Showing papers on "Trickling filter published in 2000"

Trace Analysis of Fragrance Materials in Wastewater and Treated Wastewater

Abstract: An analytical method was developed and used to measure trace levels of fragrance materials (FMs) in municipal wastewater and treated wastewater. Sixteen FMs were selected as analytes because of their wide range of physical chemical properties. The analytical method included the use of nine perdeuterated FMs as internal standards, a high-flow C18 speed disk for the extraction of FMs from aqueous matrices, and an accelerated solvent extraction system for the extraction of FMs from solid matrices. For aqueous matrices, average FM recoveries (relative to the perdeuterated FM internal standard) were 97−115%, with limits of quantitation ranging from 0.5 to 35 ng/L. For activated sludge solids and primary influent solids, the average FM recovery from the extraction procedure was 81%. Concentrations and removal of FMs at an activated sludge and a trickling filter wastewater treatment plant were determined in the U.S. FM influent concentrations ranged from 0.3 to 154 μg/L, while FM effluent concentrations ranged f...

Dyes, Environmental Chemistry

Abstract: Synthetic organic dyes are essential to satisfy the ever growing demands in terms of quality, variety, fastness, and other technical requirements for coloration of a growing number of substances. Beginning in 1970, however, the dyestuff and textile industries have become increasingly subject to international, federal, and state regulations designed to improve health, safety, and environment. Therefore, in an attempt to provide a perspective of the environmental problems posed by synthetic organic colorants, and the efforts being made by industry, academia, and government to solve these problems, this article includes the physical, chemical, and biological methods of effluent treatment of dye wastewater. Specifically, the physical methods are adsorption, sedimentation, flotation, flocculation, coagulation, foam fractionation, polymer flocculation, reverse osmosis and ultrafiltration, ionization radiation, and incineration; the chemical methods are neutralization, reduction, oxidation, electrolysis, ion exchange, and wet air oxidation; the biological methods are stabilization ponds, aerated lagoons, trickling filters, activated sludge, anaerobic digestion, and bioaugmentation. Also included are fate of dyes, analytical methods, pollution prevention, heavy metals, toxicity, and legislation.

Construction and economics of a pilot/full-scale biological trickling filter reactor for the removal of volatile organic compounds from polluted air.

Abstract: The design and the construction of an actual 8.7-m3 pilot/full-scale biotrickling filter for waste air treatment is described and compared with a previous conceptual scale-up of a laboratory reactor. The reactor construction costs are detailed and show that about one-half of the total reactor costs ($97,000 out of $178,000) was for personnel and engineering time, whereas approximately 20% was for monitoring and control equipment. A detailed treatment cost analysis demonstrated that, for an empty bed contact time of 90 sec, the overall treatment costs (including capital charges) were as low as $8.7/1000 m3air in the case where a nonchlorinated volatile organic compound (VOC) was treated, and $14/1000 m3air for chlorinated compounds such as CH2Cl2. Comparison of these costs with conventional air pollution control techniques demonstrates excellent perspectives for more field applications of biotrickling filters. As the specific costs of building and operating biotrickling filter reactors decrease with increasing size of the reactor, the cost benefit of biotrickling filtration is expected to increase for full technical-scale bioreactors.

Biotreatment of Oil-Bearing Coke-Oven Wastewater in Fixed-Film Reactor: A Viable Alternative to Activated Sludge Process

Abstract: Coke-oven wastewater is produced in the integrated steel plants at coke-oven gas-cleaning operations. It is laden with phenol, cyanide, thiocyanate, and oil. Although the activated sludge process is widely practiced in the biological treatment of coke-oven wastewater, it was observed during field visits that oil contamination and poor sludge settleability had resulted in poor maintenance of the activated sludge process. These problems can be minimized by the use of fixed-film systems such as trickling filters; however, availability of a microbial consortium, which would sustain oil contamination, was a major constraint. Research endeavor at this Institute has resulted in the development of such a microbial consortium, and the same was applied on a bench-scale fixed-film system such as a trickling filter, for the treatment of coke-oven wastewater. The unit was set up in the steel industry, and fresh coke-oven wastewater was treated over a period of 45 days. The results indicated that phenol and oil were si...

Efficiency of wastewater treatment plants at removing Giardia sp. cysts in southern France.

Abstract: A study was conducted to evaluate the removal efficiency for Giardia sp. cysts of a number of wastewater treatment plants in France. Of these, five were activated sludge systems, three were trickling filters and three were waste stabilisation pond systems. In addition, the effect upon cyst removal of disinfecting effluents prior to discharge into controlled waters by UV and chlorination was evaluated. Cysts were detected in raw wastewater at all 11 treatment plants in concentrations ranging from 130 to 41,270 cysts/litre. The removal of cysts by sewage treatment was found to range between 99.5 and 99.8% for activated sludge, 99.9 and 100% for waste stabilisation ponds, and for the trickling filter plants up to 98.3%. Despite the high removal efficiencies recorded in this study the range of cysts detected in final effluents discharged into controlled waters ranged from < 1 to 66 cysts/litre. This is undoubtedly an underestimate of actual occurrence and concentration in wastewater, given the limitations of the methods currently employed by investigators. Cysts were detected in final effluents which had been disinfected by both UV and chlorination (range 0.3-19 cysts/litre), however, it is not known whether such cysts were viable or non-viable.

Total degradation or environmental experiment

Abstract: Owing to the alarming state of health of Salmonidae in many Swiss rivers, effluents of sewage treatment plants were studied. Water-polluting substances were enriched by solid-phase extraction (reversed-phase), isolated and fractionated by thin-layer chromatography using automatic multiple development (AMD). By subsequent biological detection with Bacillus subtilis, Aspergillus niger, and Chlorella vulgaris the positions of the toxic substances were verified. The spots were scratched out and eluted, then the toxic substances were analysed by infrared spectroscopy and characterized in comparison with reference spectra. The infrared (IR) spectra of the effluents of the sewage treatment plant resembled strongly those of adducts of ethylene oxide and mono- and diglycerides, adducts of ethylene oxide and hydrogenated castor oil, amphoteric surfactants, and fatty alcohol alkoxylates. To verify the indications of the IR spectra the respective raw materials were subjected to biodegradation in an extended OECD-test 302B and a laboratory trickling filter test. Two of nine substances proved to be totally biodegradable. The refractory intermediates of the seven incompletely degradable substances were obtained through trickling filters, enriched by solid-phase extraction and analysed by infrared spectroscopy. After thin-layer chromatography and subsequent biological detection by Bacillus subtilis, only the trickling filter effluents of the amphoteric surfactants, e.g. cocoamphodiacetate and cocoamphodipropionate showed toxic effects. These substances are often used in shower gels and shampoos. To our knowledge, data on the ecotoxic or biological effects of their refractory compounds are not available. Considering the large amounts of these intermediates in surface water, further studies are necessary. The amounts are considerably larger than, for example, the amounts of drugs or pesticides (although this is not to question at all the problematic nature of drugs and pesticides). From the point of view of preventive environment t protection, substances that are used in large amounts should be completely biodegradable in sewage treatment plants under aerobic conditions.

Use of enzyme tests to monitor the biomass activity of a trickling biofilter treating domestic wastewaters

Abstract: Easy enzyme tests were used to monitor the biomass activity of a trickling biological aerated filter processing a domestic influent. Biofilter wash-waters were used as biomass source. Enzyme tests (hydrolases and dehydrogenases) carried out on wash-waters showed relationships with the process active biomass (estimated by volatile suspended solids). Differences in dehydrogenase (DHA) specific activities were observed in two sampling campaigns and were linked to process performance. The DHA activity evaluated using glucose or acetate was also related to the substrate mass applied on the biological aerated filter (kg CODt m−3 biolite). These results indicated that, under normal operation, DHA activity is related to quantity of substrate applied to the biofilter. Similar relationships were obtained for hydrolases. However, β-glucuronidase, Leu-aminopeptidase and protease, expressed specifically, were more significantly inversely related to process removal performance. This reaction was probably caused by the biomass reacting with an influent that is difficult to biodegrade. Generally speaking, these tests can be easily applied to the regular monitoring of the active biomass from a process using biological filters or simply as an indicator of the active biomass content in the process. © 2000 Society of Chemical Industry

Design and performance of a fibrous bed bioreactor for odor treatment.

Abstract: Biological processes have become popular for odor treatment. In this study, a novel fibrous bed bioreactor was applied for treatment of odorous gas. The column reactor was packed with spirally wound fibrous sheet material on which a consortium of microorganisms selected from activated sludge was immobilized. The first stage of this work comprised a preliminary study that aimed at investigating the feasibility of the fibrous bed bioreactor for treatment of odorous volatile fatty acids (VFAs). In this stage, the performance of a fibrous bed bioreactor at increasing mass loadings ranging from 9.7 to 104.2 g/(m3.h) was studied. VFA removal efficiencies above 90% were achieved at mass loadings up to 50.3 g/(m3.h). At a mass loading of 104.2 g/(m3.h), removal efficiency was found to be 87.7%. In the second stage of the work, the process was scaled up with design and operational considerations, namely, packing medium, process condition, and configuration selections. A trickling biofilter with synthetic fibrous packing medium was selected. It was operated under countercurrent flow of gas and liquid streams. The effects of inlet concentration and empty bed retention time on bioreactor performance were studied. The bioreactor was effective in treating odorous VFAs at mass loadings up to 32 g/(m3.h), at which VFAs started to accumulate in the recirculation liquid, indicating that the biofilm was unable to degrade all the VFAs introduced. Although VFAs accumulated in the liquid phase, the removal efficiency remained above 99%, implying that the biochemical reaction rate, rather than gas-to-liquid mass transfer rate, was the limiting factor of this process. The bioreactor was stable for longterm operation; no clogging and degeneration of the packing medium was observed during the 4-mo operation.

Method of obtaining methyl alcohol from raw gas and installation for carrying out said method

Abstract: In a first purification stage (1) hydrogen sulfide contained in the raw gas is separated by microbial oxidation into water and sulfur. In a second (17) and third (32) purification stage the methane contained in the desulphurized raw gas is oxidized by further microbial oxidation to yield methyl alcohol. The first purification stage (1) comprises a first fixed trickling filter device (2), the second purification stage (17) comprises a second fixed trickling filter device (18) and the third purification stage (32) comprises a third fixed trickling filter device (33). The first fixed trickling filter device (2) contains microorganisms which carry out the oxidation of H2S into sulfur. The second (18) and third (33) fixed trickling filter devices contain a mixed population of bacteria and yeasts which primarily carry out the oxidation of the methane. The wash water emerging from the wash water bottom (36) of the third purification stage (32) is filtered in a filter press (44). The filtrate flows through a microfilter device (49) and enters the distillation column (50). The distillation vapour precipitates in a condenser (51) and the distillate is collected in a product tank (52). This distillate has a methanol content of between 30 and 40 %.

Review of Methods for Biological Treatment of Food Processing Wastewater

Abstract: The food processing industries are increasingly faced with the problem of treating their wastewater before releasing to municipal wastewater treatment plants or to the receiving environment. Food processing wastewaters are almost always amenable to biological treatments. The selection of the most suitable biological treatment methods is important. The purposes of this paper are to review the available literature on different treatment methods for food processing wastewaters and to compare their differences. The methods reviewed include activated sludge processes, aerobic or anaerobic lagoon, trickling filter, anaerobic digestion, anaerobic filter, soft fiber packing media contact oxidation process (SFPMCOP), anaerobic - anoxic - oxic (AAO) process, anaerobic - aerobic system, oxidation ditch system, upflow anaerobic sludge blanket (UASB) reactor, sequencing batch reactor (SBR), anaerobic fluidised bed reactor (AFBR), aerobic jet loop reactor, biobed expandad grandular sludge bed (EGSB) reactor and batch reactor (CASSTM). Their efficiencies in treating wastewater from food processing industries such as meat packing, dairy, brewery, sugar beet, seafood processing and potato chips and snack processing are evaluated.

Development of a Chemical Fate Model for Trickling Filters Based on the Activated Sludge Model SimpleTreat: A Case Study for LAS

Abstract: A new chemical fate model for trickling filter wastewater treatment plants was developed, using the same principles as the steady-state nonequilibrium activated sludge model SimpleTreat, in combination with an existing biofilm model. To test the new model in detail, a pilot-scale (200 L) trickling filter was built and operated. Using this setup, removal of the surfactant LAS was measured under different well-characterized operating conditions. The new model could be fitted to data on LAS removal in the pilot-scale filter as well as in two full-scale domestic treatment plants. The same biodegradation rate coefficient (derived from activated sludge data) could be used in all cases, except for one laboratory experiment with higher LAS influent concentrations. It is concluded that the effect of high influent concentrations on the biodegradation rate should be further investigated.

Device for treating water for producing and breeding fry of fishes or the like and method for treating water

Abstract: PROBLEM TO BE SOLVED: To provide a device for treating water, capable of largely reducing periodic water exchange operations carried out for decreasing the concentration of nitrate-based nitrogen in a fish fry-producing field, an aquarium, etc., enabling the reutilization of culture water, not necessitating a work for inversely washing a filtration device, capable of reducing the amount of used raw water, and capable of improving the quality of the water. SOLUTION: A contact type trickling filter 12 and a hypochlorite-injecting device 16 are disposed in a route for purifying water circulated in plural water tanks 10. The water is used for producing or breeding fish fries. The water used for producing or breeding the fish fries is circulated in the trickling filter 12 to contact-treat contaminants, and then treated with chlorine in the hypochlorite-injecting device 16. Nitrate-based nitrogen is reduced into nitrogen gas by the oxidation power of the hypochlorite, and the concentration of the nitrate-based nitrogen is maintained at a low level near to that of fresh sea water.

Modelling stripping of volatile organics in an industrial trickling filter system

Abstract: A model describing the stripping of volatile organic contaminants (VOCs) in an industrial trickling filter system is developed. The aim of the model is to investigate the effect of different operating conditions (VOC loads and air flow rates) on the efficiency of the VOC stripping and the concentrations in the gas and the liquid phase. The modelling is structured in three parts. First, a hydrodynamic model of the liquid phase in the trickling filters is developed using a tracer test with lithium. Next the gas mixing in the filters is studied using continuous CO2 and O2 measurements. Both are linked using a liquid-side mass transfer model for VOC stripping. After the model calibration, simulations reveal that changing the air flow rate in the trickling filter system has little effect on the VOC stripping efficiency at steady state. However, immediately after an air flow rate change, quite high flux and concentration peaks of VOCs can be expected. These phenomena are of major importance for the design of an off-gas treatment facility.