MARCH 2010: UPDATE OF RESEARCH BEING CARRIED OUT BY THE NZ CENTER FOR BIOCHAR RESEARCH
The New Zealand Biochar Research Center (NZBRC) was founded by the NZ Biochar Initiative, and is funded by the NZ Ministry of Agriculture and Forestry (MAF) and Massey University, and is housed under the latter. It employs two researchers, Dr. Marta Camps and Dr. Jim Jones (shown in the photo to the right). Marta is an agronomist with a MS and a PhD in soil science and started working for the Center in January 2009. Jim is a chemical engineer with a background in particle technology, now specializing in pyrolysis technology since he joined the Center in October 2009. Five PhD students are currently working in the NZBRC and three are to be appointed soon. Several honor and master students have worked with the group in the past, some of them will continue their PhD with us in the near future. A post-doc researcher is currently collaborating with the NZBRC.
Experiments with biochar began in 2009, with the characterization of biochar made from different feedstocks (sewage sludge, wood and crop residues) and under different pyrolysis conditions, with the goal of relating biochar characteristics to production parameters (a poster was presented at the 1st Asia Pacific Biochar Conference, Gold Coast, Australia, 17-20 May 2009). Biochar was also treated (“activated”) with alkaline waste residues such as waste from animal skin tanneries. If successful, this will be used as a filter for farm wastewater. The goal is to eventually use this nutrient loaded biochar as a fertilizer in soil. Findings so far indicate that treating biochar with the alkaline waste increases the surface charge on the material, thus potentially improving the biochar’s ability to retain positively charged species in farm waste water (e.g. NH4+). A poster on this work was also presented at the 1st Asia Pacific Biochar Conference.
The effect of biochar made from sewage sludge on sandy soils was also tested in 2009. The sludge was sourced from a provincial city where the levels of heavy metals in the sludge were low. In a series of pot tests, ryegrass was grown and positive results were obtained when biochar was applied along with an N fertilizer, but not when applied in the absence of N fertilizer. The beneficial effects of these biochars on plant growth, in the presence of N, were attributed to their high content in available P and K. The results also indicated that the N present in the biochar – produced at 550oC – was not available, in spite of the low C/N ratio, and this was attributed to the presence of N in heterocyclic form.
NZ soils are often quite rich in organic matter, so the NZBRC team is interested in assessing the impact of applying biochar on the “resident” organic matter of NZ soils. To do this, new experiments are about to begin using stable C isotope techniques and soil of contrasting mineralogy, in the greenhouse. There is also interest within the group to study historical Maori sites. The Maori are the indigenous Polynesian people of New Zealand. Charcoal-rich areas of such sites could be used to study biochar weathering and biochar-mineral interactions across the pedo-climatic gradient afforded by NZ’s geography.
Also, the group is working on adapting methodologies for measuring the CEC, surface charge, and on the establishment of a suitable indicator for the amount of “stable” C in biochar.
Biochar used in research conducted to date was made in a small batch kiln (2-3 l reactor with a rotating vessel). The Center plans on building a 300 l continuous flow, mobile reactor which will be used to produce larger amounts of biochar for field trials, and this reactor will hopefully be flexible enough to allow the pyrolysis of a variety of NZ feedstocks under a variety of conditions, to produce biochar for experimenting in soil. As of yet a 40 l vertical batch reactor has been built as a first step. The slow pyrolysis process reuses pyrolysis gases, and produces only biochar and gases. Two summer students have worked on this unit, and the Center is looking for 2 PhD students with a chemical engineering background to further progress with this work.
The Center has appointed a PhD student to carry out life cycle analyses of biochar systems and study the potential role of biochar in NZ C markets. A new emissions trading scheme is being rolled out across all sectors of the New Zealand economy including all greenhouse gases. However, the ETS does not yet recognize biochar as a C offset.
Despite its young age, the NZBRC has made significant progress and will continue to grow in 2010, with the appointment of several new graduate students and the development of technology to produce biochar to use in field trials.