What do you mean regarding effectiveness?

I mean that the effectiveness of biochar as odor absorbent directly made from pyrolysis of sewage sludge without further treatment.

 if you cativat it, then it will be great, but put in mind the capacity for this purpose.

Biochar was used for H2S removal

http://www.sciencedirect.com/science/article/pii/S0960852413001375

http://www.mdpi.com/2071-1050/9/1/121/htm

Carbonization of sewage sludge to generate "biochar" depends of some parameters such as level of, water, hydrogen and sulfur into the sludge which influence the yield of biochart obtained but also its quality. Also the trace metals can interact and by the way can catalized or inhibitated somereaction. Some basic and very interesting works have been done about kerogen maturation to obtain high concentration of graphite. All the intermediate steps have been studied. These works has been done from the 40 up to the 70' years. I recommand you some authors such as Oberlin Agnès, Khalid Lafdi, Goma, Bonnamy Sylvie. A past very famous lab called the CRMC2 in Orléans worked onto this topic. Good luck

Dear Philippe,

Thank you very much for your advise.

Regards,

Mack Mak

Also keep in mind the potentially toxic emissions from the manufacture

Dear Mack...

The area you are venturing into has been done and dusted in the later part of 50's. However, if you wish to redo the tests, I would recommend you to rely on activators which can allow you to hold onto carbon content resulting from pyrolysis. Most of the water purifier brands have patented almost everything with regards to biochars aspect. I don't think they might have ventured into sewage sludge for sure, but I think you can still find a wealth of information if you dig deep. However, please keep a tab on the following:

1. How are you gonna tackle the issue with Sulphur? Any desulfurization will have a major impact on the resultant carbon content and I believe it will affect the sorptive capacity of the resultant biochar.

2. Sewage sludge usually has a lot of unwanted stuff and their resultant residue in the biochar will be a nuisance to handle. You will end up treating the biochar prior to using it. Don't you think it will affect the resultant product. I firmly believe it will. So, you still will end up with pre-treatment. 

I just wanted to give you heads up before venturing into it. Please do keep me updated... 

Best wishes...

Also, the pyrolysis temperature has an effect in the case of heavy metal removal.

The following reference may be consulted for biochar preparation,characterization and use for agronomic and environmental purpose.

Multiscale visualization of the structural and characteristic changes of sewage sludge biochar oriented towards potential agronomic and environmental implication. Zhang,J. et al.  Scientific Reports  5:9406 doi:10.1038/srep09406 Open Access

Dear Annanqi,

Thanks for your information.

Reards,

Mack Mak