Showing papers on "Trickling filter published in 2007"

Chapter 4.1 Removal of pharmaceutical residues during wastewater treatment

Abstract: Publisher Summary Some of the pharmaceutical residues found in wastewater treatment plants are antibiotics, blood lipid regulators, anti-inflammatories, antiepileptics, tranquillizers, X-ray contrast agents, and contraceptives. Removal of organic micropollutants in wastewater unit processes is determined by their biodegradability and physicochemical properties, their water solubility, hydrophobicity, and tendency to volatilize. Adsorption onto suspended solids, aerobic, and anaerobic biodegradation, chemical (abiotic) degradation (via processes such as hydrolysis), and volatilization are the primary removal mechanisms for pharmaceutical residues in wastewater. Biodegradation of pharmaceutical residues might occur during secondary treatment that involves both aerobic (trickling filters, activated sludge treatment) and anaerobic (sludge digestion) processes. Range of ferric chloride dosages and pH conditions showed that coagulation was ineffective in removal of steroid hormones from secondary effluent. Thus, the tertiary treatment helps in further residual removal. In addition, the remaining pharmaceutical residues can be removed during disinfection and during membrane treatment.

Preparing fermentation residue, useful in e.g. fish culture, comprises separating solid, post-fermenting, treating anaerobic discharge, separating biomass, post-purifying, adding mineral salt, concentrating and producing carbon dioxide

Abstract: Preparing fermentation residue, as a complex system for e.g. energy, comprises separating solids from fermentation residue; post-fermenting the residue; treating the anaerobic filter discharge; degrading N-substrates; separating the biomass remainder and low-molecular components; post-purifying water, ion exchanger and/or zeolites; adding mineral salt solutions through a mineral mixture; disinfecting water; concentrating the algal culture and producing the carbon dioxide for algal culture from the flue-gas wash of the combined heat and power plant (CHP) and/or from biogas cleaning. Preparation of fermentation residue, as a complex system for energy, water and nutrients, comprises separating solids (raw fibers) from the fermentation residues by means of decanters, separators or other suitable filter mechanisms; post-fermenting the fermentation residue in anaerobic fixed bed reactors for further biogas production and for C-decomposition; subsequently treating the discharge of the anaerobic filters by means of aerobic trickling filter for further C-decomposition; subsequently degrading N-substrates over a combined anaerobic/aerobic-step; separating the biomass remainder over external or immersed ultra-filtration modules; separating the low-molecular components by single- or multi-stage reverse osmosis; post-purifying water by combined cascade for the retention of residual impurities like organic compounds, ammonium or sulfide by means of activated charcoal, ion exchanger and/or zeolites; adding suitable mineral salt solutions over or through a mineral mixture for mineralizing the water for rearing fish or cattle watering tanks; disinfecting water with UV, ozone or other disinfection systems such as tetrachlorodecaoxide additives; concentrating the algal culture to algal concentrates by ultrafiltration as base for fish fodder; and producing the necessary carbon dioxide for algal culture from the flue-gas wash of the combined heat and power plant (CHP) and/or from biogas cleaning, where the low-temperature waste heat from CHP is transformed to current; the waste heat of the membrane filtration procedures (ultra-filtration and reverse osmosis) is useful for aquaculture in the produced water; and reverse osmosis concentrate is useful for algal cultures as fodder base for aquaculture.

Degradation of aromatic compounds using moving bed biofilm reactors

Abstract: For biological treatment of water, there are many different biofilm systems in use. Examples of them are trickling filters, rotating biological contactors, fixed media submerged biofilters, granular media biofilters and fluidized bed reactors. They all have their advantages and disadvantages. Hence, the Moving Bed Biofilm Reactor process was developed in Norway in the late 1980s and early 1990s to adopt the best features of the activated sludge process as well as those of the biofilter processes, without including the worst. Two cylindrical moving bed biofilm reactors were used in this study working in upflow stream conditions. Experiments have been done in aerobic batch flow regime. Laboratory experiments were conducted at room temperature (23–28C) and synthetic wastewater comprising a composition of phenol and hydroquinone in each reactor as the main organic constituents, plus balanced nutrients and alkalinity were used to feed the reactor. The ratio of influent to effluent COD was determined at different retention times. The results indicated that the removal efficiency of each selected compound is affected by the detention time. At low phenol and hydroquinone concentration (from 700 to 1000 mg/L) maximum removal efficiency (over 80 %) was obtained. By further increasing in COD loading rate up to 3000 mg/L, a decrease in COD removal rate was occurred. In the reactor containing pyrogallol in COD of 1500 mg/L, the removal rate decreased to 10 percent because of its toxicity for microorganisms.

A quantitative theory of the action of microbes attached to a packed column: Relevant to trickling filter effluent purification and to microbial action in soil

Abstract: A packed column with microorganisms attached is regarded as a series of “theoretical compartments” each separated by a “theoretical film” of biomass. Liquid medium is supposed to pass down the column so that it remains for an equal time in each compartment. The theoretical film of biomass is assumed to have an active layer in contact with the liquid medium, the thickness of the active layer of biomass is estimated from the kinetics of diffusion of the limiting substrate. The efficiency of the column is represented by the number of theoretical compartments per unit length of column. In aerobic processes it is supposed that oxygen will be the rate-limiting nutrient. Expressions are derived for the amounts of substrate that will be consumed in aerated and non-aerated columns. The theory is applied to calculate some of the parameters of a trickling filter for effluent purification. The theory may be readily tested since it involves only measurable and meaningful parameters of a microbial culture.

Fast-track evaluation of a compact chemically enhanced-trickling filter system

Abstract: With the more Stringent legislations pertinent to the management of industrial effluents, it deemed necessary to develop an efficient compact, low cost treatment system that complies with applicable laws. Numerous versions of chemically enhanced - biological treatment schemes are commercially established. Chemically enhanced-trickling filter has been perceived as an efficient intervention scheme. This paper presents a fast-track approach for estimation of the minimum total annual treatment cost for the proposed Chemically Enhanced Primary Treatment/ Trickling Filter (CEPT-TF) system under given sets of conditions. The effect of different chemicals has been incorporated through empirical performance formulas. In addition, the influence of the type and characteristic of the media filter has been also addressed. The analysis of the results of the performance of the first stage of the treatment scheme tends to indicate that about 80 % of the biological pollution load can be removed by the upstream chemical treatment at the optimal dose. The optimal economic dose of iron salts ranges from 30 to 40 ppm according to unit capacity and characteristics of the influent. Further, the effect of biological filter media type on the total annual cost has been found to be relatively insignificant (6-16) %.

Biological removal of nitrogen species from metal-processing wastewater : short communication

Abstract: Although several nitrification/denitrification processes are established for the removal of ammonia and nitrate from municipal and industrial wastewaters, there are few reported results on the removal of these ions from metal-processing and finishing wastewaters. Unlike municipal wastewater, there is very little organic content in metal-processing wastewaters. Sources of ammonia and nitrate in the wastewater include the use of ammonium-nitrate-fuel oil as a blasting agent, and the use of other nitrogen-containing reagents during processing. The objective of this work was to investigate a biological process for the removal of nitrogenous compounds from real metal-processing wastewater. The system comprised an aerobic continuously stirred tank reactor (CSTR) followed by an anaerobic packed column and was run using real wastewater from a metal-processing operation. The system was inoculated using humus sludge from a municipal trickling filter and a period of approximately four weeks was required for a denitrifying biofilm to develop. Results showed that ammonia removal occurred readily in the CSTR while nitrite oxidation was slower to develop. The CSTR was found to be suitable for ammonia oxidation; up to 89% ammonia removal was achieved. By employing an integrated process comprising nitrification and denitrification, high ammonia removal efficiencies can be obtained. An effluent that is low in ammonia can be obtained with this system with additional carbon introduced after the CSTR. The gravel-packed column reactor was found to be unsuitable for the removal of nitrate in the configuration used (maximum 15% removal efficiency). The critical parameters for denitrification are nitrate concentration, temperature, influent flow rate and mean cell retention time. Nitrate removal did not meet the expectations projected by previous authors\' work using synthetic wastewater. Water SA Vol.31 (3) 2005: pp.407-412

Study on hydrogen sulfide removal based on bench-scale experiment by bio-trickling filter

Abstract: A bench-scale experiment for control of hydrogen sulfide (H2S) emissions was carried out continuously for nearly four months by using bio-trickling filter packed with ZX01 stuffing. The results suggested that the bio-trickling filter had proven excellent performance over substantial operational periods. Removal efficiency of H2S was nearly 100% when volumetric loading of the bio-trickling filter varied from 0.64 g/(m3·h) to 38.20 g/(m3·h) and metabolism products of H2S were mainly composed of SO42−. When inlet concentration of H2S was 250 mg/m3, the optimum gas retention time was 30 s and the optimum spray water flow rate was 0.0059∼0.012 L/(cm2·h). The bio-trickling filter had good ability to resist shock of high volumetric loading, and was not blocked during experiments for nearly four months during which resistance was maintained at relatively lower value, so that the bio-trickling filter need not carry out back washing frequently and can be operated steadily for long-term.

Comparison of Shredded Tire Chips and Tire Crumbs as Packing Media in Trickling Filters

Abstract: A five stage study was conducted using two trickling filters, one with shredded tire chips (12 to 50 mm) and the other with tire crumbs (15 to 65 mm) as packing media, and both landfill leachate and synthetically prepared leachate, to evaluate treatment performance Due to increased surface area and sorption capacity, compared with other materials, a thick layer of biomass developed over the surface of tire chips and crumbs and sloughed off after approximately 21 days Biochemical oxygen demand, chemical oxygen demand, and ammonia nitrogen removal were in the range of 81 to 96%, 76 to 90%, and 15 to 68%, respectively, under stable conditions Organic removal and total dissolved solids reduction from the leachate were well correlated, with the exception of when biomass sloughing caused an increase in the organic content The trickling filter with tire crumb media exhibited a more consistent organic removal throughout the experimental program Tire chips, being readily available, could be a better alternative to crushed stone or gravel as a packing media in trickling filters Tire crumbs appeared to be promising for small scale treatment systems

[Removal of toluene waste gas by Pseudomonas putida with a bio-trickling filter].

Abstract: In transient conditions close to the industrialized application situation, the removal of toluene was investigated with a lab-scale bio-trickling filter inoculated with pure bacterial culture (Pseudomonas putida). The start-up process and the ability of resisting different toluene loading in the steady state on the performance of the bio-trickling filter were studied. The microstructure of biofilm in the filter was also observed. With inlet concentration range from 544 to 1044 mg x m(-3) at the temperature ranging from 17 to 26 degrees C, the removal efficiency of toluene was almost 100% at the residence time of 54 s and 43.2 s. The maximum volumetric removal loading of 105.35 g x (m3 x h)(-1) was achieved. The results indicate that it was feasible to remove toluene by Pseudomonas putida which had not be acclimated by toluene. In the steady state, the bio-trickling filter had a high flexibility for the load change and the removal efficiency of the reactor was not influenced by the variance of residence time and inlet concentration. The rapid increase of biofilm can be controlled by adjusting the interval of nutrition liquid accession. There were some changes in bacterial community, and lots of micro-pore existed in the biofilm. It was proved that the absorption of the biofilm was an important precondition for the biodegradation of toluene.

Waste styrene foam use sewage treatment system and method

Abstract: A wastewater treatment apparatus is provided to reduce an operating cost, be completely sealed to reduce the generation of odor, and minimize structure facilities, machinery and equipment by using waste styrene foam as microorganism media and effectively connecting a precipitating process, a filtering process, an activated sludge process, a trickling filter process and a contact oxidation process. An apparatus for treatment of wastewater using waste styrene foam comprises: an air pump tank(25) for pumping compressed air and inflow water by operating a valve; a first diffusing and aerating tank(6) for diffusing the compressed inflow water and air through a lower part of the air pump tank; a first trickling filter reactor(7) having a distributor(9) installed on an upper part thereof to distribute the compressed inflow water and air of the first diffusing and aerating tank; a second diffusing and aerating tank(10) into which the compressed inflow water and air of the first trickling filter reactor are diffused through a lower part of the second diffusing and aerating tank; a second trickling filter reactor(12) having a distributor(22) installed on an upper part thereof to distribute the compressed inflow water and air of the second diffusing and aerating tank; and a final sedimentation tank(15) having an air exhaust port which is formed on a lower part thereof, and through which the compressed air of the second trickling filter reactor is released, and a discharge port formed on an upper part thereof to discharge the inflow water into a natural atmospheric pressure.

Process for treating refractory wastewater using zero-valent iron treatment and biodegradation

Abstract: A method for treating indegradable wastewater by a zero-valent iron process and a biological process is provided to purify even wastewater containing recalcitrant contaminants by combining a physicochemical wastewater treatment process with a biological wastewater treatment process. In a wastewater treatment process for changing toxic compounds in wastewater into non-toxic compounds, a method for treating refractory wastewater by a zero-valent iron process(1) and a biological process comprises: a pretreatment process of pretreating wastewater by containing zero-valent iron as an active component in wastewater; a biological oxidation process(2) for secondly degrading the pretreated wastewater; and a solid-liquid separation process(3) of separating solid and liquid from wastewater by settling the degraded wastewater. The pretreatment process is performed by adding any one or more of sand, gravel and pyrite to wastewater according to characteristics of a removal target and wastewater. The biological oxidation process is selected from activated sludge, trickling filter, rotating biological contactor, other aerobic biological treatment, or anaerobic biological treatment processes.

Device for sterilization of sewage in small sewage treatment- and purification plant with sequencing batch reactor method, and other technical plants by simple device, consists LED producing UV radiation

Abstract: The device for sterilization of sewage in small sewage treatment- and purification plant with sequencing batch reactor method, and other technical plants by simple device, consists LED (3) producing UV radiation for sterilization of the sewage. The control of LED-light source is carried out over time, sewage quantity or other control quantity. The contamination of LED is detected by sensors. A message signal detected by the sensor is produced at the control of the sewage plant, or an automatic cleaning of the UV source is carried out. The size, arrangement and the number of UV-radiation producing LED and like wise the materials in the plant vary with respect to place, geometry and according to the requirement and size of the plant. A silver coating is provided to avoid germ reduction in piping or other pipeline system. The small sewage treatment- and purification plants are fixed bed plants, trickling filter plant and other technical plants for sterilization of sewage. In an alternative arrangement for sterilization of sewage procedure, devices are attached for the mechanical, manual or automatic cleaning of the LED.

Fate of As, Se, and Hg in a Passive Integrated System for Treatment of Fossil Plant Wastewater

Abstract: TVA is collaborating with EPRI and DOE to demonstrate a passive treatment system for removing SCR-derived ammonia and trace elements from a coal-fired power plant wastewater stream. The components of the integrated system consist of trickling filters for ammonia oxidation, reaction cells containing zero-valent iron (ZVI) for trace contaminant removal, a settling basin for storage of iron hydroxide floc, and anaerobic vertical-flow wetlands for biological denitrification. The passive integrated treatment system will treat up to 0.25 million gallons per day (gpd) of flue gas desulfurization (FGD) pond effluent, with a configuration requiring only gravity flow to obviate the need for pumps. The design of the system will enable a comparative evaluation of two parallel treatment trains, with and without the ZVI extraction trench and settling/oxidation basin components. One of the main objectives is to gain a better understanding of the chemical transformations that species of trace elements such as arsenic, selenium, and mercury undergo as they are treated in passive treatment system components with differing environmental conditions. This progress report details the design criteria for the passive integrated system for treating fossil power plant wastewater as well as performance results from the first several months of operation. Engineering work on more » the project has been completed, and construction took place during the summer of 2005. Monitoring of the passive treatment system was initiated in October 2005 and continued until May 18 2006. The results to date indicate that the treatment system is effective in reducing levels of nitrogen compounds and trace metals. Concentrations of both ammonia and trace metals were lower than expected in the influent FGD water, and additions to increase these concentrations will be done in the future to further test the removal efficiency of the treatment system. In May 2006, the wetland cells were drained of FGD water, refilled with less toxic ash pond water, and replanted due to low survival rates from the first planting the previous summer. The goals of the TVA-EPRI-DOE collaboration include building a better understanding of the chemical transformations that trace elements such as arsenic, selenium, and mercury undergo as they are treated in a passive treatment system, and to evaluate the performance of a large-scale replicated passive treatment system to provide additional design criteria and economic factors. « less

Removal of dichloromethane from waste gases using a fixed-bed biotrickling filter and a continuous stirred tank bioreactor

Abstract: A laboratory scale fixed bed biotrickling filter (BTF) and a continuous stirred tank bioreactor (CSTB) have been studied and compared for the elimination of dichloromethane from waste gases. The DCM removal efficiency in the trickling filter was > 85% for inlet loads up to 25 g.m-3.h-1 and a maximal removal capacity of about 170 g.m-3.h-1 was achieved at a load of 350 g.m-3.h-1. The continuous stirred tank bioreactor showed removal efficiencies > 90% for inlet loads up to 120 g.m-3.h-1. At this load the maximal removal capacity of the system was reached, i.e. about 100 g.m-3.h-1. Thus, higher maximum elimination capacities were reached in the BTF while higher removal efficiencies were obtained at high loads with the CSTB. Both systems presented good stability against overloads.

Bioindicators as a tool for monitoring and control biofilm reactors : a simplified approach

Abstract: The control of wastewater treatment plants requires an extensive monitoring programme based on physicochemical costly routine analysis. Microbial populations are well known indicators of operational conditions in biological reactors. This research was carried out by the CENTA and the University of Minho in the scope of the Erasmus programme. The aim of the work was the development of a simplified approach, based on biological indicators, for monitoring small biofilm wastewater treatment processes. In that regard, protozoa and metazoan were monitored at CENTA experimental plants namely a trickling filter and a rotating biological contactor -, and correlated with influent wastewater and effluent composition. The relationship between wastewater performance and the microbiological composition of the biofilm was identified and assessed. Results indicate that a methodology based on the bioindicators provides useful data for process monitoring and control of small wastewater treatment plants, thus diminishing the associated costs of routine analysis and providing information when such analysis aren’t easily available.

Development of Process for Village Scale Wastewater Treatment Using Biofilter and Sulfur-limestone

Abstract: This process which has a connection of biofilter and sulfur-limestone has been developed to treat organic substances including BOD, COD and SS etc. and to treat sulfur-limestone is for denitrification.. The whole process consists of chemical reaction tank, sedimentation tank, trickling filter, denitrification tank The trickling filter is equipped with a reactor filled with absorptive filter, and the sulfur denitrification tank is filled with sulfur-limestone mixed media. After setting up practical facilities whose capacity is 60 tons a day, we have observed the removal efficiencies of pollutants through 60 experiments during Summer and Winter seasons. The average concentration of polluted water was BOD for 3.6 mg/L, for 11.3 mg/L, SS for 2.8 mg/L, T-N for 8.6 mg/L, and T-P for 0.8 mg/L, and the rate of treatment efficiencies 96.5%, 84.7%, 96.5%, 79.2%, and 80.8%, respectively was found through the experiments. The average treatment efficiency for BOD and was 85.0% and 55.7%, respectively and the average removal efficiency for NH4+-N was 84.9% in the trickling filter. The removal efficiency in the denitrification tank is as follows; The removal rate of was as high as 93.2% within the compass of pH 6.3 to 7.3 through flown into and outflown. It had observed that this process has implemented highly efficient and advanced treatment without external carbon sources and internal recycle during its process. In conclusion, this process is suitable for a sewerage in a small village due to the merits of low power consumption and easy maintenance.