The role of hydrophyte systems in sewage treatment from rural areas

Celem badań była ocena skuteczności oczyszczania ścieków bytowo-gospodarczych w małej przydomowej oczyszczalni wierzbowej oraz doczyszczania ścieków w gminnej, mechaniczno-biologicznej oczyszczalni z filtrem piaskowo-trzcinowym. Próbki ścieków do badań pobierano w okresie od maja do grudnia 2007 r. Liczebność bakterii heterotroficznych zdolnych do wzrostu w temperaturze 22°C (jtk 22°C) i 37°C (jtk 37°C) oznaczano metodą płytek lanych zgodnie z normą PN-ISO 6222. Liczebność bakterii z grupy coli (TC) oraz bakterii termotolerancyjnych (fekalnych) z grupy coli (FC) oznaczano metodą fermentacyjną probówkową zgodnie z PN-75/C-04615/05 i PN-77/C-04615/07. Liczebność paciorkowców kałowych [FS] badano metodą filtrów membranowych zgodnie z PN-82/C-04615/25 na podłożu Slanetza-Bertleya. Wykazano znaczne zmniejszenie liczebności większości badanych grup bakterii w trakcie oczyszczania ścieków metodą hydrobotaniczną. W najmniejszym stopniu zmniejszyła się liczebność paciorkowców kałowych.One of the ways to solve the sewage treatment problems in Polish rural areas is the use of unconventional sewage treatment systems based on ponds with macrophytes or on ground filters with hydrophytes. Their function follows the model of natural wetlands. They are featured by many merits and can be used to treat sewage from single farms, small villages, land estates or agro-tourist centres. Beside abiotic processes such as sedimentation and filtration, sorption of chemical pollutants in the medium and photolytic reactions, an important role in sewage treatment play biological factors - vascular flora and microorganisms in a given object. The aim of this study was to assess the effect of sewage treatment in a small home willow treatment plant and treated sewage polishing in the communal mechanical-biological treatment plant with sand-reed filter. The sewage for analyses was sampled from May to December 2007. The number of heterotrophic bacteria capable of growing at temperatures of 22°C (cfu 22°C) and 37°C (cfu 37°C) was estimated by cast plate method according to Polish standard PN-ISO 6222. The numbers of coliform bacteria [TC] and thermo-tolerant (faecal) coliform bacteria [FC] were estimated by means of fermentation test-tube method according to Polish standards PN-75/C-04615/05 and PN-77/C-04615/07. The number of faecal streptococci (FS) was determined by the membrane filter method according to Polish standard PN-82/C-04615/25 with the use of Slanetz-Bertley medium. Considerable reduction of the majority of investigated bacteria groups was found during hydrophyte sewage treatment. The lowest reduction was observed in the number of faecal streptococci

Vliv derivátů polyhexamethylen guanidinu zakomponovaných do Polyhydroxybutyrátu na tvorbu biofilmu a aktivitu bakteriálních enzymů

Escherichia coli and Staphylococcus aureus were able to produce biofilm on the surface of polyhydroxybutyrate (PHB), but their abundance depended on type and the concentrations of the polyhexamethylene guanidine (PHMG) derivatives introduced in PHB. Different types of PHMG derivatives inhibited S. aureus ATCC 6538P biofilm formation, but PHB with PHMG salt of sulfanilic acid stimulated E. coli ATCC 8739 biofilm formation. The presence of all PHMG derivatives decreased significantly the number of viable cells of the test bacteria directly proportional to the concentration of the biocidal agent. PHMG derivatives affected the activity of microbiological hydrolases with different degrees. Some of them (PHB with PHMG stearate) stimulated activity of E. coli ATCC 8739 hydrolases, other (PHB with the PHMG salt of sulfanilic acid) inhibited activity of the S. aureus ATCC 6538P hydrolases. The PHMG derivatives introduced in PHB also inhibited the activity of bacterial dehydrogenasespublikace studuje vliv derivátů polyhexamethylen guanidinu zakomponovaných do polyhydroxybutyrátu na tvorbu biofilmu a aktivitu bakteriálních enzymů u bakterií E. coli a S. aureus

PVA-Based Films with Strontium Titanate Nanoparticles Dedicated to Wound Dressing Application

Bioactive materials may be applied in tissue regeneration, and an example of such materials are wound dressings, which are used to accelerate skin healing, especially after trauma. Here, we proposed a novel dressing enriched by a bioactive component. The aim of our study was to prepare and characterize poly(vinyl alcohol) films modified with strontium titanate nanoparticles. The physicochemical properties of films were studied, such as surface free energy and surface roughness, as well as the mechanical properties of materials. Moreover, different biological studies were carried out, like in vitro hemo- and cyto-compatibility, biocidal activity, and anti-biofilm formation. Also, the degradation of the materials’ utilization possibilities and enzymatic activity in compost were checked. The decrease of surface free energy, increase of roughness, and improvement of mechanical strength were found after the addition of nanoparticles. All developed films were cyto-compatible, and did not induce a hemolytic effect on the human erythrocytes. The PVA films containing the highest concentration of STO (20%) reduced the proliferation of Eschericha coli, Pseudomonas aeruginosa, and Staphylococcus aureus significantly. Also, all films were characterized by surface anti-biofilm activity, as they significantly lowered the bacterial biofilm abundance and its dehydrogenase activity. The films were degraded by the compost microorganism. However, PVA with the addition of 20%STO was more difficult to degrade. Based on our results, for wound dressing application, we suggest using bioactive films based on PVA + 20%STO, as they were characterized by high antibacterial properties, favorable physicochemical characteristics, and good biocompatibility with human cells