“The reality is that no one in the world has done anything on this scale. Our trial aims to show that this complete process can be cost-effective and efficient”, says NIWA scientist Dr Rupert Craggs. Twelve years of research by NIWA’s Aquatic Pollution Group has culminated in the world’s first large-scale trial of the production of algal bio-crude oil from wastewater.

The commercial feasibility of producing bio-crude oil from algae grown in wastewater is being tested at Christchurch’s wastewater treatment plant. Five hectares of ponds have been converted to so-called ‘high rate algal ponds’. Carbon dioxide is added to the ponds to enhance wastewater treatment and promote algal growth, a technique pioneered by the NIWA group. Gentle mixing with paddle wheels stimulates algal growth and assists with disinfection of the wastewater by sunlight.


  NIWA's research site at the Christchurch wasterwater treatment plant. (NIWA)

The algal biomass harvested from the ponds is converted into bio-oil using super critical water reactor (SCWR) technology, developed by Christchurch company, Solray Energy. The technology uses heat and pressure to convert biomass sources into crude bio-oil. NIWA’s study will determine the energy efficiency and economics of this process at large-scale including the co-benefits of (i) recovery of wastewater nutrients for fertiliser, and (ii) greenhouse gas abatement through low-energy wastewater treatment and off-set fossil fuel use. Dr Craggs is leading the Foundation for Research, Science and Technology-funded project.  “By demonstrating that conventional wastewater treatment ponds can be upgraded with low-cost, energy efficient enhanced ponds, we aim to prove that algal biofuel production is commercially viable today.”

Read about the bio-crude oil project in more detail.

NIWA CEO John Morgan, project leader Dr Rupert Craggs, and Energy Minister Hon Gerry Brownlee, with crude and refined bio-oil made from algae. The oil is processed by Solray Energy Ltd, NIWA's collaborators in the project. (NIWA)


A lawnmower is fuelled with bio-oil manufactured from algae at the research site in Christchurch. (NIWA) 

Contact: Dr Rupert Craggs, NIWA