Exhibit 31.2

Certification
of Chief Financial Officer of ADA-ES, Inc. Pursuant to  Rules 13a-14(a) and 15d-14(a) of
the Securities Exchange Act of 1934, as  Amended

I, Mark H.
McKinnies, Chief Financial Officer of ADA-ES, Inc. (the registrant) certify
that:

1.  I have
reviewed this Annual Report on  Form 10-K of ADA-ES, Inc.;

2.  Based on my
knowledge, this report does  not contain any untrue statement of a material  fact or omit
to state a material  fact necessary to make the statements made, in light of  the
circumstances under  which such statements were made, not misleading with respect to  the
period  covered by this report;

3.  Based on my
knowledge, the financial  statements, and other financial information  included in this
report, fairly  present in all material respects the financial  condition, results of
operations  and cash flows of the registrant as of, and for, the  periods presented in
this  report;

4.  The
registrants other certifying  officer and I are responsible for establishing  and
maintaining disclosure  controls and procedures (as defined in Exchange Act Rules
13a-15(e) and  15d-15(e)) and internal control over financial reporting (as defined in
Exchange  Act Rules 13a-15(f) and 15d-15(f)) for the registrant and  have:

(a)
Designed  such  disclosure controls and procedures, or caused such disclosure controls
and  procedures to be designed under our supervision, to ensure that material
information  relating to the registrant, including its consolidated  subsidiaries, is
made known to us  by others within those entities,  particularly during the period in
which this report is  being  prepared;

(b)
Designed such  internal control over financial reporting, or caused such internal control
over financial reporting to be designed under our supervision, to provide  reasonable
assurance regarding the reliability of financial reporting and  the preparation of
financial statements for external purposes in  accordance with generally accepted
accounting  principles;

(c)
Evaluated the  effectiveness of the registrants disclosure controls and procedures
and  presented  in this report our conclusions about the effectiveness of the  disclosure
controls and  procedures, as of the end of the period covered by  this report based on
such evaluation;  and

(d)
Disclosed in this  report any change  in the registrants internal control over
financial  reporting that occurred during  the registrants most recent fiscal
quarter  (the registrants fourth fiscal  quarter in the case of an annual report)
that has materially affected, or is reasonably  likely to materially  affect, the
registrants internal control over financial  reporting;  and

5.  The
registrants other  certifying  officer and I have disclosed, based on our most
recent evaluation of internal  control over financial reporting, to the registrants
auditors and the audit  committee of the registrants board of directors (or persons
performing the  equivalent functions):

(a)
All significant  deficiencies and material weaknesses in the design or operation of
internal control over  financial reporting which are reasonably likely to  adversely
affect the registrants  ability to record, process, summarize  and report financial
information;  and

(b)
Any fraud, whether  or not material, that involves management or other employees who have
a  significant role in the registrants internal control over financial  reporting.

Date:   March
27,  2007

/s/  Mark
H. McKinniesName:  Mark H. McKinniesTitle:  Chief Financial Officer