Improvements at the Back River Sewage Works, Baltimore, MD

The history of practically all large sewage works that have been in service for any considerable period'' has been that improvements and additions are required from time to time. In some instances, the need for these additions has been caused by an increase in sewage flow or organic load. In other cases, old treatment units have outlived their efficient usefulness and have been re~ placed by more modern equipment. The work desc ribed in this paper falls, into both categories. During the 18-year period from 1930 to 1947, inclusive, $3,859,500 was spent on new improvements at the Back River sewage works in Baltimore, Md., which serves most of the city and a considerable section of the Baltimore County Metropolitan District adjacent to the city. This project provides for primary and secondary treatment of the sewage and includes: (1) A building with mechanically cleaned bar screens; (2) three grit chambers; (3) five preliminary settling tanks; (4) activated-sludge units; (5) equipment for chlorinating the final effluent; (6) a sludge control station containing pumps for handling raw and digested sludge and gas boilers for heating the digestion tanks, together with metering equipment used in conjunction with the opera~ tion of the sludge tanks; (7) five covered sludge digestion tanks; (8) a 200,000- cu-ft gas holder; (9) four vacuum filters; (10) an electric substation; and (11) .the necessary sewer conduits and pipe lines connecting these improvements.html