Need information on septic tank cleaning.

Septic tank cleaning details

We are living in a residential cum commercial plot where every day minimum 40 persons use water to wash and for cleaning face/hand/lunch box and so on. The toilet users may be 25 to 30 for urinals & other purposes. The per week water consumption is 10000 l. All this water flows into the septic tank, and the tank is full of water always along with the toilet residue underneath (as the builder had constructed the water drainage system this a way). The excess water in the tank after a certain level will flow out into the main drain ie corporation (canal 2" x 5") outlet which is constructed along the road for this purpose.

As I have now recently occupied one of the portions for residential purpose, I want to clear the septic tank and reuse it for some more months, as the Corporation is having drainage connections in the center of the road also. I have to apply for the same, but don't know how soon it will be connected.

So I need a remedy and solution to clear the septic tank.