Main content area

Pyrolysis of urban waste streams: Their potential use as horticultural media

Kaudal, Bhawana Bhatta, Chen, Deli, Madhavan, Dinesh Babu, Downie, Adriana, Weatherley, Anthony
Journal of analytical and applied pyrolysis 2015 v.112 pp. 105-112
Fourier transform infrared spectroscopy, air, biochar, biodegradability, biosolids, bulk density, carbohydrates, carbon, cation exchange capacity, energy, growing media, moieties, nutrient content, porosity, pyrolysis, salt content, surface area, synthesis gas, temperature, waste management, water holding capacity
Biochar produced from mixture of biodegradable urban resources such as biosolids and greenwaste was slowly pyrolysed at 650°C and characterised for its chemical and physical properties. The biochar was then compared to published values for growing media. It was found that this biochar has high surface area, inherent nutrient content, high porosity, high stability, desirable water holding capacity, air filled pore space and bulk density. Comparing the results of characterisation of this biochar with ideal potting substrate showed the highly porous and nutrient rich biochar were desirable however the high salt content was problematic. Fourier transform infrared analysis shows that carboxyl/carbonyl bands were very weak in biochar spectra due to loss of carboxyl groups in the decomposition of carbohydrates in high temperature pyrolysis which also contributed to low cation exchange capacity. The pyrolysis process has multiple advantages such as waste management, energy generation in the form of syngas and long term sequestration of carbon in biochar.