Machan.. Poddak research karapan ganna kalin..
These are the cons I found
1. Gas has to burn away continuously if you are not planning to compress and store
2. if not burn away Gas produced is slightly heavier than air and settles at ground level creating a Hazardous atmosphere. (Any Spark can ignite).
3. Holding tank is sensitive for Detergent and Chemicals. So if you mistakenly add strong anti bacterial products.. U need to flush and start from scratch.