75, and 0.6 (NDF). The best operational condition was found in the C / N ratio of 0.9 (Phase III) obtaining an optimum N removal of 86.3%. In this condition, the system saved around 26.8% in total organic carbon consumption and operated at conditions of 74% lower dissolved oxygen when compared to conventional process for N-removal. This strategy can be very useful for nitrogen removal for low carbon swine wastewater as digestate from anaerobic processes.

RESUMO Os ovos são um dos alimentos que oferecem nutrientes de grande valor biológico. Entretanto, no armazenamento, alguns componentes da clara e gema podem se alterar, deteriorando a qualidade dos ovos. Assim, este trabalho objetivou avaliar semanalmente parâmetros de qualidade como unidade Haugh, perda de peso, largura/comprimento do ovo, densidade específica, dimensões da clara/gema e pH durante 9 semanas de armazenamento. Foram coletados 270 ovos de duas linhagens de poedeiras e avaliados a temperatura ambiente (20 a 35 °C no verão; 11,2 a 29,7 °C no outono) e refrigerada (0 a 5 °C no verão; -3,1 a 6,5 ºC no outono). Para as condições de armazenamento, foi realizada uma análise de desdobramento por regressão por polinômios ortogonais. Ainda, análise de componentes principais (PCA), objetivou avaliar correlações entre parâmetros de qualidade em diferentes condições de armazenamento e linhagens de poedeira. Após 9 semanas de armazenamento, os ovos refrigerados apresentaram qualidade similar àqueles armazenados a temperatura ambiente por 3 semanas. Porém, sem refrigeração, os ovos apresentaram uma degradação mais rápida da semana 1 a 5. Não foram observadas diferenças nos parâmetros de qualidade dos ovos entre as diferentes colorações de casca (linhagens de poedeiras). PCA sugere que a melhor qualidade dos ovos (primeira semana) foi associada principalmente com valores elevados de peso e densidade específica do ovo, unidade Haugh e altura do albúmen. Ovos armazenados a temperatura ambiente devem ser consumidos até duas semanas ou mantidos sob refrigeração até 8 semanas, preservando a qualidade interna desde a granja até o armazenamento no varejo.

ABSTRACT Eggs are one of nearly perfect protein foods, offering nutrients of great biological value. However, during storage, egg albumen and yolk components may alter and deteriorate egg quality. Therefore, the aim of this work was to assess egg quality during 9-week storage. Parameters such as Haugh unit, weight loss, egg width and length, specific gravity, yolk and albumen dimensions and their pH were evaluated weekly. A total of 270 eggs (n=5) collected from two different hen strains were evaluated under room (20 to 35 °C in summer; 11.2 to 29.7 °C in autumn) and refrigerated (0 to 5 °C in summer; -3.1 to 6.5 °C in autumn) temperatures. For storage time, an unfolding analysis was accomplished by regression analysis using orthogonal polynomials. As a second approach, principal component analysis (PCA) was performed in order to assess correlations among quality parameters on storage conditions and laying hen strains. By the end of the 9-week storage period, eggs kept under refrigeration presented similar quality parameters to eggs stored at room temperature for only 3 weeks. In contrast, eggs kept at room temperature presented faster degradation from week 1 to 5. No differences on egg quality parameters were noticed between white and brown shells eggs. PCA suggests that better egg quality (first week) was associated mainly with higher egg weight and its specific gravity, Haugh unit and albumen height. Eggs stored at room temperature should be consumed in 2 weeks or refrigerated until 8 weeks, preserving internal quality from farm to retail.