Worcester’s Sewerage System.
The length of the sewerage system at Worcester, Mass., is 76.59 miles. The money expended upon the system last year was $145,277.11, divided as follows: Maintenance, $14,731.38; trunk sewers, $33,228.56 ; lateral sewers, $25,745.88 ; arching Mill brook, $10,027.28 ; purification works, $61,544.01.
Concerning the new system of sewage disposal, City Engineer Allen says : “I am firmly convinced that the result will be entirely satisfactory after all the sewage of the city is brought to the works for treatment. Considerable improvement has been noted in the condition of the river already.” The works are described in detail. Since operations were begun, June 25, the average amount of sewage treated daily has been 3,000,000 gallons. If the flow is 5,000,000 gallons, 2,000,000 ‘ must be turned into the waste drain at the works and pass off into the river, it making no difference, of course, whether it gets into the river at this point or passes off with the brook at the mouth of the main sewer. This method will have to be followed until the separating system is constructed. The treatment which we have finally adopted is the * continuous ’ process. The sewage, after all matters such as paper and sticks are removed by the screen, is treated with chemicals on its way to the tanks. It takes it about six hours to pass through the six tanks. Each tank may he cut out when it is to be cleaned.
“The sludge deposited on city lands east of^the Providence Railroad, in eleven * beds,’ will he burned eventually. These beds have been in almost constant use since the works were put in operation, and there has never been the least trace of bad odor arising from them, even during the hot summer months. The sludge is removed every thirty-six hours from tanks Nos. t and 2. Tanks 4, 5 and 6 accumulate very little sludge. The sesvage is extremely acid, owing to the presence of sulphuric and muriatic acids from the iron manufacturing establishments. Therefore large quantities of lime are necessary to make the sewage alkaiine. We know that all the suspended matter is removed ; that the organic matter in solution is very largely reduced, and that the free and albuminoid ammonias are also largely reduced.”