Seafood processing is a large-scale food industrial activity, in the UK and worldwide, which requires substantial quantities of clean water for washing purposes. Therefore, the aim of this study is to assess the feasibility of ultraviolet (UV) treatment to disinfect water coming from shellfish washing process, as to safely recycle it in the process. For this reason, different operating parameters that typically affect UV treatment efficiency, namely the power output of the UV lamp (5 W, 9W, and 11 W), the turbidity of the washing water (0-52 NTU), and the initial bacterial concentration (10(4), 10(5), 10(6) CFU mL(-1)) were studied. Water disinfection was monitored by following changes in the concentration of the Escherichia coli (E. coli) bacteria. Photoreactivation of bacteria after UV disinfection was also investigated. Results showed that the UV treatment can efficiently inactivate bacteria in shellfish processing water, since E. coli (10(6) CFU mL(-1)) in turbid (i.e. 0.074-35 NTU) seafood processing water were inactivated within the first 15 s of treatment, by means of an 11 W germicidal lamp. Under these conditions, no bacteria photoreactivation was observed after 2 h of exposure to natural light. The disinfection efficiency was decreased when the initial bacterial concentration and water turbidity were increased. In addition, the increase of UV power output resulted in a substantial increase of bacterial inactivation. Furthermore, E. call were reactivated after 2 h of exposure to natural light when the turbidity of the washing water was >= 42 NTU or when the initial bacterial concentration was high (i.e. 10(5) and 10(6) CFU mL(-1)). (C) 2015 Elsevier Ltd. All rights reserved.