UV light-activated decomposition/cleaning of high concentration (>10(3)-10(4) ppm) biomass model and wastes in water involving also solid suspensions into CO2 and N-2 were achieved by using a specially designed biophotochemical cell (BPCC) comprising a nanoporous semiconductor (TiO2) film photoanode/an O-2-reducing cathode unit and a large volume bulk aqueous phase with a remarkably high internal quantum efficiency over 80 (=8000%) for pig urine. (C) 2009 Elsevier B.V. All rights reserved.