ABSTRACT
Background and Aims: Contamination of dental unit water lines has received a great deal of attraction in recent years mainly due to its role in bacterial infection among immunocom promised and vulnerable people. The purpose of this study was microbiological evaluation of dental units outflow operating in private clinics and the dental units active at dentistry faculty of Kurdistan university, Sanandaj, Iran
Materials and Methods: In this descriptive analytical study the total number of 250 water samples were collected; four specimen per unit. The samples were cultured on the specific media and the number of bacterial colonies were counted after keeping at 37[degree]c for 48 hours
Results: The result of this study showed no strong indication to claim a significant difference between private clinics and university units in terms of bacterial infections. However, in average the contamination level of the specimens obtained from the private dental clinics was lower than those found from the university's units. A notable decline of the contamination in handpieces' water was observed after flushing. Compared to the water of handpieces, the contamination of tap water was also observed to be lower
Conclusion: The result of this study showed that microbiological level of dental unit water lines is high. The dentists must be aware of the high level of microorganisms in the dental unit's water and thus minimize the risk of infection for both staff and patients
ABSTRACT
Background: Wastewater produced by a dairy in Sanandaj is a major source of environmental pollution threatening the city. The dairy uses activated sludge treatment to remove organic pollution from the wastewater. The present study evaluated the performance of this process and its compliance with national requirements for chemical oxygen demand [COD], biochemical oxygen demand [BOD], and total suspended solids [TSS] remaining in the plant effluent
Methods: A total of 48 samples were obtained from the dairy inflow and outflow. The COD, BOD, and TSS were measured for each sample. The statistical sign test was used to assess the standards
Results: The results showed that the average BOD, COD and TSS in the input wastewater was 292.25, 422.92, and 198.33 mg/l, respectively. The ratio of BOD/COD was 0.69, which indicates the capacity of biological treatment was high. The BOD decreased to 64.22 mg/l [92% removal], COD to 33.74 mg/l [92% removal], and TSS to 43.11 mg/l [94% removal] in the effluent, indicating significant removal of water contaminants. The statistical sign test showed that TSS [P < 0.0001] and BOD [P = 0.031] were incompliance with national standards, but COD exceeded standard threshold [P = 0.076]
Conclusion: Activated sludge treatment showed a good performance for TSS removal, but was not reliable for removal of BOD and COD pollutants