Assessment of the MineRalization Process Efficiency to Decompose Waste of Dry Bio-Toilet of Bio-NTK Microbial Inoculants

Composting is a controlled biodegradation process for treating human waste in water-scarce areas. Bio-NTK microbial inoculants in powder form used to treat dry bio-toilet waste are produced by solid fermentation method, using sawdust substrate, rice bran, and tapioca starch (1 : 1 : 1, w/w/w), with an additional 10% seed rate. The composition of Bio-NTK microbial inoculants consists of actinomycetes Streptomyces flavovariabilis XM21, Streptomyces griseorubens XM241, and strains of Bacillus subtilis V12, Bacillus amyloliquefaciens HG2, strain density >10⁸ CFU/g, meeting the standard TCVN 6168-2002 on the quality of microbial inoculants after 12 months of storage. The study has determined that the use of Bio-NTK inoculants help the mineralization process to decompose waste faster, in which the experiment uses sawdust as a filler for optimal treatment efficiency. Experiment with a pilot-scale dry toilet model was conducted in batches, using sawdust filler and supplemented with Bio-NTK showed no odor (concentrations of NH₃ and H₂S were not significant reaching QCVN 06: 2009/BTNMT); the total density of aerobic microorganisms in the compost sample reached >10⁹ CFU/g. The test results are the premise for the replication and synchronous deployment of Bio-NTK inoculants and a specially designed dry toilet system to treat organic waste after collection from the toilet dry into organic fertilizer in water-scarce areas.