INCREMENTAL HYDROGEN SULFIDE LOADING AND DIURNAL FLUCTUATION OF THREE OPERATING BIOFILTERS

摘要

It is well known that biofiltration can control odors associated with municipal andrnindustrial wastewater treatment and has been widely applied for the past 30 years.rnThe simplicity and economics of a properly designed and applied biofilter continues tornensure a viable position in the odor control market. In addition to the configuration ofrnthe biofilter internals, it is imperative to understand loading rates associated with odorcausingrncompounds, such as hydrogen sulfide, to allow for economical biofilter sizing.rnBiofilter performance is measured by many factors but is ultimately based on odorrncompound loading versus biofilter removal efficiency, both critical elements in biofiterrndesign. The two key sizing variables in designing biofilters are retention time and sulfurrnloading. Using these variables, a set of performance curves was developed forrnbiofilters to achieve a 99% removal efficiency rate.rnThree operating biofilters, designed according to the performance curves, were thenrnselected for a field test program to evaluate biofilter performance. The three biofiltersrnwere evaluated by applying incremental artificial and natural hydrogen sulfidernconcentration increases. The increased hydrogen sulfide loading was used tornsimulate diurnal fluctuation and peak loading events. Changes in sulfur loadingrncoupled with air flow rate modifications were then compared to empirical performancerncurves. Hydrogen sulfide concentrations were reduced greater than 99% during peakrnand non-peak periods. It was also found that 20 seconds may reflect a minimumrnretention time boundary in an efficient biofilter. These observations support arndecrease in the media bed size and ultimately a reduction in biofiltration costs.