Indirect and Direct Potable Reuse (IPR and DPR): The Power of Ozone and Biologically Activated Carbon (BAC)
Water scarcity is driving innovation in wastewater treatment, making water reuse a critical strategy for sustainable resource management. Achieving the high-quality standards required for safe reuse demands advanced purification methods. Among the most effective treatment trains is the combination of Ozone and Biologically Activated Carbon (BAC), which together form a robust barrier against persistent contaminants.
Why Use Ozone for Industrial Water Reuse?
Industrial wastewater is often loaded with complex chemical compounds, dyes, surfactants, and biological contaminants that traditional treatment methods struggle to handle. Ozone provides a powerful, chemical-free alternative.
Rapid TOC and COD Reduction: Ozone aggressively breaks down Total Organic Carbon (TOC) and Chemical Oxygen Demand (COD), making the water safe to cycle back into production.
- Color and Odor Removal: It instantly destroys the conjugated bonds responsible for color in textile dyes or pulp and paper waste, leaving water visually clear.
- Zero Disinfection Byproducts: Unlike chlorine, ozone leaves no harmful chemical residuals or salts (like chlorides) in the water, which prevents chemical buildup in closed-loop systems.
- On-Site Generation: Ozone is created on-demand from the surrounding air, eliminating the need to store, handle, or transport hazardous chemicals.
The Imperative for Advanced Treatment
Conventional wastewater treatment often leaves behind a challenging mix of trace contaminants, including:
- Micropollutants: Endocrine-disrupting chemicals (EDCs), pharmaceuticals, personal care products (PPCPs), and pesticides.
- Refractory Organics: Complex, difficult-to-degrade organic matter.
- Pathogens: Viruses, bacteria, and protozoa that must be fully inactivated.
To safely reuse water for applications like industrial processing, irrigation, or potable water supplementation, these substances must be effectively eliminated.
The Industrial Ozone Treatment Train
In an industrial setting, ozone is usually placed after primary solids removal and before final polishing filtration.
- Pre-Treatment: Dissolved Air Flotation (DAF) or screening removes heavy oils, solids, and grease that would otherwise wastefully consume ozone.
- Ozone Oxidation: The water enters a contact chamber where ozone gas is injected via venturi systems. The ozone destroys bacteria, neutralizes odors, and shears complex organics into simpler structures.
- Post-Filtration: The water passes through a Granular Activated Carbon (GAC) or Ultrafiltration (UF) membrane. This catches any remaining broken-down organic fragments and delivers crystal-clear water back to the factory line.
The Synergistic Ozone/BAC Process ensures an efficient, economic alternative to reverse osmosis (RO) systems
The success of this combination lies in the fundamental transformation that ozone facilitates, which maximizes the efficiency of the BAC system.
Treatment Step | Primary Function | Contaminant Target |
|---|---|---|
Pre-Treatment | Particle Removal | Suspended Solids, Turbidity |
1. Ozone | Oxidation and Disinfection | Micropollutants, Pathogens, Color, Refractory Organics |
2. BAC | Adsorption and Biodegradation | Ozonation Byproducts, Residual Micropollutants, Trace Organics |
This sequence ensures a sustainable and cost-effective treatment: the pre-treatment protects the system, the ozone breaks down the tough contaminants, and the BAC polishes the water while regenerating itself, minimizing the need for frequent carbon replacement.
Integrating ozone into an industrial process water reuse system is a highly effective way to close the loop on your water cycle. It allows factories, manufacturing plants, and processing facilities to clean their wastewater well enough to recycle it back into their operations, drastically reducing freshwater consumption and discharge fees.
Applications of Ozone/BAC Treated Water
Water treated with this advanced sequence meets some of the world’s most stringent quality requirements, making it suitable for:
- Groundwater Recharge
- Industrial Use (e.g., cooling water, boiler feed)
- Indirect and Direct Potable Water
- High-Quality Irrigation
1. Food and Beverage Processing
In the food industry, process water is heavily contaminated with sugars, starches, and organic matter. Ozone is used to treat wash-water, clean-in-place (CIP) systems, and bottle rinsing water. Because it reverts back to pure oxygen, it ensures there is zero chemical taint on food products.
2. Agriculture irrigation
Probably the most beneficial and sustainable approach. This direct non-potable solution has already been deployed to remove pathogens and contaminants prior to crop irrigation and non-potable reuse.
3. Textile and Dye Wastewater
Textile manufacturing generates heavily colored wastewater laden with synthetic dyes. Ozone acts as a powerful decolorizing agent, breaking the complex dye molecules apart so the water can be reused in subsequent dye cycles without ruining the fabric color profiles.
4. Pulp and Paper Mills
The paper industry uses vast amounts of water that become contaminated with lignin and bleaching chemicals. Ozone is widely used in “Closed-Mill” configurations to remove color and organic matter, allowing mills to operate with near-zero liquid discharge (ZLD).
Cost comparison of Ozone/BAC to reverse osmosis (RO)
In advanced water reuse, Ozone + BAC (Biologically Active Carbon) serves as an economical, non-membrane alternative to Reverse Osmosis (RO). Ozone + BAC degrades organic compounds biologically, while RO physically blocks almost all dissolved solids and salts. Ozone is extremely effective in neutralizing CEC’s (Contaminants of Emerging Concern) and will not produce DBP (Disinfection By-products).
The cost of an Ozone/Biologically Activated Carbon (BAC) system is generally significantly lower than a Reverse Osmosis (RO) system for both Indirect Potable Reuse (IPR) and Direct Potable Reuse (DPR), especially for inland communities.
While Reverse Osmosis (RO) is the gold standard for removing total dissolved solids (salts) and produces highly purified water, the Ozone/BAC system often proves to be the most economical choice when salinity is not the primary concern.
Feature | Ozone/BAC Treatment Train | Reverse Osmosis (RO) Treatment Train |
|---|---|---|
Primary Driver | Oxidation and Biodegradation | Physical Filtration/Salt Separation |
Typical Cost | Lower (Can be 40–50% of RO based lifecycle cost) | Higher |
Capital Costs (CAPEX) | Lower (Fewer complex mechanical parts) | Higher (High-pressure pumps, energy recovery devices, specialized membranes) |
Operating Costs (OPEX) | Operating Costs (OPEX) Lower (Mainly power for ozone generation and backwashing) Significantly Higher (Dominated by electricity for high-pressure pumping and chemical use) | Significantly Higher (Dominated by electricity for high-pressure pumping and chemical use) |
Energy Consumption | Much Lower (Estimated $0.30 kWh/m3 to $0.40 kWh/m3 Source Dept. of Energy, Dec 2021 | Much Higher (Estimated $0.84 kWh/m3 or more) Source Dept. of Energy, Dec 2021 |
Waste Stream | None (Residual solids from backwash are typically recycled to the headworks) | Brine Concentrate (Highly concentrated salt/contaminant stream requiring complex, expensive disposal) |
Contaminant Focus | Micropollutants (e.g., pharmaceuticals, pesticides), Pathogens, Organics | Total Dissolved Solids (TDS), Micropollutants, Pathogens |
How much ozone to dose?
Every installation is unique, the required ozone dosage will be based on the contaminants in the water and the intended water reuse. Typically, dosages can be as low as 2 mg/L and as high as 35 mg/L. Contact us at info@emo3.com so we can assist you.
Treatment Step | Primary Function | Contaminant Target |
|---|---|---|
Pre-Treatment | Particle Removal | Suspended Solids, Turbidity |
1. Ozone | Oxidation and Disinfection | Micropollutants, Pathogens, Color, Refractory Organics |
2. BAC | Adsorption and Biodegradation | Ozonation Byproducts, Residual Micropollutants, Trace Organics |
This sequence ensures a sustainable and cost-effective treatment: the pre-treatment protects the system, the ozone breaks down the tough contaminants, and the BAC polishes the water while regenerating itself, minimizing the need for frequent carbon replacement.
Integrating ozone into an industrial process water reuse system is a highly effective way to close the loop on your water cycle. It allows factories, manufacturing plants, and processing facilities to clean their wastewater well enough to recycle it back into their operations, drastically reducing freshwater consumption and discharge fees.
Other applications
Aquaculture
Our systems provide oxygen-rich water, free of harmful pathogens and algae, supporting better yields, stable water quality, and healthier aquatic environments.
Cooling Towers
Our systems reduce bacteria and control biofilm, prevents legionella, reduces chemical dosing, and enhances system efficiency. A smart solution for keeping your cooling systems clean, compliant, and cost-effective.
Food & Beverage Processing
Ozone is safe to use on food products such as poultry, meat and fish and has been used extensively to sanitize food products. Ozone disinfects process water, surfaces, and equipment—without chemicals. The result: safer food and a safer workspace, aligned with strict food safety standards.
Municipal Drinking Water
Ozonation replaces chlorine in disinfection, reducing by-products (like THMs and HAAs), eliminating emerging pollutants, and improving both taste and safety—while meeting regulatory standards.
Odor Control
Our ozone generators are widely used in pumping stations, treatment pits, factories, and HVAC systems to eliminate VOCs and industrial odors at the source—without masking. A compliant, community-friendly solution.
Public Aquariums
Ozone treatment ensures crystal-clear water and reliable control of bacteria and parasites, all without chemical residues. It also improves indoor air quality for visitors and staff.
Waterparks & Public Pools
Say goodbye to harsh chemicals. Ozone disinfection is fast, and residue-free, providing clean, safe water for pools, slides, and attractions. It improves user comfort and reduces operating costs.