Multistage DAF-Advanced Oxidation System for Produced Water Treatment
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Solution Overview
Problem
Conventional Dissolved Air Flotation (DAF) technology in oil and gas fracturing operations is inadequate for removing all contaminants in produced water, such as oil, grease, suspended solids, and organics, necessitating a multifunction treatment system to meet discharge limits and extend injection well life.
Innovation Solution
The Multistage DAF Advanced Oxidation (MSDAF-AO) system, comprising four stages: Enhanced Oil Recovery using lamella plates and gas ionization, Enhanced Solids Removal with recirculated air bubbles and polymers, Emulsion Breaking with hydrogen peroxide, and Disinfection through Advanced Oxidation with UV and hydrogen peroxide, providing a compact, mobile, and efficient treatment solution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional DAF technology is used, then oil and suspended solids can be removed, but it cannot remove all contaminants including emulsified oil and dissolved organics
Solution Approach 1:
The treatment system is divided into four distinct stages: (1) DAF for oil and solids removal, (2) Coagulation/flocculation for suspended solids, (3) Emulsion breaking for emulsified oil, and (4) Advanced oxidation for dissolved organics and disinfection. Each stage targets specific contaminants, transforming a single-function DAF system into a multi-function treatment train that comprehensively addresses all contaminant types in produced water.
Solution Approach 2:
The integrated system performs multiple treatment functions within a single compact unit, including flotation, coagulation, emulsion breaking, advanced oxidation, and disinfection. This universal treatment capability allows the system to handle diverse contaminants (oil, solids, emulsions, dissolved organics, bacteria) that conventional single-function DAF systems cannot remove, thereby meeting discharge limits and extending injection well life.
2Reliability
If multiple treatment processes are combined, then comprehensive contaminant removal is achieved, but system complexity increases
Solution Approach 1:
Multiple treatment processes (DAF, coagulation/flocculation, emulsion breaking, advanced oxidation, and disinfection) are merged into a single integrated unit with shared components such as the air dissolving pump, mixing chambers, and compact reaction vessels. This consolidation achieves comprehensive contaminant removal while maintaining a space-efficient and operationally simple system suitable for mobile deployment in oil and gas operations.
3Ease of operation
If a compact mobile system is designed, then ease of deployment is improved, but treatment capacity may be limited
Solution Approach 1:
The system employs vertical stacking of treatment stages and three-dimensional utilization of space through compact reaction chambers and vertical flow paths. This dimensional optimization allows multiple treatment processes to be integrated in a compact footprint, maintaining high treatment capacity while enabling mobile deployment and easy relocation to different well sites.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The MSDAF-AO system effectively enhances oil recovery, solids removal, emulsion breaking, and disinfection, achieving comprehensive contaminant removal and improving the quality of treated effluent, suitable for oil and gas, as well as other industrial wastewater treatments.
Implementation Method 1
The ionizing lamp in the gas ionizer operates at with a wavelength suitable for ionizing incoming atmospheric air... The ionized air is dissolved into a recirculating system... When entering the oil recovery chamber at atmospheric pressure, the released ionized gases, coming out of solution, form very fine bubbles. The ionization of the atmospheric gases increases the attractions between air bubbles and oil droplets
Implementation Method 2
Dissolved air flotation (DAF) is a process whereby micro-air-bubbles attach themselves to suspended materials causing them to float to the surface of a flotation chamber to achieve liquid/solids separation. Air is introduced into the pump suction and the bubbles are sheared into much smaller bubbles by the pump and then dissolved into the water by high pressure
Implementation Method 3
Stage IV Disinfection using advanced oxidation (AO)... Disinfection through Advanced Oxidation with UV and hydrogen peroxide... achieving comprehensive contaminant removal and improving the quality of treated effluent
Implementation Method 4
The water then enters the flotation chamber by passing over the influent chamber dividing wall. The velocity of the water in the flotation chamber is significantly reduced to maximize separation potential. Inside the flotation chamber, the micro-bubbles (saturated water mixture), which have attached themselves to the particle's surface, change the particle's density. This causes the previously suspended solids to float to the surface
Implementation Method 5
Heavy grit and solid particles settle onto the bottom of the DAF where they are flushed out into the sludge system via a manual valve
Implementation Method 6
A polymer, or other coagulants, will be added into the influent mixing and coagulation chamber to enhance the removals of solids or oil
Data Source
AI summary
A multistage dissolved air flotation and advanced oxidation (MDAF-AO) system/method with multi-functions in oil recovery, solids removal, emulsion breaking, and advanced oxidation. Influent, with oil and suspended solids, enters a first stage for oil recovery includes a gas ionizer and an air dissolving pump. A second stage includes of two coagulation/flotation compartments connected in serial to enhance solids removal efficiencies. Micro air bubbles are created by air dissolving pumps in each compartment. A third stage is for the emulsion breaking unit to further remove or recover the emulsified oils. A fourth stage includes advanced oxidation by using ultraviolet (UV) and hydrogen peroxide to oxidize and disinfect the bacteria and microorganisms.