We are having tremendous success with the Green Drain Waterless Drain Seal product.
Sheridan just sold 18 units, yesterday, to a contractor who wanted 2 per floor in a high rise building. He wanted to reduce odors in an effort to improve the indoor air quality. This Green Technology does help with LEED certification.
It is available in 2 inch, 3 inch, 3-1/2 inch and 4 inch. It is being used by hospitals, restaurants, commercial buildings, apartment buildings and the like. It appears to really address the concern about odors, moisture and bugs. Check out the video to understand hot to quickly install the product.
The PVC product has a one way drain valve and is easy to install and does not impair the flow rate. You will not have any trouble with plumbing maintenance.