Wastewater Treatment Plant (wastewater + treatment_plant)

Distribution by Scientific Domains
Distribution within Life Sciences

Kinds of Wastewater Treatment Plant

  • municipal wastewater treatment plant

  • Selected Abstracts

    Olive oil mineral content of two local genotypes as influenced by recycled effluent irrigation under arid environment

    Khaled M Al-Absi
    Abstract BACKGROUND: An alternative plan for saving scarce water could include use of non-conventional water resources such as reclaimed wastewater originating from wastewater treatment plants. The main health risks are associated with contamination of crops by wastewater due to its chemical composition. Therefore, the effect of recycled effluent irrigation was investigated on mineral composition and quality of olive oil of two local olive cultivars under field conditions during two complete cycles. RESULTS: The treated wastewater used in this study was taken from the HUIE Wastewater Treatment Plant. This water is mainly generated by textile firms, mixed with municipal domestic effluent. The analysis of the effluent indicated that element concentrations fall within the permissible range in irrigation water used for plants. The concentrations of mineral composition were relatively higher in olive oils irrigated with treated wastewater but lower than the maximum permissible concentration. Concentrations ranged from 8.91 to 26.16 mg kg,1 for Ca; 6.25,16.11 mg kg,1 for Na, 53.20,111.76 mg kg,1 for K, 0.19,0.36 mg kg,1 for Zn, 0.97,1.46 mg kg,1 for Mn and 0.07,0.13% for Cl. No statistically significant differences were found between the oil quality indices (peroxide and acidity). CONCLUSION: These results indicate that this kind of effluent is suitable for irrigation of olive genotypes grown for oil purposes. Copyright © 2009 Society of Chemical Industry [source]

    Clarified cashew apple juice as alternative raw material for biosurfactant production by Bacillus subtilis in a batch bioreactor

    Maria Estela Aparecida Giro
    Abstract Clarified cashew apple juice was evaluated as carbon source for surfactin production by Bacillus subtilis LAMI005 isolated from the tank of chlorination at the Wastewater Treatment Plant on Campus do Pici (WWTP-PICI) in the Federal University of Ceará, Brazil. The highest surfactin concentration using clarified cashew apple juice (CCAJ) supplemented with mineral medium (MM-CCAJ) was 123 mg/L, achieved after 48 h of fermentation. Almost 2-fold less than the amount produced using mineral medium supplemented with 10 g/L of glucose and 8.7 g/L of fructose (MM-GF). However, critical micelle concentration of the biosurfactants produced using MM-CCAJ was 2.5-fold lower than the one produced using MM-GF, which indicates it is a more efficient biosurfactant. Surface tension decreased from 38.50 ± 0.0 to 29.00 ± 0.0 dyne/cm when B. subtilis was grown on MM-CCAJ media (24.68% of reduction on surface tension) and remained constant up to 72 h. Emulsification index was 51.15 and 66.70% using soybean oil and kerosene, respectively. Surfactin produced in MM-CCAJ showed an emulsifying activity of, respectively, 1.75 and 2.3 U when n-hexadecane or soybean oil was tested. However, when mineral medium supplemented with 10 g/L of glucose (MM-G) was used an emulsifying activity of 2.0 and 1.75 U, with n-hexadecane and soybean oil, respectively, was obtained. These results indicate that it is feasible to produce surfactin from CCAJ, a renewable and low-cost carbon source. [source]

    Wastewater treatment plants as a pathway for aquatic contamination by pharmaceuticals in the Ebro river basin (Northeast Spain)

    Meritxell Gros
    Abstract The occurrence of 28 pharmaceuticals of major human consumption in Spain, including analgesics and anti-inflam-matories, lipid regulators, psychiatric drugs, antibiotics, antihistamines, and ,-blockers, was assessed along the Ebro river basin, one of the biggest irrigated lands in that country. Target compounds were simultaneously analyzed by off-line solid-phase extraction, followed by liquid chromatography-tandem mass spectrometry. The loads of detected pharmaceuticals and their removal rates were studied in seven wastewater treatment plants (WWTPs) located in the main cities along the basin. Total loads ranged from 2 to 5 and from 0.5 to 1.5 g/d/1,000 inhabitants in influent and effluent wastewaters, respectively. High removal rates (60,90%) were achieved mainly for analgesics and anti-inflammatories. The other groups showed lower rates, ranging from 20 to 60%, and in most cases, the antiepileptic carbamazepine, macrolide antibiotics, and trimethoprim were not eliminated at all. Finally, the contribution of WWTP effluents to the presence of pharmaceuticals in receiving river waters was surveyed. In receiving surface water, the most ubiquitous compounds were the analgesics and anti-inflammatories ibuprofen, diclofenac, and naproxen; the lipid regulators bezafibrate and gemfibrozil; the antibiotics erythromycin, azithromycin, sulfamethoxazole, trimethoprim, and less frequently, ofloxacin; the antiepileptic carbamazepine; the antihistamine ranitidine; and the ,-blockers atenolol and sotalol. Although levels found in WWTP effluents ranged from low ,g/L to high ng/L, pharmaceuticals in river waters occurred at levels at least one order of magnitude lower (low ng/L range) because of dilution effect. From the results obtained, it was proved that WWTP are hot spots of aquatic contamination concerning pharmaceuticals of human consumption. [source]

    Enhanced process monitoring for wastewater treatment systems

    ENVIRONMETRICS, Issue 6 2008
    Chang Kyoo Yoo
    Abstract Wastewater treatment plants (WWTPs) remain notorious for poor data quality and sensor reliability problems due to the hostile environment, missing data problems and more. Many sensors in WWTP are prone to malfunctions in harsh environments. If a WWTP contains any redundancy between sensors, monitoring methods with sensor reconstruction such as the proposed one can yield a better monitoring efficiency than without a reconstruction scheme. An enhanced robust process monitoring method combined with a sensor reconstruction scheme to tackle the sensor failure problems is proposed for biological wastewater treatment systems. The proposed method is applied to a single reactor for high activity ammonia removal over nitrite (SHARON) process. It shows robust monitoring performance in the presence of sensor faults and produces few false alarms. Moreover, it enables us to keep the monitoring system running in the case of sensor failures. This guaranteed continuity of the monitoring scheme is a necessary development in view of real-time applications in full-scale WWTPs. Copyright © 2007 John Wiley & Sons, Ltd. [source]

    Design and application of a membrane bioreactor unit to upgrade and enhance the required performance of an installed wastewater treatment plant

    Teresa Castelo-Grande
    Abstract Wastewater treatment plants (WWTPs) are nowadays common solutions to improve the quality of streams and soils. However, there are still many issues required to be solved within these plants. We were commissioned to redesign a WWTP in Amarante, Portugal, which was not working properly. Among the several units we have designed, there is a membrane bioreactor representing one of the main units of this remodelled WWTP. The biological treatment stage at the upgraded WWTP will take place in the remodelled primary and secondary settlers and in the remodelled and improved biological reactor. Hence, the primary settler is readapted in such a way that it functions as the anoxic area of the biological treatment, while the aerobic treatment will be sequentially performed at the remodelled biological reactor and at the actual secondary settler. Membrane treatment will be performed by using ultrafiltration membranes. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd. [source]

    Fate of air toxics and VOCs in the odor control scrubbers at the deer island treatment plant

    Thomas Myslinski
    Process off-gases at the Deer Island wastewater treatment plant in Boston are collected and treated and its stack emissions regulated for selected gases including volatile organic compounds (VOCs), which are monitored as nonmethane hydrocarbons (NMHC). The air treatment processes of countercurrent wet oxidation scrubbing and granulated activated carbon adsorption are available for emissions control at Deer Island. In addition, since the wastewater treatment process of biochemical oxidation is fully enclosed at the site, microbial destruction of VOCs is an intrinsic treatment process for organic gases. Surveyed results of wastewater research literature indicate that the use of scrubbers for the removal of VOCs is controversial, as the fate of volatile hydrocarbon molecules across odor control scrubbers is complex and not fully understood. Continuous emission monitoring tests across the Deer Island scrubbers have consistently shown a VOC removal efficiency in excess of 50%. The fate of the scrubber inlet VOCs at Deer Island was researched as part of a plant-wide, on-going VOC study. Removal efficiencies across the pure oxygen bioreactors were also investigated. Preliminary results of this study indicate chemical reactions involving VOCs in odor control scrubbers partially oxidize and chlorinate derivatives possibly destroying a fraction of the compounds by complete oxidation. In addition, VOC reduction across the enclosed aerobic bioreactors was found to be significant. This article represents the opinions and(legal) conclusions of the authors and not necessarily those of the MWRA. [source]

    Occurrence and fate of micropollutants in the Vidy Bay of Lake Geneva, Switzerland.

    Part II: Micropollutant removal between wastewater, raw drinking water
    Abstract The occurrence and removal of 58 pharmaceuticals, endocrine disruptors, corrosion inhibitors, biocides, and pesticides, were assessed in the wastewater treatment plant (WWTP) of the city of Lausanne, Switzerland, as well as in the effluent-receiving water body, the Vidy Bay of Lake Geneva. An analytical screening method to simultaneously measure all of the 58 micropollutants was developed based on ultra performance liquid chromatography coupled to a tandem mass spectrometer (UPLC-MS/MS). The selection of pharmaceuticals was primarily based on a prioritization study, which designated them as environmentally relevant for the Lake Geneva region. Except for the endocrine disruptor 17,-ethinylestradiol, all substances were detected in 24-h composite samples of wastewater entering the WWTP or in the treated effluent. Of these compounds, 40% were also detected in raw drinking water, pumped from the lake 3,km downstream of the WWTP. The contributions of dilution and degradation to micropollutant elimination between the WWTP outlet and the raw drinking water intake were established in different model scenarios using hypothetical residence times of the wastewater in Vidy Bay of 1, 4, or 90 d. Concentration decrease due to processes other than dilution was observed for diclofenac, beta-blockers, several antibiotics, corrosion inhibitors, and pesticides. Measured environmental concentrations (MECs) of pharmaceuticals were compared to the predicted environmental concentrations (PECs) determined in the prioritization study and agreed within one order of magnitude, but MECs were typically greater than the corresponding PECs. Predicted no-effect concentrations of the analgesic paracetamol, and the two antibiotics ciprofloxacin and sulfamethoxazole, were exceeded in raw drinking water samples and therefore present a potential risk to the ecosystem. Environ. Toxicol. Chem. 2010; 29:1658,1668. © 2010 SETAC [source]

    Antidepressants and their metabolites in municipal wastewater, and downstream exposure in an urban watershed

    Chris D. Metcalfe
    Abstract Antidepressants are a widely prescribed group of pharmaceuticals that can be biotransformed in humans to biologically active metabolites. In the present study, the distribution of six antidepressants (venlafaxine, bupropion, fluoxetine, sertraline, citalopram, and paroxetine) and five of their metabolites was determined in a municipal wastewater treatment plant (WWTP) and at sites downstream of two WWTPs in the Grand River watershed in southern Ontario, Canada. Fathead minnows (Pimephales promelas) caged in the Grand River downstream of a WWTP were also evaluated for accumulated antidepressants. Finally, drinking water was analyzed from a treatment plant that takes its water from the Grand River 17 km downstream of a WWTP. In municipal wastewater, the antidepressant compounds present in the highest concentrations (i.e., >0.5 µg/L) were venlafaxine and its two demethylation products, O - and N -desmethyl venlafaxine. Removal rates of the target analytes in a WWTP were approximately 40%. These compounds persisted in river water samples collected at sites up to several kilometers downstream of discharges from WWTPs. Venlafaxine, citalopram, and sertraline, and demethylated metabolites were detected in fathead minnows caged 10 m below the discharge from a WWTP, but concentrations were all <7 µg/kg wet weight. Venlafaxine and bupropion were detected at very low (<0.005 µg/L) concentrations in untreated drinking water, but these compounds were not detected in treated drinking water. The present study illustrates that data are needed on the distribution in the aquatic environment of both the parent compound and the biologically active metabolites of pharmaceuticals. Environ. Toxicol. Chem. 2010;29:79,89. © 2009 SETAC [source]

    Influence of heavy metals on microbial growth kinetics including lag time: Mathematical modeling and experimental verification,

    S. Sevinç, engör
    Abstract Heavy metals can significantly affect the kinetics of substrate biodegradation and microbial growth, including lag times and specific growth rates. A model to describe microbial metabolic lag as a function of the history of substrate concentration has been previously described by Wood et al. (Water Resour Res 31:553,563) and Ginn (Water Resour Res 35:1395,1408). In the present study, this model is extended by including the effect of heavy metals on metabolic lag by developing an inhibitor-dependent functional to account for the metabolic state of the microorganisms. The concentration of the inhibiting metal is explicitly incorporated into the functional. The validity of the model is tested against experimental data on the effects of zinc on Pseudomonas species isolated from Lake Coeur d'Alene sediments, Idaho, USA, as well as the effects of nickel or cobalt on a mixed microbial culture collected from the aeration tank of a wastewater treatment plant in Athens, Greece. The simulations demonstrate the ability to incorporate the effect of metals on metabolism through lag, yield coefficient, and specific growth rates. The model includes growth limitation due to insufficient transfer of oxygen into the growth medium. [source]

    Reproductive health of bass in the Potomac, USA, drainage: Part 1.

    Exploring the effects of proximity to wastewater treatment plant discharge
    Abstract Intersex (specifically, testicular oocytes) has been observed in male smallmouth bass (SMB; Micropterus dolomieu) and other centrarchids in the South Branch of the Potomac River, USA, and forks of the Shenandoah River, USA, during the past five years. This condition often is associated with exposure to estrogenic endocrine-disrupting chemicals in some fish species, but such chemicals and their sources have yet to be identified in the Potomac. In an attempt to better understand the plausible causes of this condition, we investigated the reproductive health of bass sampled up- and downstream of wastewater treatment plant (WWTP) effluent point sources on the Potomac River in Maryland, USA. Smallmouth bass were sampled from the Conococheague Creek and the Monocacy River, and largemouth bass (LMB; Micropterus salmoides) were collected near the Blue Plains WWTP on the mainstem of the Potomac River. Chemical analyses of compounds captured in passive samplers at these locations also were conducted. A high prevalence of intersex (82,100%) was identified in male SMB at all sites regardless of collection area. A lower prevalence of intersex (23%) was identified in male LMB collected at the Blue Plains site. When up- and downstream fish were compared, significant differences were noted only in fish from the Conococheague. Differences included condition factor, gonadosomatic index, plasma vitellogenin concentration, and estrogen to testosterone ratio. In general, chemicals associated with waste-water effluent, storm-water runoff, and agriculture were more prevalent at the downstream sampling sites. An exception was atrazine and its associated metabolites, which were present in greater concentrations at the upstream sites. It appears that proximity to effluent from WWTPs may influence the reproductive health of bass in the Potomac watershed, but inputs from other sources likely contribute to the widespread, high incidence of testicular oocytes. [source]

    Reproductive health of bass in the Potomac, USA, drainage: Part 2.

    Seasonal occurrence of persistent, emerging organic contaminants
    Abstract The seasonal occurrence of organic contaminants, many of which are potential endocrine disruptors, entering the Potomac River, USA, watershed was investigated using a two-pronged approach during the fall of 2005 and spring of 2006. Passive samplers (semipermeable membrane device and polar organic chemical integrative sampler [POCIS]) were deployed in tandem at sites above and below wastewater treatment plant discharges within the watershed. Analysis of the samplers resulted in detection of 84 of 138 targeted chemicals. The agricultural pesticides atrazine and metolachlor had the greatest seasonal changes in water concentrations, with a 3.1- to 91-fold increase in the spring compared with the level in the previous fall. Coinciding with the elevated concentrations of atrazine in the spring were increasing concentrations of the atrazine degradation products desethylatrazine and desisopropylatrazine in the fall following spring and summer application of the parent compound. Other targeted chemicals (organochlorine pesticides, polycyclic aromatic hydrocarbons, and organic wastewater chemicals) did not indicate seasonal changes in occurrence or concentration; however, the overall concentrations and number of chemicals present were greater at the sites downstream of wastewater treatment plant discharges. Several fragrances and flame retardants were identified in these downstream sites, which are characteristic of wastewater effluent and human activities. The bioluminescent yeast estrogen screen in vitro assay of the POCIS extracts indicated the presence of chemicals that were capable of producing an estrogenic response at all sampling sites. [source]

    Determination and fate of oxytetracycline and related compounds in oxytetracycline production wastewater and the receiving river,

    Dong Li
    Abstract This study investigated the occurrence and fate of oxytetracycline (OTC) and its related substances, 4-epi-oxytetracycline (EOTC), ,-apo-oxytetracycline (,-apo-OTC), and ,-apo-oxytetracycline (,-apo-OTC), in a wastewater treatment plant (WWTP) treating OTC production wastewater and a river receiving the effluent from the WWTP using liquid chromatography electrospray ionization mass spectrometry (LC-ESI-MS). The percent removal of OTC in the WWTP was 38.0 ± 10.5%, and the concentration of OTC was still up to 19.5 ± 2.9 mg/L in the treated outflow. The concentration slightly decreased along the river, from 641 ± 118 ,g/L at site R2 (discharging point) to 377 ± 142 ,g/L at site R4 (,20 km from site R2), which was still higher than the minimal inhibition concentration of OTC reported (,250 ,g/L). On the other hand, the total amount of its related substances in the treated effluent was less than 5% of OTC. Concentrations of ,-apo-OTC and ,-apo-OTC increased along the river, from 5.76 ± 0.63 and 2.08 ± 0.30 ,g/L at site R2 to 11.9 ± 4.9 and 12.0 ± 4.6 ,g/L at R4, respectively, although EOTC decreased from 31.5 ± 3.8 to 12.9 ± 1.1 ,g/L, respectively. The mean concentration of ,-apo-OTC in river sediments was 20.8 ± 7.8 mg/kg, and its ratio to OTC was approximately 0.11, nearly twice the ratio of ,-apo-OTC and EOTC to OTC (0.058 ± 0.014 and 0.061 ± 0.015, respectively). [source]

    Toxic event detection by respirometry and adaptive principal components analysis

    ENVIRONMETRICS, Issue 6 2005
    Sébastien Le Bonté
    Abstract Two methods based on adaptive principal components analysis (APCA) are compared to extract, from primary measurements, information related to the changes of wastewater characteristics induced by variable weather conditions and/or to the presence of toxic substances. The primary measurements are activated sludge respiratory data obtained by short-term experiments in an on-line batch respirometer, combined with indirect information on soluble pollution (UV-visible absorbance, turbidity, pH, etc.) and wastewater flow rate. The Benchmark Simulation Model 1 (BSM1), which simulates the functioning of a large wastewater treatment plant by activated sludge, has been used to obtain large data sets and to test the proposed APCA method, which has then been applied to real wastewater characteristics. Copyright © 2005 John Wiley & Sons, Ltd. [source]

    Competition between two nitrite-oxidizing bacterial populations: a model for studying the impact of wastewater treatment plant discharge on nitrification in sediment

    Christine Féray
    Abstract Nitrobacter, a ubiquitous nitrite oxidizer in natural and anthropized environments, is commonly studied as the model genus performing the second stage of nitrification. In rivers, wastewater treatment plant discharges may affect the nitrite-oxidizing activity and the responsible genera that are largely associated with sediment. We used a laboratory batch culture approach with Nitrobacter wynogradskyi ssp. agilis strain AG and Nitrobacter hamburgensis strain X14 to characterize the possible stress effect of wastewater effluent on these populations and to study the possible competition between an effluent strain (X14) and a sediment strain (AG) over a 42-day incubation time. Immunofluorescence enumerations of each strain showed that they both survived and settled in the sediment, indicating that there was no significant stress effect due to chemical changes caused by the effluent. The development of the strains' density and activity was directly correlated with the available nitrite concentration. Nevertheless, the potential specific activity was not constant along the so-called mixotrophic (non-limiting nitrite concentration) and heterotrophic (nitrite depletion) conditions. This illustrates the inducibility of the nitrite oxidoreductase and indicates the metabolic versatility of the strains. In our experimental conditions, the preferentially autotrophic AG strain appeared more competitive than the preferentially mixo- or heterotrophic X14 strain, including in heterotrophic environment. [source]

    Effects of stream restoration and wastewater treatment plant effluent on fish communities in urban streams

    FRESHWATER BIOLOGY, Issue 10 2006
    Summary 1. Fish community characteristics, resource availability and resource use were assessed in three headwater urban streams in Piedmont North Carolina, U.S.A. Three site types were examined on each stream; two urban (restored and unrestored) and a forested site downstream of urbanisation, which was impacted by effluent from a wastewater treatment plant (WWTP). Stream basal resources, aquatic macroinvertebrates, terrestrial macroinvertebrates and fish were collected at each site. 2. The WWTPs affected isotope signatures in the biota. Basal resource, aquatic macroinvertebrate and fish ,15N showed significant enrichments in the downstream sites, although ,13C signatures were not greatly influenced by the WWTP. Fish were clearly deriving a significant part of their nutrition from sewage effluent-derived sources. There was a trend towards lower richness and abundance of fish at sewage-influenced sites compared with urban restored sites, although the difference was not significant. 3. Restored stream sites had significantly higher fish richness and a trend towards greater abundance compared with unrestored sites. Although significant differences did not exist between urban restored and unrestored areas for aquatic and terrestrial macroinvertebrate abundances and biotic indices of stream health, there appeared to be a trend towards improvements in restored sites for these parameters. Additional surveys of these sites on a regular basis, along with maintenance of restored features are vital to understanding and maximising restoration effectiveness. 4. A pattern of enriched ,13C in fish in restored and unrestored streams in conjunction with enriched ,13C of terrestrial invertebrates at these sites suggests that these terrestrial subsidies are important to the fish, a conclusion also supported by isotope cross plots. Furthermore, enriched ,13C observed for terrestrial invertebrates is consistent with some utilisation of the invasive C4 plants that occur in the urban riparian areas. [source]

    Development of a correlation to study parameters affecting nitrification in a domestic wastewater treatment plant

    Gulnur Coskuner
    Abstract BACKGROUND: Nitrification performance of an activated sludge reactor treating weak domestic wastewater was investigated for 11 months. Ammonia nitrogen removals were investigated as a function of wastewater composition and operational conditions. Backward elimination experimental design was used to determine the influence of the most important independent variables on NH3 -N removal efficiencies. Influent ammonia and biological oxygen demand (BOD5) concentrations, hydraulic retention time (HRT), mixed liquid suspended solids (MLSS), temperature, pH and dissolved oxygen (DO) concentration were considered as independent variables. This study aimed to find the most important parameters to describe nitrification performance. RESULTS: The presence of nitrification was confirmed by ammonia and nitrate variations throughout the reactor; ammonia oxidizing bacteria (AOB) populations were determined using a fluorescence in situ hybridization (FISH) method. MLSS concentration, influent BOD5 concentration and temperature were found to be the most influential factors on nitrification performance. The empirical correlation using multiple linear regressions was statistically significant and produced an adjusted coefficient of multiple determinations (R2adj) of 92.5%. CONCLUSION: Correlation provides a good understanding of the various parameters that affect the nitrification process, and could be extended to other case studies. Using these results, operators can apply proper operational strategies to maintain nitrification in wastewater treatment plants. Copyright © 2007 Society of Chemical Industry [source]

    Biodegradation kinetics of benzene, methyl tert -butyl ether, and toluene as a substrate under various substrate concentrations

    Chi-Wen Lin
    Abstract Owing to the complexity of conventional methods and shortcomings in determining kinetic parameters, a convenient approach using the nonlinear regression analysis of Monod or Haldane type nonlinear equations is presented. This method has been proven to provide accurate estimates of kinetic parameters. The major work in this study consisted of the testing of aromatic compound-degrading cultures in batch experiments for the biodegradation of benzene, methyl tert -butyl ether (MTBE), and toluene. Additionally, batch growth data of three pure cultures (i.e., Pseudomonas aeruginosa YAMT421, Ralstonia sp. YABE411 and Pseudomonas sp. YATO411) isolated from an industrial petrochemical wastewater treatment plant under aerobic conditions were assessed with the nonlinear regression technique and with a trial-and-error procedure to determine the kinetic parameters. The growth rates of MTBE-, benzene-, and toluene-degrading cultures on MTBE, benzene, and toluene were significant. Monod's model was a good fit for MTBE, benzene and toluene at low substrate concentrations. In contrast, Haldane's equation fitted well in substrate inhibition concentration. Monod and Haldane's expressions were found to describe the results of these experiments well, with fitting values higher than 98%. The kinetic parameters, including a maximum specific growth rate (µm), a half-saturation constant (Ks), and an inhibition constant (Ki), were given. Copyright © 2007 Society of Chemical Industry [source]

    Sequential anaerobic/aerobic biological treatment of olive mill wastewater and municipal wastewater

    Nikolaos Gizgis
    Abstract This work investigated the efficiency of the combined anaerobic/aerobic biological co-treatment of olive mill wastewater and primary municipal wastewater. A laboratory-scale (6.5 L) upflow anaerobic sludge bed reactor received a mixture of olive mill wastewater and primary municipal wastewater at a loading rate ranging between 3 and 7 kg chemical oxygen demand (COD) m,3 day,1. The input COD concentration ranged between 1800 and 4400 mg L,1. The anaerobic reactor was operated at mesophilic conditions (35 °C). The effluent organic load was between 400 and 600 mg COD L,1, while the suspended solids removal efficiency varied between 75 and 95%. Average biogas production ranged between 3 and 4 L g,1 COD removed. The anaerobic reactor effluent was further treated in a laboratory-scale activated sludge treatment plant. Aerobic treatment reduced the organic load even further to 85,175 mg COD L,1. However, the final effluent still retained a significant level of colour. Removal of colour was possible by ozonation or coagulation. Finally, the treated effluent was non-ecotoxic, as indicated by the Daphnia magna toxicity test. This treatment method showed that it is feasible to treat olive mill wastewater in a municipal wastewater treatment plant by means of a high-rate anaerobic reactor located between the primary clarifier and the aeration tank. Copyright © 2006 Society of Chemical Industry [source]

    Evaluation of a simple batch distillation process for treating wastes from metalworking industries

    P Cańizares
    Abstract A simple batch distillation process for the treatment of two types of industrial waste generated in a metalworking factory has been evaluated. Both types of waste are oil-in-water emulsions composed of numerous compounds and each type has a high content of water-soluble species. The water-soluble nature of the wastes precludes the use of conventional treatment technologies, such as ultrafiltration or chemical emulsion breaking, since they need to be complemented with additional treatment processes that would probably increase the cost considerably. A simple characterization of the liquid,vapour equilibrium and a scale-up study has demonstrated the applicability of this technology. The process allows 90% of the waste to be recovered as water, thus achieving the required quality limits for discharge into a municipal wastewater treatment plant. An approximate estimation of capital investment and operating costs for an existing case has shown the economic viability of this process. Copyright © 2004 Society of Chemical Industry [source]

    Evaluation of the environmental implications to include structural changes in a wastewater treatment plant

    Núria Vidal
    Abstract The environmental implications of including structural changes in a wastewater treatment plant to decrease effluent concentrations of nitrogen were evaluated in this study. Environmental effects from these structural changes were assessed by using the Life Cycle Assessment theoretical framework. The wastewater treatment plant selected as a reference scenario had an activated sludge configuration. The Ludzack,Ettinger and Oxidation Ditch configurations were selected as modifications of the reference scenario. Results from this study show that the inclusion of nitrogen removal mechanisms in the configuration of the plant reduces the effect of the plant on the eutrophication, but simultaneously increases the effect on the consumption of abiotic resources, global warming, acidification and human toxicity. These general trends, however, vary depending on the configuration selected to remove nitrogen. Taking all the impacts together, the Oxidation Ditch configuration would cause less environmental impact than the Ludzack,Ettinger configuration, given the characteristics of the selected scenarios. © 2002 Society of Chemical Industry [source]

    Alternatives for Reducing the Environmental Impact of the Main Residue From a Desalination Plant

    Montse Meneses
    Summary One of the most important problems today is the scarcity of fresh water safe enough for human, industrial, and agricultural use. Desalination is an alternative source of fresh water supply in areas with severe problems of water availability. Desalination plants generate a huge amount of brine as the main residual from the plant (about 55% of collected seawater). Because of that, it is important to determine the best environmental option for the brine disposal. This article makes a global environmental analysis, under Spanish conditions, of a desalination plant and an environmental assessment of different final brine disposals, representing a range of the most common alternatives: direct disposal, wastewater treatment plant (WWTP) outflow dilution, and dilution with seawater. The environmental profile of the plant operation and a comparison of the brine final disposal alternatives were established by means of the life cycle assessment (LCA) methodology. From an analysis of the whole plant we observed that the highest environmental impact was caused by energy consumption, especially at the reverse osmosis stage, while the most relevant waste was brine. From an analysis of brine final disposal we have elaborated a comparison of the advantages and detriments of the three alternatives. As all of them might be suitable in different specific situations, the results might be useful in decisions about final brine disposal. [source]

    Development of a mechanistic model for biological nutrient removal activated sludge systems and application to a full-scale WWTP

    AICHE JOURNAL, Issue 6 2010
    Bing-Jie Ni
    Abstract In wastewater treatment plants (WWTPs) the production of nitrite as an intermediate in the biological nutrient removal (BNR) process has been widely observed, but not been taken into account by most of the conventional activated sludge models yet. This work aims to develop a mechanistic mathematical model to evaluate the BNR process after resolving such a problem. A mathematical model is developed based on the Activated Sludge Model No.3 (ASM3) and the EAWAG Bio-P model with an incorporation of the two-step nitrification,denitrification, the anoxic P uptake, and the associated two-step denitrification by phosphorus accumulating organisms. The database used for simulations originates from a full-scale BNR municipal wastewater treatment plant. The influent wastewater composition is characterized using batch tests. Model predictions are compared with the measured concentrations of chemical oxygen demand (COD), NH -N, NO -N, NO -N, PO -P, and mixed liquid volatile suspended solids. Simulation results indicate that the calibrated model is capable of predicting the microbial growth, COD removal, nitrification and denitrification, as well as aerobic and anoxic P removal. Thus, this model can be used to evaluate and simulate full-scale BNR activated sludge WWTPs. © 2009 American Institute of Chemical Engineers AIChE J, 2009 [source]

    Modeling and simulation of the sequencing batch reactor at a full-scale municipal wastewater treatment plant

    AICHE JOURNAL, Issue 8 2009
    Bing-Jie Ni
    Abstract In this work, we attempted to modify the Activated Sludge Model No.3 and to simulate the performance of a full-scale sequencing batch reactor (SBR) plant for municipal wastewater treatment. The long-term dynamic data from the continuous operation of this SBR plant were simulated. The influent wastewater composition was characterized using batch measurements. After incorporating all the relevant processes, the sensitivity of the stoichiometric and kinetic coefficients for the model was thoroughly analyzed prior to the model calibration. The modified model was calibrated and validated with the data from both batch- and full-scale experiments. Model predictions were compared with routine data in terms of chemical oxygen demand, NH4+ -N and mixed liquid volatile suspended solids in the SBR, combined with batch experimental data under different conditions. The model predictions match the experimental results well, demonstrating that the model is appropriate to simulate the performance of a full-scale wastewater treatment plant even operated under perturbation conditions. © 2009 American Institute of Chemical Engineers AIChE J, 2009 [source]

    Nutrient Uptake in a Large Urban River,

    Catherine A. Gibson
    Abstract:, Small streams have been shown to be efficient in retaining nutrients and regulating downstream nutrient fluxes, but less is known about nutrient retention in larger rivers. We quantified nutrient uptake length and uptake velocity in a regulated urban river to determine the river's ability to retain nutrients associated with wastewater treatment plant (WWTP) effluent. We measured net uptake of soluble reactive phosphorus (SRP), dissolved organic phosphorus, ammonium (NH4), nitrate, and dissolved organic nitrogen in the Chattahoochee River, Atlanta, GA by following the downstream decline of nutrients and fluoride from WWTP effluent on 10 dates under low flow conditions. Uptake of all nutrients was sporadic. On many dates, there was no evidence of measurable nutrient uptake lengths within the reach; indeed, on several dates release of inorganic N and P within the sample reach led to increased nutrient export downstream. When uptake occurred, SRP uptake length was negatively correlated with total suspended solids and temperature. Uptake velocities of SRP and NH4 in the Chattahoochee River were lower than velocities in less-modified systems, but they were similar to those measured in other WWTP impacted systems. Lower uptake velocities indicate a diminished capacity for nutrient uptake. [source]

    PLS: A versatile tool for industrial process improvement and optimization

    Alberto Ferrer
    Abstract Modern industrial processes are characterized by acquiring massive amounts of highly collinear data. In this context, partial least-squares (PLS) regression, if wisely used, can become a strategic tool for process improvement and optimization. In this paper we illustrate the versatility of this technique through several real case studies that basically differ in the structure of the X matrix (process variables) and Y matrix (response parameters). By using the PLS approach, the results show that it is possible to build predictive models (soft sensors) for monitoring the performance of a wastewater treatment plant, to help in the diagnosis of a complex batch polymerization process, to develop an automatic classifier based on image data, or to assist in the empirical model building of a continuous polymerization process. Copyright © 2008 John Wiley & Sons, Ltd. [source]

    A petri nets-based process planning system for wastewater treatment,

    Albert W. L. Yao
    Abstract It is always challenging to simulate, debug or diagnose automated systems. The aim of this paper is to present the development of a convenient tool for reengineering the control system in a complicated industrial wastewater treatment plant. In this project, a PC-based Human-Machine Interface (HMI) in conjunction with Petri nets (PN) theory is adopted to develop and simulate the operational process for wastewater treatment. The resultant tool offers many advantages to the reality of the automated control world. It not only reduces the process reengineering time and the cost of error recovery, but also builds a panel of human interface for the process. The discrete event control sequence of wastewater treatment can be easily modeled and evaluated before its build-up. Furthermore, this PN-based system can be used as an online diagnostic tool when the wastewater treatment process is malfunctioning. That is, the presented PN tool provides an adequate means for offline process development, simulation, performance evaluation, and quick online process diagnosis. Copyright © 2010 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society [source]

    Design and application of a membrane bioreactor unit to upgrade and enhance the required performance of an installed wastewater treatment plant

    Teresa Castelo-Grande
    Abstract Wastewater treatment plants (WWTPs) are nowadays common solutions to improve the quality of streams and soils. However, there are still many issues required to be solved within these plants. We were commissioned to redesign a WWTP in Amarante, Portugal, which was not working properly. Among the several units we have designed, there is a membrane bioreactor representing one of the main units of this remodelled WWTP. The biological treatment stage at the upgraded WWTP will take place in the remodelled primary and secondary settlers and in the remodelled and improved biological reactor. Hence, the primary settler is readapted in such a way that it functions as the anoxic area of the biological treatment, while the aerobic treatment will be sequentially performed at the remodelled biological reactor and at the actual secondary settler. Membrane treatment will be performed by using ultrafiltration membranes. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd. [source]

    Impact of membrane solid,liquid separation on design of biological nutrient removal activated sludge systems

    M. Ramphao
    Abstract Installing membranes for solid,liquid separation into biological nutrient removal (BNR) activated sludge (AS) systems makes a profound difference not only in the design of the BNR system itself, but also in the design approach for the whole wastewater treatment plant (WWTP). In multizone BNR systems with membranes in the aerobic reactor and fixed volumes for the anaerobic, anoxic, and aerobic zones (i.e., fixed volume fractions), the mass fractions can be controlled (within a range) with the interreactor recycle ratios. This zone mass fraction flexibility is a significant advantage in membrane BNR systems over conventional BNR systems with SSTs, because it allows for changing of the mass fractions to optimize biological N and P removal in conformity with influent wastewater characteristics and the effluent N and P concentrations required. For PWWF/ADWF ratios in the upper range (fq , 2.0), aerobic mass fractions in the lower range (fmaer < 0.60), and high (usually raw) wastewater strengths, the indicated mode of operation of MBR BNR systems is as extended aeration WWTPs. Although the volume reduction compared with equivalent conventional BNR systems with secondary settling tanks is not as large (40% to 60%), the cost of the membranes can be offset against sludge thickening and stabilization costs. Moving from a flow-unbalanced raw wastewater system to a flow-balanced (fq = 1), low (usually settled) wastewater strength system can double the ADWF capacity of the biological reactor, but the design approach of the WWTP changes from extended aeration to include primary sludge stabilization. The cost of primary sludge treatment then has to be paid from the savings from the increased WWTP capacity. © 2005 Wiley Periodicals, Inc. [source]

    Adsorption of Transition Metals in Aqueous Solutions by Fluted Pumpkin (Telfairia occidentalisHook f),Waste

    Michael Horsfall Jr.
    The adsorption of some divalent transition metal (Hg, Rh, Pt, and Pd) ions in aqueous solution onto fluted pumpkin waste biomass has been investigated. The data were discussed in terms of ionic radii, surface area, and the hard,soft acid,base (HSAB) concept. The monolayer sorption capacities as obtained by the Langmuir adsorption isotherm model were determined to be ca. 9.89,mg/g, 9.81,mg/g, 10.59,mg/g, and 6.84,mg/g for for HgII, RhII, PtII, and PdII, respectively. The results are relevant for the optimal design of a wastewater treatment plant and for prediction of model parameters of sorbate,sorbent interactions. [source]

    Three-Dimensional Optimization of Urban Drainage Systems

    A. Freire Diogo
    A global mathematical model for simultaneously obtaining the optimal layout and design of urban drainage systems for foul sewage and stormwater is presented. The model can handle every kind of network, including parallel storm and foul sewers. It selects the optimal location for pumping systems and outfalls or wastewater treatment plants (defining the natural and artificial drainage basins), and it allows the presence of special structures and existing subsystems for optimal remodeling or expansion. It is possible to identify two basic optimization levels: in the first level, the generation and transformation of general layouts (consisting of forests of trees) until a convergence criterion is reached, and in the second level, the design and evaluation of each forest. The global strategy adopted combines and develops a sequence of optimal design and plan layout subproblems. Dynamic programming is used as a very powerful technique, alongside simulated annealing and genetic algorithms, in this discrete combinatorial optimization problem of huge dimension. [source]