Smell of fecal matter is due ...

Smell of fecal matter is due to reduction of Sulphur/ sulfur compounds present in fecal matter by microbes to H2S .best possible mitigation is to reduce the activity of these microbe either by neutralizing them by disinfectant, or by biotechnology.

 use wood- charcoal. Carbon to absorb the smell and the gases associated with it. Can we try a similar experiment for this one also .

As an extension, cow-dung cakes- (gobar) are used as firewood, in rural kitchens, this ash, could be tried out for removal of fecal matter odor. The fecal matter when admixed with this ash could be composted , resulting in good manure. 

It is well known that certain bacteria are responsible for bad odor. Therefore, there are a few methods you could explore to diminish the odor.

1.       Use a cheap disinfectant to inhibit bacteria.

2.       Mask the effect bad odor with another strong but pleasant odor. Many countries have their strong natural odors for these purposes.  For example, in Sri Lanka, Lemongrass is used in public restrooms to disinfect, to mask the perception of a bad odor, and to introduce a pleasant fragrance.

3.       EGTA (ethylene glycol tetraacetic acid) or a few other chelating agents are being added to the source of bad odor at very low concentrations reduce the perception of a bad smell.

4.       The same effect can be achieved with Zn2Cl.