Class I wells are those
that inject industrial, municipal and hazardous wastes below the deepest
USDW. The acronym USDW stands for "Underground Source of Drinking
Water" and is defined on a federal level as any aquifer which contains
less than 10,000 mg/l of Total Dissolved Solids (TDS), regardless of any
other constituents. Using this definition, an aquifer containing 7
mg/l of Arsenic (which would be toxic to drink) would still be a USDW if
the TDS content was less than 10,000 mg/l. The equivalent in
Wyoming regulations to a USDW is any groundwater that meets the
definition of Class I, II, III, IV(A), or Special A under
Chapter 8
, Wyoming
Water Quality Rules and Regulations.
In Wyoming we have no injection wells which are permitted to inject hazardous waste. All of our permitted Class I wells are for the injection of non-hazardous waste, regardless of whether the waste is non-hazardous by exemption, or if it simply does not contain hazardous substances at levels high enough to be a hazardous waste.
In Wyoming, all commercial disposal operations are regulated by this department, even if they are disposing primarily of oilfield exempt waste. This was a compromise struck between this department and the Oil and Gas Conservation Commission years ago to resolve the apparent duplication of regulatory powers in the enabling legislation for the two agencies. What this means to underground injection is that all commercial disposal wells are regulated by this agency as Class I injection wells, not Class II wells under the jurisdiction of the Oil and Gas Conservation Commission.
This agency has a very comprehensive set of regulations
governing the installation and operation of Class I wells. Those
regulations are found in
Chapter 13
,
Wyoming Water Quality Rules and Regulations.
The regulations governing classification of groundwater are found in
Chapter 8
, Wyoming
Water Quality Rules and Regulations.
This agency has produced
Guidance Document Number 1
which is intended to help those applying for a
Class I injection
permit
.
This Guidance Document explains how to make the calculations for the Cone of
Influence, the Area of Emplaced Waste, and the final Area of Review.
In preparing any application, those calculations are fundamental since the
final Area of Review determines how much area you must fully research for
land ownership, mineral ownership, water rights, etc. This Guidance
Document also contains a list of Specific Industrial Waste Codes (SIC) codes
which are required by federal and state rules as part of the application,
and a discussion of Step Injection Tests for the determination of fracture
pressure in the receiver.
This agency has also produced
Guidance Document
Number 2
which is
intended to help those who may wish to dispose of waste in an existing
commercial disposal well. This document contains a discussion of
exemptions to RCRA which apply to disposal wells, a discussion of the
characteristics of hazardous waste, a list of laboratories available to do
these analysis and a list of existing wells with contact information.
If you wish to apply for a Class I injection permit, you
are encouraged to contact
John Passehl, P.G.
(307-777-5623) at Water Quality Division's Cheyenne office before
applying. John will be happy to schedule an appointment with you if
you like, and help you through the process of developing your permit
application. Discussions of various issues prior to applying may
alleviate problems during the process. We highly recommend that you
become familiar with the permitting requirements contained within
Chapter 13
prior to your meeting.
Several years ago, this agency exempted the Minnelusa
Formation in the central part of the Powder River Basin for injection.
This is a formal aquifer exemption approved by the US Environmental
Protection Agency. The final approval for this aquifer exemption
includes the legal description of the area exempted:
MINNELUSA AQUIFER EXEMPTION