Leachate treatment using wet air oxidation processes

Wet air oxidation [WAO] is one of the advanced oxidation process which reduce organic matter concentration from industrial wastewater, toxic and non biodegradable substances and, solid waste leachate,etc. In this study the efficiency of wet air oxidation method in leachate treatment generating from Esfahan Composting factory was Evaluated. The experiment was carried out by adding 1.5 Lit of pretreated leachate sample the steel reactor with the volume of 3L. The reactor then underwent 10 bar pressure at different temperature [100, 200 and 300 °C] and various retention time [30, 60 and 90 min]. Leachate sample in 18 stages from composting factory in Isfahan in the volume of 20 Lit was taken and the WAO method, was used for pre-treatments. Removal efficiency of COD, BOD, NH4-N, NO3 and TSS were examined. The results showed that the removal efficiency was more than 35% for COD, 38% for BOD, and 85% for TSS within one hour of reaction. The Maximum removal efficiency obtained in this study were 53.3% for NH4-N and 73.9% forNO3-N. the results indicate that the reaction temperatures are the most important factors affecting degradation of organic matter. COD and BODS removal efficiency by WAO process increased as the time of reaction went up. In addition, BOD5/COD ratios of the effluents, which are generally regarded as an important index of biodegradability of leachate sample, were determined and improved grately as it reached to 84%. The WAO process presented in this paper is considered an efficient process for pretreatment of leachate, as the COD, BOD5 and NO3 reduction observed in leachate samples

[Comparisons of three advanced oxidation processes in organic matter removal from Esfahan composting factory leachate]

Wet air oxidation [WAO] is one of the advanced oxidation process which is mostly used to reduce organic matter concentration from industrial wastewater, toxic and non biodegradable substance and solid waste leachate. The objective of this paper is comparisons of three advance oxidation in organic matter removal in different conditions from Esfahan composing factory leachate. The experiment was carried out by adding 1.5 Lit pretreated leachate sample to 3Lit autoclave reactor and adding 10 bar pressure at temperature of 100, 200 and 300 °C and pressure [10 bars] with retention time of 30, 60 and 90 min. leachate sample in 18 stages from composting factory in Isfahan in the volume of 20 lit was taken and the three methods WAO, WPO, and a combination of WAO/GAC were used for pre-treatments. Pure oxygen and 30% hydrogen peroxide was used as oxidation agent. The result shows significant improvement on the removal rate of COD [7.8-33.3%], BOD5 [14.7-50.6%] by WAO process. The removal efficiency of 4.6-34% COD, 24-50% BOD, was observed in the reactor. Adding the GAC to the reactor improved removal efficiency of all parameters. Combination Process [WAO/GAC] removed 48% of COD, 31-43.6% of BOD. Combination process demonstrated higher efficiency than two other previous methods as BOD5/COD ratio of 90% achieved. The WAO process presented in this paper is efficient for pretreatment of leachate, And the modified WPO process remove organic materials and ammonia moreover WAO/GAC can be considered as an excellent alternative treatment for removing reluctant organic matter [COD, BOD5] and organic nitrogen compounds, which found in leachate

annual survey of successful suicide incidence in Hamadan, Western Iran

Suicide has constituted a critical public health problem for many decades. The number of completed suicide is traditionally high in Iran. The objective of the present study was to describe the patterns of methods of suicide among registered deaths due to suicide in Hamada, western Iran In this cross-sectional study, all completed suicide cases [n=146] were included from March 2004 through March 2005 based on Hamadan's Forensic center registered deaths because of suicide. Supplementary data were gauged through a questionnaire from the attempters relatives. All statistical analyses were performed using version 13 of the statistical software package SPSS and an alpha level of .05 for all statistical tests. Prevalence of completed suicide was 8.3 per 100,000 in Hamadan, Iran. From 146 cases, the male-to-female ratio was 7.1:1. Average age of cases was 33.9 yr [Min=10, Max=94] across all age groups, males show consistently higher completed suicide rates than females. Of the 69.2% were from urban population versus 30.8% form rural population. The most common method of suicide was hanging [78.1%]. Other common methods were poisoning [11.6%], and self-burning [6.2%]. Suicide rate in Hamadan is high among males through hanging which can be due to substance dependency and unemployment

Saliva contaminated and re-etched All-in-one adhesive influence on bond strength

In this study, we have investigated the effect of using phosphoric acid on bonding efficacy of an all-in-one adhesive system, after salivary Contamination of dentin. Eighty-four extracted human molars were prepared for their superficial dentins to be exposed. The molars separated into 7 groups. Group 1 specimens were not contaminated. In groups 2-4, samples were contaminated with fresh human saliva after applying and before curing the adhesive [in group 2, adhesive was rinsed, in group 3, adhesive was not rinsed, and in group 4, after rinsing the adhesive, phosphoric acid was applied, and then rinsed]. In groups 5-7, contamination was done after adhesive curing [in group 5, only rinsing, in group 6, rinsing, and adhesive reapplication, and in group 7, rinsing, using phosphoric acid, rinsing and adhesive reapplication. Shear bond strength was measured and analyzed. There were statistically significant differences between group means, except groups 3 and 5. Groups 1 and 4 demonstrated higher bond strength than other groups. Using phosphoric acid may be effective, provided that the contamination occurs prior to curing of the adhesive