OXIDATIVE DEGRADATION OF 2-CHLOROPHENOL BY PERSULFATE

The degradation of 2-chlorophenol (2-CP) by persulfate was investigated. The kinetics of persulfate oxidation of 2-chlorophenol in aqueous solutions at various pH, oxidant concentration, temperature, Fe2+ and Cu2+ ions content was studied. Maximum of 2-CP degradation occurred at pH 8. The oxidation rate of 2-CP increased with increasing the persulfate molar excess. The degradation process was significantly influenced by temperature – the higher temperature results in a faster degradation of 2-CP. The activation of persulfate by ferrous and copper ions was also studied. Results showed that persulfate is activated more effectively by iron(II) than copper(II) ions. A comparison of different persulfate activation methods revealed that heat-activation was the most effective. Under optimal conditions, in the presence of ferrous ions at 50 °C, complete degradation of 2-chlorophenol was achieved after about 30 minutes

The Use of Supercritical Fluid Extraction in Carrier Recovery from a Spent Active Carbon–Zinc Acetate Catalyst

The present paper is aimed at showing the usefulness of supercritical fluid extraction in the removal of organic substances and zinc from the surface of a dangerous waste product, i.e. spent catalyst employed in the manufacture of vinyl acetate. The possibility of recovering active carbon (the carrier support for the catalyst concerned) so that it may be used in subsequent processes by combining supercritical fluid extraction with hydrochloric acid leaching has been demonstrated

Sediments from stormwater drainage system as sorbents of organic and inorganic pollutants

The study presents the results of tests aimed at determining variations in concentrations of polycyclic aromatic hydrocarbons (naphthalene, acenaphthylene, acenaphthene, fluorene, phenanthrene, anthracene, fluoranthene, pyrene, benzo[a]anthracene, chrysene, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene, dibenzo[a, h]anthracene, benzo[g, h, i]perylene and indeno[1, 2, 3-c, d]pyrene) and heavy metals (copper, cadmium, chromium, nickel, lead and zinc) in the sediments from the stormwater sewer system. Results of this study were then compared to Polish regulations and established ecological screening values to determine their potential risk to environment. The results suggest that stormwater sediments are moderately contaminated with PAHs and heavy metals according to domestic regulations and highly contaminated according to ecological benchmarks

Methods of assessment of stormwater sediments quality

Concentration of heavy metal (cadmium, copper, chromium, nickel, lead and zinc) in sediments collected from the stormwater treatment plant located in the urbanised catchment were investigated using geo-accumulation index and enrichment factor to determine metal accumulation and pollution status. Total metal concentrations varied widely in studied materials and the mean values were higher than their background values. The Igeo results indicate that tested sediments were uncontaminated with respect to Cd. The study area is moderately to strongly contaminated with Zn, Pb and Cu. The other elements are within the scope moderate contamination

Methods of assessment of stormwater sediments quality

Concentration of heavy metal (cadmium, copper, chromium, nickel, lead and zinc) in sediments collected from the stormwater treatment plant located in the urbanised catchment were investigated using geo-accumulation index and enrichment factor to determine metal accumulation and pollution status. Total metal concentrations varied widely in studied materials and the mean values were higher than their background values. The Igeo results indicate that tested sediments were uncontaminated with respect to Cd. The study area is moderately to strongly contaminated with Zn, Pb and Cu. The other elements are within the scope moderate contamination

Sediments from stormwater drainage system as sorbents of organic and inorganic pollutants

The study presents the results of tests aimed at determining variations in concentrations of polycyclic aromatic hydrocarbons (naphthalene, acenaphthylene, acenaphthene, fluorene, phenanthrene, anthracene, fluoranthene, pyrene, benzo[a]anthracene, chrysene, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene, dibenzo[a, h]anthracene, benzo[g, h, i]perylene and indeno[1, 2, 3-c, d]pyrene) and heavy metals (copper, cadmium, chromium, nickel, lead and zinc) in the sediments from the stormwater sewer system. Results of this study were then compared to Polish regulations and established ecological screening values to determine their potential risk to environment. The results suggest that stormwater sediments are moderately contaminated with PAHs and heavy metals according to domestic regulations and highly contaminated according to ecological benchmarks

Composite Heat Exchangers for Boiling Heat Transfer Enhancement

The paper deals with the development of high-performance composite heat exchangers made of different metals. The samples made of meshes and fine fibers have been sintered to the copper base in the reduction atmosphere to prevent oxidation. The test of boiling heat transfer performance have been carried out under ambient pressure with distilled water and ethyl alcohol as working agents. The obtained data indicates significant enhancement of heat flux of such composite heat exchangers in comparison to the smooth surface without any coating. The maximum heat flux for the microstructure covered heater has been several times higher than for the smooth surface. The enhancement has been observed to decrease as the temperature difference become higher.Artykuł dotyczy badań wysokowydajnych, kompozytowych wymienników ciepła wykonanych z różnych metali. Próbki wykonano poprzez spiekanie w atmosferze redukcyjnej (w celu uniknięcia utlenienia) warstw siatkowych i drobnych włókien metalu z podstawą miedzianą. Badania przeprowadzono pod ciśnieniem atmosferycznym dla dwóch cieczy roboczych tj. wody destylowanej i bezwodnego alkoholu etylowego. Uzyskane wyniki wskazują na znaczące możliwości zwiększenia wymienianych gęstości strumienia ciepła dla wymienników kompozytowych w porównaniu do powierzchni gładkiej bez pokrycia. Maksymalne wartości gęstości strumienia ciepła odbieranego z powierzchni z mikropokryciem nawet kilkakrotnie przewyższały te, odbierane z powierzchni gładkiej. Intensyfikacja wrzenia zmniejszała się jednak w miarę wzrostu przegrzania

Dynamics of Changes in Microbiological Composition of Stored Sediments

The composition of sediments formed in the process of pretreatment of stormwater is diversified and depends on many parameters, mainly on the quality of stormwater and the land use of the catchment. Stormater sediments are characterized by heterogeneous chemical and microbiological composition. The aim of this paper was the microbiological evaluation the sediments from four stormwater catchments in terms of hazard to humans and the environment. For the examined sediments, pH, and the content of organic and mineral matter were determined. Microbiological analysis included the determination of the total number of psychrophilic, mesophilic, and coliform bacteria, including E. coli, and also the number of faecal Enterococci, Salmonella and Shigella. The study was conducted for fresh deposits and those stored for one year in order to determine the dynamics of changes in their biological activity

Stormwater Reservoir Sizing in Respect of Uncertainty

The sizing of the stormwater reservoir, as the design of its properties, usually requires simulations of a basin runoff for a long rainfall series using a hydrodynamic model. In the case of insufficient observations, the rainfall series can be reproduced using empirical approaches. One of the crucial elements in the sizing of the stormwater reservoir is determination of duration time and intensity of rainfall (design rainfall event), for which the maximum reservoir capacity is being obtained. The outcome is, however, affected by significant uncertainty of runoff modeling. The aim of the study is to analyze the effect of the uncertainty of a rainfall-runoff model on calculated capacities of stormwater reservoirs, along with estimated duration times of the design rainfall. The characteristics of the rainfall events—intensity, duration, and frequency—were reproduced using an empirical approach of IDF (Intensity⁻Duration⁻Frequency). The basin response to the precipitation was modeled using the SWMM (Storm Water Management Model) and its uncertainty was estimated on the basis of the GLUE (Generalized Likelihood Uncertainty Estimation) method. The obtained probabilistic solution was compared with the deterministic one, neglecting the uncertainty. Duration times of the design rainfall determined in respect of the reservoir outflow using the probabilistic model were longer than those found with a deterministic approach. This has an effect on the desired capacities of the stormwater reservoir, which were overestimated when uncertainty was neglected

OXIDATIVE DEGRADATION OF 2-CHLOROPHENOL BY PERSULFATE

The degradation of 2-chlorophenol (2-CP) by persulfate was investigated. The kinetics of persulfate oxidation of 2-chlorophenol in aqueous solutions at various pH, oxidant concentration, temperature, Fe2+ and Cu2+ ions content was studied. Maximum of 2-CP degradation occurred at pH 8. The oxidation rate of 2-CP increased with increasing the persulfate molar excess. The degradation process was significantly influenced by temperature – the higher temperature results in a faster degradation of 2-CP. The activation of persulfate by ferrous and copper ions was also studied. Results showed that persulfate is activated more effectively by iron(II) than copper(II) ions. A comparison of different persulfate activation methods revealed that heat-activation was the most effective. Under optimal conditions, in the presence of ferrous ions at 50 °C, complete degradation of 2-chlorophenol was achieved after about 30 minutes