I/A septic systems are specially designed to treat wastewater beyond the capability of a standard (septic tank and leach field) septic system. For more information, see What is an I/A System?.
I/A systems can be required by your town for a number of reasons. In coastal areas and inland wetland areas, typically a system is installed to remove Total Nitrogen, a nutirent which can increase algae growth in a body of water. In other cases, an I/A system may be installed to reduce the size of a leaching field on a small lot or cases where a homeowner wished to expand the home beyond the typical number of bedrooms allowed for the lot size. In still other cases, the depth to groundwater may be the driving factor.
Yes. I/A systems typically contain some sort of mechanical component which must be serviced regularly. In the state of Massachusetts, you are required to carry a contract with a licensed wastewater treatment operator for maintenance of the system. This contract requirement exists in perpetuity i.e. for the life of the system.
In almost every case, some sort of influent or effluent sampling is required to verify that the system is operating correctly. Many towns in Massachusetts are attempting to reduce the amount of nitrogen flowing into bays and estuaries, and as such, a regular measure of the total nitrogen output is required to ensure that the system is removing the proper amount of nitrogen from the wastewater stream.
In many cases, the requirements for a system can be reduced if a system owner can demonstrate that it is operating correctly and it is doing what it was installed to do (often, to remove nitrogen). Deending on how your system was approved, you will need to petition your local Board of Health and possibly Massachusetts DEP.
As long as you provide a means for the covers to be accessed by your system operator, yes. If you bury your covers with dirt or other landscaping material and your operator cannot access them, you will be out of compliance.