A wastewater treatment plant is NOT just another pair of shoes

December 25, 2019

This is one of the wildest quotes from Herr Ludwig Sasse, author of the seminal DEWATS handbook in the late 1990s. The saying is as subtle as Germanic humour can ever get.




I know a little bit about Germany and Germans. During my High School days, my maternal Grandmother forced me to learn the German Language at the Max Mueller Bhavan on Mount road in Madras, and I did get the "Oberstufe" certificate, the highest level offered at the MMB which certified I could speak fluent German as I had to go through a tough Viva Voce test with no less an examiner than the Center Director himself.


Reaching early for class, I used to spend my time in the MMB library going through the magazines there to improve my vocabulary, and generally to get a feel for what goes on in Germany: Die Welt, Der Spiegel, Scala were my favourites. And on one such evening I was smitten by a massive crush on a young starlet whose photo in the Scala Magazine still remains fresh in my memory—Uschi Glas.


Uschi Glas (2010), photo: Udo Grimberg 


I am digressing. Let me get back to the pair of shoes of Herr Ludwig Sasse. Just as one size cannot fit all, in the matter of STPs as well, one technology does not fit all sizes. The Extended Aeration Activated Sludge (EAAS) is the Best, Most Appropriate technology for Mini and small STPs upto 5,000 KLD. Beyond that size, EAAS loses its competitive edge and gives way to MBBR. And beyond 10,000 KLD (10 MLD) one may even contemplate SBR technology, provided of course the sewage flow is fairly uniform through the day, like in a Public Municipal Treatment Plant.


On Saturday, December 21, 2019, I was invited to give a talk on STP technologies at the IIT Madras Research Park to an audience of about 90, drawn from various fields—Builders, Academicians, Chief Engineers of Star Hotels and Resorts, representatives from RWA's (Residents Welfare Association) M.Tech (Env. Engg) Students from Anna University, Utility Managers from industry, Property and Facility Managers of Commercial complexes, Top Managers from Environmental Engineering Companies, etc.


It was a sort of homecoming for me, having first entered the hallowed portals of IIT Madras in the year 1969, fifty year ago as a freshman, my First year of B.Tech in Chemical Engg. My talk was on Selection of Appropriate STP technology for Mini and small plants—a topic close to my heart and a subject in which I excel, possibly like no one else in India. Not for me "Modern Technology" or "Hi-tech" STPs. I stick to the basic principles and tenets of good Chemical Engg. Practice - The Zeroth Law. Choose the Most suitable and Most Appropriate technology for the business on hand that will deliver robust performance on a sustainable basis for decades, and at least cost of ownership - The EAAS System.



I do believe it was an eye opener, the Eureka moment for all those present in the audience. With simple unquestionable logic, Scientific and Technical arguments backed with authentic empirical data, it was crystal clear to everybody present why MBBR, SBR ,and MBR STP technologies are bound to fail when applied on a small scale. Many were heard saying, "How elementary, Dr. Ananth".


And as a little bit of extra for those who want more of the witticisms of Herr Ludwig Sasse, I am happy to share a few of his quotes which I found interspersed strategically highlighted in boxes in various pages of his book. Surely there must have been a method for this exercise. Germans are after all nothing but methodic.

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