Mariusz Dudziak

Application of membrane techniques to water purification. Removal of phthalates

Abstract Driving force membrane processes seem to be most useful for water treatment. Reverse osmosis, nanofiltration and ultrafiltration have been applied to phthalate removal from water. In the experiment three membranes RO-DS3SE were tested for reverse osmosis, membrane NF-DS5DK for nanofiltration and UF-DSGM for ultrafiltration, all of them from Osmonics, Inc. (USA). All membranes were tested under specified conditions (for RO, NF −2.0 MPa, UF −0.3 MPa) and they showed a high degree of phthalate removal from water — from 97.6% to almost 99.9%. Microextraction (solid phase extraction, SPME with CV/DVB-carbowax/divinylobenzene phase) was used for phthalate extraction from the aquatic matrix, while gas chromatography (GC) with FID detector was used for their quantitative-qualitative monitoring.

Influence of the catalyst type (TiO2 and ZnO) on the photocatalytic oxidation of pharmaceuticals in the aquatic environment

AbstractIn recent years, an increasing interest in the new group of contaminants appearing in the aquatic environments i.e. pharmaceuticals and personal care products has been observed. The effect of the long-term exposure of living organisms to sufficiently lower the concentration of pharmaceuticals, which are found to be highly reactive, is still unknown. In addition with no toxicological data of pharmaceuticals action on living organisms, including humans, their constant elimination from water dedicated to human consumption is required. In this article, the efficiency of chosen pharmaceutical compounds via photocatalysis process is discussed. The photolysis process was also performed in order to compare both solutions. Titanium dioxide (TiO2) and zinc oxide (ZnO) were used as catalysts. The photocatalytic process was also evaluated according to the toxic effect of the purified water by means of MICROTOX® analysis. The impact of the pharmaceutical concentration and oxidation time on the water samples to...

A study of selected phytoestrogens retention by reverse osmosis and nanofiltration membranes - the role of fouling and scaling

Fouling and scaling are common phenomena that accompany membrane filtration and are caused by the presence of organic and inorganic matter in water, which may affect the removal of low-molecular mass organic micropollutants. Comparative filtration of deionized water containing selected phytoestrogens (biochanin A, daidzein, genistein, and coumestrol) was carried out using one new membrane and one contaminated with organic or inorganic matter. Two commercial Osmonics DS membranes were selected for the research, reverse osmosis DS3SE and nanofiltration DS5DK. Filtration was carried out in the dead-end mode. Higher removal of phytoestrogens was caused by reverse osmosis and retention depended on the molar mass of the compound. The decrease in membrane efficiency associated with fouling or scaling brings about an increase in the retention coefficient of phytoestrogens during both reverse osmosis and nanofiltration. The highest increase in phytoestrogen retention was found for the nanofiltraton membrane which was more susceptible to fouling than the osmotic one. This confirms the effect of membrane porosity on the phenomenon studied. The increase in micropollutants removal observed after fouling or scaling was caused by the modification of the membrane surface, hindered diffusion of the compound, and intensified or limited adsorption of micropollutants on the membrane surface.

Gaseous fuels production from dried sewage sludge via air gasification.

Gasification is a perspective alternative method of dried sewage sludge thermal treatment. For the purpose of experimental investigations, a laboratory fixed-bed gasifier installation was designed and built. Two sewage sludge (SS) feedstocks, taken from two typical Polish wastewater treatment systems, were analysed: SS1, from a mechanical-biological wastewater treatment system with anaerobic stabilization (fermentation) and high temperature drying; and (SS2) from a mechanical-biological-chemical wastewater treatment system with fermentation and low temperature drying. The gasification results show that greater oxygen content in sewage sludge has a strong influence on the properties of the produced gas. Increasing the air flow caused a decrease in the heating value of the produced gas. Higher hydrogen content in the sewage sludge (from SS1) affected the produced gas composition, which was characterized by high concentrations of combustible components. In the case of the SS1 gasification, ash, charcoal, and tar were produced as byproducts. In the case of SS2 gasification, only ash and tar were produced. SS1 and solid byproducts from its gasification (ash and charcoal) were characterized by lower toxicity in comparison to SS2. However, in all analysed cases, tar samples were toxic.

Impact of peroxydisulphate on disintegration and sedimentation properties of municipal wastewater activated sludge

In the study, a thermally activated sodium peroxydisulphate (PDS; Na2S2O8) was applied in order to disintegrate wastewater activated sludge (WAS). Chemical disintegration of WAS results in organic matter and polymer transfer from the solid phase to the liquid phase. Soluble chemical oxygen demand (SCOD) is often used to characterise the disintegration efficiency of WAS flocs and microorganisms cells. The present study was conducted in order to chemically disintegrate WAS using PDS in doses of 0.2 %, 0.4 %, 0.6 %, 0.8 % and 1.0 % activated at temperatures of 50°C, 70°C and 90°C for 30 min. The temperature rise induced the PDS to form free radicals, which resulted in an increase in SCOD, i.e. for the highest dose of PDS, the SCOD value attained 2140 mg dm−3 (almost a 15-fold increase over the WAS value). A further positive effect from using this method was a decrease in the sludge volume index (SVI) from 89.8 cm3 g−1 to 30.6 cm3 g−1. On the basis of the results obtained, it may be concluded that thermally activated PDS is suitable for disintegration and has a positive impact on WAS sedimentation properties.

The Impact of Oxone on Disintegration and Dewaterability of Waste Activated Sludge.

Biochemical parameters such as soluble chemical oxygen demand (SCOD), phosphate, ammonium nitrogen and proteins are often used to characterize the efficiency of disintegration of waste activated sludge (WAS) flocs and microorganism cells. In this study, the chemical disintegration using peroxymonosulfate (MPS, Oxone) and thermally activated MPS, were evaluated for the destruction of WAS. Our study was conducted for chemical disintegration of WAS by MPS in doses between 84.7 - 847.5 mg/g(TS) activated by temperatures of 50, 70 and 90 °C over 30 minutes. The application of these methods causes an increase in the soluble COD value and protein concentration in the supernatant. Also, they positively influence the sludge volume index (SVI) which decreased from 89.8 to 17.2 ml/g. Our research work confirmed that the application of thermally activated MPS may become a new effective way of improving sewage treatment and sewage sludge processing.

Chromatographic determination and toxicological potential evaluation of selected micropollutants in aquatic environment—analytical problems

AbstractIn this study, the analytical procedures for the improved extraction and determination of the selected micropollutants (anthracene, pentachlorophenol, octylphenol, benzo(a)pyrene, and diclofenac) in aqueous environment are proposed. These methods were based on application of gas chromatography coupled with mass spectrometry and solid phase extraction for isolation of tested analytes from water samples. Compared to standard procedures currently used in the range presented in this paper, the authors’ modifications of analytical procedures allowed increasing the recovery rate of analytes. Within modification of procedures, hyamine, methanol were used. The substances increase solubility of analytes in water, for instance. Toxicological potential of samples containing tested micropollutants in different environmental matrix was evaluated. Proposed analytical procedures allow the quantitative determination of five different compounds in aquatic environment with satisfactory repeatability and precision o...

Influence of wastewater treatment and the method of sludge disposal on the gasification process

Abstract Municipal wastewater treatment results in the production of large quantities of sewage sludge, which requires proper environmentally accepted management before final disposal. Sewage sludge is a by-product of current wastewater treatment technologies. Sewage sludge disposal depends on the sludge treatment methods used in the wastewater treatment plant (anaerobic or aerobic digestion, drying, etc.). Taking into consideration presented given this information, a study concerning the effects of wastewater treatment processes and sewage sludge drying method on the sewage sludge gasification gas parameters was performed. Gasification is a prospective alternative method of sludge thermal treatment. For the purpose of experimental investigations, a laboratory fixed bed gasifier installation was designed and built. Two types of sewage sludge feedstock, SS1 and SS2, were analyzed. Sewage sludge SS1 came from a wastewater treatment plant operating in the mechanical and biological system while sewage sludge SS2 was collected in a mechanical, biological and chemical wastewater treatment plant with simultaneous phosphorus precipitation. The sludge produced at the plants was subject to fermentation and then, after being dehydrated, dried in a cylindrical drier on shelves heated up to 260ºC (sewage sludge SS1) and using hot air at a temperature of 150ºC in a belt drier (sewage SS2). The analysis shows that the sewage sludge properties strongly depend on the wastewater sources and the wastewater treatment processes. The gasification results, presented as a function of the amount of gasification agent, show that the greater oxygen content of SS1 caused a reduction in the reaction temperature. Paradoxically, this effect caused an increase in the quantity of combustible components in the gas. As expected, increasing the air flow rate caused a decrease in the heating value of the gas produced. A higher amount of oxidizer increases the amounts of noncombustible species and the volumetric fraction of nitrogen, thus reducing the heating value of the obtained gas. The higher hydrogen content in SS1 affects the gasification gas composition. As a result, combustible components are the majority of the syngas.

The assessment of sewage sludge gasification by-products toxicity by ecotoxicologial test.

The process of gasification of sewage sludge generates by-products, which may be contaminated with toxic and hazardous substances, both organic and inorganic. It is therefore important to assess the environmental risk associated with this type of waste. The feasibility of using an ecotoxicological tests for this purpose was determined in the presented study. The applied tests contained indicator organisms belonging to various biological groups (bacteria, crustaceans, plants). The subject of the study were solid (ash, char) and liquid (tar) by-products generated during gasification (in a fixed bed reactor) of dried sewage sludge from various wastewater treatment systems. The tested samples were classified based on their toxic effect. The sensitivity of the indicator organisms to the tested material was determined. In-house procedures for the preparation for toxicity analysis of both sewage sludge and by-products generated during the gasification were presented. The scope of work also included the determination of the effect of selected process parameters (temperature, amount of gasifying agent) on the toxicity of gasification by-products depending on the sewage sludge source. It was shown that both the type of sewage sludge and the parameters of the gasification process affects the toxicity of the by-products of gasification. However, the results of toxicity studies also depend on the type of ecotoxicological test used, which is associated with a different sensitivity of the indicator organisms. Nevertheless, it may be concluded that the by-products formed during the gasification of the low toxicity sewage sludge can be regarded as non-toxic or low toxic. However, the results analysis of the gasification of the toxic sludge were not conclusive, which leads to further research needs in this area.

The Presence of Compounds from the Personal Care Products Group in Swimming Pool Water

The global production of several thousands of Personal Care Products (PCPs) every year makes the release of PCPs to the environment an unavoidable by-product of a modernized lifestyle. Multiple studies have detected PCPs worldwide in various aquatic environments, including swimming pools. In the presented work, the concentrations of three selected compounds from the PCPs group were examined in 15 swimming pools with different functions. The aim of the study was to show the influence of various factors on the concentration levels of selected micropollutants. Two UV filters: BP-3 (oxybenzone), BP-8 (dioxybenzone) and one antioxidant BTH (dibutylhydroxytoluene) were selected for the research. The extraction of micropollutants from the swimming pool water matrix was carried out by Solid Phase Extraction (SPE). The extracts were analyzed using a gas chromatograph (GC) coupled to the mass detector (MS). BHT was the most common compound. Its concentration ranged from 3.8 ng/L to 5.5 ng/L. The most rarely occurring compound was BP-3. The concentration of this compound varied the most, from 18.5 ng/L to 1178.6 ng/L. BP-8 was present in 10 from 15 tested pools at the concentration level of 49.9–226.9 ng/L. The frequency of occurrence characterizing different micropollutants from PCPs group was higher in recreational pools than in sports pools. It was also observed that the applied water treatment technology may affect the presence of Personal Care Products in the swimming pool water. No impact of basic water quality parameters on the levels of tested pharmaceuticals has been shown in this research.