AQUAVAL  - Valorisation of water use in aquaculture using multi trophic systems

Project Website

paula castro 

Coordinator: Paula ML Castro


Projects  Partner and Institution:
PL Castro, Universidade Católica Portuguesa-UCP 
A Mosquera Corral, Universidade de Santiago de Compostela-USC 
B Sicuro, University of Torino-DVS  
L Arregui, Grupo TresMares-GTM 

Key words: Multi trophic systems; bacteria; microalgae; bivalves; recycling/reuse; aquaculture effluents


AquaVal is framed in the topic "water reuse and water recycling technologies in the agriculture and freshwater aquaculture sectors". Aquaculture is the fastest growing food-producing sector, accounting for more than 50% of the world's fish food. To meet the growing fish demand, it is estimated that by 2030 about 60% of the fish will be supplied by aquaculture systems. However, increasing the productivity of aquaculture, especially of the land-based systems, is hindered by lack of space and of water availability along with other environmental impacts. The AquaVal main objective was to develop technologies to enable more sustainable management of water in aquaculture – different combinations of a multitrophic system, integrating bacteria, microalgae and bivalves, were applied to treat water streams typical of aquaculture systems to quality levels allowing reuse following the circular economy precepts.

Lab-scale biological granular sludge reactors were optimized for the treatment of water streams mimicking those of aquaculture facilities, characterized by large water flows and extremely low concentrations of nutrients. An aerobic granular sludge sequencing batch reactor was operated at UCP where the main processes taking place were nitrification and heterotrophic growth, with an ammonium removal near 100% (14.5 mg NH4+-N/(L·d)). In a continuous flow granular sludge (CFGR) the processes taking place were heterotrophic growth and denitratation, with 10 - 20% of the ammonium consumed reaching rates of 90.0 mg NH4+-N/(L·d), treating extremely high flows. Both granular biomass systems produced effluents with nitrogen concentrations below the toxic levels for fish and suitable for recycling in the aquaculture farm. The AGS-SBR produced an effluent suitable for recycling to the fingerling area whereas the CFGR produced an effluent with moderate chemical quality but was able to treat larger flows suitable to recycle in the fish fattening area. Microalgae adapted to grow in aquaculture effluents were isolated from sludge at the GTM fish farm and used to bioaugment granular sludge reactors at lab and pilot scale successfully. A 30-L pilot-scale CFGR was operated at GTM farm with ammonium and nitrite removal up to 80 %. Bioaugmentation with microalgae allowed for oxygen increase in the effluent to saturation levels in the effluent, ensuring the viability of recirculating without need for external oxygenation. With the upscaling of the reactor the farm could recirculate 90% of water back to the fish and would save the discharge of 1,400 Kg of N to the surrounding water each year (for 4 months operation). This could represent 66% more growth during summer with a feed rate increase from 0,6% to 1%, obtaining 288 t extra fish in a moderate scenario. Freshwater bivalves proved efficient bioremediators at a density of 7.5 kg/m3. The concentration of Aeromonas hydrophila, (one of the most common bacterial fish pathogen in rainbow trout farms) was reduced up to 90% to 95% in counts. A fish feed containing mussel meal as a partial substitute of fish meal was produced and validated.

The expected benefits from implementing such system are the protection of natural environments from aquaculture activities and water and economic savings from water recirculation and reuse. The project website and facebook are available at and Aquaval-333197697119912/.

Project structure: A 36-month research study structured in 6 work packages is envisaged with a consortium comprising institutions with expertise in key areas: Biological water treatment – USC, Spain; UCP, Portugal; Bivalve rearing – DVS, Italy; Technology developers and risk assessment –Aquaculture production-utility – GTM, Spain. University of Gent, Belgium, will be subcontracted by UCP to benefit from the experience on microbial biofloculation and microalgae of Prof Dr. Ir Peter Bossier, whose research on the last 14 years focused on microbial community management in aquaculture systems, and on the possibility that it could contribute to nutrient recovery and health. 

WP1 Project management,
WP2 Polishing units based on bacteria and microalgae;
WP3 Bivalves filtration unitand filtration expertiments;
WP4 Field Trials;
WP5 Evaluation of the integrated system; WP6 Dissemination and Exploitation

Newer more efficient technologies based on of multi-trophic systems (bacteria, algae and bivalves) to reduce nitrogen and other pollutants to levels which will improve recirculating aquaculture systems (RAS) technology; production of water with quality sufficient for recirculation/reuse; use of bivalves as depuration units, using wastewater as a resource, converting it into bivalve biomass, potentially utilizable in aquaculture feeds; The use of bivalves rearing unit for depuration can indirectly increase biodiversity when the system is tested with endangered species.

References coordinator and  leaders of  each WP:
WP1, P Castro-UCP;
WP2, P Castro-UCP;
WP3, B Sicuro-DVS;
WP4, A Mosquera-USC;
WP5, L Arregui-GTM;
WP6 E Cardoso-UCP.

Main outputs:

  • Fra-Vázquez, A., Santorio, S., Palmeiro-Sánchez, T., Val del Río, Á., Mosquera-Corral, A. PHA accumulation of a mixed microbial culture co-exists with ammonia partial nitritation (2019) Chemical Engineering Journal, 360, pp. 1255-1261.
  • Santorio, S., Fra-Vázquez, A., Val del Rio, A., MosqueraCorral, A. Potential of endogenous PHA as electron donor for denitrification (2019) Science of the Total Environment, 695, art. no. 133747.
  • Argiz, L., Fra-Vázquez, A., del Río, Á.V., Mosquera-Corral, A. Optimization of an enriched mixed culture to increase PHA accumulation using industrial saline complex wastewater as a substrate (2020) Chemosphere, 247, art. no. 125873.
  • Argiz, L., Reyes, C., Belmonte, M., Franchi, O., Campo, R., Fra-Vázquez, A., Val del Río, A., Mosquera-Corral, A., Campos, J.L. Assessment of a fast method to predict the biochemical methane potential based on biodegradable COD obtained by fractionation respirometric tests (2020) Journal of Environmental Management, 269, art. no. 110695.

More results on the project: Data and resources

Contact Point for  Communication/Dissemination activities: E Cardoso

Contact Point for Open Data/Open Access activities: CL Amorim - UCP

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published on 2017/03/23 10:00:00 GMT+1 last modified 2022-05-10T14:09:49+01:00