In this work, a differential biofiltration reactor was used to explore the potential of metabolic uncouplers to improve pollutant (toluene) degradation rates. Metabolic uncouplers were reported to reduce the cell mass in activated sludge systems, but are untested in biofilters and the current work is the first to report the impact of different metabolic uncouplers in a biofilter. Initially soil was used as a biofilter bed and later experiments were conducted in pure cultures in a biofilm reactor. A simple diffusion system was developed to generate the desired concentration of toluene to the system. Gas chromatography and a carbon dioxide analyzer were connected online to the reactor which improved the precision of the data collected and also the robustness of the measurements. Preliminary experiments including effect of substrate concentration, different nutrients and temperature were done to optimize the conditions before starting the metabolic uncoupler screening studies in soil. Based on the results, inlet toluene concentration between 180 ppm and 250 ppm was used throughout the studies. Also it was found that the toluene degraders were nitrogen limited. Temperature studies showed that the elimination capacity (EC) increased with increasing temperature, from 34 ± 1.4 g.m-3.h-1 to 49.8 ± 2.6 g.m-3.h-1 for temperatures of 20 to 45 oC, respectively. Nine potential metabolic uncouplers were screened in batch serum bottles. The nine uncouplers tested were dinitrophenol (dNP), p-nitrophenol (pNP), benzoic acid (BA), carbonylcyanide p-trifluoromethoxy phenylhydrazone (FCCP), carbonylcyanide m-chloromethoxy phenylhydrazone (CCCP), pentachlorophenol (PCP), malonic acid (MA), m-chlorophenol (mCP) and 2, 4, 6-trichlorophenol (TCP). Other than dNP and pNP (nitrogen containing uncouplers), seven other uncouplers were further tested in the differential biofilter reactor. Only PCP and TCP increased the toluene degradation rate significantly. PCP increased the toluene degradation rate by 35% at 140 µM, whereas 4051 µM TCP increased the rate by 18%. Though FCCP behaved as a classical uncoupler when compared with others, the EC increase was not significant. Five toluene degraders were isolated from soil subjected to toluene and were identified using 16s rDNA/18s rDNA analysis. Out of five, two potential toluene degraders, Stenotrophomonas maltophilia and Pseudomonas putida were used to develop a biofilm reactor. PCP, TCP and CCCP were tested in the biofilm reactors and found that PCP increased the surface elimination capacity (SEC) by 85% at 140 µM in S. maltophilia biofilm reactor and CCCP increased the SEC by 27% at 1 µM in P. putida biofilm reactor. Finally a simple model was developed to calculate the energy uncoupling coefficient for non-growth systems like ours to quantitatively represent the uncoupling mechanism.

In response to growing concern over volatile organic compounds (VOCs) biofiltration is becoming an established economical air pollution control technology for removing VOCs from waste air stream. This study armed to develop a trickle-bed biofilter to treat emitted VOCs stream from a piant blending process. Analytical results demonstrated that the VOCs conceratration range is 10 to 1500 ppm calibrated as methane and the major components of the emitted gases are toluene, xyluene, isobutanol, methyl-isopropyl ether, etc. Originally, a full-scale biotrickling filter of 6m ¡Ñ 6m in inner cross-sectional area packed with wood chips(10 cm ¡Ñ 10 cm ¡Ñ 2 cm) to a height of 4 m was used to treat the vent gas with a flow rate of 270 m3/min. A recycle water rate of 400 L/min and a nutrient liquid (acid digested liquor of bird feather) addition rate of 1L/day. Under these operation parameters, the average VOC removal efficiency of the original trickling filter of 28% which was not as good as expected. To improve the efficiency, a pilot biofilter constructed from a 0.3-m x 1.6-m (OD x H) plastic column packed with fam chips to a height of 1 m was used for treating a sample stream of the vent gas. Empty bed retention times in the range of 9.82 to 20 s, corresponding inlet flow rates of 0.68 to 0.27 m3/min and the organic loading rates of 5.18 to 10.37 g/m3.hr were used. As the empty bad retention times was getting shorter, the removal efficiency become lower (from 80 to 75.56%). When the organic loading rose to 186.65 g/m3.hr, the removal efficient also got down to 24%. As the gas temperature droped to 10OC,the removal efficient also decreased to 43%.

Thesis (D.-Ing.)--Technische Universitat Darmstadt, 2001.

Zugl.: Darmstadt, Techn. University, Diss., 2005.

No description available.

Reciprocating biofilters known as ReCip is a viable technology to manage nutrients, mainly nitrogen, problems at livestock operations such as swine farms and dairies. Past studies have demonstrated that ReCip is more adept at total nitrogen (TN) removal than traditional subsurface flow wetland systems. The traditional substrate used to attach biomass was rock aggregate; this media may be hard to obtain for some agricultural projects, so alternate substrates are tested and compared with the rock aggregate. The purpose of the study was twofold: first, different biofilm media were tested and compared in terms of treatment performance and, second, the long-term performance of a ReCip in continuous operation for 3 years was characterized. Four, 2.67 square meter ReCip systems with different treatment media – rock aggregate, recycled concrete aggregate (RCA), vertical-flow plastic media, and walnut shells – were operated at a 2-day THRT over the course of a 16 week study. The TN removal efficiencies for rock aggregate, RCA, plastic media, and walnut shell media were 43%, 53%, 25%, and 69% respectively. Surface based mass TN removal rates for the same media were 103, 128, 172, and 276 kg/ha-d respectively. A 134.2 square meter ReCip with rock aggregate media was running concurrently with the smaller ReCip systems. This ReCip was constructed ant operated since January 2010. TN removal efficiency and mass removal rate were 44% and 105 kg/ha-day. These values were close to results from the smaller rock media system.

Sulfur-containing organic solvents or carbon disulfide have been used extensively in semiconductor, TFT-LCD, and synthetic fiber (viscous rayon) industries in the last decades. These compounds can easily be converted into reduced-sulfur ones which exhibit low odor threshold characteristics and arise public complaints once releasing into environments. This paper intended to oxide these compounds by both chemical and biological approaches for the purpose of odor reduction. The first topic was investigations on the oxidation of aqueous DMS (dimethyl sulfide) by using sodium hypochlorite as an oxidant. Results indicated that with an initial DMS concentration of 100 mg/L, it required only 0.75 min or 45 s to convert the DMS completely into its final oxidation product, DMSO2 (dimethyl sulfur dioxide). The required dosage of the oxidant was a little less than the theoretical value. In addition, it was found that initial pH of the batch reaction liquid be kept at around 8.2 for achieving a neutral final solution which emitted only a trace of gaseous chlorine and hydrochloric acid odors. The second one was a trail investigation on the biodegradation of gas-borne hydrogen sulfide and carbon disulfide by a trickling-bed biofilter packed solely with fern chips. Glucose and milk powder were used as main nutrients for microbial film development and enhancer for the biodegradation of sulfides. Results indicated that after an acclimation period of around two months, approximately 99 and 86% of the influent hydrogen sulfide (10-20 ppm) and carbon disulfide (20-60 ppm), respectively, could be removed with an empty bed retention time of around 63 s for the gas in the packed bed. Both neutral or acidic environments were suitable for the biodegradation reaction and the metabolites (mainly, sulfuric acid) could easily be removed from the chips by washing them with water. In the future, efforts should be done to increase the removal capacity of carbon disulfide.

Bayreuth, Univ., Diss., 2008.

Techn. Universiẗat, Diss., 2005--Dresden.

Utsläpp av lättflyktiga organiska föreningar (VOC) är ett växande mijlöproblem. Biofiltrering är ett relativt billigt sätt att rena luft förorenad med VOC. Biofiltrering har också en fördel i att föroreningen helt bryts ned och inte endast övergår i en annan form. Rapporten beskriver arbetet kring två biofilter av kolonntyp. Mikroberna som användes kom från främst träflis och jord. Som förorening användes limonen och α-pinen. Analys skedde med gaskromatografi. Vidare undersöktes om närvaro av silikonolja i filterbädden påverkade resultatet Reningskapaciteten uppgick i filtret utan olja till ca 10 - 12 g/m3.h under de första 25 dagarna i drift och ökade därefter till ca 15 - 20 g/m3.h. Motsvarande data för det oljeberikade filtret är ca 15 - 20 g/m3.h i båda fallen / Emissions of volatile organic compounds are a growing environmental problem. Biofiltration is a relatively cost efficient method to purify air polluted with VOC:s. Biofiltraion also has the benefit of completely degrading the pollutants rather than just transferring them into another phase/form. This report describes the work on two biofilters of column type. The microbes used were extracted from wood chips and soil. As pollutants limonene and α–pinene were used. Furthermore, it was investigated how the presence of silicone oil in the filter bed affected the filtering results. The filtering capacity in the non oil enriched filter was during the first 25days 10-12 g/m3h and thereafter some 15-20 g/m3h. The efficiency of the oil enriched filter was stable at 15-20 g/m3h.