Sharif Digital Repository

Biofiltration is a commonlypracticed biological technique to remove volatile compounds from waste gas streams. From an industrial view-point, biofilter (BF) operation should be flexible to handle temperatures and inlet load (IL) variations. A compost BF was operated at different temperatures (30-45°C) and at various inlet loading rates (ILR; 8-598gm -3h -1) under intermittent loading conditions. Complete removal of n-hexane was observed at 30 and 35°C at ILRs up to 330gm -3h -1. Besides, 20-75% of the pollutant was removed at 40°C, corresponding to the different ILs applied to the BF. Increasing the temperature to 45°C decreased the removal efficiency (RE) significantly. A feed forward... 

Biofiltration of Triethylamine (TEA) vapor used as a catalyst in casting operations was evaluated in this study The unit consisted of a 6-L three-stage biofilter containing a mixture of compost and wood chips (40:60 v/v) as the filter medium. Seed microbial population from municipal activated sludge was acclimated for a period of three weeks prior to the actual experimental runs. In the startup period, high pH values up to 10 was observed due to alkaline nature of TEA and inadequate formation of biofilm and low overall biodegradation. Steady increase of organic-N concentration along with gradual upward trend of pressure drop indicated sound establishment of microbial population. Operational... 

Two laboratory-scale biofilters filled with the same type of packing material were operated at different gas flow rates and influent concentrations of toluene and xylene in order to investigate their performance in treating waste gas streams. The columns contained a mixture of municipal compost as a base material and wood chips as a bulking agent in an 80:20 ratio; the porosity was 54%. Microbial acclimation was achieved by addition of nutrient-enriched solution along with pollutants for a week by daily mixing and natural aeration. During the start-up of the systems with inlet concentrations of 20 and 70 ppm for toluene and xylene, respectively, high biomass growth resulted in pressure drops... 

This laboratory research was carried out to evaluate the performance of a multistage anaerobic biofilm reactor, with six compartments and a working volume of 70 L, for the treatment of a strong synthetic nitrogenous and high-strength wastewater at an operational temperature of 26 ± 0.5 °C. Initially, the performance of the reactor was studied when subjected to an increase in the hydraulic retention time (HRT) at a constant influent COD concentration of 10,000 mg/L. Five different HRTs were studied: 0.25, 0.67, 1, 3 and 5 days, which were equivalent to 6, 16, 24, 72 and 120 h, respectively. By increasing the HRTs from 6 h to 1 day, COD and BOD removal efficiencies were increased from 63% to... 

Biological treatment of waste gas styrene vapor was investigated in a three-stage bench-scale biofilter. Yard waste compost mixed with shredded hard plastics in a 25:75 v/v ratio of plastics:compost was inoculated with thickened municipal activated sludge. Microbial acclimation to styrene was achieved by exposing the system to an inlet concentration (CIn) of 0.25 g m -3 styrene and an empty bed retention time (EBRT) of 360 s for 30 days. Under steady-state conditions, maximum elimination capacity (EC) obtained was 45 g m-3 h-1 at a loading rate (L) of 60 g m -3 h-1 (CIn of 2 g m-3 and EBRT of 120 s). Reduction of retention time adversely impacted the performance resulting in the maximum EC... 

The effects of leachate recycling and bed mixing on the removal rate of H 2S from waste gas stream were investigated. The experimental setup consisted of an epoxy-coated three-section biofilter with an ID of 8cm and effective bed height of 120cm. Bed material consisted of municipal solid waste compost and PVC bits with an overall porosity of 54% and dry bulk density of 0.456gcm -3. Leachate recycling had a positive effect of increasing elimination capacity (EC) up to 21gSm -3 bedh -1 at recycling rates of 75mld -1, but in the bed mixing period EC declined to 8g Sm -3bedh -1. Pressure drop had a range of zero to 18mm H 2Om -1 in the course of leachate recycling. Accumulation of sulfur reduced...