Olive mill wastewater (OMW) is a major watercourse pollutant agent with a high concentration of phenolic compounds. It is estimated that 30 million OMW m are released into rivers every year. Protecting the health of these courses against the uncontrolled discharges implies establishing an adequate legislation, where spillage control tools play a fundamental role. In this paper, a new tool for OMW spillage control is discussed. It is based on the use of a RP-HPLC-UV protocol to track p-Coumaric acid (pCA), a characteristic OMW phenolic compound, and its derivative compounds through their chemical oxidation and biological anaerobic degradation. Laboratory assays and real-life experiences allowed to determine degradation routes and apparition times for every pCA derivative, making it possible to detect an OMW spill and assess its age. Moreover, this RP-HPLC-UV introduces solid advantages over previous detection procedures, namely, quicker response times and smaller costs than HPLC methods and superior specificity than colorimetric methods. Finally, this tool was put to test in an actual OMW-polluted watercourse. In all scenarios, the tool demonstrated solid reliability.

The aim of this paper is to assess the feasibility of the co-digestion of olive mill industrial waste with urban sewage sludge from wastewater treatment plants (WWTP). These wastes include olive mill solid waste (OMSW) and olive mill effluent (OME). This co-digestion process enables the energetic exploitation of OMSW and/or OME and introduces an environmental solution for their highly pollutant compounds. The behaviour of both co-substrates was studied using biochemical methane potential assays. To determine the optimal proportions of each co-substrate, different quantities of OME and OMSW were added to a constant quantity of substrate (urban sewage sludge) and put to test. A small amount of digested sludge from WWTP was used as an inoculum to accelerate the pace of the reactions. Thus, the optimal proportions between substrate and co-substrate were defined. The samples containing OMSW showed a biodegradability around 23%, slightly above that of the substrate on its own (21.3%). Moreover, biogas production in samples containing OMSW was significantly superior to samples containing substrate only. Nevertheless, the samples containing OME as a co-substrate presented an inferior biodegradability (20.3%) to that of the substrate on its own. Similarly, biogas production in OME co-digestion remained within the usual values of urban sewage sludge biogas production. In all cases, the system remained stable and the energetic efficiency of the process was improved in comparison to the digestion of substrate only. Therefore, codigestion with urban sewage sludge proves to be a cost-effective method for OMSW and OME environmental management.