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The physicochemical quality of drinking and hot waters of 67 buildings in different parts of Finland was studied. Some of the buildings used processed groundwater and some processed surface water. Drinking water samples were taken from the first tap after the water was led into the building. Hot water samples were taken from taps and showers and from circulating hot water systems. Thy physicochemical quality of drinking water was affected by the origin of raw water used in the water plants. Drinking water from surface water plants contained more organic matter and less metals than water from groundwater plants. The quality goal for total organic carbon (TOC; < 2 mg l-1) was exceeded by all drinking water samples. In groundwaters, the variation in the content of non-purgeable organic carbon (NPOC) was great, probably because artificial groundwaters processed from surface waters were included in this group. Unlike in natural waters, the correlation between KMnO4-number and NPOC in the processed waters was weak. This result shows that KMnO4-number is an inaccurate estimate for organic carbon in processed waters. Corrosion of pipe materials was seen as elevated concentrations of iron and copper. In general, the physicochemical quality of drinking and hot waters in the buildings was rather similar.
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PMID:Physicochemical quality of drinking and hot waters in Finnish buildings originated from groundwater or surface water plants. 929 65

Degradation of 29 dyes by means of an activated carbon fiber (ACF) electrode electrolysis system was performed successfully. Almost all dye solutions tested were decolorized effectively in this ACF electrolysis process. Internal relationships between treatment mechanisms and chemical composition of the dye have been discussed in this paper. Generally, it is shown that higher solubility leads to greater degradation in the process. Dyes with many -SO3-, COO-, -SO2NH2, -OH, hydrophilic groups, and azo linkages are susceptible to reduction. However, dyes with many -C=O, -NH-and aromatic groups, and hydrophobic groups, tend to be adsorbed. For dyes with -SO3-, COOH and -OH groups, if their molecules linearly spread in solution and have a significant tendency to form colloids by hydrogenous bonding, they also tend to be adsorbed and flocculated. Typical dynamic electrolysis of dye Acid Red B, Vat Blue BO and Disperse Red E-4B shows how the two major mechanisms, degradation and adsorption, act differently during treatment. Reduction occurs evenly during treatment. During the dominant adsorption process, after certain amount of iron is generated, colloid precipitation occurs and TOC and color are rapidly removed.
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PMID:Degradation of dye solution by an activated carbon fiber electrode electrolysis system. 1137 88

Dyeing and finishing of textile yarns and fabrics are extremely important processes in terms of both quality and environmental concerns. Among the commercial textile dyes, particularly disperse dyestuffs are of environmental interest because of their widespread use, their potential for formation of toxic aromatic amines and their low removal rate during aerobic waste treatment as well as advanced chemical oxidation. Thus, in the present paper ferrous iron coagulation, ozonation and ferrous iron-catalyzed ozonation were employed at varying pH (3-13) and Fe(II)-ion doses (0.09-18mM) for the treatment of a simulated disperse dye-bath (average initial apparent color as absorbance at 566nm=815.4m(-1); COD(0)=3784mgl(-1); TOC(0)=670mgl(-1); BOD(5,0)=58mgl(-1)) that more closely resembled an actual dyehouse effluent than an aqueous disperse dye solution. Coagulation with 5000mgl(-1) FeSO4-7H2O (18mM Fe(2+)) at pH 11 removed up to 97% color and 54% COD, whereas oxidation via ozonation alone (applied ozone dose=2300mgl(-1)) was only effective at pH 3, resulting in 77% color and 11% COD removal. Fe(II)-ion-catalyzed ozonation (3.6mM Fe(2+) at pH 3; Fe(2+):O3 molar ratio 1:14) eliminated 95% color and 48% COD and appeared to be the most attractive option among the investigated chemical treatment methods as for its applicability at the natural acidic pH of the disperse dye-bath effluent and at relatively low Fe(2+)-ion doses as compared to ferrous sulfate coagulation. However, no TOC reduction was observable for ozonation and catalytic ozonation at the investigated reaction conditions (14gl(-1) O3 at pH 3). An average six-fold enhancement in the biodegradability parameter of the synthetic dye wastewater expressed in terms of the BOD(5)/COD ratio could be achieved by the investigated chemical treatment methods.
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PMID:Treatability of a simulated disperse dye-bath by ferrous iron coagulation, ozonation, and ferrous iron-catalyzed ozonation. 1148 26

Catalytic wet peroxide oxidation (CWPO) of diluted aqueous solutions of phenol has been studied over a series of heterogeneous catalysts at 100 degrees C under 1 MPa air pressure. Several catalysts were prepared and tested including zeolitic materials exchanged with metallic ions such as Fe and Cu and different mixed oxides. Likewise, a Fe-TS-1 zeolite was synthesised by isomorphous substitution of Si atoms by Fe and Ti into the MFI zeolitic framework through hydrothermal synthesis of wetness-impregnated Fe2O3-TiO2-SiO2 xerogels. This material showed a complete phenol removal and TOC reduction of up to 68% under the reaction conditions, with a low leaching of iron species as compared to Fe-exchanged zeolitic materials. Perovskite of type LaTi(0.45)Cu(0.55)O3 was also tested, showing copper leaching of 22%, with a TOC conversion of 93% and total phenol removal. The capacity of Fe and Cu containing catalysts to promote free radicals in the presence of H2O2 as well as the thermal decomposition of the oxidant under the reaction conditions have also been studied. In the absence of hydrogen peroxide, Fe and Cu catalysts were not effective in order to decrease TOC content.
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PMID:Novel heterogeneous catalysts in the wet peroxide oxidation of phenol. 1169 54

In this study, the effect of ferrate oxidation on stability of microcystins-LR (MCLR) in freeze-dried Oscillatoria amoena was investigated. The toxin was easily decomposed by oxidation with ferrate, and the stability depended on the dosage of ferrate and pH. Simultaneously the product Fe(OH)3 after ferrate oxidation could flocculate the organic compounds so that 50% TOC removal of the extract was reached. The low residual iron reflected the excellent results of coagulation and could meet the standard of drinking water. The results show that ferrate oxidation may be an effective and practical method for the removal of cyanobacterial peptide toxins from drinking water.
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PMID:[Degradation of cyanobacterial peptide hepatotoxins by ferrate]. 1204 29

In this study, the effect of a multiple function reagent-ferrate on the removal of microcystins-LR (MCLR) from freeze-dried Planktothrix sp. was investigated. The toxin was easily decomposed by oxidation with ferrate, and the removal efficiency depended on the dosage of ferrate, pH, and contact time. Simultaneously the reduction product Fe(OH)(3) after ferrate oxidation could flocculate the organic compounds so that 50% TOC removal of the extract was reached. The low residual iron reflected the excellent results of coagulation and could meet the standard of drinking water. Analysis of the treated cyanobacterial extracts by high-performance liquid chromatograph, monitoring absorbance at 210 and 238 nm, suggested that the heptapeptide ring of MCLR and its Adda group had been opened or modified, respectively. So ferrate treatment may be an effective and practical method for the removal of cyanobacterial peptide toxins from eutrophic waters, especially which hold high total organic carbon.
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PMID:Removal of cyanobacterial microcystin-LR by ferrate oxidation-coagulation. 1216 15

One of the major problems encountered in the textile industry is production of highly colored large volumes of wastewater. It is often not possible to predict the characteristics of textile wastewaters by using reported values in the literature because every textile industry is unique with respect to the type of production and the technology and chemicals used in production. Furthermore, the concentrations of pollutants in textile wastewaters vary according to the wastewater management practices and amount of water used in the production. In the first part of this study, wastewater characteristics of a cotton mill textile industry were determined by using the normal and log-normal II distribution functions for flow, COD, TOC, pH and colour. These parameters were measured in the effluent of the equalization tank and the statistical fits were evaluated by using the chi-Square test. It was found that flow and TOC values fitted normal distribution; COD values fitted log-normal II distribution. On the other hand, pH and colour did not fit in to aforementioned distributions. In the second part of this study, the treatment of textile wastewater by coagulation/flocculation/precipitation (CFP) was investigated. Lime, iron and aluminum salts with anionic polielectrolite combination were used as coagulants. Aluminum salts and the combination FeSO4 + lime + polielectrolite were used to remove the colour from mixed textile wastewaters, successfully. On the other hand, FeSO4 + lime + polielectrolite was more effective than aluminum salts to remove the colour from wastewater of indigo dyeing process. In the third part of this work, the removal of sulfide arising from indigo dyeing was investigated. Sulfide removal was accomplished by chemical oxidation and catalyzed air oxidation and removal efficiencies up to ninety percent were found. Chemical oxidation using sodium hypochlorite resulted in color removal too; however, dosages of hypochlorite have to be carefully monitored in order to avoid toxic effects of excess chlorine in water.
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PMID:Chemical treatment of textile wastewaters: statistical characterization, colour and sulfide removal. 1239 14

A fluorescence-quenching method is developed to assess the effect of pH on the coagulation mechanism of humic acids (HA) reacting with metal ions. A polyferric sulfate (PFS) synthesized in our laboratory is adopted as the coagulant to simplify the hydrolysis process and increase the experimental precision. The following results are discovered. When the concentration of PFS increases from 2 to 10 mg/L, the effective pH range of HA removal changes from 4.0-5.0 to 4.0-7.5. At increased coagulation pH, the ferric ions may still react with HA but unable to neutralize the surface charge completely. The residual concentrations of HA measured by fluorescence spectrophotometer are lower than those by TOC, as a consequence of the fluorescence-quenching effect. This demonstrates that the coagulation of HA by PFS at low pH is mainly due to charge-neutralization. The adsorption of the HA on the pre-formed iron hydroxide flocs is accompanied by the dissociation of Fe ions from the floc structure until the equilibrium has been reached, which is evidenced by the presence of the Fe-HA complexes in the solution during adsorption experiment. This is quite different from the characteristics of flocs formed by PFS associated with HA in the coagulation. Within the pH range investigated, the complex-formation and the hydrolysis are the two competitive reactions happened between the hydroxide ions in solution and the functional groups of HA. Therefore, the removal of HA is not caused by adsorbing onto the iron hydroxide resulted from PFS hydrolysis, but through the complex-formation between the PFS and the HA.
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PMID:A study of coagulation mechanisms of polyferric sulfate reacting with humic acid using a fluorescence-quenching method. 1241 61

This research is mainly to explore functional improvement by adding various kinds of metallic ions in the ozonation of 2-chlorophenol solution. During the experiment, various kinds of metallic ions (Pb+, Cu2+, Zn2+, Fe2+, Ti2+, and Mn2+) were added; it was found that the reaction rate increased in all cases. The best result was obtained by using manganese ions, followed by iron and titanium ions. At pH = 3 and 1 ppm Mn2+ concentration, the reaction rate was increased by three times. TOC removal rate was also increased from 12.6% to 38% at 60 min reaction time. Ozone self-decomposition with various kinds of metallic ions alone was tested. It was found the ozone self-decomposition coefficient is highly dependent on the reaction rate constant for ozonation of 2-chlorophenol. The improvement of reaction was relevant to the mechanism of reaction between ozone and metallic ions. Furthermore, the effect of adding manganese ions was studied. With the initial manganese concentration at 0-2 ppm, after gas exposure for 20 min the removal rate can be increased from 38% to 93%. TOC removal rate was increased from 11% to 38%. The reaction rate was improved more greatly at the initial pH = 3.
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PMID:Catalytic ozonation of 2-dichlorophenol by metallic ions. 1257 77

Factor analysis is applied to 28 groundwater samples collected from wells in the coastal blackfoot disease area of Yun-Lin, Taiwan. Correlations among 13 hydrochemical parameters are statistically examined. A two-factor model is suggested and explains over 77.8% of the total groundwater quality variation. Factor 1 (seawater salinization) includes concentrations of EC, TDS, Cl(-), SO(4)(2-), Na(+), K(+) and Mg(2+), and Factor 2 (arsenic pollutant) includes concentrations of Alk, TOC and arsenic. Maps are drawn to show the geographical distribution of the factors. These maps delineate high salinity and arsenic concentrations. The geographical distribution of the factor scores at individual wells does not reveal the sources of the constituents, which are instead, deduced from geological and hydrological evidence. The areas of high seawater salinization and arsenic pollution correspond well to the groundwater over-pumping area. Over-pumping of the local groundwater causes land subsidence and gradual salinization by seawater. The over-pumping also introduces excess dissolved oxygen that oxidizes the immobile minerals, releases arsenic by reductive dissolution of arsenic-rich iron oxyhydroxides and increases the arsenic concentration in water. The over-extraction of groundwater is the major cause of groundwater salinization and arsenic pollution in the coastal area of Yun-Lin, Taiwan.
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PMID:Application of factor analysis in the assessment of groundwater quality in a blackfoot disease area in Taiwan. 1292 62


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