Summary
Interior work includes removing existing grates (as shown in the provided diagram) from the interior drains. Cleaning out and flushing drain lines into the OWS. Then reinstalling all the existing grates and replacing any broken during removal. Exterior work includes, vacuuming out both the storm and sanitary manholes in the parking lot. Jetting the storm sewer from the manhole in the parking lot to the OWS. Disconnecting the existing the OWS outlet pipe from the storm sewer manhole in the parking lot and connect it into a new 4" x4" x 6" wye on the sanitary sewer pipe. Installing a new 6" PVC pipe from the new wye to the sanitary manhole in the parking lot. Installing a new 6" PVC pipe from the sanitary manhole in the parking lot to the sanitary manhole in the street (remove 4"). Disconnecting the storm sewer manhole in the parking lot from the OWS and plugging the outlet pipe, removing the frame and lid, filling it with flowable fill, and abandoning it in place.