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Advisor(s)
Abstract(s)
The valorization of wastewaters from the fish canning industry is of great concern, not only because of
the high quantities generated, but also economic and environmental benefits may result from a proper
treatment approach of the waste generated while reducing costs related to wastewater discharge.
A limiting factor for reuse and recycling treated fish canning wastewater into an industrial plant and
also for other uses is the high salt content, which persists even after conventional treatment. So, the
reuse of fish canning industrial wastewater was assessed by combining conventional treatments, such as
sedimentation, chemical coagulation-flocculation and aerobic biological degradation (activated sludge
process) followed by a polishing step by reverse osmosis (RO) and ultraviolet (UV) disinfection.
In this investigation all these processes were optimized in order to remove essentially the effluent
suspended particles (primary treatment), the organic matter content in the biological aerated reactor
(secondary treatment) and, finally, the remaining salts and microorganisms (tertiary treatment).
The overall removal efficiencies obtained were: 99.9% for dissolved organic carbon (DOC), 99.8% for oil
and grease (O&G), 98.4% for total suspended solids (TSS), above 96% for anions and cations and 100% for
heterotrophic bacteria expressed as colony-forming units (CFU). The final clarified effluent was found to
have the quality requirements to be recycled or reused in the industrial plant, allowing the reduction of
the effluent to be discharged, the water use and the costs of tap water for industrial use.
As regards the energy and chemicals costs, to obtain a treated effluent to be reused in the process costs
0.85 V/m3. This value can be reduced by about 60% if the goal is only to meet the legislated standards for
the effluent discharge into water bodies. Tap water for the industrial plant costs about 2.1 V/m3.
Description
Keywords
Fish canning wastewater Wastewater reuse Reverse osmosis UV disinfection Coagulation-flocculation Biological treatment
Citation
Cristóvão, Raquel O.; Botelho, Cidália M., Martins, Ramiro; Loureiro, José M.; Boaventura, Rui A.R. (2015). Fish canning industry wastewater treatment for water reuse – a case study. Journal of Cleaner Production. ISSN 0959-6526. 87, p. 603-612