Investigations on the influence of three biocides on deteriogenic microorganisms growing on exterior walls and construction elements were carried out in the Institute of Environmental Engineering at Zielona Góra University. Using microscopic analysis of fresh samples and following laboratory incubation, it was found that the biofilms covering the northern facade of the building contained aerophytic cyanobacteria (6 species), one representative of algae and fungi and small colonies of three species of lichens. Biocides were applied on the test surfaces and their efficacy was visually assessed. It was found that the efficacy of the biocides depends on their chemical composition and the type of surface being tested. The preparation applied on the stone wall proved highly effective. It contained quaternary ammonium salts, benzyl and alkyldimethyl ammonium chlorides. Research on the use of contact plates for the determination of microbial surface contamination has shown that the plates are useless for analyzing materials used for coating building materials. The paper also describes the impact of algae and other microorganism colonies on the test materials and the results of negligence in the design, construction and use of the building. The obtained results showed which microorganisms inhabited the examined walls and allow for evaluation of the efficacy of the applied biocides.

New polyurethanes with synthetic polyhydroxybutyrate in their soft segments were degraded under hydrolytic and oxidative conditions. The soft segments of the investigated polyurethanes were built of polytetramethylene glycol (PTMG) and atactic poly[(R,S)- 3-hydroxybutyrate] (a-PHB) or polycaprolactone diol (PCL) and a-PHB, whereas the hard segments consisted of 4,4'-diisocyanate dicyclohexylmethane (H12MDI) and 1,4-butane diol. For comparison PURs without a-PHB and PURs based on 4,4'-diisocyanate diphenylmethane (MDI) were also prepared. The hydrolytic degradation was carried out at 37oC for 36 weeks using a phosphate buffer solution (pH = 7.41). The oxidative degradation was done by using 0.1 M CoCl2 in 20 % H2O2 at 37oC for 16 weeks. The weight changes were estimated during the degradation process. The surface changes of the polyurethanes were tested under an optical microscope after incubation in both the environments. Polyurethane samples containing synthethic, atactic poly([R,S]-3- hydroxybutyrate) were more susceptible to oxidation than to hydrolysis. The surface of polymers incubated in the oxidizing solution was destroyed, whereas the surface of the polymers incubated in the hydrolytic solution was only slightly changed. The presence of aliphatic diisocyanate in the hard segments, in comparison with aromatic diisocyanate, was responsible for a higher rate of degradation of the polymers in the hydrolytic environment. Much more visible surface changes of polyurethanes with PTMG in their soft segments suggest a higher vulnerability to oxidation and hydrolysis of those polymers than in the case of PURs with PCL.

The presence of bacteria in tap water is the result of the imperfect processes of water treatment and disinfection,This becomes a major issue in the event of secondary microbial water contamination, which may result in the development of biofilms on the inside surfaces of water pipes. The first stage of biofilm development is the adhesion of microorganisms to the substrate, the rate of which primarily depends on the roughness of the substrate surface, and only in later stages of biofilm growth on such factors as the availability of biogenic substances in the water distribution system. Over the last few years, water pipes made of plastics such as PVC, PE, PB, and PP have become very popular and are presently used both in internal sanitary installations and in water mains and industrial installations. These materials are characterized by low roughness, which makes them less accessible for microorganisms; however, they do not demonstrate any antimicrobial properties and thus allow biofilms to develop on their surface. In addition, substances used in the pipe manufacturing process may be washed out and become a potential feed for microorganisms, thus stimulating their growth. The study covered the evaluation of the susceptibility of synthetic materials with different physical surface structure to colonisation by microorganisms present in tap water. It was demonstrated that the microorganisms present in tap water develop biofilms on the surface of PVC, PE, PB, and PP, and that these materials show varied degrees of susceptibility to biofilm development. Furthermore, corrosive changes caused by the metabolic activity of microorganisms were observed on the surface of these synthetic materials.

The principles behind planning repair work and corrosion protection activities on concrete and reinforced concrete structures for the period of their service life are described. The requirements for the properties of products and systems for the repair and protection of concrete structures are presented. Various ways of utilising the standard PN-EN 1504-9 in concrete structure maintenance schedules are discussed.