Ozone-Biofiltration

Ozone-biofiltration is a water treatment process that combines ozonation with biological filtration to remove contaminants from water. 

Ozone-Biofiltration

Ozone-biofiltration integrates a two-step process:

Step 1. Ozonation (Oxidation Step)

- Ozone (O₃) is dissolved into the water to oxidize organic and inorganic compounds.

- Converts complex organic molecules into biodegradable compounds, making them easier to remove.

- Destroys bacteria, viruses, and algae, preventing microbial regrowth.

- Added benefit, ozone oxidation breaks down micro-pollutants, such as pharmaceuticals, pesticides, and industrial chemicals.

Step 2. Biofiltration (Biological Treatment Step)

- Water passes through a biological activated carbon (BAC) filter or a sand filter.

- Beneficial microorganisms colonize the filter media, feeding on the biodegradable organic matter.

- This biodegradation step removes residual contaminants that ozonation alone cannot eliminate.

- The biofilter captures particulate matter, heavy metals, and disinfection by-products (DBPs).

Practical applications of Ozone-Biofiltration in Water Treatment:

Drinking Water Treatment

Ozone is used in municipal water treatment plants to improve raw water quality.  Ozone has proven very successful  in removing taste and odor issues caused by organic compounds such as geosmin an 2-MIB.

Enhanced Removal of Contaminants

The combination of chemical oxidation with biological treatment can remove or significantly reduce pollutants that might be resistant to traditional biological treatment alone, including pharmaceuticals, personal care products, pesticides, and other micropollutants.

Reduction in Disinfection Byproducts

By breaking down complex organics before biological treatment, the process can reduce the formation of harmful disinfection byproducts that might occur if these compounds were to react with chlorine or other disinfectants used in later stages of water treatment.

Improved Water Quality

The treated water can achieve higher quality in terms of clarity, odor, and taste, making it suitable for reuse in various applications or for discharge into sensitive environments.

Sustainability

By improving the efficiency of pollutant removal, less chemical treatment might be needed downstream, and the process can help in reducing the environmental impact of wastewater discharge.

Ozone-biofiltration is particularly appealing for upgrading existing wastewater treatment plants to meet stricter environmental regulations or for treating water where conventional methods are insufficient. However, it does require careful management due to the complexities of ozone generation and handling, as well as the need to maintain an effective biological community in the biofilter.

Advantages of Ozone-Biofiltration:

- Removes Contaminants More Efficiently – Eliminates pharmaceuticals, pesticides, and endocrine disruptors that conventional filtration misses.

- Disinfection Byproduct Reduction – Reduces trihalomethanes (THMs) and haloacetic acids (HAAs), lowering health risks.

- Sustainable & Chemical-Free – Reduces reliance on chlorine and other chemicals, making it environmentally friendly.

- Improves Biological Stability – Treated water is less prone to microbial regrowth.
Enhances Taste & Odor – Eliminates musty, earthy smells from drinking water.

- Lower Operational Costs – Compared to reverse osmosis (RO), ozone-biofiltration uses less energy and produces no brine waste.

The Future of Ozone-Biofiltration:

- With growing concerns over micro-pollutants, ozone-biofiltration is becoming a preferred alternative to traditional methods.

- Used in major cities and industries worldwide, it provides a cost-effective and environmentally friendly solution for clean water.

- Future advancements may focus on energy efficiency and integrating AI for process optimization.

Below are specific case studies and research showcasing the use of ozone-biofiltration.

Extended Field Investigations of Ozone-Biofiltration for Potable Water Reuse

Authors: V. Sundaram, K. Pagilla, T. Guarin, L. Li, R. Marfil-Vega

Abstract

This study examined the regulatory, design, and operational challenges of implementing ozone-biofiltration for potable water reuse. The findings demonstrated that ozone pre-treatment significantly enhanced biofilter performance. A long-term field study was conducted to evaluate ozone-biofiltration across different seasons, comparing its effectiveness to conventional filtration.

Key Findings

- This study focused on regulatory, design, and operational hurdles in implementing ozone-biofiltration for potable reuse.

- Demonstrated that ozone pre-treatment significantly enhanced biofilter performance.

Methodology:

- Conducted a long-term field study evaluating ozone-biofiltration across different seasons.

- Compared ozone-biofiltration vs. conventional filtration.

Results:

- 80-90% removal of pharmaceuticals and personal care products (PPCPs).

- Significant reduction in disinfection by-products (DBPs) compared to chlorination.

- Biofiltration improved microbial stability of treated water, reducing chlorine demand.

Read the full study here.

Demonstration- Scale Evaluation of Ozone– Biofiltration– Granular Activated Carbon Advanced Water Treatment for Managed Aquifer Recharge

Authors: Samantha Hogard, Germano Salazar- Benites, Robert Pearce, Tyler Nading, Larry Schimmoller, Christopher Wilson, Jamie Heisig- Mitchell, Charles Bott 

Abstract

The Sustainable Water Initiative for Tomorrow (SWIFT) program is the effort of the Hampton Roads Sanitation District to implement indirect potable reuse to recharge the depleted Potomac Aquifer. This initiative is being demonstrated at the 1- MGD SWIFT Research Center with a treatment train including coagulation/flocculation/ sedimentation (floc/sed), ozonation, biofiltration (BAF), granular activated carbon (GAC) adsorption, and UV disinfection, followed by managed aquifer recharge. Bulk total organic carbon (TOC) removal occurred via multiple treatment barriers including, floc/sed (26% removal), ozone/BAF (30% removal), and adsorption by GAC. BAF acclimation was observed during the first months of plant operation which coincided with the establishment of biological nitrification and dissolved metal removal. Bromate formation during ozonation was efficiently controlled below 10 µg/L using preformed monochloramine and preoxidation with free chlorine. N- nitrosodimethylamine (NDMA) was formed at an average concentration of 53 ng/L post- ozonation and was removed >70% by the BAFs after several months of operation. Contaminants of emerging concern were removed by multiple treatment barriers including oxidation, biological degradation, and adsorption. The breakthrough of these contaminants and bulk TOC will likely determine the replacement interval of GAC. The ozone/BAC/GAC treatment process was shown to meet all defined treatment goals for managed aquifer recharge.

Key Findings

- Investigated a combination of ozone, biofiltration, and granular activated carbon (GAC) for aquifer recharge.

- Showed that ozone improved the biodegradability of pollutants, making biofiltration more effective.

Methodology

- Evaluated water quality before and after treatment over 12 months.

Results

- Over 95% removal of micropollutants, including PFAS and pharmaceuticals.

- Reduction in total organic carbon (TOC) by 60%, lowering potential DBP formation.

- Successfully recharged groundwater with high-quality treated water.

Read the full study here.

Extended Field Investigations of Ozone-Biofiltration for Potable Water Reuse

Authors: V. Sundaram, K. Pagilla, T. Guarin, L. Li, R. Marfil-Vega

Abstract

This study examined the regulatory, design, and operational challenges of implementing ozone-biofiltration for potable water reuse. The findings demonstrated that ozone pre-treatment significantly enhanced biofilter performance. A long-term field study was conducted to evaluate ozone-biofiltration across different seasons, comparing its effectiveness to conventional filtration.

Key Findings

- This study focused on regulatory, design, and operational hurdles in implementing ozone-biofiltration for potable reuse.

- Demonstrated that ozone pre-treatment significantly enhanced biofilter performance.

Methodology:

- Conducted a long-term field study evaluating ozone-biofiltration across different seasons.

- Compared ozone-biofiltration vs. conventional filtration.

Results:

- 80-90% removal of pharmaceuticals and personal care products (PPCPs).

- Significant reduction in disinfection by-products (DBPs) compared to chlorination.

- Biofiltration improved microbial stability of treated water, reducing chlorine demand.

Read the full study here.

Effect of Ozone on Biopolymers in Biofiltration and Ultrafiltration Proccesses

Authors: B. Siembida-Lösch, W. B. Anderson, Y. M. Wang

Abstract

The focus of this full-scale study was to determine the effect of ozone on biopolymer concentrations in biofiltration and ultrafiltration (UF) processes treating surface water from Lake Ontario. Ozonation was out of service for maintenance for 9 months, hence, it was possible to investigate ozone's action on biologically active carbon contactors (BACCs) and UF, in terms of biopolymer removal. Given the importance of biopolymers for fouling, this fraction was quantified using a chromatographic technique. Ozone pre-treatment was observed to positively impact the active biomass in biofilters. However, since an increase of the active biomass did not result in higher biopolymer removal, active biomass concentration cannot be a surrogate for biofiltration performance. It was evident that increasing empty bed contact time (EBCT) from 4 to 19 min only had a positive effect on biopolymer removal through BACCs when ozone was out of service. However, as a mass balance experiment showed, ozone-free operation resulted in higher deposition of biopolymers on a UF membrane and slight deterioration in its performance.

Key Findings:

- Investigated how ozone pre-treatment affects the removal of biopolymers and dissolved organic matter.

- Found that ozone enhances ultrafiltration performance by breaking down large organic molecules.

Methodology:

- Lab-scale ozone-biofiltration system treating synthetic wastewater.

Results:

- 40-50% reduction in biofouling, prolonging membrane lifespan.

- Improved microbial activity in biofilters, increasing biodegradation efficiency.

- Significant reduction in NOM (Natural Organic Matter), leading to lower DBP formation in drinking water.

Read the full study here.

Reducing Disinfection Byproduct Prescursors and Chlorine Consuming Substances by a Special Integration of Biofiltration and Ozonation: A Pilot Study

Authors: P. D. Nguyen, T. D. Q. Le, N. H. Nguyen, K. T. Tran

Abstract

Saigon river is the primary water supply source for Ho Chi Minh City, Vietnam. Currently, the formation of harmful disinfectant by-products (DBPs) in the piped water is elevating due to the increase in both organic matter pollution in Saigon river and chloride usage at water treatment plants (WTPs). To provide safe drinking water, the WTPs should upgrade their existing conventional surface water treatment technology to reduce DBP precursors and chlorine consuming substances efficiently. In this study, the long-term performance of a pilot system, including a biofiltration-ozonation unit and a biological activated carbon (BAC) filter in removing these compounds was evaluated. Different from other studies, a tricking filter (TF) was placed before a low-dose ozone contactor for water pretreatment. By partially returning the ozonated water to the TF, the removal of dissolved organic carbon (DOC), which contains DBP precursors, in the TF-ozonation unit was doubled. Over two months operated with highly fluctuated river water quality in the rainy season, the pilot systems stably removed 50 % of DOC, 71 % of trihalomethane formation potential (THMFP), 71 % of Fe²⁺, and 74 % of N-NH₄⁺. The TF-ozonation unit was effective in removing DOC, THMFP, and NH₄⁺, while the BAC filter was more effective in removing Fe²⁺. If implemented, this system can replace the pre-chlorination process accounting for 74 % of daily chlorine consumption at Tan Hiep WTP. The obtained results indicate that retrofitting WTPs with the tested processes can provide safe drinking water for Ho Chi Minh City residents in the future.

Key Findings:

- Demonstrated how ozone-biofiltration reduces DBP precursors and chlorine demand.

Methodology:

- Tested ozone doses ranging from 1 to 5 mg/L in pilot-scale treatment systems.

Results:

- 30-50% reduction in total trihalomethanes (THMs).

- 60% reduction in haloacetic acids (HAAs).

- Improved chlorine stability in the treated water.

Read the full study here.

Persistent Contaminants of Emerging Concern in Ozone-Biofiltration Systems

Authors: M. A. Sari, J. Oppenheimer, K. Robinson

Abstract

Water quality, in combination with design and operational data collected from multiple studies, was assessed to benchmark the performance of ozone-biologically active filtration in reuse applications. A total of 149 contaminants of emerging concern, representative of multiple categories and chemical structures, were prioritized and systematically compared to elucidate apparent differences in removal capabilities as affected by multiple factors such as influent water matrix, ozone-to-organic carbon ratio, empty bed contact time, filtration media type, and initial media condition. The results were consistent with earlier findings for the removal of highly amenable compounds but demonstrate inconsistencies and knowledge gaps across multiple facilities for the more persistent compounds. Analysis of this multistudy data-mining effort also demonstrates a complicated interplay between contaminant removal and numerous design and operational variables. Hence, further systematic investigation is warranted to elucidate the underlying removal mechanisms.

Key Findings:

- Evaluated ozone-biofiltration for removing contaminants of emerging concern (CECs).

Methodology:

- Pilot-scale system using full-scale treatment plant influent.

Results:

- Over 85% removal of PFAS compounds.

- Enhanced biodegradation of complex organic pollutants.

- Maintained low turbidity and microbial regrowth.

Read the full study here.

Direct Potable Reuse Using Full Advanced Treatment Versus Ozone Biofiltration

Authors: M. Noibi, J. Hooper, K. Bell, D. Funk

Abstract

The cost of direct potable reuse (DPR) using reverse osmosis (RO) and full advanced treatment (FAT) based on advanced oxidation process was compared with a non-RO-based treatment train with ozone and biologically active filtration (BAF). Costs were calculated assuming a blend of 15% advanced treated water with the current potable water supply, Lake Lanier. The 30-year amortized capital and operational costs were US$4,830/mil gal for FAT and $1,900/mil gal for ozone-BAF. The primary additional cost associated with FAT was due to the mechanical evaporation of RO brine concentrate disposal. The costs for producing water using FAT integrating a vibratory shear-enhanced processing-RO (VSEP-RO) to further concentrate the RO brine were lower than those for mechanical evaporation alone ($3,510/mil gal). While VSEP-RO improved overall costs, ozone-BAF-based treatment was less than half the cost of FAT. Thus, ozone-BAF may provide a more economical alternative compared with FAT for inland facilities considering DPR.

Key Findings:

- Compared ozone-biofiltration vs. reverse osmosis (RO) for potable reuse.

- Found that ozone-biofiltration provided a cost-effective alternative to RO.

Methodology:

- Pilot-scale tests on municipal wastewater effluent.

Results:

- 80% PPCP removal compared to 99% in RO, but with lower energy consumption.

- No brine waste, unlike RO.

- Lower operational costs, making it viable for large-scale applications.

Read the full study here.

Pilot Testing of Direct and Indirect Potable Water Reuse Using Muli-Stage Ozone-Biofiltration without Reverse Osmosis

Authors: J. Hooper, D. Funk, K. Bell, M. Noibi, K. Vickstrom

Abstract