## 1 Introduction  
Chemical synthesis of both organic and inorganic compounds plays a paramount role in modern industrial production, as a process by which substances currently used in daily life are obtained. Its products impact everyday life directly and indirectly, creating the need for methods for their safe disposal/decomposition prior to emission to ambient media. Novel organic micro-contaminants include contaminants of emerging concern (CECs), pharmaceuticals and personal care products (PPCPs), and metabolites thereof excreted after human or animal assumption. These have been recently detected in surface waters worldwide [1; 2] and some are suspected endocrine disruptors (EDs), with potential, direct consequences on human health [3]. It has been estimated that about 80% of the 16,000 tons/year of PPCPs discarded in Germany end up flushed in toilets or disposed of with household waste, and may thus find their way into natural waters [4].  
Detection of these pollutants in the environment, and especially in water supply systems [5], from where they could negatively affect individuals' health and cause the spread of antibiotic resistance phenomena [6] is an important issue not yet satisfactorily addressed. More important, however, is the identification of suitable processes for their minimization or, possibly, complete decomposition in the containing solution. In currently operating wastewater treatment plants (WWTPs), emerging pollutants and their metabolites could be partly transformed by biological or chemical reactions, or surface processes (e.g., adsorption on solid phases). Several studies have proved that the disappearance rates of many compounds observed in solution (determined as the difference of influent and effluent concentrations) may not imply per se a correspondingly equal rate of complete degradation (mineralization), as transformation byproducts whether in the effluent, or accumulated within a different phase (i.e., excess process sludge) are often revealed [7; 8]. These byproducts may sometimes be even more hazardous than the original compound. Furthermore, often biological or chemical transformation pathways of these compounds are still undetermined [9].  
In such instances, treatment processes merely shift any environmental risk to a different triggering molecule or exposure medium. Effective technologies for their total removal from solutions are not yet fully established, nor capable to remove simultaneously all possible contaminants. Some processes have demonstrated capacity to remove some, and are adopted on case-by-case approaches. More frequently, for removal of these pollutants, processes like biodegradation [10] and Advanced Oxidation Processes (AOPs) [11] are adopted. The latter is a broad category including both homogeneous and heterogeneous processes, such as ultraviolet (UV) photolysis, Fenton, electrochemical, sonochemical, supercritical water or wet air oxidation, often in combination with chemical catalysts (e.g., TiO\({}_{2}\)) or oxidizers (e.g., O\({}_{3}\), H\({}_{2}\)O\({}_{2}\)). Mainstream AOPs may still result in the above mentioned drawbacks, although they may comply with certain water reuse regulations for specific compounds. Moreover, as concentrations of these chemicals are usually very low, specific treatment costs (cost per unit mass removed) generally turn out to be quite high [12].  
Research for more effective CEC compound destruction technologies is ongoing. Emerging technologies such as electron beam (EB) and non-thermal plasma (NTP) have recently been proposed as suitable for this purpose [13; 14] and could provide viable alternatives to the former. This paper discusses the state-of-the-art (SOTA) of these technologies for the treatment of supply and used water.