Table 4. Improvements in Dupont's waste treatment system since 1 970 



Date Waste treatment improvements 



1970 Increased aeration capacity - added one aeration tank, one air 

 blower, and one clarifier 



1972 Innproved spill control - interceptor sewer collected several 



sewers that discharged directly into the river into one which is 

 monitored continuously and diverted to waste treatment should a 

 spill occur 



1 976 Extended aeration begun followed by filtration - added 1 million 

 gallon aerated tank followed by multi-media filtration 



Increased aeration capacity - added one aeration tank and one 

 clarifier (total of 5 each) 



Added hydrogen peroxide system to reduce floating solids from 

 clarifiers 



Ended thermal discharges from Outfalls 003 and 004 



1 977 Increased aeration capacity to provide additional oxygen transfer 

 capacity for one-step nitrification - added one aeration tank 

 and two blowers 



Improved aeration capacity in blend tanks - added Kenics mixers 

 to each tank and 3 blowers 



SUMMARY 



The decade of the seventies produced compelling evidence that damaged ecosys- 

 tems can be improved. A substantial body of literature for both aquatic''^ s""! and 

 terrestrial!'; g- ''''''-^> ecosystems is available to help develop good management practi- 

 ces and avoid bad ones. Underlying ecological theory has not been neglected. <^8- 

 37,44,45) Some of the problems in implementing water quality goals mentioned by 

 Westman'** late in the decade have since been addressed as have those involving 

 control of environmental impact discussed by Westman and Gifford"*^ earlier in the 

 decade. However, most of the important problems identified by these authors 

 remain unresolved. Fragmentation of authority*** for ecosystem management 

 remains as much of a problem at the end of the decade as it was at the outset. 

 Guidelines for working environmental values into public decisions are available"' 

 but not generally used. The decade just completed produced a solid scientific 

 foundation for restoring damaged ecosystems although much research is still 

 needed. However, the damage rate still far exceeds the restoration rate. 



REFERENCES 



1. Samuel, D. E., J. R. Stauffer, C. H. Hocutt. and W. T. Mason. Jr. 1978. 

 Surface mining and fish wildlife needs in the Eastern United States. 

 FWS OBS-78 81. Office of Biological Services. Fish and Wildlife Service, 

 USDl. Washington, D.C. 386 pp. 



2. Samuel. D. E.. J. R. Stauffer. C. H. Hocutt. and W. T. Mason. Jr. 1979. 

 Addendum to surface mining and fish wildlife needs in the Eastern United 

 States. FWS, OBS-78 81 A. Office of Biological Services, Fish and Wildlife 

 Service, USDl. Washington, D.C. 125 pp. 



236 



