Most of the total nitrogen (TN) output from the Australian prawn industry is organic nitrogen, of which microalgae assimilate a large proportion. In response to the industry’s need to remove or reduce microalgae and TN from large quantities of release water, this project investigates the use of electro-coagulation (EC) technology to remove microalgae and TN from settlement pond discharge.

• Developed a Grafana display and off-site access to the pilot machine.

• Used a gravity fed EC machine capable of processing 90-120gpm.

• Trialed the EC machine in-situ with different plate materials including mild steel, aluminium, graphite and titanium plus combination of graphite X titanium.

• Observed the coagulation effects of the different plate materials with a retention time of 4 minutes.

Still pending for the different plate materials.

The growing Australian Prawn Industry is committed to improving its practices around the issues of environmental sustainability and compliance. The importance that the industry places on meeting its sustainability goals is reflected in the APFA strategic plan, with key goals to improve water quality and reduce nutrient effluent highlighted. This project aims to focus on the reduction/removal of ammonia N in order to facilitate the expansion of the industry whilst continuing to meet these sustainability targets by:

• Reduced environmental impact from farming activities.

• Smaller footprint required for bioremediation infrastructure before discharge to receiving waters - space can be used for extra production ponds, i.e. more production output for the same CAPEX OR reuse of water.

CHRISTINE HUYNH 

TONY LAND