1. Water Pollution Lecture by Dr. Ken Galli, Boston College EESC116301
Environmental Issues and Resources
July 15, 2014
Please do not distribute beyond the EESC Class.

4. 439
-15 feet
= 424 feet

6. DEER ISLAND
MWRA's Deer Island Sewage Treatment Plant is the centerpiece of MWRA'$3.8 billion program to protect Boston Harbor against pollution from Metropolitan Boston's sewer systems

7. Deer Island Includes New sludge-to-fertilizer facility
Primary and secondary treatment capabilities
Inter-Island Tunnel that ties together 2 separate sewer systems (North and South) into one
9.5-mile Effluent Outfall Tunnel to discharge treated wastewater away from shallow Boston Harbor waters and into the deeper waters and stronger currents of Massachusetts Bay

8. Deer Island Schematic
Originates in homes, businesses, industries and as storm water
Influent arrives at the plant through 4 underground tunnels
There are 3 main pump stations that lift the influent to the head of the plant
Flows then go through primary and secondary treatment where the level of pollution removal is over 85%.
The Sludge and scum are removed
A 9.5-mile 24-foot-diameter outfall tunnel transports effluent into the 100-foot deep waters of Massachusetts Bay.
Effluent is discharged through more than 50 individual diffuser pipes, each with 8 small ports, so that rapid and thorough mixing into surrounding water is achieved and water quality standards are not compromised by the discharge
The North Main Pump Station and the Winthrop Terminal Headworks, which serve the North System,
Lydia Goodhue Pump Station for the South System.

9. 2002 Influent and Effluent Data
Data provided by Charles Tyler, from MWRA, Deer Island Waste Water Treatment Plant
Only the influent was used in the water balance, because it represents the outflow from the project area.

10. Deer Island Influent Influent is normalized over LCRW
Total inches per year = in
Average Daily Flow = 0.4 in
Includes Wastewater from 43 communities, over 2 million people

11. Wastewater Data from MWRA
The MWRA was able to provide us with a more detailed Community Wastewater Reporting System file.
In order to calculate the volume of waster water in inches, million gallons per day was converted to inches-acre per day and then divided by the total acreage of the project area, 29,790.5 acres.

12. Calculations for Sewer and Stormwater
Numbers had to be converted to in./day and normalized over the total area of the LCR watershed, 29,790.5 acres.
The % of each town within the project area was multiplied by the annual total wastewater values
The total inch per year over the LCRW is 35.0 inches

13. Wastewater from Industries
Over 5,500 businesses and industries contribute wastewater
MWRA randomly surveys outflow of each business/industry
Average Daily Discharge was calculated and project throughout the year.
Total inches per year over LCRW = 0.29
Average inches per day over LCRW =

14. Combined Wastewater Flows to Deer Island
Total annual outflow to Deer Island is 35.3 in
Average Daily outflow is 0.1 inches
Industrial Contribution= .29/35.3*100 = 1%