Iranian Journal of

Backgrounds and Objectives: Reactive dyestuff has potential of toxicity, carcinogenesis and mutagenesis for mammals and aquatic organisms. The current physical and chemical methods such as adsorption, coagulation, precipitation, filtration and ... can been used for removing of dyestuff. Biological treatment which is effective and economic for decontamination of dyestuff wastewaters was preferred because of limitation and difficulty of physicochemical methods. In order to investigate the trend of pollution reduction of color compounds, ability of Remazol Black-B dyestuff removal from aqueous medium by bacterial consortium under anoxic conditions was studied.
Materials and Methods: The mix culture of bacteria from textile industries activated sludge was enriched in luria broth medium containing RB-B dyestuff as a carbon source. Then biodegradation was assessed in 4 batch reactors. Microbial population of bacterial and decolorization quantities of samples were detected by MPN and UV-Vis spectrophotometer.
Results: Decolorization efficiency by the bacterial consortium was obtained more than 99% for 50 and 250 mg/L concentrations in 72 and 144 h (3 and 6 days) respectively, while for the initial concentration of 500 mg/L was 98.1in 240 h (10 days) of biodegradation period. Dyestuff reduction rate after completed removal was about 0.69, 1.74,2 mg/L/h for initial concentration of 50, 250, 500 mg/L respectively.
Conclusion: Results showed that Alcaligenes denitrificans and Alcaligenes xylosoxidans bacteria
which were isolated from activated sludge have good potential of RB-B dyestuff removal and this removal is depending on primary concentration of dye. Removal efficiency increased as primary concentration went up.

Background and Objective: Water corrosion and scaling are known as destructive phenomenon of drinking water quality and water facilities. In this study, the groundwater tendency to corrosion or scaling in source water, water storage reservoirs and distribution system were studied. Simultaneous use of some qualitative and a quantitative index along with statistical analyses to assess the water scaling or corrosion tendency were investigated.

Materials and Methods: The data analysis of groundwater, water storage reservoirs and water distribution system in rural area of Kurdistan province were analyzed and the amount of Langelier (LI), Ryznar (RY), Pockorius (PSI) and Larson–Skold (LS) and CCPP indices were determined. Corrosion and scaling threshold for qualitative indices were determined based on CCPP index. The mean of indices was compared with the thresholds using independent t-test. ANOVA was used to assess the difference between the indices in different sources of water.

Results: The balance range for LI, RY and PSI found to be -0.1-0.05, 7-9 and 7.1-8.5. The mean CCPP for groundwater, reservoirs and networks were 9.27 ± 1.29, 9.13 ± 1.25, 11.25 ± 1.23, respectively. All three sources of water have some tendencies toward scaling; however, a significant balance status was confirmed statistically. According to Larson–Skold index, sulfate and chloride anions did not play a role in scaling process.

Conclusion: The use of qualitative indices with CCPP index can provide more accurate estimation of water tendency toward scaling or corrosion. The assessment of qualitative indices along with CCPP is recommended in drinking water corrosion monitoring studies.