Removal Efficiency

The overall goal of this work was to determine the effect of mixing the filter media of a compost biofilter on H 2 S removal efficiency. The behavior of important operational factors such as moisture of filter media, pressure drop and sulfate accumulation were evaluated, considering mixing the media. Additionally, tracer studies were performed in order to determine the effect of mixing the media on gas distribution. H 2 S removal capacity decreased over time, from 100% to 90%. When bed mixing was carried out, the removal capacity remained constant, close to 100%, and moisture content and sulfates accumulation were better controlled at 50% and at 12 mg S-SO 4 /g dry media respectively. In addition, under this operational pattern, an improvement in gas and particle size distribution was observed inside the filter media, fitting the axial dispersion model and the Ergun equation.

The physico-chemical characteristics of granulated sludge lead us to develop its use as a packing material in air biofiltration. Then, the aim of this study is to investigate the potential of unit systems packed with this support in terms of ammonia and hydrogen sulfide emissions treatment. Two laboratory scale pilot biofilters were used. A volumetric load of 680 g H 2 S m À3 empty bed day À1 and 85 g NH 3 m À3 empty bed day À1 was applied for eight weeks to a unit called BGSn (column packed with granulated sludge and mainly supplied with hydrogen sulfide); a volumetric load of 170 g H 2 S m À3 empty bed day À1 and 340 g NH 3 m À3 empty bed day À1 was applied for eight weeks to the other called BGNs (column packed with granulated sludge and mainly supplied with ammonia). Ammonia and hydrogen sulfide elimination occur in the biofilters simultaneously. The hydrogen sulphide and ammonia removal efficiencies reached are very high: 100% and 80% for BGSn; 100% and 80% for BGNs respectively. Hydrogen sulfide is oxidized into sulphate and sulfur. The ammonia oxidation products are nitrite and nitrate. The nitrogen error mass balance is high for BGSn (60%) and BGNs (36%). This result could be explained by the denitrification process which would have occurred in anaerobic zones. High percentages of ammonia or hydrogen sulfide are oxidized on the first half of the column. The oxidation of high amounts of hydrogen sulfide would involve some environmental stress on nitrifying bacterial growth and activity.

Screening level risk assessment models are used by many countries to assess the treatability of organic chemicals during the sewage treatment process, especially those that are new to commerce. The performance of one such model, the sewage treatment plant model, is evaluated in the current study by comparing model predictions with actual measurement data collected at various stages of a typical fullscale activated sludge type sewage treatment plant. A suite of ten polycyclic aromatic hydrocarbons (PAHs) with widely varying physicochemical properties were monitored for the comparison. Model predicted removal efficiencies were in very good agreement with those measured for all ten PAHs. Observed chemical concentrations and their trends at various stages of the sewage treatment process were also well simulated by the model. Results also suggest that a reasonable first approximation estimate of a range for the biodegradation half-life needed for the model may be obtained by dividing reported aqueous biodegradation half-life by scaling factors of 50 and 150.

Electro-coagulation (EC) is becoming a popular proc ess to be used for industrial wastewater treatment. In the present study, a laboratory scale electro-coagu lation (EC) process was utilized to treat the texti le wastewater in order to bring the quality up to the wastewater reu se standards and also to compare the electro-coagul ation process with the conventional coagulation treatment. Effect of various operating parameters such as operating time and voltage on COD removal efficiency was evaluated to achieve the maximum possible treatment efficiency.

Experimental investigations were conducted to evaluate the effectiveness of a retention treatment basin (RTB) with polymer coagulation for the treatment of combined sewer overflows (CSO) at high hydraulic loading rates. The TSS removal efficiency of the pilot-scale RTB at a surface overflow rate (SOR) of 11 m/h was approximately 35% without chemical addition, and 80% with a polymer dosage range of 5 to 10 milligrams per gram of influent TSS. The results demonstrated that the use of polymer coagulation significantly improved TSS removal and allowed the SOR in the RTB to be significantly increased, resulting in smaller treatment units. An empirical relationship was established to estimate removal efficiencies as a function of overflow rate. The results also compared settling characteristics of CSO, obtained from long column tests, to removal efficiencies in the high-rate RTB.

Comparative study of the artificial neural network and mechanistic model was carried out for NO removal in a bubbling fluidized bed reactor. The effects of temperature, superficial gas velocity and ammonia/nitric oxide ratio on the NO removal efficiency were determined and their optimum conditions were estimated by the experimental study, the artificial neural network and mechanistic models as well. The optimum values of ammonia/nitric oxide ratio, temperature and superficial gas velocity for the maximum NO removal efficiency were found to be 1.5, 300°C and 0.098 m/s, respectively. A mechanistic model was implemented in our previous study [Muhammad F. Irfan, Sang Done Kim and Muhammad R. Usman, 2009] and it was found that this model fitted well only at specific condition i.e. maximum conversion temperature (300°C). However, it failed to perfectly match with rest of the experimental data points at other temperatures and parametric conditions as well. To improve this, an artificial neural network modeling strategy was applied and its predictions were evaluated which were favorably matched with the experimental data rather than the mechanistic model.

The present study demonstrates the occurrence of pharmaceuticals and personal care products (PPCPs) in surface water from the Mankyung River, South Korea. Samples collected at 5 Sites along the Mankyung River were assayed using a liquid chromatograph coupled with a tandem mass spectrometer (LC/MS/MS) for 13 PPCPs. Overall, 11 out of the 13 selected PPCPs, which span a range of therapeutic classes and one personal care product, were detected in surface water samples collected from the Mankyung River. The most prevalent contaminants were ibuprofen, with average concentrations ranging from not detected (ND) to 414 ng/l, followed by carbamazepine (ND-595 ng/l), atenolol (ND-690 ng/l), clarithromycin (ND-443 ng/l), mefenamic acid (ND-326 ng/l), erythromycin (ND-137 ng/l), fluconazole (ND-111 ng/l), levofloxacin (ND-87.4 ng/l), indomethacin (ND-33.5 ng/l), propranolol (ND-40.1 ng/l), ifenprodil (ND-35.4 ng/l), disopyramide (ND) and triclosan (ND). PPCP concentrations were highest in surface water samples collected downstream from a sewage treatment plant (STP), implying possibly insufficient removal efficiency of the PPCPs in the STP. Contamination by PPCPs such as ibuprofen, carbamazepine, atenolol, mefenamic acid and clarithromycin was high in the Mankyung River compared to concentrations in other countries.

Hydrated lime is normally used as SO sorbent in spray dry scrubbers, whereas limestone is considered unreactive under conditions prevailing in such a system. However, limestone is more easily available and several times cheaper than hydrated lime. We tried to use limestone to remove SO from #ue gas in the semidry FGD process with a powder-particle spouted bed. If limestone can be utilized in the process it would be of particular advantage. In the present study, the e!ects of operating parameters on SO removal were investigated, such as Ca/S molar ratio, particle size of SO sorbent, apparent residence time of gas in the bed and approach to saturation temperature. The comparison of reactivity with SO between limestone and hydrated lime was also made based on their structural properties. The experimental results showed that SO removal e$ciency of limestone was considerably enhanced in the present process by increasing Ca/S molar ratio and decreasing the approach to saturation temperature and sorbent size. Thus, the present process with limestone as SO sorbent may be an attractive alternative to other FGD technologies in terms of removal e$ciency, price and availability of sorbent.

Centralized wastewater treatment systems require sophisticated technologies and skilled manpower for their operation and maintenance (O&M). These systems have huge construction as well as O&M costs. Therefore, a Decentralized Wastewater Treatment System (DEWATS) rather than a centralized system might be especially beneficial in developing countries. A model for DEWATS is developed in Nepal with Anaerobic Baffled Reactor (ABR) and hybrid Constructed Wetland (CW). The DEWATS treats high-strength wastewater from 80 households (400 PE). This paper summarizes the performance of the DEWATS from July 2006 to August 2007 in the removal efficiencies of TSS, BOD 5 , COD, NH 4-N, TP and FC. The ABR is very effective in the removal of organic pollutants and could achieve TSS removal up to 91%, BOD 5 up to 78% and COD up to 77%. The average removal efficiencies of the DEWATS is 96% TSS, 90% BOD 5 , 90% COD, 70% NH 4-N, 26% TP and 98% FC.

Eight pharmaceuticals, two polycyclic musk fragrances and nine endocrine disrupting chemicals were analysed in several waste water treatment plants (WWTPs). A membrane bioreactor in pilot scale was operated at different solid retention times (SRTs) and the results obtained are compared to conventional activated sludge plants (CASP) operated at different SRTs. The SRT is an important design parameter and its impact on achievable treatment efficiencies was evaluated. Different behaviours were observed for the different investigated compounds. Some compounds as the antiepileptic drug carbamazepine were not removed in any of the sampled treatment facilities and effluent concentrations in the range of influent concentrations were measured. Other compounds as bisphenol-A, the analgesic ibuprofen or the lipid regulator bezafibrate were nearly completely removed (removal rates 490%). The operation of WWTPs with SRTs suitable for nitrogen removal (SRT410 days at 10 1C) also increases the removal potential regarding selected micropollutants. No differences in treatment efficiencies were detected between the two treatment techniques. As in conventional WWTP also the removal potential of MBRs depends on the SRT. Ultrafiltration membranes do not allow any additional detention of the investigated substances due to size exclusion. However, MBRs achieve a high SRT within a compact reactor. Nonylphenolpolyehtoxylates were removed in higher extend in very lowloaded conventional WWTPs, due to variations of redox conditions, necessary for the degradation of those compounds.

When fish are recovered from ponds, the effluent is often drained, presenting both an environmental challenge and an agricultural opportunity. The effects of irrigation with pond effluent and its interaction with applied fertilizer were assessed in a field experiment using French bean (Phaseolus vulgaris) and kale (Brassica oleracea) over two growing seasons near Sagana, Kenya. Fresh and dry matter yields

Electro-coagulation (EC) is becoming a popular proc ess to be used for industrial wastewater treatment. In the present study, a laboratory scale electro-coagu lation (EC) process was utilized to treat the texti le wastewater in order to bring the quality up to the wastewater reu se standards and also to compare the electro-coagul ation process with the conventional coagulation treatment. Effect of various operating parameters such as operating time and voltage on COD removal efficiency was evaluated to achieve the maximum possible treatment efficiency.

Methyl parathion (MeP) is a very hazardous pesticide freely used in agriculture in Mexico. This pesticide and others, arriving through different processes, exert significant effects on water quality with serious consequences for environmental and human health. This study evaluates the removal efficiency of common cattail Typha latifolia L. on MeP in water and artificial sediments. The effects of the pesticide on this macrophyte after 10 days of exposure were determined using a concentration range of 0-200 mg l À1 , 198.1 ± 1.79 g average biomass, pH 7.0, 18-22°C temperature and natural daylight/darkness periods, using chlorophyll production as a biomarker. Removal kinetics were conducted under similar conditions on days 0, 3, 7, 9, 11 and 14 of exposure, using 6 mg l À1 in each system. Pesticide concentration, chlorophyll content and glutathione S-transferase (GST) activity were quantified. Results show a high removal efficiency of cattails on MeP in water and sediments relative to controls. An increase in GST activity and a decline in chlorophyll content in the test systems were not significantly different relative to controls. Cattails may thus be a good candidate for development of a phytoremediation system for MeP-contaminated water and artificial sediments.

The current theory of electrocoagulation has not been able to explain all the phenomena associated with the process, among others the differences in COD removal efficiency in differing wastewaters. In this paper, we discuss the facts associated with COD removal using EC and develop a mechanism to explain them. A brief description of the technology is done and the concepts related to chemical oxygen demand (COD) are discussed prior to showing the results from a pilot plant relative to COD removal efficiency. Two set of experiments, and a mechanism for COD removal are presented. This mechanism fits both the data and observations. It follows iron Pourbaix diagram and solubility diagrams, while agreeing with the characterization of EC by-products. Finally, the factors affecting COD removal are mentioned.

Productivity in a CHO perfusion culture reactor was maximized when pCO2 was maintained in the range of 30-76 mm Hg. Higher levels of pCO2 (> 105 mm Hg) resulted in CHO cell growth inhibition and dramatic reduction in productivity. We measured the oxygen utilization and CO2 production rates for CHO cells in perfusion culture at 5.55 x 10 -17 mol cell -1 sec -1 and 5.36 x 10 -17 mol cell -1 sec -1 respectively. A simple method to directly measure the mass transfer coefficients for oxygen and carbon dioxide was also developed. For a 500 L bioreactor using pure oxygen sparge at 0.002 VVM from a microporous frit sparger, the overall apparent transfer rates (kLa+kgA) for oxygen and carbon dioxide were 0.07264 min -1 and 0.002962 min -1 respectively. Thus, while a very low flow rate of pure oxygen microbubbles would be adequate to meet oxygen supply requirements for up to 2.1 • 107 ceUs/mL, the low CO2 removal efficiency would limit culture density to only 2.4 • 106 cells/mL. An additional model was developed to predict the effect of bubble size on oxygen and CO2 transfer rates. If pure oxygen is used in both the headspace and sparge, then the sparging rate can be minimized by the use of bubbles in the size range of 2-3 mm. For bubbles in this size range, the ratio of oxygen supply to carbon dioxide removal rates is matched to the ratio of metabolic oxygen utilization and carbon dioxide generation rates. Using this strategy in the 500 L reactor, we predict that dissolved oxygen and CO2 levels can be maintained in the range to support maximum productivity (40% DO, 76 mm Hg pCO2) for a culture at 107 cells/mL, and with a minimum sparge rate of 0.006 vessel volumes per minute. N o m e n c l a t u r e C 0 2 ( 1 ) ffi A B ffi CER = [C02] = [ C 0 2 ] * = [C02]** = volumetric agitated gas-liquid interfacial area at the top of the liquid, 1/m cell broth bleeding rate from the vessel, L/min carbon dioxide evolution rate in the bioreactor, mol/min dissolved CO2 concentration in liquid, M CO2 concentration in equilibrium with sparger gas, M CO2 concentration in equilibrium with headspace gas, M * Author for correspondence. [CT] = [CT]F = O D1 = Db = F = HL = kA = kO _-

The aim of the study was to evaluate the behaviour of mercury in the cement clinker production process. Simultaneous measurements of mercury in all important materials and gas streams were performed in three sampling periods on about 300 solid samples and about 80 samples taken from gas streams. Mercury species in flue gases at characteristic parts of the process were measured as total Hg(t), particulate Hg(p), elemental Hg 0 (g) and reactive Hg 2+ (g) mercury. Based on the results of measurements, mercury mass flows and mass balances of the whole and in certain parts of the process were evaluated. It was shown that the process comprises many mercury cycles which are strongly dependent on the operating conditions and technological specifics. Cycling of mercury causes a significant enrichment of mercury inside the process. In the annual mercury input of about 27 kg, raw materials accounted near by 60% and fuels about 40% (i.e. petrol coke 31%, waste tyres 10% and waste oil 0.4%). The annual emission of mercury represented 40-70% of the inputs, while cement clinker only contained about 10%. The difference between inputs and outputs (11-45%) obtained in the annual mass balance could be assigned to mercury recycling and significant enrichment inside the process, as well as variability between spot measurements. The parts of the process with the highest mercury mass flows and the lowest material/gas flows were identified. Such points represent an opportunity to remove a significant amount of mercury from the process at low material flows and to improve mercury control. Mercury was mainly emitted in gaseous form with 92% (direct mode) or 89% (combined mode) as Hg(g) on average, of which about 2/3 was as Hg 2+ (g), and about 1/3 as Hg 0 (g). Only a small part (the rest) was emitted as particulate Hg(p). Shares of individual mercury species in the last sampling period were 65.7% Hg 2+ (g), 34.0% Hg 0 (g) and 0.3% Hg(p) on average. Ratios between individual mercury forms were found to be related to operating modes. The quantities of Hg(t), Hg(g) and Hg 2+ (g) emitted were higher when operating with the raw mills off (direct mode). It was seen that the efficiency of Hg removal was strongly related to the dust removal efficiency. Bag filters very efficiently removed all mercury species.

This paper aims to be a quick reference guide to start-up decentralized membrane bioreactors (MBRs). The first part of this study focuses on the impact of different operational parameters on the start-up of decentralized MBRs, which can be easily reproduced in the field. Whereas wastewater is not an option to start-up decentralized MBRs, domestic activated sludge has shown to handle the input of wastewater in a better way than the municipal one. Starting-up at low mixed liquor suspended solids (MLSS) concentration is feasible, and a possible optimum concentration (~1 g L − 1 ) has been suggested. In turn, particle size distribution has shown how determined conditions release fine particles in the sub-micron range (0.1-1 μm), impacting negatively the filterability of the initial inoculum and thus the operation. However, in the case of the air scouring rate, even releasing sub-micron particles to the media, high rates demonstrated to extend the operation. Regarding ambient conditions, low temperatures and associated deflocculation processes should be avoided. Chemical oxygen demand and NH 4 + -N removal efficiencies showed values over 87% and 75% respectively whereas suspended solids and removal of pathogens maintained low values (50 mg L − 1 and absence respectively) in the permeate, allowing the reuse of regenerated water since the first day of operation under the different conditions imposed. None of the analyzed parameters (i.e., MLSS, sludge volumetric index and dissolved organic carbon), influenced significantly the filterability of the initial inoculum. Contrarily, the input of wastewater has demonstrated to be the most important factor governing the fouling process of the membrane rather than the changes in the microbiology. As a final consideration, an efficient pretreatment and both low hydraulic retention time and fluxes can help to extend the operation and reach an easy transition between the start-up and the steady-state.

The aim of study is to investigate the effect of current density and stirring speed in the treatment of poultry slaughterhouse wastewater (PSW) using electrocoagulation with aluminum electrodes. In the experiments, initial pH and current density were chosen between 3 and 7, and 0.5 and 2.0 mA/cm 2 respectively. The best removal efficiency has been obtained, when initial pH and current density were adjusted to 3.0 and 1.0 mA/cm 2 , respectively. Increasing current density values decreased COD removal efficiency. The highest removal efficiencies of 85, 85, 81 and 71% were obtained with the current density of 0.5, 1.0, 1.5 and 2.0 mA/cm 2 , respectively. Initial pH values of these removal efficiencies were 4.0, 3.0, 3.0 and 5.0. When experiments were performed to investigate the turbidity removal efficiency, it was found that current density of 1.0 mA/cm 2 provided 98% removal efficiency. Results obtained from the experiments where stirring speed of 100, 150 and 250 rpm were used showed the removal efficiency of 85, 90 and 75% respectively with the current density of 1.0 mA/cm 2 . Results showed that electrocoagulation is a suitable method for treatment of PSW. Electrical conductivity of investigated wastewater was nearly 2860 μS/cm, which caused energy consumption to be relatively lower.

A potential laser etching method has been investigated and implemented in decapsulating wafer level chip size package (WLCSP). A chemically and physically clean surface could be obtained and lead to successful solder reflowing. Firstly, fast and cost-saving transfer molding was suggested to replace underfill dispensing in encapsulation. An industrial-grade KrF excimer laser was utilized to remove the compressed molding compound (epoxy resin and silica fillers) on Au/Cu or Pb-Sn/Cu bumps. An oblique angle of incidence was found effective in achieving a filler-free and chemically clean surface. Explosion forces from epoxy underneath the fillers, together with the transient thermal expansion of whole substrate, were attributed to the higher filler removal efficiency than at normal incidence. In addition, etching rates at angular irradiation were found more balanced between the surrounding areas and the bump. Helium, in comparison with oxygen, helped to reduce polymer molecules left over the bump top. In higher laser fluence or oxygen environment, carbonyl groups with stronger bonds to metal surface (bump) were found on bump top so that success rate of solder reflowing was greatly lowered. A success rate higher than 80% was achieved at an optimal laser fluence and scanning strategy, with inert gas assistance.

The present study was conducted to investigate the chromium(VI), COD and sulphate removal efficiency from aqueous solution and treatment of real effluent (CETP) in a small scale bioreactor using sulphate reducing bacteria consortium. Effect of different hydraulic retention times (HRTs), initial metal concentrations, various carbon sources and temperatures were studied on removal of chromium(VI), COD and sulphate. Maximum chromium(VI) and sulphate removal was found to be 96.0% and 82.0%, respectively, at initial concentration of 50 mg l À1 using lactate as carbon source. However, highest COD removal was 36.2% in medium containing fructose as the carbon source and electron donor. NADH dependent chromate reductase activity was not observed which indicated the anaerobic consortium. Initially consortium medium with a strong negative oxidation reduction potential indicated the reducing activity. The FTIR spectrum of the sulphate reducing bacteria consortium clearly shows the existence of the sulphate ions and signifies that sulfate reducing bacteria have used sulfate during the growth phase.

Nutrient removal is essential for aquaculture wastewater treatment to protect receiving waters from eutrophication and for potential reuse of the treated water. A pilot-scale wastewater treatment system consisting of a free water surface (FWS) and a subsurface flow (SSF) constructed wetlands arranged in series was operated for around 8 months. The study was conducted to examine system start-up phenomena and to evaluate system performance in removing inorganic nitrogen and phosphate from aquaculture wastewater under various hydraulic loading rates (1.8 to 13.5 cm day À1 ). The wetlands system showed rapid start-up behaviors in which process stabilities were achieved in the following sequence: phosphate removal in the SSF without an adaptation period, nitrogen removal in the SSF after 1 month, nitrogen removal in the FWS after 2 to 3 months, phosphate removal in the FWS after 3 months, and vegetation cover in both wetlands after 7 months of operation. Nitrogen removals were excellent, with efficiencies of 86% to 98% for ammonium nitrogen (NH 4 -N) and 95% to 98% for total inorganic nitrogen (TIN). Removal efficiencies were affected little by the hydraulic loading trials. Phosphate removal of 32% to 71% occurred, with the efficiencies being inversely related to hydraulic loading. The FWS wetland removed most inorganic nitrogen, whereas the SSF wetland removed phosphate at a rate equal to or even greater than the FWS. Removal of ammonium and nitrite (effluent concentrations < 0.3 mg NH 4 -N l À1 and 0.01 mg NO 2 -N l À1 ) were sufficient for recycle in the aquaculture system without danger of harming the fish. D

In order to investigate the effect of temperature, hydraulic residence time (HRT), vegetation type and porous media material and grain size on the performance of horizontal subsurface flow (HSF) constructed wetlands treating wastewater, five pilot-scale units of dimensions 3 m in length and 0.75 m in width were operated continuously from January 2004 until January 2006 in parallel experiments. Three units contained medium gravel obtained from a quarry. The other two contained one fine gravel and one cobbles, both obtained from a river bed. The three units with medium gravel were planted one with common reeds and one with cattails, and one was kept unplanted. The other two units were planted with common reeds. Planting and porous media combinations were appropriate for comparison of the effect of vegetation and media type on the function of the system. Synthetic wastewater was introduced in the units. During the operation period, four HRTs (i.e., 6, 8, 14 and 20 days) were used, while wastewater temperatures varied from about 2.0 to 26.0 • C. The removal performance of the constructed wetland units was very good, since it reached on an average 89, 65 and 60% for BOD, TKN and ortho-phosphate (P-PO 4 3−), respectively. All pollutant removal efficiencies showed dependence on temperature. It seems that the 8-day HRT was adequate for acceptable removal of organic matter, TKN and P-PO 4 3− for temperatures above 15 • C. Furthermore, based on statistical testing, cattails, finer media and media obtained from a river showed higher removal efficiencies of TKN and P-PO 4 3− .

This paper aims to study fundamentally the impacts of membrane properties on the reactive dye removal from dye/salt mixtures by nanofiltration membranes. To begin with, two types of nanofiltration membranes of similar pore size, namely asymmetric cellulose acetate membrane and thin-film composite polyamide membrane were fabricated, and their key physical, chemical and performance properties were characterized. After that, these resultant membranes were employed to perform dye removal experiments with aqueous solutions of reactive black 5 and NaCl under different operational parameters. The dye removal rate and steady permeate flux were determined and correlated with the measured membrane properties. It was found that there were significant differences between the dye removal performances of the two membranes, and that the membrane properties played an important role in dye removal rate, stable permeate flux and their change behaviors under operational conditions. Surface charge was the most influential property for dye removal efficiency at low dye and salt concentration, while surface roughness was the most influential membrane property at high dye concentration or salt concentration. Additionally, the most influential membrane property which determines the change behavior of dye removal efficiency with pressure and cross-flow velocity was pure water permeability and surface roughness, respectively.

Water soluble chitosan, dissolved in hot deionized water to obtain 0.8% solution, was used for the coagulation-flocculation of skim natural rubber latex. The efficiency of coagulation-flocculation of skim rubber latex without pH adjustment was much poorer than that of neutral skim rubber latex. When adding chitosan solution to the neutral skim rubber latex with a rubber content of 5.300 %wt/vol until the concentration of chitosan in the dispersion was 0.107%, the phase separation between rubber particles and yellow serum was clearly observed. At this condition, the removal efficiency of skim rubber particles was found to be the best among all trials. It was also found that dilution of skim rubber latex with deionized water did not increase the removal efficiency. Key word : chitosan; skim rubber latex; coagulation; flocculation

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A continuous injection experiment was implemented in a pilot-scale horizontal subsurface flow constructed wetland system to evaluate the behavior of four pharmaceuticals and personal care products (i.e. ibuprofen, naproxen, diclofenac and tonalide) and a phenolic estrogenic compound (i.e. bisphenol A). The treatment system consisted of an anaerobic reactor as a primary treatment, followed by two 0.65 m 2 wetlands (B1 and B2) working in parallel and connected to a 1.65 m 2 wetland (B3) operating in series. Overall removal efficiencies for the selected compounds ranged from 97% to 99%. The response curves of the injected pollutants show that the behavior of these compounds strongly depends on their sorption and biodegradation characteristics. While about 50% of ibuprofen was removed in B1 and B2, 99% was achieved at B3, where the dissolved oxygen concentration was significantly higher (B1-B2 = 0.5 mg L À1 and B3 = 5.4 mg L À1). Naproxen and diclofenac were efficiently removed (93%) in B1 and B2, revealing anaerobic degradation as a probable removal mechanism. Moreover, tonalide and bisphenol A were readily removed in the small wetlands (94% and 83%, respectively), where the removal of total suspended solids was 93%. Therefore, given their high hydrophobicity, sorption onto the particulate matter stands for the major removal mechanism. However, the tentative identification of carboxybisphenol A as an intermediate degradation product in B3 suggested biodegradation as a relevant bisphenol A removal pathway under aerobic prevailing conditions.

Low cost bentonite clay was chemically modified using magnesium chloride in order to enhance its fluoride removal capacity. The magnesium incorporated bentonite (MB) was characterized by using XRD and SEM techniques. Batch adsorption experiments were conducted to study and optimize various operational parameters such as adsorbent dose, contact time, pH, effect of co-ions and initial fluoride concentration. It was observed that the MB works effectively over wide range of pH and showed a maximum fluoride removal capacity of 2.26 mg g −1 at an initial fluoride concentration of 5 mg L −1 , which is much better than the unmodified bentonite. The experimental data fitted well into Langmuir adsorption isotherm and follows pseudo-first-order kinetics. Thermodynamic study suggests that fluoride adsorption on MB is reasonably spontaneous and an endothermic process. MB showed significantly high fluoride removal in synthetic water as compared to field water. Desorption study of MB suggest that almost all the loaded fluoride was desorbed (∼97%) using 1 M NaOH solution however maximum fluoride removal decreases from 95.47 to 73 (%) after regeneration. From the experimental results, it may be inferred that chemical modification enhances the fluoride removal efficiency of bentonite and it works as an effective adsorbent for defluoridation of water.

We demonstrate the ability of non-thermal plasma to promote blood coagulation and tissue sterilization in under 15 seconds of treatment. We demonstrate no gross (visible) or microscopic damage to tissue in as much as 5 minutes of plasma treatment. This procedure would be safe for patients since there are no exposed electrodes, discharge is cold, and current is low. Initial experimental results obtained using cadaver organs and donor blood support the fact that the DBD plasma can simultaneously sterilize skin and promote coagulation in bleeding tissue. This technique will decrease wound healing time and virtually eliminate wound infections with skin flora.

An installation containing a DC negative corona discharge reactor, a pulse corona discharge reactor and a combined electron beam and microwave induced plasma reactor is presented. SO 2 is removed up to 42% through spontaneous reaction with ammonia without electron beam or microwave irradiation at the temperature below 70 1C. For the same removal efficiency of 98% for SO 2 and 80% for NO x at separate EB irradiation of 40 kGy, the required absorbed dose is about two times smaller for simultaneous electron beam and microwave irradiation. The SO 2 removal efficiency of simultaneous DC or positive discharge and microwave discharge is higher than separate DC, pulse and MW discharge. Also, the applied voltage level at which the removal efficiency reaches the maximum value is less than for the separate application of DC or pulse discharge. The NO x removal efficiency of DC or pulse discharge suffers little change by additional use of the microwave energy.

In order to ensure a stable and reliable operation of municipal MBR plants, an enhanced mechanical pretreatment of the raw wastewater is essential. Removal of hair, fibrous material and other contraries which can lead to operational problems at the membrane modules is of particular importance. As the number of full scale applications is continuously increasing, now appropriate investigations can be carried out to determine the removal efficiency of different units (screens, sieves) or different combination of units (multi staged system). First results of such investigations on two German MBR plants were already presented [F.-B.

Spent liquor from washing of aluminum section materials after etching with caustic soda (NaOH) has been treated. Aluminum was removed from the liquor and caustic soda was regenerated by: (a) adding precipitating agents to hydrolyze sodium aluminate (Na 2 AlO 2), (b) separating the aluminum precipitate, and (c) concentrating free NaOH in the resulting solution which is reused in the etching process. Four systems were investigated: hydrated lime {Ca(OH) 2 }, hydrogen peroxide (H 2 O 2), H 2 O 2 /Ca(OH) 2 mixture, and dry lime (CaO). Different parameters, such as additives concentration, time and temperature were investigated. Results obtained revealed that CaO was more efficient in the removal of aluminum from the spent liquor with higher hydrolyzing rate of Na 2 AlO 2 than Ca(OH) 2 , H 2 O 2 , or their mixture. The removal efficiency value of aluminum was 96.1% with 100 g/L of CaO at 60 • C after 30 min treatment, while the efficiency values were 83.2 and 90.1% with Ca(OH) 2 and H 2 O 2 , respectively after 2 h treatment. The presence of Ca(OH) 2 in the H 2 O 2 /Ca(OH) 2 mixture has no great effect on the Al removing efficiency comparing to that using H 2 O 2 alone, however, it greatly facilitated the separation of the Al precipitate from the solution as calcium aluminate hydrate. Caustic soda concentration of 102 g/L, which is applicable for reusing as etching solution, was obtained by heating the solution for 1 h at 95 • C.

Alexandria Sanitary Drainage Company (ASDCO), Alexandria, Egypt has two primary treatment plants, the eastern and the western wastewater treatment plants (EWTP and WWTP) that receive mixed domesticindustrial influents and discharge into L. Mariut. The lake is subjected therefore to severe levels of pollution and dominated by members of cyanobacteria that can cope with the high pollution load in the lake water. Isolation and utilization of the locally generated cyanobacterial biomass for remediation processes of highly toxic pollutants offers a very efficient and cheap tool for governmental or private industrial activities in Alexandria and will generate a source of revenue in Egyptian localities. The main objective of the present study was to investigate the biodegradation and biosorption capacity of some potential cyanobacterial species dominating the lake ecosystem toward organic and inorganic contaminants polluting the primary-treated effluents of the EWTP and WWTP. The primary effluents were subjected to biological treatment using three axenic cyanobacterial strains (Anabaena oryzae, Anabaena variabilis and Tolypothrix ceytonica) as batch system for 7 days. Removal efficiencies (RE) of the different contaminants were evaluated and compared. Results confirmed the high efficiencies of the investigated species for the removal of the target contaminants which were species and contaminant-dependent. BOD 5 and COD recorded 89.29 and 73.68% as maximum RE(s) achieved by Anabaena variabilis and Anabaena oryzae, respectively. The highest RE of the TSS recorded 64.37% achieved by Tolypothrix ceytonica, while 38.84% was recorded as the highest TSD RE achieved by Anabaena variabilis. Tolypothrix ceytonica also exhibited the highest RE for FOG recorded 93.75%. Concerning the contaminant metals, Tolypothrix ceytonica showed the highest biosorption capacity where 86.12 and 94.63% RE were achieved for Zn and Cu, respectively. In conclusion, results of the present study confirmed the advantageous potential of using the tested cyanobacterial species for the treatment of contaminated wastewater. Results also clearly showed the quality improvement of the discharged wastewater which in turn will eliminate or at least minimize the expected deterioration of the receiving environment.

Five fluidized bed incinerators combusting municipal solid waste were assessed for the impact of coplanar PCBs on total TEQ emission. In 17 stack measurements, the coplanar PCBs contributed on average less than 3% to total TEQ with a maximum contribution of 7.5% to total TEQ in one measurement. Differences in the design of the flue gas cooling section did not show an effect on the impact of coplanar PCBs on total TEQ. The effect of emission control devices on the impact of coplanar PCBs on the total TEQ was studied in more detail at one incinerator. The relative contribution of PCBs to total TEQ increased along the flue gas line. This was caused by a slightly higher removal efficiency for TEQ relevant PCDDs/PCDFs compared to coplanar PCBs by the bag filters and a higher destruction efficiency for PCDDs/PCDFs compared to PCBs by the SCR catalyst. Additionally, the removal efficiencies of the emission control devices (bag filters and catalyst) for other chlorinated aromatic compounds which have been proposed as TEQ indicator compounds (polychlorinated benzenes and polychlorinated phenols) were compared with those for PCDDs/PCDFs and coplanar PCBs. Removal efficiencies for polychlorinated benzenes or polychlorinated phenols considerably differed from those of PCDD/PCDF and coplanar PCBs. Implications for TEQ assessments using indicator compounds as proposed in the literature are discussed.

Abstract}This study was conducted to investigate the performance of the upflow anaerobic sludge blanket (UASB) reactor treating leachate from acidogenic fermenter in the two-phase anaerobic digestion of food waste. The chemical oxygen demand (COD) removal efficiency was consistently over 96% up to the loading rates of 15.8 g COD/l d. The methane production rate increased to 5.5 l/l d. Of all the COD removed, 92% was converted to methane and the remaining presumably to biomass. At loading rates over 18.7 g COD/l d, the COD removal efficiency decreased due to sludge flotation and washout in the reactor, which resulted from short HRT of less than 10.6 h. The residual propionate concentration was the highest among the volatile fatty acids (VFA) in the effluent. The specific methanogenic activity (SMA) analysis showed that the VFA-degrading activity of granule was the highest for butyrate, and the lowest for propionate. Typical granules were found to be mainly composed of microcolonies of Methanosaeta. The size distribution of sludge particles indicated that partially granulated sludge could maintain the original structure of granular sludge and continue to gain size in the UASB reactor treating leachate from acidogenic fermenter. #

Two pilot-scale trickling filters were constructed and tested for manganese removal from potable water, using different fractions of silicic gravel as support media (mono-and multilayer filter). Manganese oxidation in drinking water was found to be cause by both biological oxidation and heterogeneous catalytic paths. Mixed culture populations were used to inoculate the trickling filters and the feed manganese concentrations and volumetric flow rates (VFRs) were between 0.6-2.0 mg/l and 500-2000 ml/min, respectively. The monolayer filter was flooded for high VFRs, and it was very effective for all conditions tested (100% removal efficiency, up to 2850 mg Mn/day). The multilayer filter was less effective for high manganese concentrations but it could remove up to 3250 mg Mn/day. A new mathematical model was developed assuming heterogeneous autocatalytic and biological as the main oxidation manganese paths. First order kinetics was used to describe the heterogeneous catalytic oxidation, while Monod-type kinetics was used to describe the net biological manganese oxidation. The simplicity of the pilot-scale design, the lack of need for an external mechanical aeration source and the ability to predict operation of the system offers a very attractive solution for manganese removal from potable water.

Reverse osmosis (RO) reject recovery from the water reclamation process was demonstrated feasible using an integrated pretreatment scheme followed by the Capacitive Deionization (CDI) process. The RO reject had an average total dissolved solids (TDS) of 1276 AE 166 mg/L. Water recovery of 85% with water quality comparable with the RO feed was achieved. Pretreatments using biological activated carbon (BAC) and BAC-ultrafiltration (UF) attained total organic carbon (TOC) removal efficiencies of 23.5 AE 6.0% and 39.9 AE 9.0%, respectively. Organics removal of RO reject was attributed to simultaneous adsorption and biodegradation in the BAC pretreatment, while further biodegradation in the submerged UF membrane tank provided additional organics removal. Membrane and CDI fouling was reduced by pH adjustment of the pretreated RO reject to approximately 6.5, which prolonged the CDI operation time by at least two times. The CDI process was able to achieve more than 88 and 87% TDS and ion removals, respectively, while PO 4 3À and TOC removals were at 52-81% and 50-63%, respectively.

An azo dye, acid orange 7 (AO7), was selected to study the role of Phragmites australis (P. australis) peroxidases (POD) activity in its degradation in a vertical flow constructed wetland (VFCW). Crude plant extract was found to degrade AO7 and its aromatic amines, after 120 h in contact with H 2 O 2 , and removals of 3.2-5.7 mg AO7 g −1 P. australis were obtained for 40 mg AO7 l −1 (8 mg AO7 g −1 P. australis ). The VFCW was found to be suitable to treat an effluent containing an azo dye. For influent concentrations of 130 mg AO7 l −1 POD activity increased 2.1-, 4.3-and 12.9-fold for leaves, stems and roots, respectively. At 700 mg AO7 l −1 , inhibition of POD activity occurred immediately, but it returned to the previous levels after only 2 days. An AO7 organic load of 21 up to 105 g COD m 2 day −1 , revealed non-toxicity, being expectable to achieve removals of 11 up to 67 g COD m 2 day −1 . Both [AO7] and TOC removal efficiencies were found to be similar (approximately 70%), which is indicative of AO7 mineralization. A 3 h cycle was found to be sufficient to degrade AO7 and a system buffering capacity from 5 to 25 min cycle −1 was demonstrated by flooding level control.

Ponds Hybrid natural systems PPCP Enantiomeric ratio a b s t r a c t This study assessed the ability to remove pharmaceuticals and personal care products (PPCPs) of three different full-scale hybrid pond-constructed wetlands and a conventional wastewater treatment plant (WWTP). The four systems were fed with primary-treated urban wastewaters. The three hybrid systems consisted of several different subsystems (ponds, surface flow constructed wetlands and horizontal subsurface flow constructed wetlands) connected in series, and their PPCP degradation efficiency was monitored. In addition, the enantiomeric behaviour of ibuprofen was studied in all the subsystems. The hybrid systems were at least as efficient in PPCP removal as the WWTP, removal efficiencies mainly exceeding 70%. Moreover, enantiomeric analysis indicates that ibuprofen removal followed a predominantly aerobic and microbiological pathway. Constructed wetlands and ponds are therefore successful technologies for removing PPCPs from wastewater and the most significant removal process in these systems is biologically mediated. .es (V. Matamoros), jmarv@unileon.es (J. Martín-Villacorta), ebecm@unileon.es (E. Bé cares), jbtqam@cid.csic.es (J.M. Bayona).

Microbial monitoring was conducted over a period of more than 1 year at three full-scale riverbank filtration (RBF) facilities, located in the United States along the Ohio, Missouri, and Wabash Rivers. Results of this study demonstrated the potential for RBF to provide substantial reductions in microorganism concentrations relative to the raw water sources. Cryptosporidium and Giardia were detected occasionally in the river waters but never in any of the well waters. Average concentrations and log reductions of Cryptosporidium and Giardia could not be accurately determined due to the low and variable concentrations in the river waters and the lack of detectible concentrations in the well waters. Average concentrations of aerobic and anaerobic spore-forming bacteria, which have both been proposed as potential surrogates for the protozoans, were reduced at the three facilities by 0.8 to 43.1 logs and 0.4 to 44.9 logs, respectively. Average concentrations of male-specific and somatic bacteriophage were reduced by 42.1 logs and X3.2 logs, respectively. Total coliforms were rarely detected in the well waters, with 5.5 and 6.1 log reductions in average concentrations at the two wells at one of the sites relative to the river water. Average turbidity reductions upon RBF at the three sites were between 2.2 and 3.3 logs. Turbidity and microbial concentrations in the river waters generally tracked the river discharge; a similar relationship between the well water concentrations and river discharge was not observed, due to the low, relatively constant well water turbidities and lack of a significant number of detections of microorganisms in the well waters. Further research is needed to better understand the relationships among transport of pathogens (e.g., Cryptosporidium, Giardia, viruses) and potential surrogate parameters (including bacterial spores and bacteriophage) during RBF and the effects of water and sediment characteristics on removal efficiency.

The recently imposed maximum contaminant level (MCL) of 10 mg/L for arsenic has necessitated many water providers to implement efficient treatment systems to reduce the arsenic content in potable water supplies across the United States. A popular, cost-effective solution is to adsorb the arsenic onto hydrous iron oxide-based granular media. Hybrid media, consisting of hydrous iron oxides impregnated into a polymeric substrate in order to improve mechanical stability, have also been developed. The effective operational bed life of these adsorptive media is strongly dependent on the chemistry of the water being treated. High levels of silica combined with pH values greater than 8 have been shown to have a detrimental effect on the arsenic removal efficiency of all adsorptive media. Batch arsenate (arsenic(V)) adsorption experiments were performed to evaluate the effect of pH and silica on the static arsenic capacity of two iron oxide-based hybrid media, ArsenX np (a commercially available media) and npRio (a developmental media). From the data obtained, it was evident that the presence of increased levels of silica enhanced the detrimental effect of elevated pH on arsenic capacity, being most noticeable at pH 8 and above. In a solution containing 30 ppm of SiO 2 , a decrease in arsenic capacity as high as 71.8% was observed when the pH was increased from 7 to 9. Reducing the pH of the water prior to treatment may therefore be an economic option for improving media performance in drinking waters containing high concentrations of silica.