Dear Pawan,
Great that you will be working on high water table solutions in Bihar. As you mentioned, there was a "sustainable sanitation" project in Bihar, coordinated by colleagues at SEI (Kim Andersson and Cecilia Ruben) and Prakash Kumar at WASHi. I think it would be really interesting to learn some lessons from post-project sustainability of these different Bihar pilots.
Kim Andersson at SEI made a post to the forum with all the fact-sheets produced after the project in 2014:
forum.susana.org/175-urine-reuse-or-infi...-agricultural-trials
The long term composting toilet might be interesting to continue adapt and improve on?
Best
Linus

Dear Linus
I know the Eco San project in Bihar well and had discussion with Cecilia whenever she visited Delhi. Such project is most suited for high ground water table areas as there is no chance of contamination of ground water at all. But to make it culturally acceptable for most of the people, proper awareness is required as people use water for cleaning and flushing. I am giving one such option under the project and will be happy to implement EcoSan toilets in some households in the targeted village.

regards

Pawan