Site Name: SHERIDAN DISPOSAL SERVICES
EPA ID: TXD062132147 EPA Region: 06 Metro Statistical Area: 3360
CLARK BOTTOM RD, HEMPSTEAD, TX 77445
Operable Unit:
ROD ID: EPA/ROD/R06-89/051 ROD Date: 09/27/89
Contaminant: VOCS; BENZENE; PCE; TCE; METALS; ARSENIC
Keys: BENZENE; BIODEGRADATION/LAND APPLICATION; CAPPING; CARBON ADSORPTION (GAC); DEBRIS; DECONTAMINATION; DIRECT CONTACT; EXCAVATION; FLOODPLAIN; GROUNDWATER MONITORING; INCINERATION/THERMAL DESTRUCTION; INSTITUTIONAL CONTROLS; LEVEES; O&M; OFFSITE DISPOSAL; OILS; ONSITE DISCHARGE; ONSITE DISPOSAL; ONSITE TREATMENT; ORGANICS; PCBS; PUBLIC EXPOSURE; SLUDGE; SOIL; SURFACE WATER; COLLECTION/DIVERSION; TOLUENE; TOXIC SUBSTANCES CONTROL ACT; TREATABILITY STUDIES; TREATMENT TECHNOLOGY; VOCS;
Abstract:
THE 110-ACRE SHERIDAN DISPOSAL SERVICES SITE IS APPROXIMATELY 9 MILES NORTHWEST OF THE CITY OF HEMPSTEAD IN WALLER COUNTY, TEXAS. THE SITE IS LOCATED ON THE 100-YEAR FLOODPLAIN OF THE BRAZOS RIVER AND IS BORDERED BY A LAKE TO THE SOUTH, FARMLAND, AND A COMMUNITY OF 20 RESIDENCES TO THE NORTH. THE EVANGELINE AQUIFER, WHICH RUNS UNDER THE SITE, IS USED TO MEET THE DRINKING WATER NEEDS OF SEVERAL COMMUNITIES NEARBY. SHERIDAN DISPOSAL SERVICES OPERATED AS A COMMERCIAL WASTE DISPOSAL FACILITY FROM ABOUT 1958 TO 1984 USING STEAM DISTILLATION, OPEN BURNING, INCINERATION, AND DIRECT DISPOSAL INTO A WASTE LAGOON TO DISPOSE OF VARIOUS ORGANIC AND INORGANIC CHEMICAL AND SOLID WASTES. THE SITE INCLUDES A 12 TO 22-ACRE LAGOON, A 17-ACRE DIKE SURROUNDING THE LAGOON, A 42-ACRE EVAPORATION/LAND IRRIGATION SYSTEM, AND AN INCINERATOR AND 9 WASTE STORAGE AND TREATMENT TANKS LOCATED ON THE LAGOON DIKES. THE PRIMARY CONTAMINANTS OF CONCERN AFFECTING THE SOIL AND SLUDGE ARE VOCS INCLUDING BENZENE AND TOLUENE, AND OTHER ORGANICS INCLUDING PCBS. THE SELECTED REMEDIAL ACTION FOR THE SITE INCLUDES EXCAVATION OF ALL MATERIAL WITH PCB CONCENTRATIONS GREATER THAN 25 MG/KG INCLUDING 13,000 YD3 OF POND AND DIKE SOIL, 31,000 YD3 OF POND SLUDGE, AND 300 YD3 OF FLOATING OIL AND EMULSION IN THE POND AND STORAGE TANKS. THIS WILL BE FOLLOWED BY ONSITE BIOTREATMENT OF CONTAMINATED SOIL, SLUDGE, AND OIL WITH STABILIZATION AND ONSITE DISPOSAL OF RESIDUALS IN THE POND. IF PCB CONCENTRATIONS IN THE RESIDUALS ARE LESS THAN 50 MG/KG, THEY WILL BE PLACED UNDER A RCRA-COMPLIANT CAP. RESIDUALS WITH PCB CONCENTRATIONS GREATER THAN 50 MG/KG PCB WILL BE PLACED IN A RCRA-COMPLIANT LANDFILL IN THE POND AREA. IN ADDITION, THE REMEDIATION REQUIRES CAPPING THE ENTIRE POND AND DIKE AREA; DECONTAMINATION AND OFFSITE DISPOSAL OF TANKS, DRUMS, AND DEBRIS; TREATMENT TO BEST AVAILABLE TECHNOLOGY (BAT) OF ANY CONTAMINATED WASTEWATER AND STORMWATER WITH DISCHARGE TO THE RIVER; IMPLEMENTATION OF ENGINEERING CONTROLS TO PREVENT BANK EROSION ON THE RIVER; AND GROUND WATER MONITORING. THE ESTIMATED PRESENT WORTH COST FOR THIS REMEDIAL ACTION IS $27,956,000, WHICH INCLUDES TOTAL O&M COSTS OF $863,000.
Remedy:
UPON REVIEW OF THE INFORMATION CONTAINED IN THE ADMINISTRATIVE RECORD, IT IS EPA'S JUDGMENT THAT ONSITE BIOTREATMENT OF WASTES APPEARS TO BEST SERVE BOTH STATUTORY AND SELECTION CRITERIA IN RELATION TO THE OTHER SOLUTIONS EVALUATED. A DETAILED DESCRIPTION OF THIS REMEDY AND AN EXPLANATION OF HOW IT MEETS STATUTORY REQUIREMENTS IS CONTAINED IN THE ATTACHED "SUMMARY OF REMEDIAL ALTERNATIVE SELECTION". IMPLEMENTATION OF THE NATURAL ATTENUATION ALTERNATIVE REQUIRES THE FOLLOWING COMPONENTS:
1. THE ESTABLISHMENT OF ALTERNATE CONCENTRATION LIMITS (ACLS) AS THE SITE GROUND WATER PROTECTION STANDARDS.
2. GROUND WATER MONITORING TO ENSURE ACLS ARE NOT EXCEEDED.
3. SAMPLING AND ANALYSIS OF THE BRAZOS RIVER IMMEDIATELY DOWNGRADIENT AND UPGRADIENT OF THE POINT OF ENTRY OF GROUND WATER FROM THE SITE INTO THE RIVER.
4. IMPLEMENTATION OF CONTROLS TO PRECLUDE POTENTIAL USE OF CONTAMINATED GROUND WATER.
5. IN THE EVENT ACLS ARE EXCEEDED AT SOMETIME IN THE FUTURE, THE IMPLEMENTATION OF A CORRECTIVE ACTION PLAN TO ENSURE THAT PROTECTIVE LEVELS ARE MET AT THE POINT OF POTENTIAL EXPOSURE.
IMPLEMENTATION OF THESE ACTIVITIES ADDRESSES THE PRINCIPAL THREAT POSED BY THE SITE BY PREVENTING EXPOSURE TO CONTAMINATED GROUND WATER AND BY MAINTAINING SAFE LEVELS IN THE BRAZOS RIVER.