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Application of Fenton's Reagent in the Textile Wastewater Treatment Under Industrial Conditions

Application of reactive dyes is very popular in textile industry as these dyestuffs are characterized by good fastness properties. Constapel et al in 2009 estimated the production of this type of dyes for over 140,000 Mg/year. The reactive dyes are mostly (50%) employed for coloration of cellulosic fibers, however they can also be applied on wool and nylon. Unfortunately, they possess a low degree of fixation (50÷90%), since the functional groups also bond to water, creating hydrolysis and the excess of dyes applied cause a colored pollution of aqueous environment. Moreover, dyeing process requires the use of: electrolytes in the form of aqueous solutions of NaCl or Na2SO4 in the concentration up to 100 g/dm3, alkaline environment (pH > 10) and textile auxiliary agents (including detergents). Therefore, the wastewater generated during the reactive dyeing processes is characterized by high salinity, pH value and color, and due to low value of the BOD5/COD ratio are nonbiodegradable. The successful methods of textile wastewater treatment could be Advanced Oxidation Processes (AOPs), amongst which the Fenton reagent seems to be most promising as it is the cheapest and easy in use. Based on the newest literature survey it was found that many successful tests with Fenton reaction were performed mainly in decolorization. However, not enough attention was devoted to decolorization of real industrial wastewater containing dyes, detergents and salts NaCl, or Na2SO4. The experiments carried out in a laboratory scale were focused on the impact of NaCl and textile auxiliary agent (liquid dispersing and sequestering agent) on an inhibition of decolorization process by Fenton's reagent. The objects of the investigation were synthetic mixtures simulating the composition of real textile wastewater as well as the real industrial wastewater generated in the reactive dyeing. The inhibition of the Fenton decolorization in the presence of NaCl and liquid dispersing and sequestering agent was demonstrated. Additional experiments using pulse radiolysis were carried out in order to confirm the inhibition of chloride in the decolorization process.

Wet Oxidation of Dairy Sewage

Results of kinetic studies on the process of wet oxidation of dairy sewage are presented. Experiments were carried out in a stirred batch tank reactor at the oxygen partial pressure equal to 1 MPa and at temperature ranging from 473 to 523 K. Dairy sewage was subjected to oxidation at a natural pH close to 4. The efficiency of decomposition of organic compounds was estimated on the basis of TOC measurement. The highest TOC reduction rate reached 79.6%. A kinetic model of the process was proposed and its parameters were determined experimentally. Good agreement of the experimental and calculated results was obtained.

Abstract

The article presents the results of kinetic studies of the wet oxidation process of dairy sewage. The dairy sewage, obtained straight from the production line, was subjected to oxidation at pH close to the natural value of 7. Experiments were carried out in a stirred batch tank reactor at the oxygen partial pressure equal to 1 MPa and at temperature ranging from 473 to 593 K. The effectiveness of organic compounds decomposition was estimated based on the measurement of TOC. The kinetics of decomposition of milk components, ie lactose, protein and fat, as well as the kinetics of oxidation of intermediate products was the aim of the study. Measurement of the concentration of protein, fat and lactose was done with a milk composition analyzer, calibrated in relation to the dairy sewage. The obtained results were used to develop a mathematical model of wet oxidation of dairy sewage, including the group of analyzed compounds.

Abstract

The important factors that strongly influence the particle size distributions measured by the laser diffraction method are the optical parameters of the suspension (refractive index and absorption coefficient). Knowledge of the values of these parameters is necessary for Mie theory. Mie theory is applied for conversion of the intensity of light recorded on detectors into particle size distribution (PSD) of tested material. Both wastewater and activated sludge are mixtures of a variety of elements (mineral or organic, including living organisms). In practice, it is not possible to define clearly the values of the optical parameters, as the composition of the suspension changes over time. The aim of the study was to estimate the impact of assumed values of the optical parameters on particle size distributions obtained. The PSDs of suspensions sampled in different stages of wastewater treatment are the most reproducible when the following optical parameters are defined: absorption coefficients - 1.0 and the refractive index - 1.52.

Abstract

Escherichia coli is Gram-negative optionally anaerobic roads which belongs to Enterobacteriaceae family. Includes in a physiological bacterial flora of human and warm-blooded animals large intestine. Escherichia coli is being met in abiotic elements of the environment so as waters, wastewater, sewage sludge, soil and the food. This bacterium is showing the pathogenicity in named terms for the peoples, triggering diseases mainly: gastrointestinal tract and urinary.

Quality and quantitative proposed detections method of the bacteria E. coli contains five/six steps:

- appointment dry suspended solid,

- preparation averaged, test of sample and resuscitation of bacteria,

- making dilutions,

- enrichment and differentiation in chromogenic-selective medium,

- enumerating the amount of cfu E. coli in 1 g of a dry weight,

- optionally, the biochemical identification

Abstract

The aim of the study was to determine the level of calcium, magnesium, sodium, phosphorus and potassium in the waters flowing from the roofs of houses with varying degrees of coverage on the background of their contents in rain waters. On the basis of the Minister of Environment Decree of 24 July 2006 on conditions to be met for the introduction of sewage into the water or ground and on substances particularly harmful to the aquatic environment, runoff from paved areas shall be treated as sewage, and runoff from roofs of buildings are treated as pure water and can be discharged into the environment without a permit. However, literature data indicate the possibility of a significant enrichment of rainwater at the time of contact with the roof covering. The study included 24 roofs of houses or small trade buildings. As background to the research used rainwater collected in two randomly selected locations within the area of research. The study was conducted in areas with low human impact, in order to best capture the effect of the type of roofing material on the formation of water chemistry. Research area was located in the Luslawice in the Tarnow county in Malopolska province. The study included the most common roofs in the surveyed area: cement tile, ceramic tile, bituminous, unpainted galvanized metal, copper and asbestos cement. The tested water samples to determine the content of calcium, phosphorus, magnesium, sodium and potassium. In addition, it was determined the pH value of water and electrolytic conductivity. The results of this study indicate that the water runs off the roofs of respondents in each case contained a greater quantity of the analyzed elements in comparison with rainwater. For example, while the average content of magnesium in the water flowing from the tile cement was almost ten times higher than in rain water, in the case of tile ceramic was almost five times more water from the bituminous coverings contained about three times more magnesium, and water from the galvanized metal contained about six times more as compared with rainwater. Also in the case of most other elements enrichment factors found in the waters cover the cement (tile, and asbestos cement) then galvanized and coated while the lowest were recorded in the enrichment of waters from the roofs of the covering of ceramic tiles. Also noted an increase in the conductivity values in waters from the roofs of the coverings of cement, galvanized steel and ceramic tiles. All runoff from the roofs were of generally higher pH value compared with rainwater, the biggest reaction - about 8 found in the water with cement tiles, slightly lower, about 7.0 in water from roofs with ceramic tiles and sheet copper. pH of the water in the coated sheet was lower than in water, rainwater and oscillating within 5.5. Rainwater pH was 5.94.

Galvanic Wastewater Treatment by Means of Anionic Polymer Enhanced Ultrafiltration

This work is focused on polyelectrolyte enhanced ultrafiltration as an effective heavy metal separation technique. Three types of effluents, containing Zn(II), Cu(II) and Ni(II) ions, were subjected to the separation process. Poly(sodium 4-styrenesulfonate) - PSSS, a water soluble anionic polyelectrolyte was used as a metal binding agent. Two Sepa® CF (Osmonics) membranes: EW, made of polysulfone and a modified polyacrylonitrile membrane MW, were used in the ultrafiltration process. The preliminary UF tests were carried out on model solutions with target metal ion concentrations of 10, 100 and 250 mg dm-3. The main parameters affecting the metal retention (the polyelectrolyte quantity and solution pH) were examined. The values of pH 6 and polymer : metal concentration ratio CPSSS : CM = 7.5 : 1 (mol of mer unit per mol of metal) were selected to perform the galvanic wastewater ultrafiltration-concentration tests. Three types of wastewater containing Zn(II), Ni(II) and Cu(II) ions within the concentration range of 30÷70 mg dm-3 were used in the investigations. Very high metal retention coefficients, up to > 99%, were achieved. The retentates obtained were subjected to the decomplexation-ultrafiltration (pH = 1) and subsequent diafiltration step, which enabled partial recovery of concentrated metal ions and the polyelectrolyte. The recovered polyelectrolyte was reused toward Ni(II) ions and the high effectiveness of metal separation has been achieved.

Treatment of the Processing Wastewaters Containing Heavy Metals with the Method Based on Flotation

The aim of the studies carried out at full technological scale was to indicate optimal systems of the two-stage precipitation and coagulation (PIX 113 - SAX 18, PAX XL1 - SAX 18, ALCAT 102 - lime milk and SAX 18 - PAX 16) in the process of eliminating heavy metals from wastewaters made in the processing plant producing sub-systems for domestic appliances. Precipitated pollutions were thickened by flocculation and separated by hydrogen peroxide enhanced pressure flotation. The experimental installation of maximal flow capacity: 10.0 m3/d consisted of: the storage-equalization tank, the processing pipe reactor, the pressure flotation station, and the reagent preparation and dosing station. Optimal doses of reagents and a flocculent as well as pressure and saturation time were defined for which maximal reductions in the load of heavy metals were achieved. The usefulness of hydrogen peroxide as a means of enhancing flotation was tested. The use of two-stage precipitation permitted the reduction in heavy metals (Cd, Cu, Cr, Ni, Sn, Zn), eg by applying ALCAT 102 - lime milk at the level exceeding 80%.

Distillation Cleanup Preceded GC Determination of Short-Chain Monocarboxylic Acids in Aqueous and Solid Samples of Wastewater Origin

Short-chain monocarboxylic acids (SCMAs) (C2-C5) formed in the process of aerobic biodegradation of larger organic molecules should often be monitored to optimize wastewater biological treatment and study the processes of converting organic waste matter into methane, etc. Gas chromatography (GC) seems a method of choice for such a task. Majority of samples require clean up before they can be injected into GC system. In this work a special refluxing apparatus is applied to concentrate and clean up the troublesome environment samples before injection into GC. To optimize separation of SCMAs in aqueous sample a special arrangement of two capillary columns, of very different polarity was used. The operational parameters of sample preparation were optimized and enrichment factors determined. The procedure developed was applied to determine SCMAs in troublesome aqueous and solid samples of wastewater treatment origin.

Effectiveness of Removal of Humic Substances and Heavy Metals from Landfill Leachates During their Pretreatment Process in the SBR Reactor

In the paper the removal efficiency of heavy metals as well as humic compounds, in the treatment of leachate mixed with municipal waste in a sequencing batch reactor was studied. Also, the accumulation of those metals in the activated sludge was examined. It has been shown that the removal efficiency of contamination with humic compounds, for Bx ranging from 0.23 to 0.45 mg COD mg-1 d.m. can reach 71÷74%. An increase in the concentrations of heavy metals in the activated sludge was recorded for Bx in the range 0.23÷1.64 mg COD mg-1 d.m. The amount of heavy metals in the effluent of the SBR in carrying out the process at Bx = 0.23÷0.96 mg COD mg-1 d.m. does not limit their discharge into water and sewer system.