In this study, removal of organic matter and nitrogen from a cattle slaughterhouse wastewater was investigated in a two‐stage anoxic–aerobic biological system, followed by UV‐C disinfection. Ecotoxicity of the raw, biotreated, and disinfected wastewater against the microalgae Scenedesmus sp. was evaluated in short‐term tests, while the potential of the microalgae as a nutrient removal step was addressed in long‐term experiments. Throughout 5 operational phases, the biological system was subjected to gradual reduction of the hydraulic retention time (8–1.5 day), increasing the organic (0.21–1.11 kgCOD·m−3·day−1) and nitrogen (0.05–0.28 kgN·m−3· day−1) loading rates. COD and total ammoniacal nitrogen (TAN) removal ranged within 83%–97% and 83%–99%, respectively. While providing alkalinity source, effluent TAN concentrations were below 5 mg·L‐1. Nitrate was the main nitrification product, while nitrite levels remained low (<1 mgN·L‐1). Upon supplementation of external COD as ethanol, total nitrogen removal reached up to 90% at the highest load (0.28 kgN·m−3·day−1). After UV‐C treatment, 3‐log reduction of total coliforms was attained. The 96‐hr ecotoxicity tests showed that all non‐diluted samples tested (raw, biologically treated and UV‐C irradiated wastewater) were toxic to microalgae. Nevertheless, these organisms were able to acclimate and grow under the imposed conditions, allowing to achieve nitrogen and phosphorous removal up to 99.1% and 43.0%, respectively. Practitioner points The treatment of a slaughterhouse wastewater in an anoxic–aerobic biological system followed by a UV‐C disinfection step was assessed. The pre‐denitrification system showed efficient simultaneous removal of organic matter and nitrogen from the wastewater under increasing applied loads. UV‐C disinfection worked effectively in reducing coliforms from the biotreated effluent, boosting the performance of microalgae on nutrients removal. Despite the toxicity to microalgae, they were capable to acclimate to the aqueous matrices tested, reducing efficiently the nutrients content. The combined stages of treatment presented great capacity for depleting up to 97% COD, 99% nitrogen, and 43% phosphorous.

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O objetivo foi verificar a relação entre Sintomas de Disfunção Temporomandibular (DTM), bruxismo, estresse e fatores sociodemograficos em estudantes universitários. Foram aplicados questionários em 362 estudantes de Odontologia, na faixa etária de 17 a 56 anos de ambos os sexos. A coleta de dados foi realizada através do questionário para triagem para Dor Orofacial e DTM recomendado pela Academia Americana de Dor Orofacial, questionário de sintomas de Bruxismo baseado nos critérios da Academia Americana de Medicina do Sono, Escala de Estresse Percebido (PSS-14) e um questionário estruturado sociodemográfico. Os dados foram analisados por meio de regressão logística múltipla, considerando um nível de significância de 5%. Os sintomas de DTM foram relatados por 60%, o bruxismo por 37% e o estresse em 52% dos estudantes universitários avaliados. Verificou-se que universitários do sexo feminino, que estudam no período noturno e com estresse têm 3.36 (IC95%: 1.87-6.01), 1.71 (IC95%: 1.05-2.79) e 1.90 (IC95%: 1.17-3.08) vezes mais chance, respectivamente, de apresentar pelo menos um sintoma de DTM (P<0.05). Pessoas com um, dois e três ou mais sintomas de bruxismo têm 3.24 (IC95%: 1.57-6.69), 4.62 (IC95%: 1.91-11.16) e 18.75 (IC95%: 4.39-80.13) vezes mais chance, respectivamente, de apresentar DTM do que as pessoas sem sintomas de bruxismo (P<0.05). Conclui-se que houve associação entre a presença de sintomas de DTM, bruxismo e estresse.

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Proper treatment and reuse of industrial wastewaters are efficient ways to mitigate their environmental impacts. In this work, a pesticide formulation wastewater pretreated by activated carbon was combined with sewage (4:96) and subjected to biotreatment in a lab-scale moving-bed biofilm reactor (MBBR) with 50% media filling ratio and 6h HRT. Throughout 180 days, efficient removal was achieved for organic matter (86%, tCOD) and ammonium (88%). Additionally, the MBBR effluent exhibited higher quality than the water of the river used by the pesticide industry. For evaluating the possibility of wastewater reuse, the effluents from the MBBR (M) and a lubricant industry (L, from the same industrial site) were combined with the river water (R) that feeds the industrial water treatment plant (WTP) and submitted to a lab-scale reproduced WTP: coagulation/flocculation, sedimentation, sand filtration and microfiltration. River water and two combinations (RM: 85:15 and RML: 80:15:5) were assessed. The mixtures improved the efficiency of the lab-reproduced WTP; however, the fouling potential was high (SDI15>5) for reverse osmosis at the end of the WTP. Thus, after microfiltration, two ultrafiltration (UF) membranes (10 and 50 kDa) were tested, producing similar quality water (0.02 NTU, low SDI and color). After UF, the total turbidity and color removals for R, RM and RML were, respectively, 99.87%, 99.84% and 99.81%, and 96.2%, 87.3% and 93.1%. The UF implementation produced stable high-quality water, implying a reduction of RO membrane costs and cleaning frequency, while increasing the permeate flux. Ultimately, complete wastewater reuse was enabled by the proposed chain.