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Open access

Maria Tomaszewska

Industrial wastewater treatment by means of membrane techniques

The importance of membrane processes in wastewater treatment is continuously growing. Membranes can be used for the separation of liquids, dissolved or suspended solids or solutes in the colloid form. The main features of membrane processes application for the treatment of spent solutions are possibilities of removal or recovery of valuable or harmful components as well as the possibility of closing water systems what reduce fresh water consumption. Very often the use of membrane processes allow to purify wastewater to a degree difficult to achieve by conventional techniques. The possibility of an application of pressure driven techniques such as ultrafiltration (UF), nanofiltration (NF) and reverse osmosis (RO) for oily wastewater treatment, has been presented. The studies on the two-stage treatment of bilge water combining UF and RO or NF have demonstrated a high effectiveness of purification. NF could also be applied to recover glycols from spent coolant liquids. The utilization of membrane distillation for saline wastewater concentration or for the treatment of spent metal pickling solutions was demonstrated.

The potential application of a hybrid process combining photocatalytic degradation of organic matter with membrane separation for the treatment of wastewaters from textile industry has been shown.

Open access

Aleksander Orecki and Maria Tomaszewska

The oily wastewater treatment using the nanofiltration process

The objective of this work was to investigate the possibility of oily wastewater treatment using the nanofiltration (NF) process. The NF studies were carried out with a permeate obtained from ultrafiltration (UF) (used for the treatment of the oily wastewater from metal industry). The influence of transmembrane pressure on a permeate flux, the degree of the rejection of oil and inorganic compounds was investigated. The studies on the NF treatment of oily wastewater demonstrated a high effectiveness of the rejection of oil and inorganic compounds. The permeate obtained from the treatment was free of oil. Moreover, the retention coefficient of the inorganic compounds was higher than 75% for all the cations examined (Na+, K+, Mg2+, Ca2+, Zn2+, Cu2+) and higher than 95% for sulphates. Therefore, the permeate obtained in the NF process can be reused for fresh emulsion preparation.

Open access

Maria Tomaszewska and Lidia Białończyk

The investigation of ethanol separation by the membrane distillation process

Separation of ethanol from solutions with different concentrations in a BIOTRON bioreactor integrated with the direct contact membrane distillation system has been investigated. The experiments were carried out using immersed, capillary polypropylene membranes. The permeability of the membrane at the feed inlet temperatures of 308, 318 and 333K was determined. The permeate and ethanol flux was strongly affected by the vapour pressure which increased with the feed temperature and it was also associated with ethanol concentration in the feed. It was found that the membrane distillation can be successfully applied for the separation of volatile components such as ethanol.

Open access

Maria Tomaszewska and Agnieszka Mientka

Separation of HCl from the mixture of KCl and HCl using membrane distillation

Membrane distillation (MD) was applied for the concentration of solutions containing hydrochloric acid and potassium chloride. The studies of the concentration and separation of HCl through the hydrophobic membrane were performed. In the investigations plate and frame or capillary modules, equipped with membranes from polytetrafluoroethylene and polypropylene were applied, respectively. The feed temperature amounted to 333 K or 343 K and permeate 293 K at the inlet of the module. Under the MD operation conditions the transfer of water vapour and hydrogen chloride from potassium chloride and hydrochloric acid solutions through the hydrophobic membranes took place, whereas the potassium chloride as a nonvolatile component underwent concentration in the feed. The influence of acid concentration and salt presence in the feed on the HCl molar flux through the membrane was systematically studied. The increase of the temperature and salt concentration in the feed caused higher partial pressure volatile of HCl and the resultant HCl Flux through a membrane was higher.

During MD for the initial concentration in the feed equal 50 g KCl/dm3 and 40g HCl/dm3, at the feed temperature 343K, the permeate flux decreased from 353 dm3/m2d to 289 dm3/m2d, whereas the HCl flux increased to 6 mol/m2d for the capillary module. At higher KCl concentration in the feed, amounting to 100g KCl/dm3 and under the same operation conditions, the permeate flux decreased to 285 dm3/m2d, but the molar flux HCl increased to 18 mol/m2d. The results were compared with the data obtained for the plate and frame module.

Open access

Maria Tomaszewska and Lidia Białończyk

Ultrafiltration (UF) is one of the membrane processes which is mostly used in the dairy industry for the separation and concentration of whey components or fermentation broth. Fouling of UF membranes in the food industry is primarily due to a deposition of microorganisms, proteins, fats and minerals on the membrane surface. Thus, cleaning of the membranes is an essential step of UF separation. The results from investigations of chemical cleaning of a ceramic UF membrane fouled by precipitation of whey components and yeast contained in the fermentation broth are presented. The effect of cleaning procedure on the degree of permeability restoration by the fouled membrane was studied. The results demonstrated that a combination of sodium hydroxide, phosphoric acid and sodium hypochlorite as a disinfectant could be successfully used to achieve an optimum recovery of the membrane properties.

Open access

Bożena Seredyńska-Sobecka and Maria Tomaszewska

The influence of ozonation on the activated carbon adsorption of phenol and humic acid

To study the influence of ozonation on the activated carbon adsorption, a model solution containing approximately 8 mg/dm3 of humic acid and approximately 1 mg/dm3 of phenol has been ozonated, and then adsorption kintetics and adsorption isotherm experiments have been performed. The applied ozone doses ranged from 1 to 3 mg O3/dm3, and a contact time was 1 min. In the adsorption experiments, the commercial activated carbon CWZ-30 (Gryfskand Sp. z o.o., Hajnówka, Poland) has been used. Phenol adsorption under equilibrium conditions was determined by the Freundlich isotherm equation, and the modified Freudlich isotherm equation has been employed for the determination of humic acid equilibrium adsorption. The applied oxidation conditions resulted in color, chemical oxygen demand (COD), total organic carbon (TOC) and UV254 absorbance removal, by 4 - 13%, 3 - 6%, 3 - 7%, respectively. After ozonation, phenol concentration decreased by 6 - 23%. These changes in the model solution did not affect the humic acid adsorption, however, they deteriorated phenol adsorption.

Open access

Małgorzata Tomaszewska-Kowalska, Krzysztof Kołomecki and Maria Wieloch-Torzecka

Abstract

Surgical site infections on surgical wards are the most common cause of postoperative complications. Prevalence of surgical site infections depends on the surgical specialization. Analysis of the causes of surgical site infections allows to conclude that microorganisms from the patient’s own microbiota – Gram-negative rod-shaped bacteria from the family Enterobacteriacae and from the patient’s skin microbiota – Gram-positive cocci – Staphylococcus are the most common agents inducing surgical site infections.

The aim of the study was to assess prevalence and characteristics of surgical site infections caused by Gram-negative rod-shaped bacteria from the family Eneterobacteriacae and Gram-positive cocci from the genus Staphylococcus in patients who underwent surgical procedures at the Regional Specialist Hospital named after M. Copernika in Łódź on selected surgical wards.

Material and methods. The study was performed based on retrospective analysis of medical documentation of the treated patients. The study included 195 patients of the Regional Specialist Hospital named after M. Copernik in Łódź who were treated between 2012 and 2014 on the wards of: Vascular, General and Oncological Surgery, Trauma and Orthopaedic Surgery, Neosurgery and Nervous System Tumors and the Ward of Endocrine Surgery – in the Clinic of Endocrine Surgery. The study included 84 women and 111 men. Mean age was 59 years (18 – 94 years old). \

Results. Surgical site infections caused by Gram-negative rod-shaped bacteria from the family Enterobacteriacae were reported in 84 out of 195 patients (43.08% of the study group) and by Gram-positive cocci from the genus Staphylococcus were reported in 52 patients (26.67% of the study group). Mixed microbiota was an etiological agent of surgical site infections in four patients (2.5% of the study group).

Conclusions. Etiological agent of surgical site infections depends on the ward profile, surgical field cleanliness and a form of surgical site infection.

Open access

Maria Andrzejczak, Adam Bogacz, Klara Tomaszewska and Magda Podlaska

Abstract

The aim of the study was to show the impact of the peat extraction on the development and properties of organic soils and plant habitat in post-extraction sites. The study was conducted in the complex of the Trzcińskie Mokradła Peatlands (Sudetes Mts., SW Poland). The Trzcińskie Mokradła Peatlands began to form in Preboreal (10960–9330 ±50BP) so that they are one of the oldest peatlands in the Sudetes. We analyzed 8 soil profiles (42 samples). Peat forming process there is still active in the moderate or strong degree (PtII-PtIII). The floristic composition of the studied areas was typical of transition peatlands. Successive dry and moist periods were observed in the developed of organic soils. The time gaps in peat profiles covering hundreds of years prove their extraction in the past.

Open access

Marek Gryta, Marta Waszak and Maria Tomaszewska

Abstract

In this work a fouling study of polypropylene membranes used for microfiltration of glycerol solutions fermented by Citrobacter freundii bacteria was presented. The permeate free of C. freundii bacteria and having a turbidity in the range of 0.72–1.46 NTU was obtained. However, the initial permeate flux (100–110 L/m2h at 30 kPa of transmembrane pressure) was decreased 3–5 fold during 2–3 h of process duration. The performed scanning electron microscope observations confirmed that the filtered bacteria and suspensions present in the broth formed a cake layer on the membrane surface. A method of periodical module rinsing was used for restriction of the fouling influence on a flux decline. Rinsing with water removed most of the bacteria from the membrane surface, but did not permit to restore the initial permeate flux. It was confirmed that the irreversible fouling was dominated during broth filtration. The formed deposit was removed using a 1 wt% solution of sodium hydroxide as a rinsing solution.