The pounding noises, billowing dust clouds and wafting odors coming from the Charles River bank near Boylston St. are not from an oversized alarm clock. The rumbling is the product of a Metropolitan District Commission (MDC) sewer project aimed at curbing pollution of the river.

"Sewage is still being dumped into the Charles even though the federal Environmental Protection Agency has made regulations making such dumping illegal," William Owen, on-site project supervisor, said yesterday.

The MDC's relief sewer system will hook up with the sewage drainage pipes of private firms on the Charles that have used the river as a dumping ground in the past, Owen said.

The MDC originally planned to finish work on the area east of Anderson Bridge before September 15 so that the grass could be reseeded and returned to public use by spring.

But four labor strikes cost the project seven weeks and so the work continues. Restoration will have to wait until spring, Owen said yesterday.

The present construction project will extend the drainage sewer built along the Charles River's north bank between 1971 and 1973. That sewer line ends at Plympton St., where work began this summer--and still continues.

The relief sewer will supplement the overloaded storm and sanitation system built under Mount Auburn St. over 70 years ago, Owen said.

The MDC plans to tunnel under Boylston St. at the north end of Anderson Bridge, and then to extend the system another half mile west to Mount Auburn hospital. Owens said the project will be finished within two years, adding he is unaware of any other plans for work on the Charles near Harvard.

The new sewer pipes, six feet in diameter, will carry the sewage to the chlorination station near the Boston University Bridge for treatment. Catch basins will still dump into the river because it is mainly rain water and would not warrant the expense of treatment, Owen said.

Before MDC construction crews can move their gear west, Owen said he expects another month's delay, since the Cambridge Conservation Commission has decided that it will not be safe to work near the trees until all the leaves fall off.