"Regulations? We don neet no stinkin' regoooolaaaations!"
But seriously folks...
As of this date (September 2014) we aren't aware of any regulations concerning small scale (10m3 and under) biodigesters specifically. The regulations would probably fall under those written for home septic tanks, home water storage tanks and possibly home use of Natural Gas and LPG bottles. When an urban planner came to our house we showed him our system and his reaction was "it's a full tank of dirty water". He then saw that the overflow discharge went right down the drain to the sewer system. We had used up all the gas when he arrived. All he saw from that part of the system was a plastic barrel submerged in another plastic barrel filled with water and an empty pvc bag. Remember that you are storing unpressurized gas in flexible containers over or near water. They can't explode because there isn't any air in them and they don't contain enough gas nor occupy enough rigidity to pose a danger. And you use it up every day. When you go away, you don't feed the system so it produces almost no gas. In the event that it produces more gas than you can store, the overage simply burps out in little pulses or "farts" and can not be ignited. Biogas is lighter than air so it disperses and disappears almost immediately. We have never been able to get small gas leaks or burps to ignite.
No doubt as our movement goes forward somebody will try to regulate it. We will have to stay one step ahead of them and demonstrate the safety, efficacy and value of this solution to waste and energy problems in the world. For now all we can say is "it is much much much much much much much safer than all the alternatives you are currently using." Tell them that. Show them that.
Surely "the government"/"multi-national corporation"/"military-industrial complex"/"my anxious mother" ain't gonna let "we the people" get away with building our own perfect clean home energy/in-situ waste management/free fertilizer solution, right? What are the regs?