ABSTRACT
RESUMO Neste trabalho, realizaram-se modificações nos sistemas produtivo e de tratamento de efluentes em um complexo industrial automotivo a fim de possibilitar a utilização do efluente tratado no sistema de torres de resfriamento. Inicialmente, realizou-se um balanço hídrico nos processos industriais para determinar o consumo de água e analisou-se a qualidade do efluente tratado quanto aos parâmetros físico-químicos em dois pontos do sistema de tratamento de efluentes: no decantador secundário (P1) do tratamento físico-químico e na saída da lagoa de polimento (P2). Essas análises mostraram que o efluente tratado no decantador secundário não tem capacidade de atender às especificações da água de circulação das torres de resfriamento sem a realização de muitas alterações em seu tratamento, optando-se pela utilização do efluente tratado na saída da lagoa de polimento após modificações, como: alteração na concentração de ácido fosfórico e de ácido nítrico da solução de limpeza dos tanques de fosfatização, elevação em 50% da capacidade de aeração da lagoa aerada e troca do coagulante sulfato de alumínio pelo cloreto férrico no tratamento físico-químico. Assim, os parâmetros do efluente tratado na lagoa de polimento aproximaram-se aos parâmetros especificados para água de torres de resfriamento. A introdução desse efluente na proporção de 40% do volume da água de circulação na torre de resfriamento resultou em elevação do ciclo de dureza e redução no ciclo de sílica. A utilização de um filtro abrandador na saída da lagoa de polimento proporcionou a redução dos parâmetros de qualidade da água para valores similares aos da água de recirculação nas torres de resfriamento.
ABSTRACT In this work, some changes in the productive system and in the effluent treatment plant of an automotive industrial complex have been performed in order to enable the treated effluent use in the cooling towers of the industry. Initially, a hydric balance in the industrial processes was performed, allowing the determination of water consumption. After, the effluent quality was analysed through its physico-chemical parameters at two sites of the effluent treatment plant: in the secondary settling tank (P1) of the physico-chemical treatment and in the exit of the polishing pond (P2). These analyses showed that the effluent from the settle tank does not have the ability to contemplate the specifications for water used in the cooling towers without much change in effluent treatment so that the effluent from polishing pond was used for testing in the cooling towers after some changes. These changes have included: phosphoric acid and nitric acid concentration changes in the cleaning solution of phosphating tanks, 50% increase in the aeration capacity of the aerated lagoon and replacement of aluminum sulfate coagulant by ferric chloride in physico-chemical treatment. With these modifications, the effluent from polishing pond approached the parameters specified for water cooling towers. The use of this treated effluent as 40% of water volume of the cooling tower resulted in hardness cycle increase and reduction in silica cycle. The use of a softener filter after the polishing pond decreased the effluent quality parameters to similar values to those for water cooling towers.
ABSTRACT
This study was conducted on 103 male workers exposed to local vibration (exposure workers) and 23 male clergical workers not exposed to local vibration (reference workers) to evaluate the effect of local vibration in a automobile industry workers who had used vibratory tools such as electric bolt impacter or grinder. The assessment methods of this study were some tests recommended by Wasserman and Taylor. None of reference workers complained sensorineural symptoms, but 43.7% of exposed workers complained over one of those symptoms. The proportion of non-recovery type, which means that there was no full recovery of temperature of finger tips, was from 0% to 31. 3% in reference workers and from 10.7% to 15.5% in exposure workers. There was statistically significant difference of recovery time of plethysmogram after cold provocation between mean recovery time of 0.44 minutes in reference workers and that of 3.05 minutes in exposure workers. The proportion of bad plethysmogram was from 0% to 4.4% in reference workers and from 3.9% to 7.8% in exposure workers. There was statistically significant difference of discrimination sense between mean length of 2.04 mm in reference workers and that of 2.9 mm in exposure workers. There were also statistically significant difference of pain sense between mean weights of from 5.02 g to 5.26 g in reference workers and those of from 6.81 g to 7.6 g in exposure workers. By the results of multiple stepwise regression analysis the statistically significant variable affecting discrimination and pain sense was exposure and those affecting vibration sense were exposure and age. We concluded that exposure of local vibration in automobile workers was significaritly associated with decrease of sensorineural sense regardless of age and other, possible related variables.
Subject(s)
Humans , Male , Automobiles , Discrimination, Psychological , Fingers , Hand-Arm Vibration Syndrome , Vibration , Weights and MeasuresABSTRACT
This study was conducted on 103 male workers exposed to local vibration (exposure workers) and 23 male clergical workers not exposed to local vibration (reference workers) to evaluate the effect of local vibration in a automobile industry workers who had used vibratory tools such as electric bolt impacter or grinder. The assessment methods of this study were some tests recommended by Wasserman and Taylor. None of reference workers complained sensorineural symptoms, but 43.7% of exposed workers complained over one of those symptoms. The proportion of non-recovery type, which means that there was no full recovery of temperature of finger tips, was from 0% to 31. 3% in reference workers and from 10.7% to 15.5% in exposure workers. There was statistically significant difference of recovery time of plethysmogram after cold provocation between mean recovery time of 0.44 minutes in reference workers and that of 3.05 minutes in exposure workers. The proportion of bad plethysmogram was from 0% to 4.4% in reference workers and from 3.9% to 7.8% in exposure workers. There was statistically significant difference of discrimination sense between mean length of 2.04 mm in reference workers and that of 2.9 mm in exposure workers. There were also statistically significant difference of pain sense between mean weights of from 5.02 g to 5.26 g in reference workers and those of from 6.81 g to 7.6 g in exposure workers. By the results of multiple stepwise regression analysis the statistically significant variable affecting discrimination and pain sense was exposure and those affecting vibration sense were exposure and age. We concluded that exposure of local vibration in automobile workers was significaritly associated with decrease of sensorineural sense regardless of age and other, possible related variables.