The City of Los Angeles owns and operates four treatment plants with a combined treatment capacity of over 460 million gallons per day. Discharging into this treatment system are over 9,000 industrial users. Flow into this system not only includes the City of Los Angeles, but an additional 29 contract agencies including eight cities. Universal City, and the Long Beach Naval Shipyard.
The operation of these four treatment plants generates approximately 260 dry tons/day of sludge. Since November of 1987, the method of ocean disposal of this sludge has ceased. This has left the City with various land disposal options. With these disposal options comes specific pollutant concentrations established by the federal government and which may not be exceeded if this sludge is to be used for alternative uses or disposed of in a sanitary landfill.
The Bureau of Sanitation, Enforcement Division was given the task to initiate a heavy metals reduction program in an effort to reduce the amount of heavy metals entering the wastewater collection system. This project commenced in June of 1988 with these major objectives:
Sources included industrial users in the City of Los Angeles, contract, cities that discharge into the Los Angeles sewer collection system, and influences from domestic sources.
2. ESTIMATION OF QUANTITIES
Once the sources were identified, methodology would be set to determine the percent contribution from each source.
After a preliminary investigation of the current influent loadings of each metal entering the Hyperion Treatment Plant (HTP) a program would be developed in which consideration would be given to areas having the greatest potential for reduction, priortization of target metals, and cost effectiveness of program implementation.
4. PROGRAM IMPLEMENTATION
Once the above steps were completed, program implementation would commence with monitoring being conducted to ascertain program success.
With the completion of steps one and two, in June 1988 Phase I - Cadmium Reduction commenced.
Phase I Results;
After targeting cadmium as the metal of first concern, a program was developed in which an estimated 25-30% reduction of cadmium was obtainable. The program targeted industrial users in the City of Los Angeles which had significant amount of cadmium onsite. These facilities were further divided into groups according to geographical region and cumulative impact on the Hyperion system. The first group consisted of industrial users in the San Fernando Valley.
The program consisted of an indepth monitoring and site assessment of firms known to be using cadmium. Site assessment included a review of process operations which used cadmium, pretreatment capabilities, wastewater discharge analysis, and hazardous waste management techniques.
Once this information was gathered, appropriate action was taken which included progressive enforcement actions against facilities in violation of discharge standards, and limited onsite instruction on proper hazardous waste management techniques.
As a result of the implementation of this program, there has been a discernable reduction of the cadmium entering the Hyperion system. This was also apparent in the reduced cadmium concentration in the sludge at Hyperion Treatment Plant.
This program is continuing and will be expanded to include future reductions through increased enforcement, permitting, and providing technical assistance in areas of waste management and reduction.
Source Reduction Opportunities
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