Pilot-UASB reactor tests for anaerobic valorisation of high-loaded liquid substrates in friulian mountain area

•Cheese whey, condensate water and OFMSW leachate were treated in UASB reactor.•Diluted cheese whey was treated with high efficiency and stability.•Low COD removal was obtained on leachate, given its low-strength characteristics.•An energy saving of 101.3 kW was estimated with condensate water UASB treatment.•Odour analysis showed the substrate relative impact in smell nuisance production. This work was focused on the start-up of a pilot-UASB reactor, to valorise high-loaded liquid substrates available in the mountain area of Friuli-Venezia Giulia region; technical and economic convenience of full-scale UASB reactor activation, treating condensate pulp and paper wastewater, was evaluated. Leachate, obtained from organic fraction of municipal solid waste, and cheese whey were studied as well, as alternative feeds for UASB reactor, given the availability of these substrate in the analysed area. The results of the pilot tests highlighted a good adaptation of granular biomass to diluted cheese whey (1:50 v/v), with stable operations (mean COD removal of 84.6%), while lower COD abatements were obtained on condensate water (mean 53.6%) and, mostly, OFMSW leachate (mean 37.0%). Organic loading rate could be progressively increased in a following step, as for cheese whey, augmenting CH4 production (mean obtained yield of 0.149 m3 CH4/kg CODremoved). Condensate water tests were useful to plan the revamping of full-scale UASB reactor: the approximated energy saving in the aerobic line was evaluated as 101.3 kW (2,430 kW h/d). As for OFMSW, it was concluded that alternative different liquid-solid separation methods to percolation, such as mechanical pressing, should be preferred, to increase influent COD (mean obtained value of 750 mg/L), given also the low amount of available waste in the analysed territory (4142 t/year), improving potential energy recovery.