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  • Author: Joanna Surmacz-Górska x
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Photochemical Degradation of Sulfadiazine

Abstract

The photochemical degradation of the sulfadiazine (SDZ) was studied. The photochemical processes used in degradation of SDZ were UV and UV/H2O2. In the experiments hydrogen peroxide was applied at different concentrations: 10 mg/dm3 (2.94*10-4 M), 100 mg/dm3 (2.94*10-3 M), 1 g/dm3 (2.94*10-2 M) and 10 g/dm3 (2.94*10-1 M). The concentrations of SDZ during the experiment were controlled by means of HPLC. The best results of sulfadiazine degradation, the 100% removal of the compound, were achieved by photolysis using UV radiation in the presence of 100 mg H2O2/dm3 (2.94*10-3 M). The determined rate constant of sulfadiazine reaction with hydroxyl radicals kOH was equal 1.98*109 M-1s-1.

Open access
The effect of temperature on the efficiency of industrial wastewater nitrification and its (geno)toxicity

Abstract

The paper deals with the problem of the determination of the effects of temperature on the efficiency of the nitrification process of industrial wastewater, as well as its toxicity to the test organisms. The study on nitrification efficiency was performed using wastewater from one of Polish chemical factories. The chemical factory produces nitrogen fertilizers and various chemicals. The investigated wastewater was taken from the influent to the industrial mechanical-biological wastewater treatment plant (WWTP). The WWTP guaranteed high removal efficiency of organic compounds defined as chemical oxygen demand (COD) but periodical failure of nitrification performance was noted in last years of the WWTP operation. The research aim was to establish the cause of recurring failures of nitrification process in the above mentioned WWTP. The tested wastewater was not acutely toxic to activated sludge microorganisms. However, the wastewater was genotoxic to activated sludge microorganisms and the genotoxicity was greater in winter than in spring time. Analysis of almost 3 years’ period of the WWTP operation data and laboratory batch tests showed that activated sludge from the WWTP under study is very sensitive to temperature changes and the nitrification efficiency collapses rapidly under 16°C. Additionally, it was calculated that in order to provide the stable nitrification, in winter period the sludge age (SRT) in the WWTP should be higher than 35 days.

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Molecular Monitoring Of Bacterial And Microalgal Biocenoses’ Biodiversity In High Loaded Farming Ponds

Abstract

Eutrophication process is a serious problem in water ecosystems. There is a great need to study the relation between the physico-chemical condition of water and the influence of these parameters on the diversity of biological life, especially on changes in the structure of microbiocenoses. The most interesting are bacteria and microalgae, due to the important roles they play in maintaining the balance of the aquatic environment. In this study, biodiversity analysis of eukaryotic microalgae and bacteria in two artificial water ecosystems - fish farming ponds - was performed. Aquaculture was based on IMTA technology, in which every part of the trophic chain plays a significant role in maintaining the balance in the ecosystems. Experimental intensive - extensive systems differed in terms of nutrient loads, ponds were characterized by high loads of organic and inorganic nitrogen and phosphorus. During the experimental period, the physicochemical conditions, quantitative genotypic structure of the two biocenoses being studied and the relation between these factors were monitored and investigated. For the biodiversity analysis, the PCR - DGGE technique was used. The results of preliminary research showed that there is a correlation between nutrient loads, diversity expressed in the Shannon-Wiener Index and the overall condition of experimental systems. Higher loadings of nutrient promote the development of bacteria and microalgae without any influence on the balance in the artificial ecosystem being tested.

Open access
Detection of antibiotic resistance genes in wastewater treatment plant – molecular and classical approach

Abstract

Antibiotics are a group of substances potentially harmful to the environment. They can play a role in bacterial resistance transfer among pathogenic and non-pathogenic bacteria. In this experiment three representatives of medically important chemotherapeutics, confirmed to be present in high concentrations in wastewater treatment plants with HPLC analysis were used: erythromycin, sulfamethoxazole and trimethoprim. Erythromycin concentration in activated sludge was not higher than 20 ng L−1. N-acetylo-sulfamethoxazole concentration was 3349 ± 719 in winter and 2933 ± 429 ng L−1 in summer. Trimethoprim was present in wastewater at concentrations 400 ± 22 and 364 ± 60 ng L−1, respectively in winter and summer. Due to a wide variety of PCR-detectable resistance mechanisms towards these substances, the most common found in literature was chosen. For erythromycin: erm and mef genes, for sulfamethoxazole: sul1, sul2, sul3 genes, in the case of trimethoprim resistance dhfrA1 and dhfr14 were used in this study. The presence of resistance genes were analyzed in pure strains isolated from activated sludge and in the activated sludge sample itself. The research revealed that the value of minimal inhibitory concentration (MIC) did not correspond with the expected presence of more than one resistance mechanisms. Most of the isolates possessed only one of the genes responsible for a particular chemotherapeutic resistance. It was confirmed that it is possible to monitor the presence of resistance genes directly in activated sludge using PCR. Due to the limited isolates number used in the experiment these results should be regarded as preliminary.

Open access