PTAB

IPR2017-01468

Frontier Water Systems LLC v. Zenon Technology Partnership

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Petition
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1. Case Identification

2. Patent Overview

  • Title: Apparatus and Method for Treating FGD Blowdown or Similar Liquids
  • Brief Description: The ’034 patent describes a system and method for treating Flue Gas Desulfurization (FGD) wastewater. The process involves a physicochemical pretreatment stage to precipitate suspended solids and soften the water, followed by biological treatment in one or more bioreactors for denitrification and selenium removal.

3. Grounds for Unpatentability

Ground 1: Anticipation of Claims 1 and 3 by Fukase

  • Prior Art Relied Upon: Fukase (JPH0938694A).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Fukase, which teaches a treatment system for FGD wastewater, disclosed every element of claims 1 and 3. Fukase described a physical and chemical pretreatment process using a coagulant and soda ash (for softening) to remove suspended solids. This stage was followed by biological treatment in a fixed film bioreactor to perform both denitrification and selenium removal, directly mapping to all limitations of independent claim 1. Petitioner further contended that Fukase’s disclosure of an aerobic nitrification step occurring upstream of the denitrification and selenium removal stage anticipated all elements of dependent claim 3.

Ground 2: Obviousness of Claims 1-3, 5-7, and 9-15 over Fukase in view of Downing

  • Prior Art Relied Upon: Fukase (JPH0938694A) and Downing (Patent 4,725,357).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner asserted that Fukase provided the overall framework for treating FGD wastewater, including a pretreatment stage and a subsequent biological treatment stage. The petition argued that Downing supplemented Fukase by teaching specific details of the biological treatment, namely anoxic denitrification followed by anoxic selenium removal within fixed film bioreactors. Downing also taught removing other contaminants like heavy metals (arsenic, mercury) and sulfur, which Petitioner mapped to dependent claims 2 and 11. Additionally, Downing’s disclosure of maintaining an oxidation-reduction potential (ORP) below -100 mV was argued to render claim 6 obvious.
    • Motivation to Combine: A person of ordinary skill in the art (POSITA) would combine Fukase’s FGD pretreatment system with Downing’s established biological treatment process. The motivation was to improve the bioreactor’s design, enhance its functionality to remove additional known contaminants, and achieve specific ORP targets for more efficient and predictable operation.
    • Expectation of Success: A POSITA would have a reasonable expectation of success, as combining a known pretreatment process tailored for a specific wastewater type (Fukase) with a compatible and well-understood biological treatment process (Downing) represented a standard and logical approach in wastewater treatment design.

Ground 3: Obviousness of Claims 1-3, 5-7, and 9-15 over Katagawa in view of Downing, further in view of Okazoe

  • Prior Art Relied Upon: Katagawa (JPH01304100A), Downing (Patent 4,725,357), and Okazoe (JPH10249392).

  • Core Argument for this Ground:

    • Prior Art Mapping: Petitioner contended this three-reference combination rendered all challenged claims obvious. Katagawa was cited for teaching a robust physicochemical pretreatment system for FGD wastewater using lime and coagulants followed by settling, which met the pretreatment limitations of independent claims 1 and 9. Downing was cited for providing the core biological treatment stage for denitrification and selenium removal. Okazoe was added to provide specific teachings on process control, describing the importance of monitoring and maintaining ORP within specific ranges by adjusting nutrient dosages to ensure effective biological treatment. This teaching was argued to directly address the limitations of ORP-related dependent claims 5 and 7.
    • Motivation to Combine: A POSITA tasked with designing a system to meet modern selenium regulations would select an effective biological method like Downing. To prepare the specific FGD wastewater for this treatment, the POSITA would be led to a compatible pretreatment system like that in Katagawa. To optimize the combined process for efficiency and cost-effectiveness, the POSITA would then incorporate the advanced ORP control methods taught by Okazoe, which was a logical and well-known step to refine a biological treatment system.
    • Expectation of Success: Success was predictable because the combination involved the methodical integration of well-understood, discrete unit operations—pretreatment (Katagawa), biological treatment (Downing), and process optimization/control (Okazoe)—for their known and intended functions.

  • Additional Grounds: Petitioner asserted additional obviousness challenges based on Fukase alone; Katagawa in view of Downing; and Fukase in view of Downing and Okazoe, but these relied on similar design modification and combination theories.

4. Key Claim Construction Positions

  • Petitioner proposed constructions for key terms based on their broadest reasonable interpretation in light of the specification to support its invalidity arguments:
    • "bioreactor" and "one or more reactors configured to provide...removal by biological treatment": proposed as "a reaction vessel where biological treatment occurs."
    • "soften the waste stream": proposed as to "add a chemical that reduces the hardness of the wastewater."

5. Relief Requested

  • Petitioner requested institution of an inter partes review on all grounds for claims 1-3, 5-7, and 9-15, and for those claims to subsequently be found unpatentable and cancelled.