You need to contact the township’s Sewage Enforcement Officer for permit.
Required by State Law, however depends upon whether the Township or Local Municipality actually enforces the law.
It could also be a county sewage enforcement officer. One thing I learned along time ago with this type of agency (and individuals) is to ask the question, and phrase it this way: "I know you cannot recommend anyone specifically to do the work, but if you were having this done, who would you call to point you in the right direction?" These guys know who does the work, who does quality work, and who to stay away from.