<PAGE>

EXHIBIT 10.4

THIS WARRANT AND THE SHARES OF COMMON STOCK ISSUABLE UPON EXERCISE OF THIS
WARRANT HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED
(THE "SECURITIES ACT"), OR ANY STATE SECURITIES LAWS. THIS WARRANT AND THE
COMMON STOCK ISSUABLE UPON EXERCISE OF THIS WARRANT MAY NOT BE SOLD, OFFERED FOR
SALE, PLEDGED OR HYPOTHECATED IN THE ABSENCE OF AN EFFECTIVE REGISTRATION
STATEMENT AS TO THIS WARRANT UNDER SAID ACT OR AN OPINION OF COUNSEL REASONABLY
SATISFACTORY TO CLEANTECH BIOFUELS, INC., THAT SUCH REGISTRATION IS NOT
REQUIRED.

---------------------------------------- --------------------------------------
OCTOBER 22, 2008                                                WARRANT NO.: 2
---------------------------------------- --------------------------------------

                          COMMON STOCK PURCHASE WARRANT

               Right to Purchase 900,000 Shares of Common Stock of

                            CLEANTECH BIOFUELS, INC.

         CLEANTECH BIOFUELS, INC., a corporation organized under the laws of the
State of Delaware (the "Company"), hereby certifies that, for value received,
World Waste Technologies, Inc. or its successors or assigns (the "Holder") is
entitled to purchase from the Company upon the due exercise hereof, and subject
to the terms and conditions herein, from the date of issue of this warrant (the
"Warrant") until the fifth (5th) anniversary of the issuance hereof (the
"Expiration Date"), all or any part of 900,000 fully paid and non-assessable
shares of common stock, par value $0.001 per share (the "Common Stock") of the
Company, upon surrender hereof, with the exercise form annexed hereto duly
completed and executed, at the office of the Company and upon simultaneous
payment therefore in cash or by certified or official bank check, payable to the
order of the Company, at a per share exercise price ("Exercise Price") of $0.45,
subject to adjustment as provided herein.

         1. RESTRICTION ON TRANSFER. No resale of the Warrant or of any of the
shares of Common Stock underlying the exercise of the Warrant (the "Underlying
Stock") will be made unless such resale is registered pursuant to a registration
statement filed by the Company with the Securities and Exchange Commission (the
"Commission") or an exemption from registration under the Securities Act of
1933, as amended (the "Securities Act"). By acceptance of this agreement, the
Holder agrees, for itself and all subsequent holders, that prior to making any
disposition of the Warrant or of any Underlying Stock, the Holder shall give
written notice to the Company describing briefly the proposed disposition; and
no such disposition shall be made unless and until (i) the Company has notified
the Holder that, in the opinion of counsel satisfactory to it, no registration
or other action under the Securities Act is required with respect to such
disposition (which opinion may be conditioned upon the transferee's assuming the
Holder's obligation hereunder); or (ii) a registration statement under the
Securities Act has been filed by the Company and declared effective by the
Commission or other such similar action has been taken.


                                       1
<PAGE>

         2. EXPIRATION OF WARRANT. Unless this Warrant and the Exercise Price
are tendered as herein provided before the close of business on the Expiration
Date, this Warrant will become wholly void and all rights and obligations set
forth herein shall expire and terminate.

         3. PARTIAL EXERCISE. If this Warrant is exercised for less than all the
shares that may be purchased upon the exercise hereof, this Warrant shall be
surrendered by the Holder and replaced with a new warrant of like tender in the
name of the Holder providing for the right to purchase the number of shares of
Underlying Stock as to which this Warrant has not yet been exercised.

         4. CASHLESS EXERCISE. The Holder may exercise the Warrant, in whole or
in part, without payment of the exercise price in cash by surrendering such
Warrant and, in exchange therefor, receiving such number of Underlying Shares
multiplied by the Cashless Exercise Ratio (as defined below). The "Cashless
Exercise Ratio" shall equal a fraction, the numerator of which is the excess of
the "Fair Market Value" (Fair Market Value on a given date means the average of
the high and low price of a share of Common Stock, as reported by the principal
national securities exchange or other trading system on which the Common Stock
is traded, or, if no such prices are available, as mutually agreed upon by the
Holder and the Company) per share of Common Stock on the date of exercise over
the exercise price per share of Common Stock as of the date of exercise and the
denominator of which is the Fair Market Value per share of Common Stock on the
date of exercise. All provisions of this Agreement shall be applicable with
respect to a Cashless Exercise of a Warrant for less than the full number of
Underlying Stock represented thereby. In the event of an exercise of a Warrant
for less than all the Underlying Stock (after giving effort to the Cashless
Exercise) the Company shall promptly issue a Warrant representing the right to
purchase the balance of such Underlying Shares containing the same terms and
provisions as are contained in this Warrant.

         5. ADJUSTMENTS. The Exercise Price and the number of shares of
Underlying Stock of the Company issuable pursuant to such exercise is subject to
adjustment as follows:

                  (a) In case the Company shall at any time declare a stock
dividend or stock split on the outstanding shares of Common Stock in shares of
its Common Stock, then the Exercise Price and number of shares of Underlying
Stock shall be proportionately adjusted so that the Holder shall be entitled to
receive the aggregate number and kind of shares which it would have been
entitled to receive by virtue of such dividend if such Warrant had been
exercised immediately prior to such time.

                  (b) In case the Company shall at any time subdivide or combine
the outstanding shares of the Common Stock, the Exercise Price, initial or
adjusted, in effect immediately prior to such subdivision or combination shall
forthwith be proportionately decreased in the case of subdivision or increased
in the case of combination.

                  (c) In case of any capital reorganization, sale of
substantially all the assets of the Company, or any reclassification of the
shares of Common Stock of the Company, or in case of any consolidation with or
merger of the Company into or with another corporation, then as a part of such
reorganization sale reclassification, consolidation or merger, as the case may
be, provision shall be made so that the registered owner of the Warrant


                                       2
<PAGE>

evidenced hereby shall have the right thereafter to receive upon the exercise
thereof the kind and amount of shares of stock or other securities or property
which it would have been entitled to receive if immediately prior to such
reorganization, reclassification, consolidation or merger, it had held the
number of shares of Underlying Stock which were then issuable upon the exercise
of the Warrant evidenced hereby, to the end that the provisions set forth herein
(including provisions with respect to adjustments of the Exercise Price) shall
thereafter be applicable, as nearly as reasonably may be, in relation to any
shares of stock or other property thereafter deliverable upon the exercise of
this Warrant.

                  (d) If the Company at any time makes any spin-off, split-off,
or distribution of assets upon or with respect to its Common Stock, as a
liquidating or partial liquidating dividend, spin-off, or by way of return of
capital, or other than as dividend payable out of earnings or any surplus
legally available for dividends, the Holder then outstanding shall, upon the
exercise of this Warrant, receive, in addition to the shares of Common Stock
then issuable on exercise of this Warrant, the amount of such assets (or, at the
option of the Company, a sum equal to the value thereof at the time of the
distributions) which would have been payable to the Holder had it exercised this
Warrant immediately prior to the record date for such distribution.

                  (e) When any adjustment is required to be made to the Exercise
Price, the number of shares of Common Stock issuable shall be determined as
provided for in paragraph (f) hereof. No fractional shares of Common Stock shall
be issued upon the exercise of this Warrant. The Company shall round all
fractional shares up to the next whole share.

                  (f) Whenever the Exercise Price is adjusted as provided above,
the number of shares of Underlying Stock immediately prior to such adjustment
shall be increased, effective simultaneously with such adjustment, by a number
of shares of Common Stock computed by multiplying such number of shares of
Common Stock by a fraction, the numerator of which is the Exercise Price in
effect immediately prior to such adjustment and the denominator of which is the
Exercise Price in effect upon such adjustment, and the number of shares of
Underlying Stock arrived at by making said computation shall be added to the
number of shares of Underlying Stock immediately prior to such adjustment. The
total number of shares arrived at by making the computation provided for in the
immediately preceding sentence shall thereupon be the number of shares of Common
Stock issuable upon exercise or the Warrant and the Company shall forthwith
determine the new Exercise Price.

         6. DELIVERY OF UNDERLYING STOCK. As soon as practicable after the
exercise hereof, but not more than five (5) days thereafter, the Company shall
deliver a certificate or certificates for the number of full shares of
Underlying Stock, all of which shall be fully paid and nonassessable, to the
person or persons entitled to receive the same provided no sale, offer to sell
or transfer of the Underlying Stock or of this Warrant, or of any shares or
other securities issued in exchange for or in respect of such shares, shall be
made unless a registration statement under the Act, with respect to such shares,
is in effect or an exemption from the registration requirements of such Act is
applicable to such shares.

         7. CONDITION OF EXERCISE OF WARRANT.

                  (a) Unless exercised pursuant to an effective registration
statement under the Securities Act which includes the Underlying Stock, it shall
be a condition to any exercise of this Warrant that the Company shall have


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<PAGE>

received, at the time of such exercise, a representation in writing from the
recipient in the form attached hereto as Exhibit A-1, that the Shares being
issued upon exercise, are being acquired for investment and not with a view to
any sale or distribution thereof.

                  (b) Each certificate evidencing the Underlying Stock issued
upon exercise of this Warrant, shall be stamped or imprinted with a legend
substantially in the following form:

                  "The securities represented by this certificate have not been
                  registered under the Securities Act of 1933, as amended. The
                  securities have been acquired for investment and may not be
                  sold, transferred or assigned in the absence of an effective
                  registration statement for the securities under said Act, or
                  an opinion of counsel, in form, substance and scope reasonably
                  acceptable to the Company, that registration is not required
                  under said Act or unless sold pursuant to Rule 144 under said
                  Act."

         Subject to this Section 7, the Company may instruct its transfer agent
not to register the transfer of all or a part of this Warrant, or any of the
Shares, unless one of the conditions specified in the above legend is satisfied.

         8. REPRESENTATIONS AND WARRANTIES OF THE COMPANY. The Company
represents and warrants to the Holder as follows:

                  (a) This Warrant has been duly authorized and executed by the
Company and is a valid and binding obligation of the Company enforceable in
accordance with its terms;

                  (b) The Underlying Stock has been duly authorized and reserved
for issuance by the Company and, when issued in accordance with the terms
hereof, will be validly issued, fully paid and nonassessable;

                  (c) The execution and delivery of this Warrant are not, and
the issuance of the Underlying Stock upon exercise of this Warrant in accordance
with the terms hereof will not be, inconsistent with the Company's Articles of
Incorporation or By-laws, as amended.

         9. REPRESENTATIONS AND WARRANTIES BY THE HOLDER. The Holder represents
and warrants to the Company as follows:

                  (a) This Warrant is being acquired for its own account, for
investment and not with a view to, or for resale in connection with, any
distribution or public offering thereof within the meaning of the Securities
Act. Upon exercise of this Warrant, the Holder shall, if so requested by the
Company, confirm in writing, in a form reasonably satisfactory to the Company,
that the Underlying Stock issuable upon exercise of this Warrant is being
acquired for investment and not with a view toward distribution or resale.

                  (b) The Holder understands that this Warrant and the
Underlying Stock have not been registered under the Securities Act by reason of
their issuance in a transaction exempt from the registration and prospectus
delivery requirements of the Securities Act pursuant to Section 4(2) thereof,
and that they must be held by the Holder indefinitely, and that the Holder must


                                       4
<PAGE>

therefore bear the economic risk of such investment indefinitely, unless a
subsequent disposition thereof is registered under the Securities Act or is
exempted from such registration.

                  (c) The Holder has such knowledge and experience in financial
and business matters that it is capable of evaluating the merits and risks of
the purchase of this Warrant and the Underlying Stock and of protecting its
interests in connection therewith.

                  (d) The Holder is able to bear the economic risk of the
purchase of the Underlying Stock pursuant to the terms of this Warrant.

         10. RIGHTS OF STOCKHOLDERS. No holder of this Warrant shall be
entitled, as a warrant-holder, to vote or receive dividends or be deemed the
holder of Common Stock or any other securities of the Company which may at any
time be issuable on the exercise hereof for any purpose, nor shall anything
contained herein be construed to confer upon the holder of this Warrant, as
such, any of the rights of a stockholder of the Company or any right to vote for
the election of directors or upon any matter submitted to stockholders at any
meeting thereof, or to give or withhold consent to any corporate action (whether
upon any recapitalization, issuance of stock, reclassification of stock, change
of par value, consolidation, merger, conveyance, or otherwise) or to receive
notice of meetings, or to receive dividends or subscription rights or otherwise
until the Warrant shall have been exercised and the Shares purchasable upon the
exercise hereof shall have become deliverable, as provided herein.

         11. MISCELLANEOUS.

                  (a) This Warrant and any term hereof may be changed, waived,
discharged or terminated only by an instrument in writing signed by the party
against which enforcement of such change, waiver, discharge or termination is
sought.

                  (b) This Warrant shall be governed by and construed in
accordance with the laws of State of New York without regard to principles of
conflicts of laws.

                  (c) The invalidity or unenforceability of any provision hereof
shall in no way affect the validity or enforceability of any other provision.

                  (d) The headings in this Warrant are for purposes of reference
only, and shall not limit or otherwise affect any of the terms hereof.

                  (e) The terms of this Warrant shall be binding upon and shall
inure to the benefit of any successors or assigns of the Company and of the
holder or holders hereof and of the Underlying Stock.

                  (f) This Warrant and the other documents delivered pursuant
hereto constitute the full and entire understanding and agreement between the
parties with regard to the subjects hereof and thereof.

                  (g) Upon receipt of evidence reasonably satisfactory to the
Company of the loss, theft, destruction or mutilation of this Warrant and, in
the case of any such loss, theft or destruction, upon delivery of an indemnity
agreement reasonably satisfactory in form and amount to the Company or, in the


                                       5
<PAGE>

case of any such mutilation, upon surrender and cancellation of such Warrant,
the Company at its expense will execute and deliver to the holder of record, in
lieu thereof, a new Warrant of like date and tenor.

                  (h) This Warrant and any provision hereof may be amended,
waived or terminated only by an instrument in writing signed by the Company and
the Holder.

                  (i) Receipt of this Warrant by the Holder hereof shall
constitute acceptance of and agreement to the foregoing terms and conditions.

         IN WITNESS WHEREOF, the Company has caused this Warrant to be signed by
its duly authorized officer.

Dated: October 22, 2008

                            CLEANTECH BIOFUELS, INC.

By:  ________________________________________________
     Name:___________________________________________
     Title: _________________________________________


Warrant Holder: _____________________________________

Address:

_____________________________________________________

_____________________________________________________

_____________________________________________________


                                       6
<PAGE>

                                    EXHIBIT A

                               NOTICE OF EXERCISE

TO:      CLEANTECH BIOFUELS, INC.

         1. The undersigned hereby elects to purchase ________ shares of Common
Stock of CLEANTECH BIOFUELS, INC. pursuant to the terms of this Warrant, and
tenders herewith payment of the purchase price of such shares in full in the
form of cash and/or shares of Common Stock received upon exercise of the
attached Warrant, which shares have the current market value equal to such
payment.

         2. Please issue a certificate or certificates representing said shares
of Common Stock in the name of the undersigned or in such other name as is
specified below:

           _____________________________________________________
           (Name)

           _____________________________________________________
           (Address)

           _____________________________________________________


         3. The undersigned hereby represents and warrants that the aforesaid
shares of Common Stock are being acquired for the account of the undersigned for
investment and not with a view to, or for resale, in connection with the
distribution thereof, and that the undersigned has no present intention of
distributing or reselling such shares and all representations and warranties of
the undersigned set forth in Section 9 of the attached Warrant are true and
correct as of the date hereof. In support thereof, the undersigned agrees to
execute an Investment Representation Statement in a form substantially similar
to the form attached to the Warrant as EXHIBIT A-1.

                                            ____________________________________
                                            (Signature)

                                            By:_________________________________

                                            Title:______________________________

                                            Date:_________________, 200__


                                      A - 1
<PAGE>

                                   EXHIBIT A-1

                       INVESTMENT REPRESENTATION STATEMENT

         PURCHASER:                 ______________________

         SELLER:                    ______________________

         COMPANY:                   CLEANTECH BIOFUELS, INC.

         SECURITIES:                COMMON STOCK ISSUED UPON EXERCISE
                                    OF THE WARRANTS ISSUED ON
                                    October 22, 2008

         AMOUNT:                    __________ SHARES

         DATE:                      ____________, 20__

In connection with the purchase of the above-listed Securities, I, the
Purchaser, represent to the Seller and to the Company the following:

         (a) I am aware of the Company's business affairs and financial
condition, and have acquired sufficient information about the Company to reach
an informed and knowledgeable decision to acquire the Securities. I am
purchasing these Securities for my own account for investment purposes only and
not with a view to, or for the resale in connection with, any "distribution"
thereof for purposes of the Securities Act of 1933, as amended (the "Securities
Act").

         (b) I understand that the Securities have not been registered under the
Securities Act in reliance upon a specific exemption therefrom, which exemption
depends upon, among other things, the bona fide nature of my investment intent
as expressed herein. In this connection, I understand that, in the view of the
Securities and Exchange Commission (the "Commission"), the statutory basis for
such exemption may be unavailable if my representation was predicated solely
upon a present intention to hold these Securities for the minimum capital gains
period specified under tax statutes, for a deferred sale, for or until an
increase or decrease in the market price of the Securities, or for a period of
one year or any other fixed period in the future.

         (c) I further understand that the Securities must be held indefinitely
unless subsequently registered under the Securities Act or unless an exemption
from registration is otherwise available. Moreover, I understand that the
Company is under no obligation to register the Securities. In addition, I
understand that the certificate evidencing the Securities will be imprinted with
a legend which prohibits the transfer of the Securities unless they are
registered or such registration is not required in the opinion of counsel for
the Company.

         (d) I am familiar with the provisions of Rule 144, promulgated under
the Securities Act, which, in substance, permits limited public resale of
"restricted securities" acquired, directly or indirectly, from the issuer
thereof, in a non-public offering subject to the satisfaction of certain
conditions.


                                       A-1 - 1
<PAGE>

         The Securities may be resold in certain limited circumstances subject
to the provisions of Rule 144, which requires among other things: (1) the
availability of certain public information about the Company, (2) the resale
occurring not less than six months after the party has purchased, and made full
payment for, within the meaning of Rule 144, the securities to be sold; and (3)
such other requirements that apply to holders who are affiliates.

         (e) I further understand that in the event all of the applicable
requirements of Rule 144 are not satisfied, registration under the Securities
Act, compliance with Regulation A, or some other registration exemption will be
required; and that, notwithstanding the fact that Rule 144 is not exclusive, the
Commission has expressed its opinion that persons proposing to sell private
placement securities other than in a registered offering and otherwise than
pursuant to Rule 144 will have a substantial burden of proof in establishing
that an exemption from registration is available for such offers or sales, and
that such persons and their respective brokers who participate in such
transactions do so at their own risk.

                                            ____________________________________
                                            (Signature)

                                            By:_________________________________

                                            Title:______________________________

                                            Date:_________________, 200__



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