A new approach to energy-efficient treatment of wastewater produced by the fish industry in Vietnam

Abstract

Economic growth in Vietnam in the last few years has brought about an increasing demand for energy and has had a severe environmental impact. Fish processing is one of the fastest-growing industries that discharge organically-polluted wastewater. To counter these environmental problems, new technologies for energy-efficient treatment are needed. By coupling innovative nitrogen removal systems with anaerobic treatment processes, it is possible to realise such technologies. In the present project, a combined deammonification and anaerobic carbon removal system is presented. Special requirements to enable reliable treatment are discussed, taking industrial wastewater characteristics into consideration. To evaluate energetic efficiency, energy balance calculations based on data from a fish-processing factory are made. The determined specific energy consumption and production rates show that energy recovery is possible, even when COD and nitrogen removal efficiencies of over 90% are achieved. Depending on the pre-treatment employed, energy recovery rates ranging from 0.6 to 2.5 kWh/mt raw fish can be reached.

Activity of Ammonium-Oxidizing Bacteria—An Essential Parameter for Model-Based N2O Mitigation Control Strategies for Biofilms

“…Substantial amounts of the GHG nitrous oxide (N 2 O) can be formed and emitted during the nitrification/denitrification process if the operating conditions are not adjusted with regard to minimized greenhouse gas formation. Due to high N 2 O emission factors-up to 20% of the influent nitrogen (e.g., [1])-and the high global warming potential of 265 g CO 2 e/g N 2 O [2], the direct N 2 O emissions often exceed the indirect CO 2 e emissions caused by energy consumption (e.g., [3]). However, several investigations on large-scale plants have also shown that N 2 O emissions close to zero are achievable for low-load systems (e.g., [4,5]).…”

Energy and carbon footprints of different technologies for energy recovery from wastewater of the Vietnamese seafood processing industry

“…The wastewater of most seafood processing companies in the Mekong Delta contains high loads of carbon in the form of fish fat and is conventionally treated aerobically (Trautmann et al, 2011). This results in high energy demands and high amounts of excess sludge that may not always be treated adequately.…”