The term “domestic” means wastewater that essentially comes from homes.  It comprises substances of human metabolic waste along with residuals from cooking (food waste), cleaning, and bathing.  It is claimed that such substances and residuals in sewage influent constitutes about 0.1% by weight and the rest is water. 

If it is this gauntly content of 0.1 wt% of substances and residues that must be removed from sewage to render it harmless, and if it is that vast content of 99.9% by weight of water that should be recovered for reuse and/or discharge into receiving body-types; then why has it been so difficult to attain for over a century (since 1914)? 

Has this long-lasting treatment produced anything other than different forms of diluted streams laced with toxicity and nutrients and concentrated wastes enriched with toxicity and nutrients?  What if this difficulty turns out to be persistent economic exploiting opportunities in some places in addition to the silent health and pronounced environmental consequences? What would it be like if we alternatively harvested this content of 0.1 wt% without economic exploitations and environmental destructions? 

The fact is that bacteria in nature and especially in the mostly used activated sludge step are extraordinarily diverse in types, numerously duplicate in numbers, and largely driven by their local environment conditions; thereby, broad pre-specified design and conditions for bacterial growth/death produce waste activated sludge in continuous man-made systems (WWTP) are highly variable and rarely optimal. These systems are bound to be both wholly inefficient and strongly dependent on skilled operators.

Along came the use of hydrophilic membranes in the 1980s to reclaim effluents, which is as “bi-polar” as the activated sludge; wherein “bi-polar”, again, means a portion of a feed stream is diluted in substances as product and another portion of the feed stream is subsequently concentrated in the substances as reject.  Clearly, this bi-polarity is not only pointless for the treatment of a feed stream comprising a mixture of toxic substances as we should have no different substances at the end (product and reject) than at the beginning (feed); but also harmful as we should have concentrated the toxic substances in the reject by many fold.

DESUL innovation, when experience and integrity counts, is the answer to the last question (above).