The tug Vinik No. 6 came down the North River Friday afternoon with the sludge barge Lisa in tow, heading for Newark Bay. New York City’s DEP continues to employ the privately owned barge to make occasional pick ups at the North River water treatment plant as well as the Owl’s Head plant in Bay Ridge for de-watering at the Passaic Valley Sewage Commission plant in Newark, which handles some of NYC’s sludge under contract.

The appearance of the Lisa this year has coincided with a number of the DEP’s own sludge tankers being out of service: the tanker Hunts Point is at Caddell’s dry dock now after spending month’s tied up at Wards Island after a fatal explosion while loading at the North River plant in May, while the old North River tanker has been out of service all year. Use of the Lisa might also have something to do with draft conditions at the Passaic Valley plant, as the DEP’s Red Hook, Rockaway and Port Richmond tankers all seem to be moving sludge to the DEP’s own centrifuges in Hunts Point and Wards Island.