Tokyo Treats Drinking Water with Ozone Biofiltration to Ultra High Quality

Not surprisingly, Tokyo has high quality water available from every faucet in the city. Japan is known for cleanliness and technology, and they combine these passions to treat their drinking water in their capital city.

There are many people who don’t like drinking from the tap and are instead willing to pay for bottles of water. The reality is that many drinking water plants produce water that is equal to or superior to bottled water. This is the case in Tokyo.

The basic quality of Tokyo drinking water is protected by 51 strict quality standards set by the Ministry of Health, Labor, and Welfare, including checks for toxicity and harmful contaminants, along with tests to ensure a palatable tint, clarity, and smell. Japan’s regulations for public water supplies are more stringent than those governing bottled spring water. What takes Tokyo’s water a step higher, though, is the metropolitan waterworks’ strict treatment regimen that includes roughly 200 parameters for safety and quality.

Five treatment plants run by the Tokyo Waterworks supply the city. The Misono plant is one of the five and has a daily treatment capacity of 300,000 cubic meters (about 80 MGD) and utilizes conventional treatment along ozone and biological activated carbon. This additional step removes virtually all remaining contaminants from the water.

Ozone is a strong oxidizing agent that reacts with various contaminants, including carcinogenic compounds, along with microorganisms such as bacteria and protozoa, eliminating potential health risks and improving the taste and odor.

In the second step of the process, water flows from the ozone contact chamber to the bio filtration ponds containing different grades of biological activated carbon. In addition to filtering out organic contaminants, much like a home water purifier, the microporous carbon also supports microorganisms that break down impurities and other byproducts of ozone treatment. If left behind, these contaminants can degrade the taste and smell of water.

The quality of source water determines the level of water treatment. Tokyo currently gets 80% of its water from the Tonegawa and Arakawa Rivers, drawing the remaining 20% from the Tamagawa River. The Tamagawa is pure enough that it only needs standard treatment to make it drinkable. Tonegawa and Arakawa Rivers require the advanced treatment explained above.

In the US and Canada many large drinking water plants have adopted the ozone biofiltration treatment process. In fact, in the US over 1.6 billion gallons of water a day are treated with ozone. Many of these plants have held contests where customer try to determine which is better in a blind taste test, tap water or bottled water. In many of the cities using advanced ozone water treatment, tap water wins.

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Poughkeepsie Looks to Upgrade to Ozone Biofiltration Process

Poughkeepsies’ Water Treatment Facility selected a system that uses ozone and biologically activated carbon to upgrade the facility at a cost of $18 million. the new process will reduce the organic material that serves as a precursor for potentially dangerous disinfection byproducts. One of these byproducts, trihalomethanes, has been found at high levels in the Greenbush water district in the Town of Hyde Park and the Hopewell Glen district in the Town of East Fishkill.

Ozone water treatment breaks down organic molecules to smaller more biodegradeable compounds while oxygenating the water. This creates an environment where aerobic bacteria can readily consume the organics. The biologically activated active carbon serves as a place for the bacteria to live. This type of carbon has a large surface area so that the number of bacreria is high for the volume of the carbon bed. Thus large amounts of organic material can be removed efficiently.

The process will ensure that each distribution system that receives treated drinking water from the plant remains in compliance with stiffer testing procedures mandated by the Environmental Protection Agency. Those new procedures will roll out this fall.

Water drawn from the Hudson River is treated at the plant and then sent to water systems in the Town and City of Poughkeepsie, the Town of Hyde Park and the Town of East Fishkill.

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Colorado Springs to us Ozone Biofiltration to treat Raw Water from the Pueblo Reservoir

The Southern Delivery System (SDS) has broken ground on a $125 million facility to treat the “raw” water that will be pumped from the Pueblo Reservoir to Colorado Springs. The SDS water treatment plant, which is being built on 124 acres east of Marksheffel Road between U.S. 24 and Colorado Highway 94, will consist of seven buildings, water storage tanks, drying beds, lagoons, pump stations and a drainage pond. It will be able to treat 50 million gallons of water per day.

SDS is expected to be operational in early 2016, and it could take nearly that long to complete the water treatment plant. The 82,000 square-foot water treatment plant will use ozone biological filtration to treat water piped from the Pueblo Reservoir. The plant’s capacity can be expanded to treat up to 130 million gallons of water per day based on future demand.

Ozone biolfiltration is an effective method for removing naturally occurring organic materials from water. It has been used extensively in the US for various surface water sources.

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Unique Ozone Biofilter Technology Developed for the Textile Industry Wastewater Treatment

A new fashion season results in a flood of new fabrics in a variety of colors. With the beauty comes the reality that producing these textiles comes at a cost to the environment as heavy polluting dyes find their way into the textile industry’s wastewater.

Anew water clean-up technology, developed as part of an EU-funded project, could help the fashion industry clean up its act. The new Sequencing Batch Biofiltration Granular Reactor (SBBGR) helps remove the most polluting textile dyes components – so-called recalcitrant organic compounds – by breaking them down using ozone treatment before applying an innovative wastewater bio-filtering technique.

Benefits of the SBBGR are that it integrates biological treatment with a chemical oxidation treatment, based on ozone, while physically separating these two steps.

Unlike traditional biological systems, this novel biological treatment filter relies on microorganisms growing in aggregates and is separated from the basin containing ozone and the waste. The wastewater is poured over the microorganisms, which process pollutants, and each aggregate holds up to 10 times more microorganisms than conventional technologies.

This new system produces 80% less sludge than traditional biological ones. Sludge is reduced because microorganisms only just survive in these conditions without being able to reproduce. However, there are some negative aspects to the new technology which need to be investigated further; it is expensive to run and consumes a lot of electricity. One of its main positive attributes when faced with competing available wastewater treatment technologies is its ability to be scaled up.

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Ozone Biofiltration Enhances Drinking Water Treatment

Biological aerated filters (BAF) use submerged granular media to support biological growth and act as filtration medium, eliminating the need for clarifiers. If aerated, the filter can be used for carbon removal and nitrification. In an unaerated mode and in the presence of sufficient carbon source, this technology provides denitrification. BAF can be installed in separate stages for carbon removal, nitrification, and denitrification.

The first large-scale installation with a capacity of 14 mgd has been operating in Roanoke, VA, for two years, and similar size plants in Minnesota are starting up. Two large plants with peak flows close to 100 mgd are now under construction in Binghamton and Syracuse, NY, corresponding to hundreds of installations with different BAF systems in the UK, German-speaking countries, France, Scandinavia, and Japan.

Biologically active filtration is also applied in drinking water to reduce the biodegradable matter which might lead to regrowth of bacteria in distribution systems using ozone to enhance pollutant bioavailability and supply oxygen, downstream contactors of activated carbon or anthracite provide growth surfaces for biomass.

In contact times of 5 to 10 minutes, a significant amount of biodegradable matter can be removed, lowering the necessary disinfection dosage and reducing the formation of halogenated byproducts. The world’s largest plant with ozone/biofiltration is currently being completed at Southern Nevada Water Authority’s Alfred Merrit Smith water treatment plant in Las Vegas, with a daily flow of up to 600 mgd from Lake Mead.

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Treatment of Land Fill Leachates with Ozone and Biological Processes

Land fill leachates are the result of water percolating through solid waste buried at the site. Land fill make provisions to capture this water for treatment. The waste can be a significant challenge to treat because of high content of organic matter, ammonia, salts and metals. Leachates vary due to a variety of factors including landfill age. New landfills produces leachates that are more biodegradable which are easier to treat. As the land fill ages biodegradability of the organic matter decreases. This means that treatment processes must include non biological treatment steps such as physical, and chemical process for older land fills.

At the recent International Ozone Association meeting a paper was presented on the use of ozone in combination with biological treatment (Ozone-Enhanced Biological Treatment of Landfill Leachates, Claudio Di Iaconi(1) , Antonio Lopez(1) and Achim Ried(2), 1 Water Research Institute, CNR, Bari, Italy; 2 ITT W&WW Herford, Germany). Normally to treat COD the ozone dose is typically between 2-3 mg Ozone per mg of COD. This can make the treatment process expensive. Ozone tends to make refractory organic compounds more biodegradable. Therefore, by pretreating the wastewater with ozone, the biological treatment process can assume a larger portion of the treatment burden. In addition, because ozone adds oxygen to the wastewater, the biological process is more efficient. the paper indicates that in some configurations the ozone demand is lowered to less than 0.7 mg Ozone per mg of COD.

Ozone is used in a similar manner for treatment of raw surface water to reduce organic levels in combination with biofiltration with GAC.

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City in Norway Uses Ozone Biofiltration for Color Removal

Skien Municipality in southern Norway is rebuilding Steinsvika Water Treatment Plant into an ozonation/biofiltration process. Steinsvika WTP will have a max production capacity of 1650 m3/h (39 600 m3/day) and a normal production of 650 – 1250 m3/h (15 600 – 30 000 m3/day). The plant will be in full operation by the end of February 2010.

The raw water of the plant is taken from the lake Norsjø. The main issue for the treatment process is removal of Natural Organic Matter (NOM) that gives color to the water and to ensure good hygienic barriers.

The NOM removal will be done by adding ozone at the inlet of the plant. The ozone breaks up the large NOM molecules into smaller molecules that are easily biodegradable. It also kills any micro organisms that might be in the water and increases the UV transmission of the water, so that the UV disinfection will be more effective. In the biofilters bacteria will use the organic molecules produced in the ozonation process as “food”. As a final step the water is disinfected, first by UV light and finally with chlorination.

Ozone biofiltration is used around the world to remove organic matter not only for elimination of color, but also to reduce the formation of chlorinated organics that might result fromt eh reaction of chlorine with teh NOM.

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