Topics

Bioreactors and biochar


Ron Larson
 

Lou and list:

1.  I changed the thread title to better reflect your input and the paper you referenced (sponsored by a biochar person).  I too was surprised to see biochar mentioned only very peripherally.

2.  The paper is downloadable at http://joann-whalen.research.mcgill.ca/publications/Journal%20of%20Soil%20and%20Water%20Conservation%2073--263-273.pdf .  Like Lou,  I doubt anyone will learn much about biochar from this paper.  But maybe I am missing something.

3.  I got into the reading after wondering if there is a bigger role for biochar produced (very small scale) in charcoal-making stoves.   Can this bioreactor application of char for phosphorus removal help in some way to encourage more use of charcoal-making stoves?

Ron



On May 17, 2020, at 1:33 PM, Lou Puls <lou.puls@...> wrote:

Interesting discussion and links.  

Related, I think, as far as 'technology' is concerned, is the following Abstract, and my puzzlement as to why sawdust would be of interest in regard to water treatment, as opposed to biochar -- which seems obviously far superior in a bioreactor to sawdust?

Removal of phosphorus from agricultural subsurface drainage water with woodchip and mixed-media bioreactors

B.R. HuskJ.S. SanchezB.C. AndersonJ.K. Whalen and B.C. Wootton

Abstract

Woodchip bioreactors that stimulate denitrification are proposed to reduce nitrogen (N) loads emanating from subsurface agricultural drainage. However, agricultural drainage water contains both N and phosphorus (P), frequently in concentrations exceeding environmental criteria. A mixed-media bioreactor containing woodchips plus reactive media that binds soluble P could concurrently lower both N and P loads in subsurface agricultural drainage. This study evaluated the P concentration and load reductions achieved with woodchip and mixed-media bioreactors in full-scale field installations in the cold, humid climate of Quebec, Canada, during a three-year period. Bioreactors contained either woodchips-only or woodchips plus an activated alumina/gravel mixture (mixed media). Total P, particulate P, soluble P, soluble reactive P, and soluble organic P concentrations and loads for the bioreactor influents and effluents were assessed weekly and also following >10 mm rainfall events. In the first two months of operation, both woodchips-only and mixed-media bioreactors released P but became either a negligible source or net sink for P retention within the first year of operation. While the mixed-media bioreactor had 9% lower total P concentration and about 19 times greater reduction in total P load than woodchips-only bioreactors during the study period, the total P concentration was not reduced to the critical environmental threshold level of 0.03 mg L−1 with either bioreactor type. Both configurations were effective at reducing the soluble P fraction, especially the soluble reactive P species that are bioavailable and thus contribute directly to eutrophication. A woodchips-only bioreactor can adsorb P from subsurface agricultural drainage; however, a woodchips bioreactor containing the activated alumina/gravel mixture has greater P sorption capacity and should be considered as part of an integrated system for concurrent N and P removal from subsurface agricultural drainage.