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Two two-stage sequencing batch reactors (TSSBR), one attached-growth and one suspended-growth, were operated under three levels of wastewater concentration (approximately 4,000, 2,000 and 500 TOC mg/L), respectively, to compare the pH and ORP (oxidation-reduction potential) patterns and system performance. In both TSSBR systems, the pH and ORP profiles varied with organic loading yet exhibited consistent patterns with distinctive features suitable for real-time control. For all runs at the three levels of influent, both systems achieved similar levels of treatment for BOD5, TOC and TSS of over 97.5, 93.4, and 97.3%, respectively. The attached-growth system out performed the suspended-growth system in achieving the same levels of treatment at much shorter aeration cycle times. The treatment efficiency for NO3(-)-N and PO4(-3) was greatly affected by the carbon content in the wastewater, and the best treatment was achieved during the TOC approximately 4,000 mg/L runs with final effluent at 4.0 and 21.3 mg/L, respectively.
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PMID:Swine wastewater treatment using attached-growth and suspended-growth two stage sequencing batch reactors with real-time control. 1140 98

This is the first of two papers each dealing with a specific technological option for replacing the Fenton's reagent with simpler processes for treating industrial wastewater. In particular, the paper reports the results of an investigation aimed to check, at lab scale, the effectiveness of a chemical process (i.e., alkalinisation with or without post-ozonation) for treating tannery wastewater whose residual COD, measured after conventional biological treatment, result still higher than the Italian COD Maximum Allowable Concentration (MAC) value (i.e., 160 mgO2/L). The results have demonstrated that when the value of residual COD lies in the range 200 divided by 250 mgO2/L, a simple alkalinisation with NaOH, up to pH 12.5, allows to reach the MAC value with an alkali consumption equivalent to the acid consumption required by the Fenton treatment and with a chemical sludge production significantly lower, i.e. approximately 0.7 kg(dry)/m3 instead of approximately 1.5 kg(dry)/m3. Conversely, when the value of the residual COD lies in a higher range (i.e. 300 divided by 350 mgO2/L), in order to reach the COD MAC value, alkalinisation (from pH 8 to pH 12.5) must be followed by an ozonation post-treatment. From the chemical stand point, the paper clearly demonstrates that analyzing only simple "gross parameters" (i.e., TSS, TOC, COD, BOD5 and EC20) it is possible to get useful information about the chemical properties of the organic pollutants occurring in tannery wastewater.
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PMID:Treatment options for tannery wastewater. I: Alkalinization with or without post-ozonation. 1177 Jan 58

The objective of this research is to explore a precise and fast way of monitoring water chemical and biochemical quality in the reservoirs of Shenzhen, China. Water quality change in 1988 and 1996 are detected by synthesizing satellite data and ground-based data. One scene Thematic Mapper (TM) image in winter of 1996 was acquired and the simultaneous in situ measurement, sampling and analysis were performed. Main methods include radiometric calibration of TM remote sensor, atmospheric correction to image data and statistical model construction. The results indicate that satellite-based estimates and in situ measured water reflectance have very high correlation, and the root mean square differences between two kinds of indices are close to 0.02-0.03 for each TM band in Visible-Near Infrared (VI-NIR) range. Statistical relationship between calibrated image data (average of 5 x 5 pixels) of TM bands and laboratory analyzed data of water samples indicated reflectance of TM band 1 to band 4 and organic pollution measurements such as TOC, BOD and COD had higher correlation. The same scene TM data in the winter of 1988 was processed in the same procedure. Results indicate that water quality of most reservoirs have become worse. Water of eastern reservoirs near Dongjiang River is characterized with higher TOC and TSS, and water of western reservoirs is characterized with higher BOD and COD.
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PMID:Water quality change in reservoirs of Shenzhen, China: detection using LANDSAT/TM data. 1520 84

Runoff quality draining from 17.14 km2 urban catchment in Johor Bahru, Malaysia, was analysed. The land-use consists of residential (30.3%), agricultural (27.3%), open space (27.9%), industrial (8.1%) and commercial (6.4%) areas. Three storm events were sampled in detail. These storms produced stormflow between 0.84 mm and 27.82 mm, and peakflow from 2.19 m3/s to 42.36 m3/s. Water quality showed marked variation during storms especially for TSS, BOD and COD with maximum concentrations of 778 mg/l, 135 mg/l and 358 mg/l, respectively. Concentrations of TOC, DOC, NH3-N, Fe and level of colour were also high. In general, the river quality is badly polluted and falls in Class V based on the Malaysian Interim National Water Quality Standards. Event Mean Concentrations (EMC) for various parameters varied considerably between storms. The largest storm produced higher EMC for TSS, NO3-N and SS whereas the smaller storms tend to register higher EMC for BOD, COD, NH3-N, TOC, Ca, K, Mg, Fe and Zn. Such variations could be explained in terms of pollutant availability and the effects of flushing and dilution. Based on a three-month average recurrence interval (ARI) of rainfall, the estimated event loadings (ton/ha) of TSS, BOD, COD, TOC, NH3-N and NO3-N were 0.055, 0.016, 0.012, 0.039, 0.010, 0.0007 and 0.0002, respectively. Heavy metals present in trace quantities. Storms with 3 months ARI could capture about 70% of the total annual loads of major pollutants.
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PMID:Runoff quality and pollution loadings from a tropical urban catchment. 1644 81

Characteristics of pollutants from urban surface runoff were investigated. Two catchments with a seperated system in Macau were selected for sampling on rainfall events during the period of August to November, 2005. Water quality parameters such as pH, turbidity, TSS, COD, TOC, TN, TP, Zn, Pb, and Cu were analyzed. The results show that the commercial-residential urban catchment shows high level of COD, TN, TP, and the park urban catchment has high TN and TP concentration. From the pollutograph analysis, the peak of TSS, TN, TP concentration appears in the first and the third sample respectively in ELH and YLF catchments, and then the pollutants concentration tend to decrease. Regression analysis between TSS and TN & TP in two urban catchments resulted in a high value (R2 > 0.95) of the coefficient of determination R2 indicating a close relationship between soil losses and nitrogen & phosphorus discharged from surface runoff. The profile of TSS and COD discharged from surface runoff relates greatly to the surface flow change, whereas the surface flow change has little influence on the profile of TN and TP. The heavy metals such as Zn, Pb and Cu fluctuate with the continuous input of vehicles during rainfall events. Pollutants such as TSS, TN, COD discharged from surface runoff depend greatly on the dry periods and storms intensity in such two urban catchments.
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PMID:[Characterization of urban surface runoff in two urban catchments in Macau]. 1711 27

Highway stormwater runoff quality data were collected from throughout California during 2000-2003. Samples were analyzed for conventional pollutants (pH, conductivity, hardness, and temperature); aggregates (TSS, TDS, TOC, DOC); total and dissolved metals (As, Cd, Cr, Cu, Ni, Pb, and Zn); and nutrients (NO(3)-N, TKN, total P, and ortho-P). Storm event and site characteristics for each sampling site were recorded. A statistical summary for chemical characteristics of highway runoff is provided based on statewide urban and non-urban highways. Constituent event mean concentrations (EMCs) were generally higher in urban highways than in non-urban highways. The chemical characteristics of highway runoff in California were compared with national highway runoff chemical characterization data. The results obtained in California were generally similar to those found in other states. The median EMC for Pb measured in studies conducted in previous decades was much higher than the current median Pb EMC in California. The lower Pb EMC in California compared to previous highway runoff monitoring is believed to be due to the elimination of leaded gasoline. An attempt was also made to identify surrogate constituents within a general family of water quality categories using Spearman correlations and selected pairs with Spearman coefficients greater than 0.8. The strongest correlations were observed among parameters associated with dissolved minerals (EC, TDS, and chloride); organic carbon (TOC and DOC); petroleum hydrocarbons (TPH and O & G); and particulate matter (TSS and turbidity). Within the metals category, total iron concentration was highly correlated with most total metal concentrations. The correlations between total and dissolved concentrations were all less than 0.8, even between total and dissolved concentrations of the same metals. Multiple linear regression (MLR) analyses were performed to evaluate the impact of various site and storm event variables on highway runoff constituent EMCs. Parameters found to have significant impacts on highway runoff constituent EMCs include: total event rainfall (TER); cumulative seasonal rainfall (CSR); antecedent dry period (ADP); contributing drainage area (DA); and annual average daily traffic (AADT). Surrounding land use and geographic regions were also determined to have a significant impact on runoff quality. The MLR model was also used to predict constituent EMCs. Model performance determined by comparing predicted and measured values showed good agreement for most constituents.
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PMID:Characterization and prediction of highway runoff constituent event mean concentration. 1716 4

A method is described to evaluate two methods of phosphorus (P) management in lakes using aluminum sulfate (alum)--in-lake and tributary (inflow) treatment--and compare the resulting in-lake P levels. For in-lake treatment, a technique is described to calculate the optimum alum dose based on measurement of "mobile P" in lake sediments. Mobile P is defined as loosely sorbed and Fe-P, the fraction of sediment P subject to release under anoxic conditions. A linear relationship (r2 = 0.90) was found between P-release rate and the mobile-P content in sediment cores. Addition of alum to aliquots of sediment showed predictable relationships between (i) alum dose and aluminum-bound P (Al-P) formed and (ii) mobile-P loss and Al-P formation. The decrease in sediment P release that would result from in-lake alum treatment was estimated from the residual mobile P after treatment. A method also is presented to estimate the amount of alum needed to bind potentially mineralizable sediment organic P. For inflow treatment, jar tests with urban runoff in metropolitan St. Paul and Minneapolis, Minnesota (USA) were used to study effects of alum dose on P removal from water. With sufficient mixing, a dose of 8 mg AlL(-1) reduced total P (TP) and soluble reactive P to low levels regardless of pH, TSS, and TOC, but doses <or= 4 mg AlL(-1) did not significantly reduce TP compared with settling alone. A modeling approach is described to compare the effects of inflow and in-lake treatment, and a case study is developed to illustrate the approach for typical eutrophic lakes.
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PMID:A method for comparative evaluation of whole-lake and inflow alum treatment. 1729 15

Petroleum production wastewater is highly saline and contains large amounts of Ca, Mg, sulphides and hydrocarbons. The reuse of this wastewater in the secondary oil recovery can provide pollution prevention and water conservation benefits. Injection of water to the oil deposits is a frequently used method for secondary oil recovery. This operation is performed at high pressures and temperatures, because of which a suitable water quality is required to avoid deposit formation, scaling and clogging effects. The objective of this study was to select the best treatment system for the oil production wastewater, generated in one of the Mexican oil extraction facilities, for the implementation of this kind of reuse by injecting the treated water to sand formations with 12-15% porosity. A complete characterization of the petroleum production wastewater was done. Based on laboratory tests, three basic treatment options were suggested and evaluated in a pilot plant. The most suitable treatment was determined by injecting the different treated waters in samples of the real formations. The selected system consists in softening, followed by oxidation, decarbonation and filtration. This train allowed 99.8% hardness removal, a complete S(2-) removal, as well as 99% TSS, 78% TOC, 98% Sr, 86% Ba, 51% Si and 17% Fe removals.
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PMID:Treatment of petroleum production wastewater for reuse in secondary oil recovery. 1841 48

The use of an integrated treatment scheme consisting of wet hydrogen peroxide catalytic oxidation (WHPCO) followed by two-stage upflow anaerobic sludge blanket (UASB) reactor (10l each) for the treatment of olive mill wastewater was the subject of this study. The diluted wastewater (1:1) was pre-treated using Fenton's reaction. Optimum operating conditions namely, pH, H(2)O(2) dose, Fe(+2), COD:H(2)O(2) ratio and Fe(+2):H(2)O(2) ratio were determined. The UASB reactor was fed continuously with the pre-treated wastewater. The hydraulic retention time was kept constant at 48h (24h for each stage). The conventional parameters such as COD, BOD, TOC, TKN, TP, TSS, oil and grease, and total phenols were determined. The concentrations of polyphenolic compounds in raw wastewater and effluents of each treatment step were measured using HPLC. The results indicated a good quality final effluent. Residual concentrations of individual organic compounds ranged from 0.432 mg l(-1) for rho-hydroxy-benzaldhyde to 3.273 mg l(-1) for cinnamic acid.
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PMID:Integrated treatment of olive mill wastewater (OMW) by the combination of Fenton's reaction and anaerobic treatment. 1870 83

The catalytically oxidized olive mill wastewater (OMW) was subjected to continuous anaerobic treatment using two treatment schemes. The 1st step in both schemes was an up-flow anaerobic sludge blanket (UASB) reactor (20l). The 2nd step was either a hybrid UASB reactor or a classical one (10l, each). The 1st stage was operated at constant hydraulic retention time (HRT) of 24h. The organic loading rate (OLR) varied from 3.4 to 4.8 kg COD/m(3)d depending on the quality of the pretreated wastewater. The results obtained indicated that, the 1st step UASB reactor achieved a COD percentage removal value of 53.9%. Corresponding total BOD(5) and TSS removal were 51.5% and 68.3%, respectively. The results obtained indicated that the hybrid UASB reactor as a 2nd step produced better quality effluent as compared to the classical one. This could be attributed to the presence of the packing curtain sponge with active biomass in the sedimentation part of hybrid UASB reactor which minimizes suspended solids washout, consequently enhancement of the efficiency of the reactor. Available data showed that a two stage system consisting of a classical and a hybrid UASB reactor operated at a total HRT of 48h and OLR of 2.0 kg COD/m(3)d provided promising results. Removal values of COD(total), BOD(5 total), TOC, VFA, oil and grease were 83%, 84%, 81%, 93% and 81%, respectively. Based on the available data, the use of a two stage anaerobic system consisting of a classical UASB reactor followed by a hybrid UASB as a post-treatment step for catalytically oxidized OMW is recommended.
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PMID:Potentials of anaerobic treatment for catalytically oxidized olive mill wastewater (OMW). 1907 Apr 81


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