Want to install a sewage treatment plant in an independent house - Need details regarding capacity, make, cost and footprint

I am looking for a suitable sewage treatment plant for installation in an independent house not having municipal sewer connection. My house has 4 bath rooms and toilets and there are 5 occupants in the house. 

Can anybody suggest whether such a small capacity STP is available in the market and if so

• what should be its capacity
• who is the manufacturer/ vendor of such a small unit
• what process will be used
• how much will it cost
• what is its foot print size

Thanks in advance