|(a) Facilities that have closed in accordance with §§330.453, 330.455, or 330.457 of this title (relating to Closure Requirements for Municipal Solid Waste Landfill Units that Stopped Receiving Waste Prior to October 9, 1991, Type IV Landfills, and Municipal Solid Waste Sites; Closure Requirements for Municipal Solid Waste Landfill Units that Received Waste on or after October 9, 1991, but Stopped Receiving Waste Prior to October 9, 1993; or Closure Requirements for Municipal Solid Waste Landfill Units that Receive Waste on or after October 9, 1993) prior to the effective date of the comprehensive rule revisions in this chapter as adopted in 2006 (2006 Revisions) may continue to monitor groundwater using the well location requirements contained in previously issued authorizations, as allowed by §330.1(a)(1) of this title (relating to Purpose and Applicability). (b) Owners and operators of landfill units shall comply with the 2006 Revisions to this subchapter by applying for a permit modification with public notice in accordance with §305.70(l) of this title (relating to Municipal Solid Waste Permit and Registration Modifications) to revise any inconsistent permit provisions within two years from the effective date of the 2006 Revisions. If an approved groundwater sampling and analysis plan allows for filtering groundwater samples, owners or operators may continue to sample and analyze groundwater in accordance with their approved groundwater sampling and analysis plan while also collecting and analyzing unfiltered groundwater samples to reestablish background groundwater constituent concentrations. The requirements in this subchapter apply to all municipal solid waste landfill units, except for Type IAE and Type IVAE landfills as provided in §330.5(b) of this title (relating to Classification of Municipal Solid Waste Facilities) and except as provided in §330.417 of this title (relating to Groundwater Monitoring at Type IV Landfills). Additionally, the executive director may establish groundwater monitoring requirements for solid waste management units other than Type I or Type IV landfills where site-specific conditions and operations have the potential for groundwater contamination. (c) Composting operations that require a permit are subject to the groundwater monitoring requirements of §332.47(6)(C)(ii) of this title (relating to Permit Application Preparation). (d) Groundwater monitoring requirements under §330.403 of this title (relating to Groundwater Monitoring Systems), §330.405 of this title (relating to Groundwater Sampling and Analysis Requirements), §330.407 of this title (relating to Detection Monitoring Program for Type I Landfills), and §330.409 of this title (relating to Assessment Monitoring Program) may be suspended by the executive director for a solid waste management unit if the owner or operator can demonstrate that there is no potential for migration of hazardous constituents from that solid waste management unit to the uppermost aquifer as defined in §330.3 of this title (relating to Definitions) during the active life and the closure and post-closure care period of the unit. This demonstration shall be certified by a qualified groundwater scientist and approved by the executive director, and must be based upon: (1) site-specific field-collected measurements, sampling, and analysis of physical, chemical, and biological processes affecting contaminant fate and transport; and (2) contaminant fate and transport predictions that maximize contaminant migration and consider impacts on human health and the environment. (e) Owners or operators of new solid waste management units must submit to the executive director a documented certification signed by a qualified groundwater scientist that the facility is in compliance with the groundwater monitoring requirements specified in §§330.403, 330.405, 330.407, and 330.409 of this title before waste can be placed in the unit. (f) Once established at a solid waste management unit, groundwater monitoring must be conducted throughout the active life and any required post-closure care period of that solid waste management unit as specified in §330.463 of this title (relating to Post-Closure Care Requirements).