ABSTRACT
Background and aims: Crude oil is very complex composition with harmful effect in human health, such as carcinogenesis and blood dyscrasia. Because of the entry of relatively high volume of these compounds in aquatic environments, effective controlling is very important. The aim of this study was to investigate the effect of powdered activated carbon [PAC] for reducing the toxicity of crude oil in water
Methods: Water soluble fraction standard samples were prepared with one part crude oil in 9 part water. For toxicity test, different concentrations of crude oil water soluble fraction in water and larvae of rainbow trout were used. Before and after the addition of 10, 20, 40 and 60 mg/l powdered activated carbon, TOC and bioassay tests were performed. LC50 and evaluation of results was done with probit statistic program
Results: LC50 for samples 24, 48, 96 hrs after addition of different concentration of PAC were 94.8, 106.6, 117.8, 138.3 and 181.5 mg/l. Values of TOC for these samples was 44.81, 43.88, 38.16, 36.62 and 35.14 mg/l
Conclusion: The use of activated carbon reduced toxicity and TOC. With increase in the concentration of activated carbon, toxicity was decreased, but intensity of TOC removal wasn't similar to toxicity removal. Using of powdered activated carbon for treatment, in case of accidents and entering crude oil in drinking water supplies, can be considered
ABSTRACT
Corrosion is one of the most complex and costiy problems related to drinking water. Corrosion can affect the public health, acceptability of the drinking water source and supplying costs. The aim of this study was to determine the corrosion potentiality of drinking water in Shiraz city in 2007- 2008 through corrosion and stability index [Langlier Saturation Index, Ryznar Stability Index, Aggressiveness Index and Pockurius Scaling Index]. The results indicate the mean and standard deviation for temperature, pH, and pHs were equal to 22.84 and 2.93 °C, 7.69 and 0.28, and 6.83 and 0.24 respectively. Also the mean and standard deviation of total suspended solid [TDS], calcium hardness, and total alkalinity was equal to 656.8 and 190.9, 465.37 and 121, and 271.6 and 67 respectively. Also Langlier Saturation Index was equal to 0.86 and 0.23, respectively and for Ryznar Stability Index [RSI] was equal 5.95 and 0.36, respectively. Obtained results showed that the mean and standard deviation for Aggressiveness Index [AI] and Pockurius Scaling Index [PSI] was equal to 10.54 and 0.23, and 8.06 and 0.15, respectively. By studying the corrosion indexes it was found that most of these indexes in Shiraz drinking water have scaling potentiality and only in a few instances station have corrosion potentiality