The aim of this study was to determine the chemical composition of wet depositions in two locations from urban and rural area near Bucharest from January to May 2017. For all the samples, pH, conductivity, anions, cations and heavy metals were determined. For anions (Cl -, NO3 -and SO4 2-) and cations (Ca 2+ , K + , Mg 2+ , Na 2+ ) determination an ion chromatographic method was used. Heavy metals (Co, Cr, Cu, Mn, Ni, Pb and Zn) were determined using AAS with flame and graphite chamber. Results showed the presence of the interested compounds in wet depositions samples with SO42-and Ca 2+ as the dominant anion and cation. Heavy metals concentration followed the trend: Zn > Mn > Cu > Pb > Ni > Cr > Co. Analysing the results obtained the potential sources of ambient air pollution were also suggested.

The research aimed to provide an optimized method for the determination of phosphorous concentration in different types of solid waste using inductive coupled plasma mass spectrometry (ICP-MS) technique. The analyzed waste matrices are: a) vegetable waste (P1), b) ash from the incineration of medical waste (P2) c) sewage sludge (P3) and d) sludge from the meat processing industry (P4). The results obtained by the ICP-MS method were compared with the UV-VIS spectrophotometric method for the determination of total phosphorus. In the case of using the colorimetric method by UV-VIS technique, lower results were obtained compared to the ICP-MS method due to the interferences given by the reagents used to determine the total phosphorus. The interferences given by other elements (metals) were also investigated and the performance parameters were determined such as detection limit, quantification limit, recovery and expandend incertainty using ICP-MS technique.

The aim of this work is to apply an ion-chromatography method which was initially developed for the determination of sulfur content in fuels, on other classes of samples as municipal waste and oil and sewage sludge. With respect to their physical properties and texture, solid waste materials as municipal waste, are typically strongly heterogeneous and thus, sample preparation can be critical in obtaining reliable analysis results so that, particle size reduction and homogenizing of the municipal waste was an important step in conducting the experiments. The homogenization of the samples was performed by cutting and then grinding the material in two steps: first a reduction of the particles to diameters passing a 10-mm sieve and secondly to diameters passing a 2-mm sieve. The sulfur extraction from the homogenized waste samples was carried out by the combustion method in the calorimetric bomb. Sulfur as sulfate anion was then analyzed by ion-chromatography and gravimetric techniques and the results were compared. Depending on the nature and sulfur content of the sample, the repeatability standard deviation sr and the relative repeatability standard deviation RSD of the results were of the same order of magnitude for the both gravimetric and ionchromatography methods and they were in the range of about 0.01-0.05 % for sr and in the range of about 3.23-6.25 % for RSD.

Sewage sludge from urban wastewater treatment plants come from different stages of wastewater treatment and are considered as waste, falling under the waste regulations. In order to reduce the negative environmental impacts, the removal of sewage sludge on landfill is considered as the last waste management option. One of the sludge management alternatives is to recover energy from the sewage sludge by incineration in waste incinerators or co-combustion in cement or thermal power plants. The use of sewage sludge as a source of renewable energy is an ecologically and economically efficient option, both in the EU and Romania sludge management strategy. Total organic carbon is a key environmental indicator for soil, sludge and sediment and a parameter for characterizing sludge for energy recovery. The paper presents the methodology for total organic carbon determination from acidified sludge samples by dry combustion, in an oxygen atmosphere using FlashEA 1112 Series Analyser. From the experimental laboratory researches the following aspects were highlighted: the interdependence between the total organic carbon content and the heating value of sludge samples, an important factor for energy recovery/elimination by incineration, co-combustion and utilization as secondary raw materials in cement plants.

A good function of waste-to-energy installation requires knowledge of the combustion characteristics of the fuel and fusion characteristics of the ash produced in the combustion process. Sewage sludge could be considered as renewable fuel due the high quantity of organics of sufficiently high calorific value. The combustion of sewage sludge can cause operating problems due to high ash content containing mineral compounds. This paper presents the oxide composition of three kinds of sewage sludge ashes and the influence on the slagging and fouling process in combustion. For comparation, two coal samples were selected, a low and a high rank coal. The mineral matter were investigated by the X-ray fluorescence analytical technique using the Rigaku CG X-ray Spectrofluorimeter. The evaluation of slagging and fouling process was performed on the basis of some indices: the basic oxides, the base-to-acid ratio, the slagging index and the fouling index. The conclusion based on experimental studies is that depending on mineral content the sewage sludge ash can cause high to moderate slagging and fouling hazard.