Showing papers on "Trickling filter published in 2012"

Effectiveness of Conventional and Low-Cost Wastewater Treatments in the Removal of Pharmaceutically Active Compounds

Abstract: In the present work, the effectiveness of conventional wastewater treatments (activated sludge and oxidation ditches) and low-cost wastewater treatments (trickling filter beds, anaerobic lagooning and constructed wetlands) in the removal of pharmaceutically active compounds has been studied. To evaluate the efficiency of removal, 16 pharmaceutically active compounds belonging to seven therapeutic groups (anti-inflammatory drugs, antibiotics, antiepileptic drugs, β-blockers, nervous stimulants, estrogens and lipid regulators) have been monitored during 1-year period in influent and effluent wastewater from 11 wastewater treatment plants of Spain. Mean removal rates of pharmaceutically active compounds achieved in conventional wastewater treatments were slightly higher than those achieved in low-cost treatments, being 64% and 55%, respectively. Ibuprofen, naproxen, salicylic acid and caffeine were the pharmaceutical compounds most efficiently removed, regardless the wastewater treatment applied, with removal rates up to 99%. Anaerobic lagooning was the less effective treatment for the removal of the most persistent compounds: carbamazepine and propranolol.

Fundamentals of Wastewater Treatment and Engineering

Abstract: Sustainable Wastewater Treatment and Engineering Introduction and history Current practice Emerging issues Future directions Regulatory requirements References Reaction Kinetics and Chemical Reactors Reaction kinetics How to find the order of a reaction Zero order reaction First order reaction Second order reaction Reactors Batch reactor Continuous-flow stirred tank reactor Reactors in series Semibatch or semiflow reactors Problems References Wastewater Microbiology Introduction Bacteria Archaea Protozoa Algae Fungi Virus Problems References Natural Purification Processes Impurities in water Dilution Sedimentation Microbial degradation Measurement of organic matter Dissolved oxygen balance Problems References Wastewater Treatment Fundamentals Introduction Sources of wastewater Wastewater constituents Wastewater treatment methods Levels of wastewater treatment Residuals and biosolids management Flow diagrams of treatment options Types of biological treatment processes Problems References Preliminary Treatment Introduction Screens Shredder/grinder Grit chamber Problems References Primary Treatment Introduction Types of settling/sedimentation Type I sedimentation Type II sedimentation Primary sedimentation Chemically enhanced primary treatment Problems References Secondary Treatment: Suspended Growth Processes Introduction Microbial growth kinetics Activated sludge process (for BOD removal) Modeling suspended growth processes Types of suspended growth processes Stabilization ponds and lagoons Problems References Secondary Treatment: Attached Growth and Combined Processes Introduction System microbiology and biofilms Important media characteristics Loading rates Stone media trickling filter Biotower Rotating biological contactor Hybrid processes Combined processes Problems References Secondary Clarification Introduction Secondary clarifier for attached growth process Secondary clarifier for suspended growth process Problems References Anaerobic Wastewater Treatment Introduction Process chemistry and microbiology Methanogenic bacteria Sulfate-reducing bacteria Environmental requirements and toxicity Methane gas production Anaerobic growth kinetics Anaerobic suspended growth processes Anaerobic attached growth processes Hybrid processes Problems References Solids Processing and Disposal Introduction Characteristics of municipal sludge Sludge quantification Sludge thickening Sludge stabilization Conditioning of biosolids Biosolids dewatering Disposal of biosolids Biosolids disposal regulations in the United States Problems References Advanced Treatment Processes Introduction Nitrogen removal Phosphorus removal Solids removal Problems References Appendix Index

Removal of pharmaceuticals in biologically treated wastewater by chlorine dioxide or peracetic acid

Abstract: Removal of six active pharmaceutical ingredients in wastewater was investigated using chlorine dioxide (ClO2) or peracetic acid (PAA) as chemical oxidants. Four non-steroidal anti-inflammatory drugs (ibuprofen, naproxen, diclofenac and mefenamic acid) and two lipid-regulating agents (gemfibrozil and clofibric acid, a metabolite of clofibrate) were used as target substances at 40 μg/L initial concentration. Three different wastewaters types originating from two wastewater treatment plants (WWTPs) were used. One wastewater was collected after extended nitrogen removal in activated sludge, one after treatment with high-loaded activated sludge without nitrification, and one from the final effluent from the same plant where nitrogen removal was made in trickling filters for nitrification and moving-bed biofilm reactors for denitrification following the high-loaded plant. Of the six investigated compounds, only clofibric acid and ibuprofen were not removed when treated with ClO2 up to 20 mg/L. With increasing P...

Water and wastewater treatment: biological processes

Abstract: Population growth in urban areas is leading to an expansion in industrial development, which in turn creates increased volumes of wastewater with ever more complex compositions. The wastewater that is generated is discharged into water sources that supply drinking water to other urban areas, causing higher levels of pollution. One option for the treatment of water and wastewater is the use of biological processes, which offer certain advantages over other common treatment technologies. The organic contaminants to be destroyed are used and transformed by bacteria or other organisms as a source of food. Thus the water/wastewater treatment process is used to dispose of waste in a non-toxic and sanitary manner. This chapter discusses the major biological options for water and wastewater treatment.

Wastewater treatment in trickling filters using luffa cyllindrica as biofilm supporting medium

Abstract: Domestic sewage treatment experiments were conducted in trickling filters in laboratory pilot plants in which the peeled dehydrated fruits of Luffa cyllindrica were used as a support medium for microbiological growth, in order to verify its capacity to remove organic matter, measured in terms of Biochemical Oxygen Demand (BOD5,20) and Chemical Oxygen Demand (COD). Other parameters such as suspended and settleable solids were also measured. The results obtained, when compared to results from similar pilot plant using stones as supporting medium, and with the removals predicted by classic formulas used for trickling filters design, indicated that this support medium may substitute with advantages, under specific conditions, the traditional support media. Further studies are recommended.

Improvements in Biofilm Processes for Wastewater Treatment

Abstract: 2 Abstract: This review paper intends to provide an overall vision of biofilm technology as an alternative method for treating waste waters. This technology has been gaining popularity through the years, mainly because many wastewater treatment plants, which are still used Activated Sludge Process (AS) are present some shortcomings when exposed to increased hydraulic and organic loads. Fundamental research into biofilms is presented in three sections, Biofilm Types and Characterization, Advantages and Drawbacks and Design Parameters. The reactor types covered in this review are: un-submerged fixed film systems (trickling filters and rotating biological contactors) and submerged fixed film systems (biological aerated flooded filters, submerged aerated filters, biofilm up-flow sludge blanket, fluidized bed, expanded granular sludge blanket, biofilm airlift suspension, internal circulation, moving bed biofilm and membrane biofilm) reactors.

Sequential Application of Plastic Media- Trickling Filter and Sand Filter for Domestic Wastewater Treatment at Low Temperature Condition

Abstract: Present research was aimed towards designing and construction of efficient plastic media-trickling filter (TF) for the treatment of domestic wastewater. The hydraulic flow rate through the TF was maintained at80±2 ml/min at a temperature range of 5 -15∫C by selecting treatmenttime of 12, 24, 36 and 48 hrs. Parameters like COD, BOD 5, TSS, turbidity, NO 3, NO2, SO4, PO4 and pathogenic indicator microbes were monitored after treatment of 12, 24, 36 and 48 hrs. The efficiency of the TF was improved with increase of time from 12 to 48 hrs. Maximum efficiency of TF was observed after 48 hrs treatment viz. 93.45, 93, 86.25, 57.8, 63.15, 25, 32.43, 99.95 and 86.3% reduction from the zero time value forBOD 5, COD, TSS, PO 4, SO4, NO3, NO2, turbidityand fecal coliforms respectively.Finally 48 hrs treated sample was passed through sand filter (SF) for further final polishing and a pproximately, 95.72, 95, 100, 73.5, 65.8, 58.3, 37.83, 100 and 91.5% reduction in BOD5, COD, TSS, PO 4, SO4, NO3, NO2, turbidity and fecal coliforms was observed. This study showed that plastic media -trickling filter along with sand filter is a

Gallionella spp. in trickling filtration of subsurface aerated and natural groundwater

Abstract: The growth of iron-oxidizing bacteria, generally regarded as obligate microaerophilic at neutral pH conditions, has been reported in a wide range of environments, including engineered systems for drinking water production. This research focused on intensively aerated trickling filters treating deep anaerobic and subsurface aerated groundwater. The two systems, each comprising groundwater abstraction and trickling filtration, were monitored over a period of 9 months. Gallionella spp. were quantified by qPCR with specifically designed 16S rRNA primers and identified directly in the environmental samples using clone libraries with the same primers. In addition, enrichments in gradient tubes were evaluated after DGGE separation with general bacterial primers. No other iron-oxidizing bacteria than Gallionella spp. were found in the gradient tubes. qPCR provided an effective method to evaluate the growth of Gallionella spp. in these filter systems. The growth of Gallionella spp. was stimulated by subsurface aeration, but these bacteria hardly grew in the trickling filter. In the uninfluenced, natural anaerobic groundwater, Gallionella spp. were only present in low numbers, but they grew extensively in the trickling filter. Identification revealed that Gallionella spp., growing in the trickling filter were phylogenetically distinct from the species found growing during subsurface aeration, indicating that the different conditions in both systems selected for niche organisms, while inhibiting other groups. The results suggest a minor direct significance for inoculation of Gallionella spp. during filtration of subsurface aerated groundwater.

Hydrogen sulfide removal performance of a bio-trickling filter employing Thiobacillus thiparus immobilized on polyurethane foam under various starvation regimes

Abstract: In the present study a biotrickling filter (BTF) with countercurrent gas/liquid flow packed with open-pore polyurethane foam — as a carrier of Thiobacillus thioparus (DSMZ5368) — was subjected to various starvation regimes such as non-contaminant loading, idleness, and complete shutdown. During the starvation periods specific oxygen uptake rates of microorganisms (SOUR) on packing were monitored. The BTF was subjected to non-contaminant loading (up to 16 h), cyclic non-contaminant loading (for 4 days) and gas shut-off (up to 24 h), and it recovered to its pre-starvation removal efficiency within a 2 ∼ 3 h period after resuming normal operating conditions. The recovery time values obtained during the runs in which these starvation regimes were imposed could be indirectly correlated with the corresponding SOUR values suggesting that the recovery time after such starvation regimes are dependent on the degree to which the aerobic biological activity has been reduced as a result of the imposed starvation regime. In the case of the complete shutdown of the BTF, the recovery time increased substantially after 1 and 2 days of complete shutdown, and after 5 days of complete shutdown the pre-starvation removal efficiency was not achieved even after 12 days of normal operation.

Sewage treatment system

Abstract: The sewage treatment system (1) of an embodiment of the invention is provided with a solid-liquid separating device (2) prior to a trickling filter bed (3). The solid-liquid separating device (2) has a first filter material-filled layer in which a specified filter material is filled and passes sewage (W1) into the first filter material-filled layer with an upward flow to separate the sewage (W1) into solid components and filtrate (W2). The solid-liquid separating device (2) also back-washes the first filter material-filled layer with a prescribed timing by passing the filtrate (W2) into the first filter material-filled layer with a downward flow. The trickling filter bed (3) has a second filter material-filled layer that is filled with a filter material with adherent microorganisms. The filtrate (W2) is spread on the top of the second filter material-filled layer, the filtrate (W2) is made to flow down into the second filter material-filled layer, and the treated water (W3) obtained by bio-treating the filtrate (W2) using the microorganisms is drained out.

Full-scale trials of external nitrification on plastic media nitrifying trickling filter

Abstract: The full-scale single-stage tertiary nitrifying trickling filter (NTF) at the Citrusdal Wastewater Treatment Plant provides for external nitrification of unclarified effluent from the facultative aerobic lagoon in order to meet standard effluent ammonia concentration requirements. The apparent ammonia nitrification rate (ApANR, gN/m2 media surface·d) of the NTF was sensitive to particulate organic loading rates which were predominantly in the form of algae, and the soluble COD removal rates increased under cold climates. Installation of forced-air ventilation fans improved the nitrification efficiency from 15% to 43%. An increase in hydraulic loading rate (HLR) by effluent recirculation significantly improved the ApANR, eradicated filter flies and decreased the prevalence of worms. Maximum ApANR of ~1.0 gN/m2·d was achieved yielding an ammonia- removal efficiency of approximately 71%. Profile samples collected along the NTF media depth indicated poor media wetting at low HLR resulting in low ApANR (<0.5 gN/m2·d). Also during the cold and rainy winter period, poor biofilm activity and prevalence of motile algae were observed, and under low hydraulic loading rates and warmer temperatures, a dominance of filter flies and fly larvae were observed. In contrast, in controlled laboratory studies, ApANRs up to 1.72 gN/m2·d (22.1 mgN/l removal) were attained, which, in conformity with full-scale, was also found to be sensitive to hydraulic loading conditions.

Nitrogen and phosphorus removal bio-trickling filter by artificially strengthening natural ventilation

Abstract: The invention relates to a nitrogen and phosphorus removal bio-trickling filter by artificially strengthening natural ventilation, belonging to the environmental protection technical field. The bio-trickling filter comprises a filter body, a water inlet and distribution pipe, a water collection and outlet pipe, an unpowered ventilating device, a bearing layer and a filter material layer. The bio-trickling filter is characterized in that the filter material layer is positioned in the filter body; the bearing layer is positioned at the bottom of the filter material layer and is internally equipped with the water collection and outlet pipe; the water inlet and distribution pipe is positioned above the filter material layer; the unpowered ventilating device is arranged on the top of the filter body; and the filter material layer consists of an aerobic area, an facultative area, an anoxic area and an anaerobic area from top to bottom. In the invention, by strengthening the natural ventilation strength through the omnidirectional unpowered ventilating device on the top of the bio-trickling filter and utilizing the number change of the open pores on side walls of the filter and the particle size change of a filter material from top to bottom, the ventilating conditions of different areas in a reactor are controlled and the ventilation rate is adjusted so as to form the integrated aerobic, facultative, anoxic and anaerobic bio-trickling filter, thus achieving the purpose of removing organic matters, nitrogen and phosphorus.

Device for performing biological deodorization and waste gas treatment on sewage

Abstract: The utility model provides a device for performing biological deodorization and waste gas treatment on sewage. The device comprises a degreaser, a first biological trickling filter tower, a second biological trickling filter tower, a biological filter tank, a cyclic water box, a waste gas collection pot and a water compensation pool, wherein the waste gas collection pot is sequentially connected with the degreaser, the first biological trickling filter tower, the second biological trickling filter tower and the biological filter tank; the cyclic water box is respectively connected with the first biological trickling filter tower, the second biological trickling filter tower and the biological filter tank; the water compensation pool is respectively connected with the first biological trickling filter tower and the biological filter tank; and the biological filter tank is connected with a chimney through a centrifugal fan. By the device, stinky substances such as volatile organic compounds (VOC), H2S and NH3 in the waste gas can be effectively removed; the device has the advantages of low construction cost investment, high treatment efficiency, obvious removal effect and the like, and an ideal purification technology by which the VOC air pollution is avoided, and the atmospheric environment is protected is provided.

Composite ecological fillers and preparation method thereof

Abstract: The invention discloses composite ecological fillers and a preparation method of the composite ecological fillers. Adsorption functions of steel slag, anthracite and zeolite to nitrogen and phosphorus substances in sewage are utilized to optimize three types of fillers and enable the fillers to have a modularized characteristic. The composite ecological fillers are applicable to a trickling filter bed, an anaerobic biological filter tank, a filter tank, an aeration biological filter tank, a high-load biological filter tank, an active biological filter tank and the like, and can be used for river and lake slope protection materials.

Efficiency of subsurface flow constructed wetland with trickling filter.

Abstract: Effective wastewater purification in subsurface flow constructed wetlands must include adequate pretreatment and ensure a sufficient amount of dissolved oxygen. In a pilot-scale operation, a subsurface flow constructed wetland (CW) consisted of a primary settlement tank, a trickling filter for pretreatment and two serially assembled basins. The trickling filter was added to ensure sufficient aeration, increase purification of the wastewater and shorten the wastewater purification time. The estimated nominal flow was 0.7 m3/d. The experiments were conducted using the wastewater from the municipal sewage canal of the city of Zagreb, with utilization of three different flows: 0.72 (A), 1.44 (B) and 2.88 (C) m3/d. The efficiency of the purification process was monitored over a period of three years (TSS, BOD5, COD, NH4-N, NO2-N, PO4-P, dissolved oxygen, temperature and pH). The experimental results showed an increase in the removal efficiency with a doubling of the nominal flow from 0.7 to 1.44 m3/d, which co...

Effect of environmental and operating conditions on a full-scale trickling filter for well water treatment

Abstract: The effect of temperature, hydraulics and pollutant loading on a full-scale trickling filter performance for simultaneous ammonium, iron, and manganese removal was studied. Pollutant concentrations fluctuate sharply in raw well water, exceeding many times the maximum permitted limits. Measurements taken during the one-year continuous operation of the filter, as well as the 24 h experiments performed in various seasons, have shown a dependence of the pollutant removal efficiencies on temperature (8–28°C) and hydraulic loading (5–12 m3/h) shocks. However, in all environmental and operating conditions, high removal efficiencies were achieved for ammonium, iron and manganese maintaining final concentrations at the filter outlet to below EC parametric values.

Polyurethane Trickling Filter in Combination with Anaerobic Hybrid Reactor for Treatment of Tomato Industry Wastewater

Abstract: © 2012 Tawfik, licensee InTech. This is an open access chapter distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Polyurethane Trickling Filter in Combination with Anaerobic Hybrid Reactor for Treatment of Tomato Industry Wastewater

Biofilms in Nitrogen Removal - Bacterial Population Dynamics and Spatial Distribution

Abstract: Efficient nitrogen removal at wastewater treatment plants (WWTPs) is necessary to avoid eutrophication of recipient waters. The most commonly used approach consists of aerobic nitrification and subsequent anaerobic denitrification resulting in the release of dinitrogen gas into the atmosphere. Nitrification is a two-step process performed by ammoniaoxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB) often grown in biofilms at WWTPs. An alternative approach is anaerobic ammonium oxidation (anammox) where anammox bacteria convert ammonium and nitrite directly into dinitrogen gas. These groups of bacteria grow very slowly and are sensitive to perturbations, which may result in decreased efficiency or even breakdown of the process. Therefore, the ecology and activity of these bacteria and the structure of the biofilms in which they grow require detailed investigation to improve the understanding of nitrification and to facilitate the design of efficient nitrogen-removal strategies. To facilitate such studies of relevance for wastewater treatment, a nitrifying pilotplant was built where environmental conditions and especially ammonium concentrations could be controlled. In an experiment on model nitrifying trickling filters (NTFs), it was shown that biofilms subjected to intermittent feeding regimes of alternating high and low ammonium concentration in the water, could maintain a higher nitrification potential than biofilms constantly fed with low ammonium water. Such ammonium feed strategies can be used to optimize wastewater treatment performance. Different AOB populations within the N. oligotropha lineage were shown to respond differently to changes in environmental conditions, indicating microdiversity within this lineage which may be of importance for wastewater treatment. This diversity was further investigated through the development of new image analysis methods for analyzing bacterial spatial distribution in biofilms. The diversity within the N. oligotropha lineage was also reflected in the positioning of two such populations in the biofilm, where the vertical distribution patterns and relative positions compared to the NOB Nitrospira were different. In combination with a cryosectioning approach for retrieval of intact biofilm from small biofilm carrier compartments, the new image analysis methods showed a threedimensonal stratification of AOB-anammox biofilms. This may be of importance for mathematical modeling of such biofilms and the design of new biofilm carriers.

Device for biological treatment of high-temperature malodorous waste gases

Abstract: The utility model relates to a device for biological treatment of high-temperature malodorous waste gases, which is applied to treat high-temperature malodorous waste gases generated during industrial production processes. The device comprises a ceramsite-filled biological trickling filter bed region, a biological activated carbon trickling filter bed region, a multi-step spray device, a demister and a circulating liquid storage tank, which are connected in sequence. The device is a counter-flow tower-type or cross-flow horizontal type device formed at lease by connection of the two trickling filter bed regions. A stainless steel porous plate and a gas re-distributor are arranged at the lower part of each trickling filter bed, and a liquid sprayer is arranged at the upper part of each trickling filter bed. An aeration tube, a dissolved oxygen probe and a pH probe are arranged inside the circulating liquid storage tank. The malodorous waste gases are turned into nontoxic and odorless substances by degradation with thermophilic microorganisms and cooling in the ceramsite-filled biological trickling filter bed region and then adsorption and biodegradation in the biological activated carbon trickling filter bed region. The device for biological treatment of high-temperature malodorous waste gases overcomes the defects in the prior art that the conventional biological deodorization equipment can not work under a high-temperature environment and have poor deodorization effect, has a simple process, is convenient for maintenance and management, needs less investment and running costs, and has high deodorization efficiency.

System for treating acid wastewater containing heavy metal

Abstract: PROBLEM TO BE SOLVED: To provide a long-life cycle passive treatment type system for treating wastewater in which maintenance such as removal of iron precipitates inevitably generated during treating acid wastewater containing heavy metals mainly composed of iron is easily carried out.SOLUTION: The system includes the following components in this order: a trickling filter having a part filled with filter media, where, when trickled wastewater passes through the filled part, ferrous ions contained in the wastewater are oxidized into ferric ions; a sedimentation tank where primary treated water flowing down from the trickling filter and containing ferrous ions is made to reside for a certain time to cause the ferric ions to be precipitated and to be settled, and its supernatant is enabled to flow out as secondary treated water; a calcic water channel where block-shaped limestones are provided on the bottom in advance to neutralize the secondary treated water, and gates each of which upper veranda is served as a flow-out part for tertiary treated water are provided; and an aerobic artificial marsh where an ecological zone with a constant depth of water is provided and a precipitate deposition zone of which water depth is deeper than that of the ecological zone is provided beneath the flow-out part of the calcic water channel in series with the ecological zone.

Removal of Pharmaceuticals in Biofilm and Activated Sludge Systems

Abstract: The present work investigates i) the occurrence and removal of pharmaceuticals at Swedish WWTPs, and ii) potential causes for differences in the removal efficiency of pharmaceuticals at wastewater treatment plants. Particular attention is directed at the biological treatment and the pharmaceutical removal capacity per unit biomass of activated sludges and carrier biofilms of different origins. Influent and effluent concentrations of pharmaceuticals at wastewater treatment plants are compiled from several Swedish screening programs. Based on the compiled data, 70 non-antibiotic pharmaceuticals have been detected in incoming wastewater at concentrations ranging from a few ng/L to several µg/L. For some of these pharmaceuticals, a higher removal degree is observed for activated sludge treatment plants with nitrogen removal than for trickling filter plants. The pharmaceutical removal capacity of activated sludge and carrier biofilms from several municipal wastewater treatment plants are assessed in batch experiments. Three notable differences in the removal capacity per unit biomass are observed. Activated sludges with oxic sludge ages of >7 days appear to have higher removal capacities for some pharmaceuticals than sludges with oxic sludge ages of <3 days. The anoxic and oxic conditions in nitrogen removal processes are shown to affect the pharmaceutical removal - some pharmaceuticals are being degraded both oxically and anoxically, while others appear to be stable in the absence of molecular oxygen. Compared to activated sludges, carrier biofilms show considerably higher removal capacities for several pharmaceuticals. From the broader perspective of micropollutant removal at wastewater treatment plants, the high pharmaceutical removal capacity of carrier biofilms suggests that new biological treatment solutions for enhanced micropollutant removal are within reach.

Method of improving nitrification in a trickling filter

Abstract: A method of improving nitrification in a wastewater treatment plant is provided. The method comprises the steps of a) providing a trickling filter effluent water basin having biological filter media placed on a support platform positioned at least three feet above a bottom of the basin; and (b) contacting the filter media with the wastewater. Nitrification (removal of ammonia by conversion to nitrate) can be improved at least 30% as compared to a trickling filter without the invention.

Settlement water supply system with physical-chemical treatment works

Abstract: FIELD: process engineering ^ SUBSTANCE: invention relates treatment and decontamination of whatever effluents and may be used in treatment plants of minor settlements, cottages and camps, educational and medical centers, etc Proposed system comprises settler with thin-layer modules, high-rate trickling filter with granular packing, plasma chemical reactor with HV pulse generator with pulse repetition frequency of 01-02 Hz, wells communicated with pipelines, manifolds and sewage pump station, grids, sand trap, catalytic electrochemical reactor, biological pond with compressor and botanical site with higher aquatic vegetation, clean water pump station, manifolds to feed cleaned water into filtration trenches Catalytic electrochemical reactor is composed of standard high-rate trickling filter with distribution and collection system Filter packing represents alternating and screen-isolated electrically negative granulated material, for example, manganese-alumina catalyst AOK-7541 and electrically positive carbon-bearing granulated material, for example, active carbon AC-3 ^ EFFECT: closed-circuit nonpolluting water supply system, reduced power consumption ^ 2 cl, 2 dwg, 2 tbl, 2 ex

Open trickling filter: an innovative, cheap and simple form of post-treatment of sanitary effluents from anaerobic reactors in small communities

Abstract: We aimed to evaluate the performance and cost savings of an innovative design of a trickling filter (TF) for small population sizes, developed at the Federal University of Minas Gerais, Brazil referred to as an open trickling filter ( OTF ). The OTF had no side walls and no perforated bottom slab, and was applied for the post-treatment of sanitary sewage from an upflow anaerobic sludge blanket (UASB) reactor. The OTF had crushed-stone packing (3.5 m high) and was operated with an average surface hydraulic loading rate of 4.1 m 3 m -2 d -1 and an average volumetric organic loading rate of 0.10 kg BOD m -3 d -1 (biochemical oxygen demand). The average concentrations obtained at the OTF effluent were 48 mg TSS L -1 (total suspended solids), 132 mg COD L -1 (chemical oxygen demand), 51 mg BOD L -1 , 19 mg TKN L -1 (total Kjeldahl nitrogen), 16 mg NH + 4 -N L -1 and 10 mg NO - 3 -N L -1 , complying with local discharge standards. Analysis of the construction costs indicated savings of 74% compared to conventional TF. Based on the performance, compactness, simplicity and reduced capital costs, it is believed that the proposed OTF is a good alternative for small communities, especially in developing countries.

Water Treatment and Related Technologies

Abstract: This chapter explores the techniques of water treatment. It illustrates a schematic representation of a general municipal water treatment plant. A combination of biological, chemical, and physical treatment processes allow treatment plants the ability to make available a sufficient supply of clean water for domestic, agricultural, and industrial use is employed. Such processes also help keep surrounding surface waterways uncontaminated as the result of regulated water discharge. The initial stage in the treatment of domestic wastewater is termed primary treatment. During this stage, physical processes such as screening and shredding in the bar rack remove debris (e.g., sticks and rags) and a portion of the contaminants that settle or float. Following this, secondary treatment begins with biological oxidation through activated sludge, trickling filters, or stabilization pond processes (or a combination of all of these). Finally, after the secondary treatment, the clarified effluent may require additional aeration and other chemical treatment (tertiary treatment) to destroy bacteria remaining from the secondary treating stage and to increase the content of dissolved oxygen (DO) needed for oxidation of the residual biological oxygen demand (BOD).