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Sludge
Kinds of Sludge Terms modified by Sludge Selected AbstractsBonding Form Analysis of Metals and Sulfur Fractionation in Methanol-Grown Anaerobic Granular SludgeENGINEERING IN LIFE SCIENCES (ELECTRONIC), Issue 5 2007A. van der Veen Abstract This study investigates the metal and sulfur bonding form distribution in mesophilic (30,°C, pH 7) methanol-grown anaerobic granular sludge from upflow anaerobic sludge bed reactors operating at an organic loading rate of 3.8,g CH3OH-COD/L d. This was achieved by applying a modified Tessier sequential extraction scheme to investigate the metal bonding forms and a sequential extraction scheme for sulfur and simultaneously extracted metals to granular sludge samples of the reactors after 0, 22, 35 and 43 days of operation. Metals were also determined in the sulfur extracts. Co and Ni predominated in their oxidizable bonding forms, which increased together with the pseudo-total content during reactor operation. An omission of Co and Ni from the influent led to only a minor decline of the pseudo-total content in the sludge, mainly from the acid-soluble fraction. The ratio of simultaneously extracted metals (Co, Fe, Mn, Ni) to acid-volatile sulfides was lower than 1, indicating that the sludge contained sufficient sulfide to bind the metals as metal monosulfides. The bioavailability of metals in the methanol-grown anaerobic granular sludge investigated is therefore mainly controlled by sulfide formation/dissolution. [source] Comparison of Suppressiveness of Vermicomposts Produced from Animal Manures and Sewage Sludge against Phytophthora nicotianae Breda de Haan var. nicotianaeJOURNAL OF PHYTOPATHOLOGY, Issue 2 2001M. Szczech The degrees of suppression produced by vermicomposts produced from cattle manure, sheep manure or horse manure and by vermicomposts produced from sewage sludge were compared in greenhouse experiments. The effect of these vermicomposts on the growth and infection of tomato seedlings by Phytophthora nicotianae var. nicotianae was studied. The density of the pathogen and the number of micro-organisms in container media amended with vermicomposts were also analysed. The vermicomposts produced from animal manure significantly reduced the infection of tomato seedlings by the pathogen. The density of P. nicotianae in media which included these vermicomposts was similar to that in infested peat substrate (control treatment). The vermicomposts from sewage sludge did not protect tomato seedlings against P. nicotianae. They also significantly inhibited growth of the plants as well as decreasing the density of the pathogen in container media. In general the vermicomposts had no effect on total number of micro-organisms in potting media compared with control. They only had higher levels of actinomycetes but this did not appear to correspond with their ability to suppress the pathogen. Ein Vergleich der Suppressivität von Vermikomposten aus tierischem Mist bzw. Klärschlamm gegenüber Phytophthora nicotianae Breda de Haan var. nicotianae In Gewächshausversuchen wurde die Suppressivität von Vermikomposten, die aus Rinder-, Schaf- bzw. Pferdemist hergestellt worden waren, mit solchen, die aus Klärschlamm gewonnen wurden, verglichen. Der Einfluss dieser Komposttypen auf die Infektion von Tomatensämlingen mit Phytophthora nicotianae var. nicotianae wurde untersucht. Außerdem wurden sowohl die Inokulumdichte als auch eine Gesamtkeimzahl der mit den Komposten versetzten Topferden ermittelt. Die aus tierischem Mist hergestellten Vermikomposte reduzierten die Infektion der Tomatensämlinge mit dem Pathogen signifikant. Die P. nicotianae -Dichte in Topferden versetzt mit diesen Vermikomposten war vergleichbar mit inokuliertem Torfsubstrat (die Kontrolle). Die Vermikomposte aus Klärschlamm lieferten den Tomatensämlingen keinen Schutz gegen P. nicotianae. Außerdem verursachten sie eine signifikante Wachstumshemmung der Pflanzen und reduzierten zusätzlich die P. nicotianae -Dichte im Topfsubstrat. Im allgemein wurde die Gesamtzahl an Mikroorganismen in den Topfsubstraten durch die Vermikomposte nicht beeinflusst. Die Actinomyceten-Populationen nahmen zu, eine Beobachtung, die jedoch keine Korrelation zu deren Pathogensuppressivität hatte. [source] Biological Treatment of Sludge from a Recirculating Aquaculture System Using a Sequencing Batch ReactorJOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 4 2005Ramaraj Boopathy [source] Effect of settled sludge on dissolved ammonia concentration in tanks used to grow abalone (Haliotis midae L.) fed a formulated dietAQUACULTURE RESEARCH, Issue 2 2009Rowan D Yearsley Abstract The relative contribution that solid waste or ,sludge', which accumulates at the bottom of abalone (Haliotis midae L.) tanks, makes to dissolved ammonia has not been established. Sludge was allowed to accumulate in 10 fully stocked abalone tanks, fed a formulated feed (Abfeed®; Marifeed, South Africa), for 24 days. Sludge was subsequently siphoned from five of these tanks. Total ammonia nitrogen (TAN) production and toxic, free ammonia nitrogen (FAN) were recorded in the tanks from which sludge was removed and compared with those from which sludge was not removed over the subsequent 50 h. Tanks with neither abalone nor sludge present were used as a control. The mean production of TAN (±standard deviation) was an average of 44% higher in tanks from which sludge was not removed compared with those from which it was, indicating that the sludge was a significant contributor to dissolved ammonia in the tanks. The toxic FAN concentrations were correspondingly higher in tanks with sludge present (2.3±0.3 ,L,1) compared with cleaned tanks (1.9±0.1 ,L,1). Our results indicate that regular removal of sludge from abalone tanks should significantly reduce the dissolved ammonia levels, thereby improving water quality in the culture environment. [source] Modeling And Robust Pi Control Of A Fluidized Bed Combustor For Sewage SludgeASIAN JOURNAL OF CONTROL, Issue 4 2002Yingmin Jia ABSTRACT Based on experimental data, a fluidized bed combustor is modeled as an interval system. Severe model uncertainty and large time delays lead to the main difficulties in solving the control problem. The design uses the stability test of closed-loop systems as the main guideline for developing a robust PI controller. In particular, a new formula to compute the maximal magnitude of an edge rational function at a fixed frequency is derived, which provides a way to deal with time delay by transforming it into multiplicative uncertainty. Both the theoretical and the experimental results show that the designed PI controller can satisfy the desired performance requirements. [source] Microbial Hydrogen Production with Immobilized Sewage SludgeBIOTECHNOLOGY PROGRESS, Issue 5 2002Shu-Yii Wu Municipal sewage sludge was immobilized to produce hydrogen gas under anaerobic conditions. Cell immobilization was essentially achieved by gel entrapment approaches, which were physically or chemically modified by addition of activated carbon (AC), polyurethane (PU), and acrylic latex plus silicone (ALSC). The performance of hydrogen fermentation with a variety of immobilized-cell systems was assessed to identify the optimal type of immobilized cells for practical uses. With sucrose as the limiting carbon source, hydrogen production was more efficient with the immobilized-cell system than with the suspended-cell system, and in both cases the predominant soluble metabolites were butyric acid and acetic acid. Addition of activated carbon into alginate gel (denoted as CA/AC cells) enhanced the hydrogen production rate ( vH2) and substrate-based yield ( YH2/sucrose) by 70% and 52%, respectively, over the conventional alginate-immobilized cells. Further supplementation of polyurethane or acrylic latex/silicone increased the mechanical strength and operation stability of the immobilized cells but caused a decrease in the hydrogen production rate. Kinetic studies show that the dependence of specific hydrogen production rates on the concentration of limiting substrate (sucrose) can be described by Michaelis-Menten model with good agreement. The kinetic analysis suggests that CA/AC cells may contain higher concentration of active biocatalysts for hydrogen production, while PU and ALSC cells had better affinity to the substrate. Acclimation of the immobilized cells led to a remarkable enhancement in vH2 with a 25-fold increase for CA/AC and ca. 10- to 15-fold increases for PU and ALSC cells. However, the ALSC cells were found to have better durability than PU and CA/AC cells as they allowed stable hydrogen production for over 24 repeated runs. [source] Bonding Form Analysis of Metals and Sulfur Fractionation in Methanol-Grown Anaerobic Granular SludgeENGINEERING IN LIFE SCIENCES (ELECTRONIC), Issue 5 2007A. van der Veen Abstract This study investigates the metal and sulfur bonding form distribution in mesophilic (30,°C, pH 7) methanol-grown anaerobic granular sludge from upflow anaerobic sludge bed reactors operating at an organic loading rate of 3.8,g CH3OH-COD/L d. This was achieved by applying a modified Tessier sequential extraction scheme to investigate the metal bonding forms and a sequential extraction scheme for sulfur and simultaneously extracted metals to granular sludge samples of the reactors after 0, 22, 35 and 43 days of operation. Metals were also determined in the sulfur extracts. Co and Ni predominated in their oxidizable bonding forms, which increased together with the pseudo-total content during reactor operation. An omission of Co and Ni from the influent led to only a minor decline of the pseudo-total content in the sludge, mainly from the acid-soluble fraction. The ratio of simultaneously extracted metals (Co, Fe, Mn, Ni) to acid-volatile sulfides was lower than 1, indicating that the sludge contained sufficient sulfide to bind the metals as metal monosulfides. The bioavailability of metals in the methanol-grown anaerobic granular sludge investigated is therefore mainly controlled by sulfide formation/dissolution. [source] Acclimation Strategy of a Biohydrogen Producing Population in a Continuous-Flow Reactor with Carbohydrate FermentationENGINEERING IN LIFE SCIENCES (ELECTRONIC), Issue 4 2006Q. Ren Abstract Poor startup of biological hydrogen production systems can cause an ineffective hydrogen production rate and poor biomass growth at a high hydraulic retention time (HRT), or cause a prolonged period of acclimation. In this paper a new startup strategy was developed in order to improve the enrichment of the hydrogen-producing population and the efficiency of hydrogen production. A continuously-stirred tank reactor (CSTR) and molasses were used to evaluate the hydrogen productivity of the sewage sludge microflora at a temperature of 35,°C. The experimental results indicated that the feed to microorganism ratio (F/M ratio) was a key parameter for the enrichment of hydrogen producing sludge in a continuous-flow reactor. When the initial biomass was inoculated with 6.24,g of volatile suspended solids (VSS)/L, an HRT of 6,h, an initial organic loading rate (OLR) of 7.0,kg chemical oxygen demand (COD)/(m3,×,d) and an feed to microorganism ratio (F/M) ratio of about 2,3,g COD/(g of volatile suspended solids (VSS) per day) were maintained during startup. Under these conditions, a hydrogen producing population at an equilibrium state could be established within 30,days. The main liquid fermentation products were acetate and ethanol. Biogas was composed of H2 and CO2. The hydrogen content in the biogas amounted to 47.5,%. The average hydrogen yield was 2.01,mol/mol hexose consumed. It was also observed that a special hydrogen producing population was formed when this startup strategy was used. It is supposed that the population may have had some special metabolic pathways to produce hydrogen along with ethanol as the main fermentation products. [source] Trace Metals in Anaerobic Granular Sludge Reactors: Bioavailability and Dosing StrategiesENGINEERING IN LIFE SCIENCES (ELECTRONIC), Issue 3 2006H. Zandvoort Abstract The trace metal dynamics in anaerobic granular sludge bed reactors and their influence on reactor performance is reviewed in this paper. An insight into the metal dynamics is required from a practical point of view in order to be able to early recognize limitations for essential trace elements, viz., to know when dosing of these elements is required in full-scale anaerobic bioreactor applications. Further such knowledge is indispensable for a rational dosage of these metals, e.g., to ensure maximum substrate conversion rates and to prevent disturbances in reactor performance using a minimum amount of metals. Therefore, the retention, accumulation and release of trace metals in anaerobic granular sludge and the factors affecting these processes need to be known. [source] Detection of denitrification genes by in situ rolling circle amplification-fluorescence in situ hybridization to link metabolic potential with identity inside bacterial cellsENVIRONMENTAL MICROBIOLOGY, Issue 9 2010Tatsuhiko Hoshino Summary A target-primed in situ rolling circle amplification (in situ RCA) protocol was developed for detection of single-copy genes inside bacterial cells and optimized with Pseudomonas stutzeri, targeting nitrite and nitrous oxide reductase genes (nirS and nosZ). Two padlock probes were designed per gene to target both DNA strands; the target DNA was cut by a restriction endonuclease close to the probe binding sites, which subsequently were made accessible by 5,-3, exonucleolysis. After hybridization, the padlock probe was circularized by ligation and served as template for in situ RCA, primed by the probe target site. Finally, the RCA product inside the cells was detected by standard fluorescence in situ hybridization (FISH). The optimized protocol showed high specificity and signal-to-noise ratio but low detection frequency (up to 15% for single-copy genes and up to 43% for the multi-copy 16S rRNA gene). Nevertheless, multiple genes (nirS and nosZ; nirS and the 16S rRNA gene) could be detected simultaneously in P. stutzeri. Environmental application of in situ RCA-FISH was demonstrated on activated sludge by the differential detection of two types of nirS -defined denitrifiers; one of them was identified as Candidatus Accumulibacter phosphatis by combining in situ RCA-FISH with 16S rRNA-targeted FISH. While not suitable for quantification because of its low detection frequency, in situ RCA-FISH will allow to link metabolic potential with 16S rRNA (gene)-based identification of single microbial cells. [source] Stable augmentation of activated sludge with foreign catabolic genes harboured by an indigenous dominant bacteriumENVIRONMENTAL MICROBIOLOGY, Issue 10 2002Kazuya Watanabe Summary Comamonas sp. rN7 is a phenol-degrading bacterium that represents the dominant catabolic population in activated sludge. The present study examined the utility of this bacterium for establishing foreign catabolic genes in phenol-digesting activated sludge. The phc genes coding for phenol hydroxylase and its transcriptional regulators of C. testosteroni R5 were integrated into the chromosome of strain rN7. The specific phenol-oxygenating activity of a resultant transformant designated rN7(R503) was three times higher than the activity of strain rN7, and the phc genes were stably inherited by rN7(R503) grown in a non-selective laboratory medium. Inoculation of phenol-acclimatized activated sludge with rN7(R503) resulted in a high phenol-oxygenating activity and improved resistance to phenol-shock loading compared to sludge inoculated with either no cells, rN7 or R5. Quantitative competitive polymerase chain reaction (PCR) showed that the phc genes were retained in the rN7(R503)-inoculated sludge at a density of more than 108 copies per ml of mixed liquor for more than 35 days, whereas those in the R5-inoculated sludge disappeared rapidly. No transfer of the phc genes to other indigenous populations was apparent in the rN7(R503)-harbouring sludge. From these results, we concluded that the phenol treatment of the activated sludge was enhanced by the phc genes harboured by the rN7(R503) population. This study suggests a possible bioaugmentation strategy for stably utilizing foreign catabolic genes in natural ecosystems. [source] Design and application of oligonucleotide probes for fluorescent in situ identification of the filamentous bacterial morphotype Nostocoida limicola in activated sludgeENVIRONMENTAL MICROBIOLOGY, Issue 9 2001Jian Rong Liu 16S rRNA targeted probes, designed using sequence data from pure cultures of the three morphotypes of the filamentous bulking bacteria Nostocoida limicola I, II and III and their successful application to the in situ identification of these bacteria in activated sludge biomass samples are described here. Two probes were required to detect all the sequenced N. limicola II isolates. Results from fluorescent in situ hybridization suggest that the morphotypes N. limicola I and II contain at least two phylogenetically unrelated bacteria. The N. limicola II filaments that did not respond to the probes designed in this study fluoresced instead with the probes previously designed for the ,-Proteobacteria. The data also suggest that both N. limicola I and III can exist in activated sludge as single, paired or clumped cells and thus in a form not recognizable microscopically as this morphotype. Some N. limicola II filaments which responded to the probes designed here were much thinner than the filaments conventionally ,identified' as this morphotype and better fitted the descriptions often used in the literature for N. limicola I. [source] Characteristic improvement of metal-contaminated sludge using mineralization technologyENVIRONMENTAL PROGRESS & SUSTAINABLE ENERGY, Issue 1 2010Shao-Hua Hu Abstract This study focuses on improving crystalline characteristics of metal-contaminated sludge. The mineralization behavior of Cu/Al or Cu/Fe coexisting in solution is surveyed, and the characteristics of residue and suspension settling are discussed in the context of water content of residue and settling/specific filtration resistance of suspensions. Experimental data show that the hydrate of Cu4SO4(OH)6 forms during mineralization of copper sulfate solution when hydroxide ion concentration, reaction time, and temperature are not controlled appropriately. Mineral characteristics of the residue are usually poor when the Cu4SO4(OH)6 forms in Cu/Al or Cu/Fe solution. However, Cu4SO4(OH)6 can be further transformed into CuO with wet oxidation or ferrite method, respectively (i.e., mineralization treatment). Water reduction of the residue is from 96.8% to 72.8% in the Cu/Al case or 95.6% to 66.6% in the Cu/Fe case, and the mineralized residue volume is only 1/10 of the hydrate sediment. This is particularly beneficial for sludge disposal. © 2009 American Institute of Chemical Engineers Environ Prog, 2010 [source] Changes in microbial community composition following treatment of methanogenic granules with chloroformENVIRONMENTAL PROGRESS & SUSTAINABLE ENERGY, Issue 1 2009Bo Hu Abstract Eliminating hydrogen consuming bacteria is a critical step in anaerobic fermentation for biohydrogen production. Treatment of anaerobic granular sludge with chloroform was reported as effective in transforming a methane-producing system into a hydrogen-producing system by eliminating methane production. This study, using 16S rRNA gene sequences, further assessed changes in microbial community composition as a result of chloroform treatment and during continuous cultivation of chloroform-treated granules in a continuous upflow reactor employing immobilized cells. Profiles of terminal restriction fragment length polymorphisms (T-RFLP) of 16S rRNA genes sequences cloned from samples before and after chloroform treatment showed that methanogenic hydrogen consumers and Methanosaeta harundinacea sp. were eliminated. Methanosaeta concilii, however, was not eliminated from the hydrogen-producing system, which might explain, in part, the granulation phenomena in the anaerobic hydrogen fermentation system. The results also showed that Clostridium butyricum dominated the hydrogen-production system. © 2009 American Institute of Chemical Engineers Environ Prog, 2009 [source] Long-term stability of biological denitrification process for high strength nitrate removal from wastewater of uranium industryENVIRONMENTAL PROGRESS & SUSTAINABLE ENERGY, Issue 3 2008Prashant M. Biradar Abstract The aim of the present study was to biologically denitrify uranium nitrate raffinate (UNR) from nuclear industry, which is a principle source of high strength nitrate waste. To denitrify the high nitrate waste, a pilot-scale continuous stirred tank reactor was designed with two inbuilt settlers. Acclimatization of mixed culture with synthetic waste was carried out prior to the inoculation of the acclimatized sludge into the reactor. Initial concentration of nitrate in uranium raffinate was 77,000 mg/L NO3. It was diluted and used as a feed to the reactor. Concentration of nitrate in feed was increased gradually from 10,000 mg/L NO3 to 40,000 mg/L NO3 with hydraulic retention time (HRT) maintained at 34.4 h. Complete denitrification of 40,000 mg/L NO3 was achieved in a specified HRT. To facilitate understanding of the treatablity and long-term stability of biological denitrification of UNR, study was carried out for 211 days by periodical perturbation of the system. Furthermore, to find the volume ratio of reactor to settler required for the full-scale design of the denitrification plant, settling of acclimatized sludge was carried out. © 2008 American Institute of Chemical Engineers Environ Prog, 2008 [source] A study of copper recovery from copper-contaminated sludge with ferrite and selective leaching processesENVIRONMENTAL PROGRESS & SUSTAINABLE ENERGY, Issue 1 2007S.H. Hu Abstract The purpose of this study was to develop an effective resource recovery and leached residue stabilization process for copper-contaminated sludge. To this end, a treatment procedure utilizing ferrite and selective leaching processes was developed. The XRD examination of ferrite complex revealed the crystalline phases to be mainly Fe3O4, CuO, and 6CuO·Cu2O. A selective leaching process was followed to recover the copper content of the ferrite complex. To promote the dissolution percentage of copper and repress that of iron, additional 0.5 N sulfuric acid was added at intervals to the suspension in the second step of the selective leaching process. The purpose of this operation was to return the suspension pH back to 3 to promote the dissolution of copper oxide and repress the dissolution of iron. Finally, the heavy metal (i.e., Cu, Pb, Cr, and Cd) dissolution of the above residue was examined with toxicity characteristic leaching procedure (TCLP) testing and all met the regulatory standard. © 2007 American Institute of Chemical Engineers Environ Prog 26:104,112, 2007 [source] Alkaline leaching of printed circuit board sludgeENVIRONMENTAL PROGRESS & SUSTAINABLE ENERGY, Issue 3 2006S.H. Hu Abstract The purpose of this study was to develop a treatment procedure for processing aluminum-contaminated sludge produced from the coagulation/flocculation process of wastewater treatment in the manufacture of printed circuit boards (PCBs). In this study, the reagent sodium hydroxide (2 N) was used to leach the heavy metal sludge and the dissolution of sludge's aluminum content was roughly 70%. The weight loss of the heavy metal sludge was caused by the dissolution of aluminum content of nearly 20%. Although dissolution of a small amount of copper occurred simultaneously during this leaching process, the dissolution of copper content was restricted within 0.72% in the leaching operation and the copper content was concentrated in the residue to increase the copper level. The large amounts of sodium hydroxide and Al3+ remaining in the leachate were recycled as neutralization and coagulation agents in wastewater treatment. Synthetic heavy metal wastewater was neutralized with the preceding leachate to estimate the reuse feasibility of recovered coagulant. The heavy metal concentration of the effluent met regulation standards after neutralization and precipitation. The settling rate could be significantly enhanced by the addition of 100 ppm supplemental polyacrylamide (PAM). © 2006 American Institute of Chemical Engineers Environ Prog, 2006 [source] Ultrasonic treatment of waste activated sludgeENVIRONMENTAL PROGRESS & SUSTAINABLE ENERGY, Issue 2 2006Raf Dewil Abstract Activated sludge processes are key technologies to treat wastewater. These biological processes produce huge amounts of waste activated sludge (WAS), now commonly called biosolids. Mechanical, thermal, and/or chemical WAS conditioning techniques have been proposed to reduce the sludge burden. The ultrasonic treatment of WAS is quite novel. The present paper reports on extensive investigations using an ultrasonic treatment of WAS, to study its potential to meet one or all of four objectives: (1) reduce WAS quantities; (2) achieve a better dewaterability; (3) provoke a release of soluble chemical oxygen demand (COD) from the biosolids, preferably transformed into biodegradable organics; and (4) possibly destroy the filamentous microorganisms responsible for sludge bulking. Although meeting these objectives would help to solve the problems cited, the energy consumption could be a considerable drawback: the paper will thus assess whether all or some objectives are met, and at what operational cost. A literature survey defines the occurring phenomena (cavitation) and the important operation parameters [such as frequency, duration, specific energy input (SE)]. The experiments are carried out in a batch reactor of volume up to 2.3 L. The ultrasonic equipment consisted of a generator, a converter, and a sonotrode, supplied by Alpha Ultrasonics under the brand name of Telsonic. Three different kinds of sludge were tested, with different concentrations of dry solids (DS) between approximately 3.5 and 14 g DS/L WAS. Ultrasonic energy was introduced in a continuous manner (against possible pulsed operation). The major operational parameters studied include duration of the ultrasonic treatment and specific energy input. The applied frequency was set at 20 kHz. The release of COD from the WAS phase into the filtrate phase is a function of the specific energy input with yields of nearly 30% achievable at SE values of 30,000 kJ/kg DS. A major fraction of the COD is transformed into biodegradable organics (BOD). The reduction in DS fraction of the sludge is proportional to the COD release rates. Although the DS content is reduced, the dewaterability of the sludge is not improved. This reflects itself in increased filtration times during vacuum filtration and in increased values of the capillary suction time (CST). This more difficult dewaterability is the result of considerably reduced floc sizes, offering an extended surface area: more surface water is bound (CST increases) and the filterability decreases as a result of clogging of the cake. To reach the same dryness as for the untreated cake, the required dosage of polyelectrolyte is nearly doubled when the SE of the ultrasound treatment is increased from 7500 to 20,000 kJ/kg DS. The ultrasonic reduction of filamentous WAS organisms is not conclusive and very little effect is seen at low intensities and short treatment durations. Microscopic analysis of the WAS identified the dominant presence of Actynomyces. The release of soluble COD and BOD certainly merit further research. © 2006 American Institute of Chemical Engineers Environ Prog, 2006 [source] Optimization of the simultaneous removal of nitrogen and organic matter from fishery wastewatersENVIRONMENTAL PROGRESS & SUSTAINABLE ENERGY, Issue 3 2005Estrella Aspé Abstract Anaerobic treatment of saline and protein-rich effluents reduces the organic concentration but forms ammonium that hinders nitrogen removal in a later aerobic treatment. The goal of this work was to optimize the design of a denitrifying,nitrifying system for the simultaneous removal of organic matter and nitrogenous compounds from fishery effluents to meet the Chilean legal standards and to compare pre- and postdenitrification processes in the biological treatment of high-strength effluents to minimize the total volume of biological reactors required. A predenitrifying system, that included three reactors,acidifying anaerobic filter, denitrifying (anoxic) filter, and aerobic-active sludge (nitrifying reactor) with recycle to the denitrifying reactor,reduced nitrogen to 0.33 g of total ammonia nitrogen (TAN) L,1, well above the allowed 0.05 g total nitrogen L,1. The predenitrifying system with a second denitrifying reactor, to which organic matter was added, met the legal organic matter and nitrogen emission concentrations (0.042 g TAN L,1). Conversions were 99.0, 92.5, 90.9, and 99.0% for the anaerobic digestion, first denitrification, nitrification, and second denitrification, respectively. © 2005 American Institute of Chemical Engineers Environ Prog, 2005 [source] CMP wastewater management using the concepts of design for environmentENVIRONMENTAL PROGRESS & SUSTAINABLE ENERGY, Issue 1 2002Gordon C. C. YangArticle first published online: 20 APR 200 Application of design for environment (DfE) concepts to management of wastewater from chemical mechanical polishing (CMP) processes are presented in this paper. Today, DfE is a prevailing concept and is widely adopted by advanced nations in lieu of the traditional "command and control" approach to control waste and toxic emissions. Designing environmentally-benign processes and products is a new and challenging frontier for engineering professionals, including those in the semiconductor industry. An insatiable need for water and subsequent wastewater treatment has imposed a chilling effect on semiconductor industry growth. It was estimated that semiconductor producers consumed more than 5.523 × 108 m3 of water in 2000. Of this amount, CMP processes accounted for 40% of the total. The CMP tool market and CMP slurry market are estimated to have 36% and 29% annual growth rates, respectively between 2000 and 2005. Inevitably, a tremendous amount of waste slurry and post-CMP rinse water will be generated and have to be managed properly. CMP wastewater is characterized by its high content of suspended solids having sub-micron particle sizes, high turbidity, and high conductivity. Traditional wastewater treatment technologies, such as chemical coagulation/precipitation, do not work well for CMP wastewater, because it would generate a large volume of sludge, which might cause disposal problems in many countries, such as Taiwan. Therefore, utilizing pollution prevention principles in the design of CMP tools, development of new CMP slurries, and improved plant operations are necessary to minimize environmental damage. Reclamation of process water is also a common requirement in the semiconductor industry. To this end, several alternatives for source reduction of CMP wastewater and water reclamation are presented in this paper. [source] Bioconcentrations of metals (Fe, Cu, Zn, Pb) in earthworms (Eisenia fetida), inoculated in municipal sewage sludge: Do earthworms pose a possible risk of terrestrial food chain contamination?ENVIRONMENTAL TOXICOLOGY, Issue 1 2009Surindra Suthar Abstract Efforts have been made to evaluate the possible risks of metal bioaccumulation in composting earthworms during vermicomposting of hazardous wastes, e.g., sewage sludge. The sewage sludge was diluted by mixing cow dung in different proportions, and vermicomposted sludge as well as inoculated earthworms were analyzed for metal (Fe, Cu, Zn, Pb) contents. The sludge processed by worms showed a significant reduction in concentration of metals, Cu (29.4,51.6%), Fe (13.1,19.9%), Zn (15.2,25.8%), and Pb (4.6,46.9%), at the end. A considerable concentration of metals, total Cu (16.7,27.6 mg kg,1), total Fe (42.9,89.8 mg kg,1), total Zn (5.85,75.0 mg kg,1), and total Pb (1.79,12.4 mg kg,1), in composting earthworms was also recorded. The greater values of bioconcentration factors for metals suggested the possible risk of entering contaminants in higher food chains; since, earthworms are near to the terrestrial food chain, they can potentially mediate metal transfer from soil to a range of predators, including birds. Therefore, feasibility of vermitechnology in hazardous waste recycling needs close attention in respect to possible risk of environmental contamination. © 2008 Wiley Periodicals, Inc. Environ Toxicol, 2009. [source] Impact of five selected xenobiotics on isolated ammonium oxidizers and on nitrifying activated sludgeENVIRONMENTAL TOXICOLOGY, Issue 4 2006S. N. Dokianakis Abstract Sewage treatment plants (STPs) are usual receptors of xenobiotic compounds that have to be cotreated with municipal wastewaters before being discharged to the water environment. The presence of organic contaminants, such as surfactants, polycyclic aromatic hydrocarbons (PAHs), phthalates, and their primary degradation products in the influents of STPs may inhibit irreversibly sensitive biological processes, such as nitrification. The first step of nitrification, i.e., the oxidation of ammonium to nitrite (nitritification), is particularly sensitive. Inhibition of this step under uncontrolled conditions may completely inhibit biological nitrogen removal. The aim of this work was to study the possible inhibitory effect of five selected xenobiotics on (a) a mixed culture of ammonium-oxidizing bacteria isolated from activated sludge and (b) nitrifying activated sludge directly. The xenobiotics that were tested include nonylphenols (NP), nonylphenolethoxylates (NPEO), linear alkylbenzene sulfonates (LAS), di(2-ethylhexyl) phthalate (DEHP), as a representative phthalate ester, and the PAH phenanthrene. Remarkable inhibitory effects for all tested compounds were observed in this study even at xenobiotic concentrations as low as 1 mg/L. The observed inhibition of xenobiotics on nitrifying activated sludge was less pronounced, because of the masking effect exerted by the sludge flocs, but was still significant for many of the tested substances at concentrations up to 10 mg/L. © 2006 Wiley Periodicals, Inc. Environ Toxicol 21: 310,316, 2006. [source] Estrogenic effect of leachates and soil extracts from lysimeters spiked with sewage sludge and reference endocrine disruptersENVIRONMENTAL TOXICOLOGY, Issue 2 2002Halim Dizer Abstract Several experiments were conducted to evaluate the behavior and performance of some potential endocrine disrupters (ECDs). Two in vitro screening assays, one based on MCF7-cell proliferation (E-screen test) and the other on estrogenic receptor activity [enzyme-linked receptor assay (ELRA)], were used for the tests, which were done in lysimeters 80 cm in diameter with depths of 30 cm (shallow) or 90 cm (deep). A sandy soil was used to fill in all lysimeters, which were spiked on the surface with either: (a) a sewage sludge (SS) at a dose equivalent to 20 tons ha,1; (b) a mixture of reference ECDs, comprising 17,- and 17,-estradiol (E2), nonylphenol, octylphenol, and bisphenol A at doses 100 times higher than the maximum concentrations respectively found in the applied SS; or (c) a mixture of ECDs and SS. After percolation of the lysimeters with rain and/or artificial water, five leachates were sampled from each lysimeter during a period of 210 days. Immediately after the lysimeter percolation experiments, four and six soil fractions were dissected from, respectively, the 30-cm and 90-cm lysimeters and extracted by water. Both the leachate and soil extract samples were analyzed for their estrogenicity using the assays indicated above. The E-screen assay was highly sensitive only for some leachate and extract samples but gave no response for most leachates and soil extracts. The results of the ELRA assay suggests a significantly higher estrogenicity of leachate samples from shallow lysimeters compared with that of leachates from deep lysimeters. In contrast, the estrogenic effect measured for soil extracts of shallow lysimeters was lower than that measured for soil extracts of deep lysimeters. The results of the E-screen assay suggests the occurrence of a fast mobilization of applied ECDs and a moderate retardation effect of native ECDs contained in applied SS in the sandy soil used in the lysimeters. In lysimeters spiked with a mixture of SS and ECDs, the washing-out effect of ECDs in the first leachate fraction decreased, but the distribution of ECDs in the lysimeters increased. The relatively high estrogenic impact measured for soil water extracts suggests that the ECDs were mostly associated with water-soluble fractions of organic matter and/or water-suspended fractions of the mineral soil matrix. The application of SS to agricultural and forest fields may determine the immobilization of ECDs in soil or their movement to surface and/or groundwater. Therefore, an endocrine risk of exposure exists for the water and soil organisms. © 2002 Wiley Periodicals, Inc. Environ Toxicol 17: 105,112, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/tox.10038 [source] Occurrence of pharmaceuticals and hormones in sewage sludgeENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 7 2010Antonio Nieto Abstract The present study evaluates the presence of nine hormones and their conjugates and 20 pharmaceuticals such as anti-inflammatories, lipid regulators, and antibiotics among others in sewage sludge from two sewage treatment plants (STPs) in the Tarragona area (Spain) for the period March 2007 until March 2008. Target analytes have been determined using different methods involving pressurized liquid extraction and liquid chromatography (electrospray ionization) tandem mass spectrometry (MS-MS). Most of the pharmaceuticals and hormones were found at low micrograms per kilogram dry weight levels in the sewage sludge samples analyzed. Some compounds were present in all samples, such as acetaminophen, caffeine, carbamazepine, and ibuprofen, among others. Other compounds, such as estriol, were found only in the STP of Reus. The compounds that showed the highest concentration in both STPs were roxithromycin and tylosin (1,446 and 1,958,µg/kg dry wt, respectively). The presence of these compounds in sewage sludge demonstrated that they are partially or totally removed from the influent wastewater by sorption into the sewage sludge. Environ. Toxicol. Chem. 2010;29:1484,1489. © 2010 SETAC [source] Modeling the environmental fate of perfluorooctanoate and its precursors from global fluorotelomer acrylate polymer useENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 11 2008Rosalie van Zelm Abstract The environment contains various direct and indirect sources of perfluorooctanoic acid (PFOA). The present study uses a dynamic multispecies environmental fate model to analyze the potential formation of perfluorooctanoate (PFO), the anion of PFOA, in the environment from fluorotelomer acrylate polymer (FTacrylate) emitted to landfills and wastewater, residual fluorotelomer alcohol (8:2 FTOH) in FTacrylate, and residual PFOA in FTacrylate. A multispecies version of the SimpleBox model, which is capable of determining the fate of a chemical and its degradation products, was developed for this purpose. An uncertainty analysis on the chemical-specific input parameters was performed to examine for uncertainty in modeled concentrations. In 2005, residual 8:2 FTOH made up 80% of the total contribution of FTacrylate use to PFO concentrations in global oceans, and residual PFOA in FTacrylate contributed 15% to PFO concentrations from FTacrylate use in global oceans. After hundreds of years, however, the main source of PFO from total historical FTacrylate production is predicted to be FTacrylate degrading in soil following land application of sludge from sewage treatment plants, followed by FTacrylate still present in landfills. Uncertainty in modeled PFO concentrations was up to a factor of 3.3. Current FTacrylate use contributes less than 1% of the PFO in seawater, but because direct PFOA emission sources are reduced and PFOA continues to be formed from FTacrylate in soil and in landfills, this fraction grows over time. [source] Volatile organic sulfur compounds in anaerobic sludge and sediments: Biodegradation and toxicityENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 12 2006Robin C. van Leerdam Abstract A variety of environmental samples was screened for anaerobic degradation of methanethiol, ethanethiol, propanethiol, dimethylsulfide, and dimethyldisulfide. All sludge and sediment samples degraded methanethiol, dimethylsulfide, and dimethyldisulfide anaerobically. In contrast, ethanethiol and propanethiol were not degraded by the samples investigated under any of the conditions tested. Methanethiol, dimethylsulfide, and dimethyldisulfide were mainly degraded by methanogenic archaea. In the presence of sulfate and the methanogenic inhibitor bromoethane sulfonate, degradation of these compounds coupled to sulfate reduction occurred as well, but at much lower rates. Besides their biodegradability, also the toxicity of methanethiol, ethanethiol, and propanethiol to methanogenesis with methanol, acetate, and H2/CO2 as the substrates was assessed. The 50% inhibition concentration of methanethiol on the methane production from these substrates ranged between 7 and 10 mM. The 50% inhibition concentration values of ethanethiol and propanethiol for the degradation of methanol and acetate were between 6 and 8 mM, whereas hydrogen consumers were less affected by ethanethiol and propanethiol, as indicated by their higher 50% inhibition concentration (14 mM). Sulfide inhibited methanethiol degradation already at relatively low concentrations: methanethioldegradation was almost completely inhibited at an initial sulfide concentration of 8 mM. These results define the operational limits of anaerobic technologies for the treatment of volatile organic sulfur compounds in sulfide-containing wastewater streams. [source] Geckos as indicators of mining pollutionENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 9 2006Dean E. Fletcher Abstract Catastrophic collapse of a mine tailings dam released several million cubic meters of toxic mud and acidic water into the Guadiamar River valley, southern Spain, in 1998. Remediation efforts removed most of the sludge from the floodplain, but contamination persists. Clean-up activities also produced clouds of aerosolized materials that further contaminated the surrounding landscape. Whole-body concentrations of 21 elements in the Moorish wall gecko, Tarentola mauritanica, a common inhabitant of both rural and urban areas, were compared among seven locations. Locations spanned an expected contamination gradient and included a rural and an urban non,mine-affected location, two mine-affected towns, and three locations on the contaminated floodplain. Multivariate analyses of whole-body concentrations identified pollutants that increased across the expected contamination gradient, a trend particularly evident for As, Pb, and Cd. Additionally, higher contaminant concentrations occurred in prey items eaten by geckos from mine-affected areas. Comparison of element concentrations in tails and whole bodies suggests that tail clips are a viable nondestructive index of contaminant accumulation. Our results indicate that areas polluted by the mine continue to experience contamination of the terrestrial food chain. Where abundant, geckos represent useful taxa to study the bioavailability of some hazardous pollutants. [source] Effect of ethoxylate number and alkyl chain length on the pathway and kinetics of linear alcohol ethoxylate biodegradation in activated sludgeENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 12 2004Nina R. Itrich Abstract Batch activated-sludge die-away studies were conducted with various pure homologs to determine the effect of ethoxylate number and alkyl chain length on the kinetics of primary and ultimate biodegradation of linear alcohol ethoxylates. The 14C-(ethoxylate) homologs C14E1, C14E3, C14E6, and C14E9 were used to investigate the effect of ethoxylate number, and 14C-(ethoxylate) homologs C12E6, C14E6, and C16E6 were used to examine the effect of chain length. Activated sludge was dosed with a trace concentration (0.2 ,M) of each homolog, and the disappearance of parent, formation of metabolites, production of 14CO2, and uptake into solids were monitored with time. Ethoxylate number had little effect on the first-order decay rates for primary biodegradation, which ranged from 61 to 78 h,1. However, alkyl chain length had a larger effect, with the C16 chain-length homolog exhibiting a slower rate of parent decay (18 h,1) compared to its corresponding C12 and C14 homologs (61,69 h,1). Ethoxylate number affected the mechanism of biodegradation, with fission of the central ether bond to yield the corresponding fatty alcohol and (poly)ethylene glycol group increasing in dominance with increasing ethoxylate number. Based upon the measured rates of primary biodegradation, removal of parent during activated-sludge treatment was predicted to range between 99.7 and 99.8% for all homologs except C16E6, which had a predicted removal of 98.9%. Based upon the measured rates of ultimate biodegradation, removal of ethoxylate-containing metabolites was predicted to exceed 83% for all homologs. These predictions corresponded closely with previously published removal measurements in laboratory continuous activated-sludge systems and actual treatment plants. [source] Anaerobic transformation of compounds of technical toxaphene.ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 11 2003Abstract Technical toxaphene (Melipax) and the single compounds of technical toxaphene (CTTs) 2,2,5- endo, 6- exo, 8,8,9,10- octachlorobornane (B8-806), 2,2,5- endo, 6- exo, 8,9,9,10-octachlorobornane (B8-809), 2,2,5,5,8,9,9,10,10-nonachlorobornane (B9- 1025), 2- endo, 3- exo, 5- endo, 6- exo, 8,8,9,10,10-nonochlorobornane (B9-1679), 2- endo, 3- exo, 5- endo, 6- exo, 8,9,10,10-octachlorobornane (B8-1414), 2- endo, 3- exo, 5- endo, 6- exo, 8,8,9,10-octachlorobornane (B8-1412), and 2- exo, 3- endo, 5- exo, 9,9,10,10-heptachlorobornane (B7-1453) were treated with suspensions of the anaerobic bacterium Dehalospirillum multivorans. After 7 d, more than 50% of technical toxaphene was transformed, and the relative amount of early eluting CTTs increased. After 16 d, only 2- exo, 3- endo, 6- exo, 8,9,10-hexachlorobornane (B6-923), 2- endo, 3- exo, 5- endo, 6- exo, 8,9,10-heptachlorobornane (B7-1001), and a few minor penta- and hexachloro-CTTs were detected in the samples. The result of the transformation was comparable with observations in naturally contaminated sediments and soil. However, the performance with D. multivorans was more simple and reproducible, as well as faster, than use of soil, sediment, or anaerobic sewage sludge. In agreement with reports in the literature, reductive dechlorination at geminal chlorine atoms (gem -Cls) was found to be the major CTT transformation pathway. Experiments conducted with CTTs and gem -Cls at both primary and secondary carbons clarified that the initial Cl -> H substitution takes place at the secondary carbon C2. Furthermore, the 2- endo -Cl position was preferably substituted with hydrogen. In the case of B8-806, the dechlorination at the secondary carbon C2 was approximately 20-fold faster than the subsequent, slow reduction at the primary carbon C8. The three different formerly unknown heptachloro-CTTs, 2- exo, 3- endo, 6- exo, 8,9,9,10-heptachlorobornane (B7-1473), 2- exo, 3- endo, 6- endo, 8,9,9,10-hepatchlorobornane (B7-1461), and 2- exo, 3- endo, 6- exo, 8,8,9,10-heptachlorobornane (B7-1470) were found as intermediates of the B8-806/809 transformation. Treatment of B9-1679 with D. multivorans indicated that gem -Cls on the bridge (C8 and C9) are dechlorinated faster than gem -Cls on the bridgehead (C10). [source] Application of sewage sludge to arable land,soil concentrations of polybrominated diphenyl ethers and polychorinated dibenzo- p -dioxins, dibenzofurans, and biphenyls, and their accumulation in earthwormsENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 12 2002Nadja Matscheko Abstract Soils from five agricultural sites, three research sites, and two privately owned farms were analyzed for polychlorinated dibenzo- p -dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), polychlorinated biphenyls (PCBs), and polybronimated diphenylethers (PBDEs). In soils that had not been treated with sludge (reference soils), the international toxic equivalents (I-TEQs) were 0.6 to 1.5 pg/g dry matter (DM) for the PCDD/Fs, which are low compared to generally reported background soil levels in Europe. The concentrations of sum of six penta- and hexa-PCBs were 450 to 1,400 pg/g DM. The PBDEs 47 and 99 dominated among the tri- to hepta-PBDEs analyzed (8,80 pg/g DM). The impact of adding 1 to 3 tonnes of sludge (DM) per hectare per year on the concentrations was studied at the three research sites by calculating ratios of the compounds in sludge-treated soil to reference soil (S/R ratio). The concentrations of I-TEQs did not increase in the sludge-treated soil, whereas the S/R ratios for PBDEs were greater than one. Also, although the PCB contents were higher in the sludge-treated soils, the background sources were more important for the concentrations of PCBs than of PBDEs. The largest increase in the S/R ratios was found at a private farm where large amounts of sludge had been used in the past. Accumulation of the compounds in earthworms from the sites also was investigated. The biota-soil accumulation factors (BSAFs) of the tested compounds declined in the following order: ortho -PCBs , PBDEs > non-ortho -PCBs > 2,3,7,8-substituted PCDD/Fs. The average BSAF for ortho -PCBs was five (organic matter/lipids), and the lowest BSAFs (0.1,0.8) found were for octachlorodibenzo- p -dioxin. To our knowledge, accumulation of PBDEs in earthworms has not been published previously. [source] | |||||||||||||||||||||||||||||||||||||||||||