ABSTRACT
Background: The biosorption process has found numerous applications due to low cost, availability, biosorbent reuse, and utilization of excess sludge from wastewater treatment facilities. The aim of the present study was to evaluate the efficiency of dried activated sludge in removing Reactive Orange 3R dye
Materials and Methods: For this experimental, laboratory study, dye solutions were prepared in three concentrations: 50, 100, and 150 mg/L. The solutions were then subjected to adsorbent in weights 0.2, 0.4, 0.6, 0.8, and 1.0 g for various durations [0.5, 1, 1.5, 2, 2.5, and 3 hours] in different pH levels [4, 7, and 12]. Data was analyzed using Excel software
Results: Increasing contact time from 0.5h to 3h, the dye removal efficiency increased from 56% to 76%. When the weight of the biomass increased from 0.2g to 0.8g, the dye removal efficiency increased from 58% to 72%. High initial iron concentration had an adverse effect on iron removal efficiency
Increasing initial dye concentration from 50 to 150 mg/L decreased iron removal efficiency from 71% to 62%. Freundlich isotherm models could describe the adsorption equilibrium of the dye onto the activated sludge. Freundlich isotherm represented a better correlation compared to other isotherms [R2>0.952]. Also, second-order models fit well with experimental data [R2>0.979]
Conclusion: This technology for dye removal from industrial wastewater, in addition to the optimal use of biomass from wastewater, can help resolve the environmental problem of wastewater dye excretion
ABSTRACT
Photochemical smogs, CO, NO[2] and SO[2] are among the major air pollutants with known effects and complications. The present study was designed to investigate the density of these pollutants in Sabzevar, Iran. This descriptive cross-sectional study intended to measure the air pollutants in different parts of Sazbevar, Iran. Sampling was done with stratified time sampling based on NIOSH 4800 and 6004 methods for SO[2] and NO[2], and method 6604 for CO. Sampling instruments included pump [debi 5 L/min], impinger, detector tube and ratameter. Based on traffic intensity, four points in the city were located and observe for 12 months, three day a month and three times per day; total sample swere 324. Data analyssi was done in SPSS 16 usingdescriptive measures as well as Pearson correlation coefficient ad one-sample t-test. Significantly highest rate of CO intensity was observed in Mordad [August] [64.1 mg/m3] and Esfand [March] [63.11 mg/m3] [P < 0.01]. The lowest one-hou intensity of CO was seen in Tabas square [21.71 mg/m3] and the highest in Post square [97.13]. Mean annual concentration of SO[2] ranged from 2.61 to 95.34 mg/m3, with the highest amount in Mehr [September] [83 mg/m3] [p < 0.05]. The highest annual concentrtion of NO[2] was seen in Aban [October] [87.89] [P < 0.05]. The results showed that the density of CO throughout the year and that of SO[2] during some months of the year were above the standard amounts but the density of NO[2] was not higher throughout the year
ABSTRACT
Background and Purpose: Subsurface flow wetlands are one of the successful treatment methods used for municipal and industrial wastewater treatment, and are economical in terms of energy consumption and workforce. Much research has been conducted on wetland operation output in wastewater treatment, but no enough information is available on their start-up and maintenance. The present study investigates the circumstance of starting up and implementing a wetland
Methods and Materials: In this experimental study, two subsurface flow wetlands with a two-day detention time and two pretreatment units were built. The former was similar to Primary Settling tank with a 4-hour detention time and the latter was similar to anaerobic pond equipped a with digestion pit with a two-day detention time in a pilot scale. The wastewater [BoD5 = 250 mg/l, Tss=320 mg.l and ph=7.2] from municipal network in Sabzevar, Iran was used for irrigation; the pilot implementation and maintenance took one year
Results: Pilot operation indicated that the principal factors in implementing subsurface flow wetland were temperature, nonpenetrateability of the bed, and wastewater ingredients. However, pretreatment and bed obstruction were the limiting parameters of the wetland maintenance
Conclusion: Pretreatment of the subsurface flow of wetlands does not yield a high output; and if anaerobic ponds equipped with digestion pits are used, the treatment output is significantly enhanced, and the wetland operation will face minimum barriers
ABSTRACT
Background and Purpose: History of implementing civil projects and plans in Iran indicates a lowered attention to environmental effects of civil projects in the past, leading to contamination of various environmental resources nationwide. In order to avoid such threats particularly in establishing composting plants, evaluation of environmental effects must be considered. Therefore, we decided to take a step forward for sustained development by evaluating the environmental effects before a composting plant is established in Sabzevar, Iran
Methods and Materials: In this descriptive study, three geographical zones were selected around Sabzevar for establishing the plant, and two of them were rejected and the third one [5 km from the city] was chosen for further evaluation. The positive and negative environmental effects were also considered
Results: The negative effects of establishing the plant for the time of operation were given 11 points and for the time of construction were 18 points; its positive effects were given 27 points for both construction and operation times. The algebraic sum of negative and positive points came up to be 16 positive and 9 negative points
Conclusion: The study results and the comparison of negative and positive effects of establishing the composting plant in the specified location in Sabzevar, Iran can be considered positive and its implementation is feasible