Sewage phosphorus recovery through sachets loaded with water treatment plant sludge.

Conventional wastewater treatment plants (WWTPs) present low phosphorus (P) removal capacity. Conversely, water treatment plants (WTPs) produce sludge with great P sorption from wastewater; however, directly adding the sludge into the wastewater treatment system could increase the effluent turbidity. As a novel approach, the present study evaluated the performance of WTP sludge within paper sachets for P removal from treated sewage. Different sludge concentrations (2-30 g L-1) and contact times (1-27 d) were applied to treat sewage from a university WWTP outlet. The sludge was characterized by P, Fe, and Al content. Larger sludge masses showed higher P removal efficiencies due to their high Fe content, especially at longer contact times (up to 100% at the final of the experiment). However, there is a more significant P reduction in the first 10 d (more than 90% in the most efficient treatment - 30 mg L-1). Based on the kinetic and isotherm analyses and the sludge chemical composition, precipitation proved to be a mechanism of great importance in P removal. Therefore, WTP sludge sachets can be a promising way to remove P from sewage, and the formed solid waste might be reused as an alternative fertilizer.

As emissões otoacústicas no diagnóstico diferencial das perdas auditivas induzidas por ruído / Otoacoustic emissions in the differential diagnosis of the noise-induced auditory losses

TEMA: artigos relacionados a emissões otoacústicas no diagnóstico diferencial da perda auditiva induzida por ruído (PAIR). OBJETIVOS: evidenciar a importância da utilização das emissões otoacústicas no diagnóstico diferencial da perda auditiva induzida por ruído (PAIR). CONCLUSÃO: confirmou-se que tanto as emissões otoacústicas transientes (EOAT) quanto às emissões otoacústicas por produto de distorção (EOAPD) são úteis no diagnóstico precoce da PAIR sendo que as EOAT se revelam mais sensíveis às mudanças temporárias de limiar que as EOAPD e as EOAPD se destacam mais eficazes no diagnóstico precoce da PAIR em indivíduos com audição aparentemente normal por captar respostas nas frequências mais agudas que são primeiramente atingidas na PAIR. Acredita-se, ainda, que este estudo possa beneficiar a população quanto à prevenção e controle da PAIR e incentivar a criação de políticas públicas que contribuirão com a prevenção das alterações auditivas dentro do âmbito ocupacional.

BACKGROUND: articles related of otoacoustic emissions in differential diagnosis of noise-induced hearing loss (NIHL). PURPOSES: to demonstrate the importance of using otoacoustic emissions in the differential diagnosis of noise-induced hearing loss (NIHL). CONCLUSION: it was confirmed that both the transient-evoked otoacoustic emissions (TEOAE) and distortion-product otoacoustic emissions (DPOAE) are useful in the early diagnosis of and the TEOAE and are more sensitive to temporary alterations in the DPOAE threshold, and DPOAE stand out more effectively in the early diagnosis of NIHL in individuals with apparently normal hearing responses by capturing responses more acute frequencies in that are first affected in NIHL. It is also believed that this study can benefit the population on the NIHL prevention and control and foment the creation of public policies that shall contribute to the prevention of hearing impairment within the occupational field.

Eficácia de alguns aparelhos geradores de luz visível na polimerizaçäo de resinas compostas / Eficacy of some visible light generator devices for the photopolimerization of composite resins

Foram testados 5 aparelhos de fotopolimerizaçäo, geradores de luz visível, quanto à eficàcia na profundidade de polimerizaçäo, variando a voltagem e a cor de uma mesma resina. Encontraram diferenças significantes quanto à cor e quanto aos aparelhos. Na variaçäo de voltagem houve sobreposiçäo de médias, levando a indefiniçöes

A inclinação das paredes de cavidades de Classes I e II para amálgama / The inclination of the wall canties of Classes I and II for amalgama

Os autores fazem um acompanhamento histórico das modificações introduzidas por diversos autores nas cavidades de Classes I e II para amálgama