Articles

Environmental pollution and global warming effects are a particular problem for the protection of historical monuments and heritage objects. More than 1400 wooden churches have been built in Romania until 1918. They form a precious nationally and globally heritage that needs to be preserved and transmitted to future generations. A fist step in this process is the indoor air quality assessment to identify the sources of pollution and potential aggressive compounds with the goal of reducing the effects on wooden structure and heritage objects. The paper presents a case study conducted in 2014 in order to assess the air quality inside a wooden church from Bucharest; the sampling campaigns were conducted inside and outside the building for simultaneously air pollutants (NO2, SO2, CO2, O3, PM2.5 and microflra) and micro-climate factors (temperature, humidity) monitoring using automated methods that allow results storage, statistical treatment and interpretation. In order to identify the pollution sources and their impact on indoor air quality have been used indoor/outdoor (I/O) ratio values and the Pearson correlation which indicated that the major pollution sources are the outdoor air pollution and people attending the church services.

Wastewater treatment plants are major interface between rural and urban activities and the natural environment with problems relating to the survival and transmission of the fecal bacteria into streams and rivers. The main goal of this paper was to showed the impact of WWTPs on fecal populations bacteria and their dissemination into the aquatic ecosystems. The sampling campaigns were conducted in 2019 where the hospital and WWTPs wastewater from three cities from the south-eastern part of Romania and the surface water of their emissaries were trimestral collected. The quantitative and qualitative analysis of total and fecal coliforms indicated the efficiency of wastewater treatment processes but at the same time, the contribution of contamination with hospital effluents has been demonstrated. Also, the microbiological results showed the selectivity of the destruction of fecal coliform bacteria between wastewater and surface water.

The widespread use of detergents has raised concern with regard to the environmental pollution caused by their active substances, which are biorefractory, toxic or persistent. Even though anionic and non-ionic surfactants often used in commercial detergents composition are reasonably degradable under aerobic conditions and not particularly toxic at low concentrations, high concentration of surfactants influenced the activated sludge activity and are harmful for the aquatic environment. In the literature, data on the biodegradability and/or ecotoxicity of a certain type of surfactant (anionic, nonionic, cationic) are usually presented. Our study aimed to assess the biodegradability of a mixture of two types of surfactants (anionic mixed with non-ionic) and also, effects caused by their presence of elevated concentrations to the activated sludge microorganisms, within a batch experiment. We performed a biodegradability test (according Zahn Wellens method) on 2 synthetic solutions with high concentrations of anionic surfactant –methyl dodecylbenzene sulfonate (15-25 mg/L) and non-ionic surfactant -4-nonylphenyl-polyethylene glycol (10 mg/L). The study established different percent of biodegradability (measured by COD decrease and surfactants removal) depending on initial concentrations of anionic and nonionic surfactants in the tested solutions. High surfactants concentrations modulated the activity and morphology of activated sludge, so its degradation efficiency of the organic substrate has decreased. Surfactant solutions resulting from biodegradability experiment have been tested for toxicity to planktonic crustaceans (Daphnia magna).

In the last 20 years, moving bed biofilm reactor (MBBR) has been established as a simple yet robust, flexible, and compact technology for wastewater treatment. It is one of the advanced aerobic wastewater treatment processes by taking advantage of both attached and suspended growth systems. The vast majority of bacteria adhere to surfaces and form complex and heterogeneous microbial communities termed biofilms which have tremendous positive potential in biotechnology for biocatalysis and waste treatment. In this work, we studied the Escherichia coli (E. coli) adhesion properties on synthetic artificial materials (SAMs), also known as biofilm carriers, based on High-Density Polyethylene (HDPE). The results showed that E. coli adherence to SAMs is not only preserved but is also enhanced by the presence of 7% cellulose in SAM’s composition.