Case Study – Waste Water Reuse In Aquaculture Applications Campbell Update 2nd Quarter 2015

In many processes there are wastes that can be repurposed or reclaimed for use in secondary applications. This is especially important in processes that use water as a key resource such as fresh water fish farms and aquaculture.

At the University of South Australia, a research project is underway to determine appropriate methods to reuse wastewater and solids from intensive inland freshwater fish farming. This project makes use of the CR800 data logger abilities to measure, calculate and store data, send and respond to SMS messages and communicate with LoggerLink by 3G TCP/IP for remote mobile data access.

A 6 x 3m insulated shed houses a pilot scale recirculating aquaculture system (RAS) and an adjacent greenhouse has been erected to utilise waste water and solids.

The 7000L combined fish tank and water treatment system supports 80kg of Jade Perch (a species native to northern Australia) in an aerated and heated 4000L tank.

The health of fish is critical and apart from daily visits the system must be monitored remotely. To monitor the supply of oxygen, a DO sensor is located in the fish tank and a temperature sensor is attached to the aerator pump. If the sensors record readings outside of a predetermined range, the telemetry system notifies the operator by SMS. The system can also be accessed using Campbell Scientific’s mobile app LoggerLink for real time data and trending by utilising dynamic DNS (eg. yourname.dyndns.org).

Adjacent to the RAS is a 6 x 18m greenhouse.  A constant stream of waste water (10% of fish tank volume per day) and solids is supplied from the RAS to reservoirs in the greenhouse. This water and the solids are applied to crop vessels within the greenhouse through a combination of drip irrigation and manual application. The crop vessels are grouped for comparison of crops grown with waste water and fresh water irrigation.

To determine the evapotranspiration potential inside the greenhouse an additional set of sensors for relative humidity, temperature and solar radiation are deployed for measurements and calculation within the CR800 data logger. This data allows more accurate irrigation scheduling and a comparison of the greenhouse’s ability to ‘consume’ water relative to outdoor conditions.