ABSTRACT
Water filtration units have been faced problems in water turbidity removal related to their media, which is determined by qualitative indices. Moreover, Current qualitative indices such as turbidity and escaping particle number could not precisely determine the efficiency of the media in water filtration, so defining new indices is essential. In this study, the efficiency of Anthracite-Silica and LECA-Silica media in turbidity removal were compared in different operating condition by using modified qualitative indices. The pilot consisted of a filter column [one meter depth] which consisted of a layer of LECA [450 mm depth] and a layer of Silica sand [350 mm depth. Turbidities of 10, 20, and 30 NTU, coagulant concentrations of 4, 8, and 12 ppm and filtration rates of 10, 15, and 20 m/h were considered as variables. The LECA-Silica media is suitable media for water filtration. Averages of turbidity removal efficiencies in different condition for the LECA-Silica media were 85.8 +/- 5.37 percent in stable phase and 69.75 +/- 3.37 percent in whole operation phase, while the efficiency of total system were 98.31 +/- 0.63 and 94.49 +/- 2.97 percent, respectively. The LECA layer efficiency in turbidity removal was independent from filtration rates and due to its low head loss; LECA can be used as a proper medium for treatment plants. Results also showed that the particle index [PI] was a suitable index as a substitute for turbidity and EPN indices
Subject(s)
Water , Coal , Silicon Dioxide , Aluminum SilicatesABSTRACT
Treatment of colored wastewater is one of the important challenges of environmental engineers. Adsorption process is a key option for removal of organic matter from wastewater. The aim of present work was to investigate pumice stone as an adsorbent for removal of Acid Black 1 from aqueous solution. Removal of Acid Black 1 by pumice stone was investigated. Acid Hyrdo Chloric[HCL] 1 N was used to increse adsorbent porosity. Various parameters such as pH, initial dye concentration and contact time were studied. Results showed that removal of Acid Black 1 was increased by increasing of contact time and initial dyeconcentration although it was decreased by increasing of pH. Experimental data was best fitted to Longmuir isotherm model [r2>0.98]. Study of diffusion model revealed that intraparticle diffusion is rate-controlling step in removal of Acid Black 1 by pumice stone. The results indicated that pumice stone was a dominant adsorbent for Acid Black 1 removal
ABSTRACT
Tannery industries effluent disposal into environment causes hazardous effects in environment. The goals were to determine the tolurance limit P. chrysosporium in the tanning house effluent and potential of chromium removal in the bench scale. At first, sampling of tanning house effluent, in order to effluent quality evaluation was carried out. Then adjusting carbon to nitrogen ratio from 10-12. Dry weight of fungi mass [0.35% - 2.1%] inoculated to sterile samples with Cr[+3] concentration 120 - 1080 mg/I. Samples were put in shaker incubator. Also effect of pH, temperature, shaking velocity and nutrients for finding optimum conditions, biomass growth and chromium removal rate were studied. Findings showed that maximum biomass growth and chromium removal rate were occurred in the sample that chromium concentration and inoculum size were 240 mg/I and 0.07% [dry weight], respectively. Also biomass growth and chromium removal rate were 0.04823% and 76.7%, respectively. Biomass growth and chromium removal in best condition and 26h detention time rate were 0.2934% and 95.8%, respectively. This study showed by optimizing environmental conditions, with 95% confidence [P<0.001], after 26h. biomass growth and chromium removal rate would be 0.29% and 95.8% respectively