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        <link:definition>9955524 - Disclosure - FAIR VALUE OF FINANCIAL INSTRUMENTS (Tables)</link:definition>
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        <link:definition>9955525 - Disclosure - INCOME TAXES (Tables)</link:definition>
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        <link:definition>9955530 - Disclosure - SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Estimated Useful Lives of Assets (Details)</link:definition>
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        <link:definition>9955531 - Disclosure - SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Landfill and Lease Accounting (Details)</link:definition>
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  <xs:element id="cwst_A2006IncentivePlanMember" abstract="true" name="A2006IncentivePlanMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="cwst_AmendedAndRestatedNineteenNinetySevenEmployeeStockPurchasePlanMember" abstract="true" name="AmendedAndRestatedNineteenNinetySevenEmployeeStockPurchasePlanMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="cwst_NonEmployeeDirectorMember" abstract="true" name="NonEmployeeDirectorMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="cwst_RestrictedStockAwardsRestrictedStockUnitsAndPerformanceStockUnitsMember" abstract="true" name="RestrictedStockAwardsRestrictedStockUnitsAndPerformanceStockUnitsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="cwst_RestrictedStockAwardsMember" abstract="true" name="RestrictedStockAwardsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="cwst_PerformanceStockUnitMember" abstract="true" name="PerformanceStockUnitMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="cwst_MarketbasedPerformanceStockUnitsMember" abstract="true" name="MarketbasedPerformanceStockUnitsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="cwst_AdditionalSharesIssuedMaximumAttainmentLevel" abstract="false" name="AdditionalSharesIssuedMaximumAttainmentLevel" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:sharesItemType"/>
  <xs:element id="cwst_DerivativeAssetStatementOfFinancialPositionExtensibleEnumerationNotDisclosedFlag" abstract="false" name="DerivativeAssetStatementOfFinancialPositionExtensibleEnumerationNotDisclosedFlag" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="cwst_DerivativeLiabilityStatementOfFinancialPositionExtensibleEnumerationNotDisclosedFlag" abstract="false" name="DerivativeLiabilityStatementOfFinancialPositionExtensibleEnumerationNotDisclosedFlag" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="cwst_DefinedContributionPlanMatchingContributionHierarchyAxis" abstract="true" name="DefinedContributionPlanMatchingContributionHierarchyAxis" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:dimensionItem" type="xbrli:stringItemType"/>
  <xs:element id="cwst_DefinedContributionPlanMatchingContributionHierarchyDomain" abstract="true" name="DefinedContributionPlanMatchingContributionHierarchyDomain" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="cwst_DefinedContributionPlanFirstMatchingContributionMember" abstract="true" name="DefinedContributionPlanFirstMatchingContributionMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="cwst_DefinedContributionPlanSecondMatchingContributionMember" abstract="true" name="DefinedContributionPlanSecondMatchingContributionMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="cwst_HourlyEmployeeMember" abstract="true" name="HourlyEmployeeMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="cwst_SalaryEmployeeMember" abstract="true" name="SalaryEmployeeMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="cwst_MultiemployerPlansWithdrawalObligationContingentLiabilityTerm" abstract="false" name="MultiemployerPlansWithdrawalObligationContingentLiabilityTerm" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <xs:element id="cwst_MultiemployerPlansWithdrawalObligationUndiscounted" abstract="false" name="MultiemployerPlansWithdrawalObligationUndiscounted" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="cwst_MultiemployerPlansCompleteWithdrawalEstimatedAccumulatedBenefitObligation" abstract="false" name="MultiemployerPlansCompleteWithdrawalEstimatedAccumulatedBenefitObligation" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="cwst_EffectiveIncomeTaxRateReconciliationValuationAllowanceReleaseAmount" abstract="false" name="EffectiveIncomeTaxRateReconciliationValuationAllowanceReleaseAmount" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="cwst_EffectiveIncomeTaxRateReconciliationExpiredTaxAttributes" abstract="false" name="EffectiveIncomeTaxRateReconciliationExpiredTaxAttributes" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="cwst_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseOfficerCompensation" abstract="false" name="EffectiveIncomeTaxRateReconciliationNondeductibleExpenseOfficerCompensation" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="cwst_EffectiveIncomeTaxRateReconciliationDeductibleStockAwards" abstract="false" name="EffectiveIncomeTaxRateReconciliationDeductibleStockAwards" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="cwst_EffectiveIncomeTaxRateReconciliationTaxCreditIncludingTrueUpAdjustmentAmount" abstract="false" name="EffectiveIncomeTaxRateReconciliationTaxCreditIncludingTrueUpAdjustmentAmount" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="cwst_EffectiveIncomeTaxRateReconciliationReversalOfDisproportionateTaxEffectsOtherComprehensiveIncomeAmount" abstract="false" name="EffectiveIncomeTaxRateReconciliationReversalOfDisproportionateTaxEffectsOtherComprehensiveIncomeAmount" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="cwst_DeferredTaxAssetsGainLossOnDerivativeInstruments" abstract="false" name="DeferredTaxAssetsGainLossOnDerivativeInstruments" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="cwst_LandfillClosureProjectCreditCharge" abstract="false" name="LandfillClosureProjectCreditCharge" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="cwst_NumberOfLeases" abstract="false" name="NumberOfLeases" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:integerItemType"/>
  <xs:element id="cwst_OtherNonoperatingIncomeExpenseAdjusted" abstract="false" name="OtherNonoperatingIncomeExpenseAdjusted" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="cwst_DisposalServicesMember" abstract="true" name="DisposalServicesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="cwst_PaulJLigonMember" abstract="true" name="PaulJLigonMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
</xs:schema>
