Conference Papers

Large amounts of sewage sludge are produced at waste water treatment plants and its disposal is an environmental problem. In this context and in accordance with the European Commission communication on the role of waste-to-energy in the Circular Economy, one of the objectives of Romania Waste Management-Strategy Plan for municipal waste, is incineration of the solid waste in dedicated incinerators, with energy recovery. When the incineration of the sewage sludge with energy recovery is chosen as the final path of disposal, the optimal energy gain, have to be correlated with the limits provided of the legislation in force for the air pollution emissions and with the quantities of the waste which must be minimized. The presence of sulfur in sewage sludge has significant implications in incineration processes, due to its transformation at high temperature into SO2 which is released into the atmosphere, and on the other hand, there is a risk of high-temperature corrosion of the pipes and pumps, depending of the molar ratio 2S/Cl. The paper presents a study on the determination of the technological forms of sulfur and total sulfur in sewage sludge to be incinerated. The results obtained show that the total sulfur is mostly represented by the combustible sulfur which is in a proportion of about 88% and the rest of about 12 % is the sulfur remaining in the ash.

This paper proposed an optimized method used for determination of minor elements (Cu, Zn, Mn) from Romanian biomass ash from three different biomass ash using ICP-MS technique. The purpose of the study was to find a suitable method of analysis for the complex matrix of biomass ash by comparing two samples preparation methods: at 5500C and 8200C. For this study the content of metals from three different samples from forestry and related industries (P1), forestry and exploitation (P2) and agriculture (P3) was analyzed. The results obtained were compared with the value of certified reference material (CRM), to demonstrate the accuracy of the method and the quality of the results. The analysis method chosen in this study was highlighted as optimal for biomass ash analysis using performance parameters: precision, accuracy, detection limit, quantification limit, and expanded uncertainty. The determined elements were some of those considered to be of great concern for the environment, such as Cu, Zn, Mn. In all samples, the ash studied, Mn had the highest concentration among other minor elements. If we know the chemical composition of ash biomass, we can recycle biomass and reuse him as solid fuels. The method used has proven to be reliable, simple, selective and relatively inexpensive, and therefore allows rapid determination of Cu, Zn and Mn.

The present paper concretises a current assessment of the quality of the environmental components by characterizing the soil and groundwater samples in 4 agricultural areas in Romania, chosen as case studies according to the criteria of their vulnerability to climate change. The important data obtained from laboratory physical and chemical characterization of soil and groundwater samples taken from these areas, have been analyzed in close correlation with current agricultural practices identified and their local specifics. The general conclusions resulting from the analysis of the results of the analyzed quality indicators, the direct observations from the terrain, as well as the documented information on the geomorphological, lithological, hydrogeological, climatic conditions, converge to the evidence of contamination vulnerabilities, corroborated with the use of resources in intensive agriculture. It is absolutely necessary to undertake a joint effort of the actors involved in this type of intensive agriculture to focus on adapting to climate change as well as on sustainable management of the natural resources involved (soil, groundwater). Good practice in agriculture remains one of the most important links for the sustainable maintenance of natural resources involved in human activities.

This paper presents a recent study regarding choosing and optimizing of the appropriate test methods to characterization and analysis of used oils from different sectors of activity, in order to evaluate the heavy metal content. In the first step, the samples preparation stage for metal analysis, a number of preparation methods have been tested and finally chosen as optimal, a microwave digestion method. For comparison the metals were analyzed by inductively coupled plasma mass spectrometry (ICP-MS) and atomic absorption spectrometry (AAS). The results obtained by the two methods are comparative and indicate in all analyzed samples the presence of heavy metals such as Fe, Ni, Zn, Cr and Mn. The methods used have been demonstrated to be appropriate by use of the certified reference material for metals in lubricating oils. From the results obtained it is found that the methods of characterization and analysis can be used as optimal and good methods for evaluation of the content of metals in used oils.