Evaluating the efficiency of lettuce disinfection according to the official protocol in Iran

The objective of this study was to evaluate the efficacy of Sanitization of Lettuce according to the protocols set forth by Iranian Ministry of Health and Medical Education for reducing populations of total coliform, fecal coliform, and helminth eggs present on lettuce. In the present study, we determined the load of total coliform, fecal coliform, and parasites of lettuce. The lettuce was sanitized by protocol of Iranian Ministry of Health and Medical Education. The protocol consists of 3 levels to disinfect the fruits and vegetables. The procedure was as follows: first washing stage. The leaves of leafy vegetables washed with tap water, second stage, separation of helminth eggs by 3 to 5 droplets of detergent per liter for 5 min; third stage, disinfection of vegetables by calcium hypochlorite solution [with 200 mg/1 free chlorine] for 5 min; and finally the disinfected vegetables were washed with tap water. The average initial levels of total coliform and fecal coliform in the samples were 3.36 Iog[10]cfu/g and 2.31 log[10]cfu/g, respectively. Helminth eggs were not detected in any of the samples tested. The efficiency of total coliform and fecal coliform removal were 78.1% [0.75 Iog[10]cfu/g] and 79.6% [0.67 Iog[10]cfu/g], respectively, after washing. This increased up to 94.8[1.44 Iog[10]cfu/g] and 98.5% [1.90 log[10]cfu/g] after the use of detergent. Chlorine disinfection rose these amounts up to 98.3% [2.18 Iog[10]cfu/g] and 100% [2.31 Iog[10]cfu/g], respectively. By applying the protocol large parts of microorganisms existing on lettuce have indeed been removed

Decolorization and biological degradation of azo dye reactive red2 by anaerobic/aerobic sequential process

This study investigates the anaerobic treat ability of reactive Red2 in an anaerobic/aerobic sequential process. Laboratory scale anaerobic baffled reactor and fixed activated sludge reactor were operated at different organic loadings and hydraulic retention times. The effects of shock dye concentration on the chemical oxygen demand and color removal efficiencies were investigated in the anaerobic baffled reactor. The effect of hydraulic retention time on the color and chemical oxygen demand removal efficiencies were also investigated in the aerobic reactor. The studies were carried out in continuous mode and the effluent of the anaerobic baffled reactor was used as feed for the fixed activated sludge reactor. Chemical oxygen demand removal efficiency of 54.5% was obtained at HRT =1 day in the anaerobic reactor. The average color removal was 89.5%. Chemical oxygen demand removal efficiency of 69% was obtained at HRT =7 h in the aerobic fixed activated sludge reactor. A slight decrease of the color was also observed in the aerobic reactor. This investigation has shown that successful treatment of a highly colored wastewater is possible in the anaerobic baffled reactor. Also the results showed that, anaerobic biological system has higher efficiency in dye removal than fixed activated sludge system, while aerobic system has higher efficiency in chemical oxygen demand removal comparing with the anaerobic baffled reactor