Treatment Plant Inadequacies 



Although almost all municipal and industrial waste discharges into the aquatic en- 

 vironment are now regulated, large quantities of contaminants are still contained in 

 the permitted waste discharges owing to operational and maintenance inadequacies 

 of treatment plants that restrict the degree to which permitted discharge rates can be 

 maintained. Over 70 percent of the sewered areas in the New York metropolitan 

 region have combined sewers. During dry weather they function as sanitary sewers, 

 conveying all flows to the treatment plants. During wet weather, large volumes of 

 rainfall runoff enter the system — the average storm triples the normal dry weather 

 flow, but peak flow can be as much as 50 times the normal flow. Waterfront regula- 

 tors are built into the sewage systems to act as relief valves to prevent flooding of 

 treatment plants during wet weather. These regulators allow no more than twice the 

 average dry weather flow to reach the plants so that even during the average storm a 

 large proportion of the combined flow is simply discharged through the regulators 

 without treatment. In addition many of the regulatorsare not in good operating con- 

 dition and leak during dry weather. 



Table 1 shows the average daily quantities of various contaminants released by 

 New York and New Jersey municipal wastewater treatment works. The New York 

 City raw bypass is untreated sewage discharged where no treatment plant has yet 

 been constructed and where several treatment plants were closed for construction. 

 The noncontrolled discharges (regulator leakage, combined sewer overflows, and 

 storm runoff) contribute a large proportion of the total amount of the various con- 

 taminants released. Although there are plans to upgrade and repair regulators and to 

 partially treat combined sewer overflows, it is unlikely that these inputs can be sub- 

 stantially reduced and maintained at a low level unless major technological progress 

 is made or major new treatment capabilities constructed. 



For comparative purposes, the total quantities of the same contaminants in 

 sewage sludge generated by the New York-New Jersey treatment plants are also in- 

 cluded in Table I. The quantity of the metals released through the effluents of oper- 

 ating treatment plants, not even considering storm runoff, combined sewer over- 

 flows, and regulator leakage, far exceeds the quantity retained in the sewage sludge 

 and barged for ocean dumping. This is an important point, since at present the laws 

 and regulations governing wastewater treatment and disposal emphasize more 

 strongly the elimination of ocean sewage sludge dumping than control of the other 

 treatment plant discharges and storm runoff. This may not be the optimal strategy 

 for achie\ing the maximum immediate environmental benefit through use of the 

 limited funds available for environmental improvement. 



The general areas of regulatory shortcomings briefly discussed above are only 

 three of many. The process of amending our young body of environmental laws and 

 regulations into a coherent and effective whole will take several years, but further ef- 

 forts should be made in the interim either to enforce or rescind existing regulations 

 not being implemented. 



In the realm of regulatory techniques or strategies, it is clear that there are con- 

 straints on monitoring compliance, particularly when regulating the large numbers 

 of small sources or nonpoint sources not now regulated or ineffectively regulated. In 

 recognition of these constraints, a system of incentives must be developed to ensure 

 that the discharger seeks to maintain good management practices, not simply to 

 avoid possible detection and prosecution of v iolations that the discharger knows are 

 unlikely but out of self interest. Designing such a scheme of incentives may well be 

 the greatest environmental challenge of the 1980s. 



One of the most vital scientific information needs for improved environmental 

 management is the determination of the capacity of natural ecosystems to assimilate, 

 or otherwise cope with, various wastes and waste components (Goldberg, 1979). 

 Such knowledge is essential not only to enable limits to be placed on the quantities of 

 contaminants released to the environment but also to allow forthe management of 

 the releases themselves in the most environmentally sound and cost effective manner. 



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