ALTHOUGH NEWS about sludge has diminished, the sludge hasn't. On Thursday, a New Jersey court ordered an immediate halt to Camden's practice of dumping its sludge 35 miles off the Maryland and Delaware coasts. Take it out further, the court said - to 60 miles, which would be beyond the continental shelf and the shellfishing area.

The court order is but the latest shake given to sleeping Camden, a town not yet awakened to its environmental responsibilities. For 12 years, Maryland officials, with the eastern shore resort areas in mind, have been trying to persuade Camden of two facts: first, that the ocean is not a sinkhole and, second, that other ways exist for disposing of the untreated waste. But Camden has stuck to its deep-sixing, even though it has had a permit to dump onluy on condition that it seek alternative methods of treatment.

The court order to dump the sludge further out merley gives Camden a little more time. The Environmental Protection Agency, under the terms of the 1972 Marine Protection, Research and Sanctuaries Act, has already told the city to develop land-based dumping methods; to that sensible end, EPA recently provided a $1.3 million grant.

Camden need not worry that the science of sludge composting is a dark mystery. It isn't. In fact, once the hang of it is mastered, a little civic pride can be enjoyed. According to an official at the Department of Agriculture's biological waste management laboratory in Beltsville, Md., Washington's sludge compost (via the Blue Plains plant) is of a higher quality than what is found in other cities. There is no reason for Camden's not retiring its sludge barges. the ways of converting sludge into compost are easily learned. New Jersey, being the Garden State, should be delighted to have the contributions of Camden. Better to mulch New Jersey than contaminate the Atlantic.