Site Name: NORTHSIDE LANDFILL
EPA ID: WAD980511778 EPA Region: 10 Metro Statistical Area: 7840
W 5502 NINEMILE RD, SPOKANE, WA 99211
Operable Unit:
ROD ID: EPA/ROD/R10-89/019 ROD Date: 09/30/89
Contaminant: VOCS; PCE; TCA; TCE; LEAD
Keys: ALTERNATE WATER SUPPLY; CAPPING; CARCINOGENIC COMPOUNDS; CLEAN AIR ACT; CLEAN WATER ACT; DIRECT CONTACT; DRINKING WATER CONTAMINANTS; GROUND WATER; GROUND WATER MONITORING; GROUND WATER TREATMENT; INSTITUTIONAL CONTROLS; LANDFILL CLOSURE; MCLS; METALS; OFFSITE DISCHARGE; O&M; ONSITE CONTAINMENT; ONSITE TREATMENT; ORGANICS; PCE; RCRA; SAFE DRINKING WATER ACT; SOLE-SOURCE AQUIFER; SOLVENTS; STATE STANDARDS/REGULATIONS; TCE; VOCS; WATER QUALITY CRITERIA
Abstract:
; THE 345-ACRE NORTHSIDE LANDFILL IS IN A MIXED RESIDENTIAL AND AGRICULTURAL AREA, IN THE NORTHWEST CORNER OF THE CITY OF SPOKANE, SPOKANE COUNTY, WASHINGTON. THE LANDFILL HAS BEEN USED SINCE THE 1930S BY THE CITY OF SPOKANE AND A VARIETY OF PRIVATE AND PUBLIC HAULERS FOR DISPOSAL OF RESIDENTIAL AND LIGHT COMMERCIAL REFUSE. THE LANDFILL IS DIVIDED INTO FOUR DISPOSAL UNITS; A REFUSE UNIT, A GREASE SKIMMINGS UNIT, AN OLD OPEN BURN UNIT AND A SEWAGE SLUDGE UNIT. ONLY THE REFUSE UNIT IS ACTIVE. HOWEVER, THIS UNIT IS SCHEDULED TO CLOSE BY 1992. THE WESTERN ONE-THIRD OF THE LANDFILL LIES OVER THE LARGE SPOKANE VALLEY-RATHDRUM PRAIRIE AQUIFER (SVRPA). THE SVRPA WAS DESIGNATED AS A SOLE SOURCE OF WATER SUPPLY FOR THE SPOKANE-COEUR D'ALENE AREA BY EPA IN 1978. INVESTIGATIONS CONDUCTED IN 1981 AND 1983 INDICATED THE PRESENCE OF VOLATILE ORGANIC COMPOUNDS (VOCS) BENEATH THE SITE AND IN OFFSITE RESIDENTIAL WELLS LOCATED NORTHWEST OF THE LANDFILL. THE CITY IMMEDIATELY SUPPLIED THE 19 AFFECTED RESIDENCES WITH BOTTLED WATER AND HAS SINCE EXTENDED MUNICIPAL WATER LINES TO THE AREA. THE PRIMARY CONTAMINANTS OF CONCERN AFFECTING THE GROUND WATER ARE VOCS INCLUDING PCE, TCA, AND TCE. IN ADDITION, IRON AND LEAD EXCEED THE SECONDARY DRINKING WATER STANDARDS OFFSITE.
THE SELECTED REMEDIAL ACTION FOR THIS SITE INCLUDES IMMEDIATE CLOSING OF THE INACTIVE UNITS OF THE LANDFILL WITH FINAL CLOSING OF THE ACTIVE PORTION BY 1992; CAPPING ALL DISPOSAL UNITS; CONSTRUCTING AN INTERIM PUMPING AND TREATMENT FACILITY FOR GROUND WATER REMEDIATION UNTIL LANDFILL CLOSURE EFFECTIVELY REDUCES CONTAMINANTS TO BELOW THE MCLS, FOLLOWED BY OFFSITE DISCHARGE OF TREATED WATER INTO THE SPOKANE RIVER; GROUND WATER MONITORING; PROVIDING AN ALTERNATE SUPPLY OF DRINKING WATER TO RESIDENCES AFFECTED BY THE CONTAMINATED GROUND WATER; IMPLEMENTING INSTITUTIONAL CONTROLS TO RESTRICT SITE ACCESS, PROTECT THE LANDFILL CAP, AND PREVENT CONSTRUCTION OF DOMESTIC WELLS IN THE CONTAMINATED PLUME; AND CONTROLLING LANDFILL GAS EMISSIONS. THE ESTIMATED PRESENT WORTH COST OF THIS REMEDY IS $41,500,000 TO $51,500,000, WHICH INCLUDES AN ANNUAL O&M COST OF $489,000 FOR 10 TO 30 YEARS.
Remedy:
THE REMEDY DOCUMENTED BY THIS ROD IS DESIGNED TO PROTECT PUBLIC HEALTH AND THE ENVIRONMENT BY PREVENTING THE CONSUMPTION OF GROUNDWATER WHICH HAS BEEN CONTAMINATED BY SOLVENTS FROM THE LANDFILL, AND BY REDUCING THE MIGRATION OF THOSE CONTAMINANTS. MAJOR ELEMENTS OF THE SELECTED REMEDY INCLUDE:
* REQUIRING CLOSURE OF THE LANDFILL AS SOON AS POSSIBLE;
* CAPPING THE LANDFILL AFTER CLOSURE TO MINIMIZE ENTRY OF PRECIPITATION INTO THE WASTES;
* PUMPING AND TREATING THE CONTAMINATED GROUNDWATER TO REDUCE THE AMOUNT OF CONTAMINANTS ENTERING THE AQUIFER (THIS IS A PROTECTIVE MEASURE WHICH WILL OPERATE UNTIL THE CLOSURE AND CAPPING ACTIONS PROVE EFFECTIVE IN REDUCING AQUIFER CONTAMINATION);
* MONITORING GROUNDWATER AROUND THE LANDFILL AND DOWNGRADIENT FROM IT TO TRACK CHANGES IN THE EXTENT AND NATURE OF THE CONTAMINATION PLUME;
* PROVIDING AN ALTERNATE SUPPLY OF DRINKING WATER TO THOSE RESIDENTS WHOSE WELL SUPPLY HAS BECOME CONTAMINATED BY THE LANDFILL;
* ENACTING ADMINISTRATIVE RESTRICTIONS TO PROTECT THE LANDFILL CAP CLOSED UNITS, AND MONITORING WELLS FROM UNAUTHORIZED ACCESS, AND ADDRESS CONSTRUCTION OF DOMESTIC WELLS IN THE CONTAMINANT PLUME; AND
* CONTROLLING LANDFILL GAS EMISSIONS (THE CITY OF SPOKANE IS DEVELOPING A SEPARATE LANDFILL GAS MANAGEMENT REPORT TO ADDRESS THIS ISSUE).
FOR THE PURPOSE OF SELECTING A REMEDY, THE NORTH LANDFILL SITE WAS DIVIDED INTO FIVE UNITS. FOUR OF THESE UNITS ARE AREAS OF THE LANDFILL. THEY ARE THE REFUSE, SKIMMINGS, OLD BURN, AND SEWAGE SLUDGE UNITS; ONLY THE REFUSE UNIT IS CURRENTLY IN USE. THE FIFTH UNIT IS THE AQUIFER BENEATH THE SITE. THE SELECTED REMEDY IS THE SAME (CAPPING) FOR EACH PORTION OF THE LANDFILL. THE CAP WILL BE DESIGNED TO REDUCE LANDFILL LEACHATE GENERATION AND THUS CONTROL FUTURE CONTAMINATION OF THE GROUNDWATER BENEATH THE SITE. PART OF THE SITE IS STILL ACTIVELY RECEIVING REFUSE AND WILL CONTINUE TO DO SO UNTIL DECEMBER 31, 1991. BEGINNING IN 1992, ALL REFUSE WILL BE DIVERTED EITHER TO A PLANNED WASTE-TO-ENERGY FACILITY, NEW UNITS WILL BE CONSTRUCTED AT NORTHSIDE, OR AN ALTERNATE LANDFILL SITE. CLOSURE OF THE NON-ACTIVE UNITS MAY BEGIN AFTER APPROVAL OF THE CLOSURE PLAN, WITH FINAL CLOSURE BEGINNING IN 1992 AFTER THE EXISTING REFUSE UNIT IS NO LONGER RECEIVING WASTES. THE PUMP AND TREATMENT REMEDIAL ACTION WILL ACTIVELY CONTROL THE SOURCE OF GROUNDWATER CONTAMINATION LEAVING THE LANDFILL. THIS WILL ALLOW THE CONTAMINATION TO NATURALLY ATTENUATE AND RESTORE ITS USEFULNESS.