Geothermal nutrient removal

Progress has been made with trials to remove nitrogen from geothermal sources to Lake Rotorua. 

Currently around 20 to 25 tonnes of nitrogen enters Lake Rotorua annually from the Waiohewa Stream due to geothermal activity. 

We have trialled innovative methods to remove the nitrogen from the stream before it reaches the lake.

The small scale trials were undertaken using locally mined zeolite and have been successful in removing nitrogen from the stream waters.  A larger scale trial was undertaken to confirm specific performance aspects for the design of a full scale plant.

Larger scale trials proved successful and the construction of a full scale plant is likely to begin 2018/19.