###### Abstract
The chemical reduction by an organo-iron compound (liquid ferrous lactate), combined with emulsified vegetable oil, was employed to minimize the accumulation of the tetrachloroethene by-product in groundwater. Ferrous lactate (FL) forms aqueous solutions that are convenient for injection during in situ operations and that may have a longer distance of transmission than solid, zerovalent iron. The used mixture was effectively adsorbed into soil pores and continued to release electron donors; it had at least 90 days of slow-release effect and reached a minimum distance of 5 m. Moreover, the metabolites did not accumulate in a notable manner in areas where FL concentration was adequate. The tolerance mechanisms developed by microorganisms that inhabit the impacted sites could be exploited in remediation processes, for example in [12], where it is reported that marine bacteria collected from seven Portuguese fishing ports were isolated and grown in the presence of Tributyltin (TBT). The bacteria that exhibited higher growth were evaluated for their capability to degrade this highly toxic, endocrine disrupting compound. The results were ascertained using ecotoxicological tests. Two strains were selected and identified as _Pseudomonas putida_ and _Serratia marcescens_. _P. putida_ showed the highest degradation potential. After 96 h of exposure to _S. marcescens_, the media was still toxic, suggesting the need for longer contact time or the production of toxic by-products. An effective remediation of polluted water was obtained by removing the unwanted chemicals by physical absorption mechanisms on nanomaterials, thanks to the large specific surface area [13]. Multi-walled carbon nanotubes (MWCNTs) were synthesized, purified, functionalized, and used as an adsorbent for the removal of Ismate violet 2R dye from the contaminated water. The morphological structure, the physical, chemical, thermodynamic, and kinetics properties were evaluated throughout. The adsorption is a physisorption process and under optimal conditions, the percentage of removal of the MWCNTs from real wastewater reached 88%. The in situ degradation of pesticide containing agro-wastewaters (remnant volumes from spraying activities or leftover pesticide waste) was realized by a portable photo-reactor prototype, employing UV lamps and H\({}_{2}\)O\({}_{2}\)[14]. The degradation process was evaluated by the pesticides' absorbance decrease, the mineralization process by measuring the TOC values, and the toxic effects of irradiated and non-irradiated solutions by biological tests. The photo-reactor prototype was able to remove about 80% (mean value) of the active molecules in an acceptable time (8 h). The mean mineralization rate was about 44%. These results were extremely positive, since the photoproducts are more prone to inherent water remediation processes than the parent compounds. The effectiveness of a TiO\({}_{2}\) photo-catalysis in removing glucocorticoids (GCs) under simulated and natural sunlight from solutions prepared in tap water or in river water at environmental concentrations has been evaluated [15]. The degradation profiles followed a pseudo-first order kinetics and the TiO\({}_{2}\)-assisted photo-catalysis appeared to be independent of the chemical structure of the GCs. The photocatalytic process was from one to two orders of magnitude faster than the not-catalysed photolysis. The two main photo-oxidation paths, directly linked to OH radicals from the irradiated TiO\({}_{2}\) catalyst, were defined. The author concluded that the great stability of the titania crystals under irradiation, coupled with the good adsorption properties and catalytic activity, overcome any other depollution method. The paper [16] reports the degradation of the highly toxic pesticide methicor (MC) by electrochemical oxidation in aqueous solutions, utilizing a boron-doped diamond anode and two different supporting electrolytes. The removal rate, total organic carbon (TOC), and total nitrogen (TN) were determined.