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.


Ozone Considered for Improving Water Quality in Tyler Texas

The City of Tyler has released the results of an independent review of its water treatment process conducted by Enprotec/Hibbs & Todd, Inc. The study looked at the causes and possible remedies for high levels of haloacetic acids in the water. Haloacetic acids are a disinfection byproducts (DBP) which are regulated by the US EPA. They are formed when organic compounds in raw water react with chlorine to form chlorinated organic compounds such as haloacetic acids and trihalomethanes. In October of 2015 the city had received notification of high haloacetic acid levels in its drinking water.

The study recommended some operational changes to reduce the haloacetic acid levels, but some of the issues are due to the age of the water plant where the acid levels are the highest. The facility was constructed in 1950s before the onset of increased regulations on water quality. A newer facility uses ozone as a pre-treatment. The study recommends utilizing the ozone at the older water treatment plant, thereby reducing the amount of byproducts created by chlorine.

Ozone has been used extensively in the US and Europe to reduce the formation of chlorine based DBP’s.


Emporium KS Upgrades Ozone Disinfection Drinking Water System

The Emporia City, KS Commission approved a request authorizing the Public Works Department to proceed with an Ozone Equipment purchase Wednesday afternoon during an active session. The current equipment at the Water Treatment Plant uses atmospheric air and bubble diffusers and was installed in 1995, with an expected life of 15 to 20 years. The Ozone equipment and process is the primary disinfection action at the Water Treatment Plant. The equipment, which is slated to be installed in 2016, with a project construction cost estimate of $2.6 million.

Ozone equipment installed 20 years ago was primary based on air feed as the source of oxygen for ozone generation. Using air as the feed gas results in lower concentration ozone of 1-3 percent ozone. Newer oxygen fed ozone generators produce ozone at 10 percent concentration. Higher concentration ozone dissolves more readily in water for more efficient use of the ozone produced.

There is also a reduction in the size of the generator to produce the same mass of ozone, normally indicated in pounds/day. The reduction in the nitrogen levels also minimizes damage tot he generator due to the formation of nitric acid.

As a result of these advantages newer ozone systems have shifted to some form of oxygen feed, either from liquid oxygen supplied by gas companies or made on site using oxygen concentrators. The latter take air and remove the nitrogen to get to oxygen levels of 93%.

The first ozone systems were installed 20-30 years ago and are now being upgraded as the one in Emporium is later next year.


Brits Water Plant in South Africa Adds Ozone

According to Kormorant news papers the upgrading of the Brits Water Treatment Plant at a cost of R578 million could help alleviate the water problems the Madibeng Local Municipality. The upgrade will not only improve the capacity of water provision, but quality as well. As part of the project, the Ozone Purification System which could see the municipality receiving a Blue Drop status, will be installed. The Ozone Purification System is a system used to kill bacteria, i.e. disinfect water and is used by many municipalities throughout the world.


Ozone Systems Market Expected to be $1.25 billion in 2020

A recent market study by Persistence Market Research suggests that global market for ozone technology market was $715 million in 2013 and is expected to grow to 1,242 million in 2020.

Ozone technology is used for a wide variety of applications, but primarily for water purification, disinfection and the removal of organic and inorganic contaminants. Ozone technology equipment has promising growth rate in the waste water treatment equipment, in municipalities, and other water treatment segment which include swimming pools and spas. This growth is attributed to the many benefits associated with the technology. High oxidation potential, quicker processing time compared to other traditional disinfection techniques, with no harmful by-product.

The increasing global health concerns due to surge in urbanization, increasing water contamination and increasing level of industrialization are driving the ozone technology market globally. The government expenditure on upgrading water infrastructure has increased in the past decades across all regions., Municipalities are upgrading from traditional chlorine-based disinfection to UV and ozone technology based disinfection which has boosted ozone technology market. There is also an interest for both municipalities and industry to remove organic contaminants from water, ozone and ozone based advanced oxidation processes have been found to be useful in this regard. Water treatment related regulations in some of the countries are also compelling water and waste water service establishments to modify their water treatment techniques to improve safety level of water.


Celina, Ohio Deals with Algae Blooms Using Ozone and GAC

Recent news regarding the algae related water quality problems in Toledo have raised issues about the potential for algae blooms and the release of toxic chemicals from the algae elsewhere in the US and especially in Northwest Ohio.

Celina, another town in Ohio, uses Grand Lake as its water source, which has encountered problems with the algae blooms and the toxins they release since 2009. Celina, however, has updated treatment system to deal with these issues.

The city uses two methods of water treatment to make its water safe, ozone and granular activated carbon treatments. Ozone is a powerful oxidant and highly effective disinfectant. It is a technology that has been in continual commercial use for more than 100 years and has distinct properties that allow disinfection of even heavily compromised water streams.

The GAC treatment is an extremely versatile technology and in many cases has proved to be a cost effective option. GAC absorption is particularly effective in treating low concentration waste streams and in meeting stringent treatment levels. GAC is known to remove a wide variety of toxic organic compounds to non-detectable levels.
As with any water treatment technology, suitability on a specific application normally depends on costs as they relate to the amount of carbon consumed.


Yorkshire Water Adds Ozone Water Treatment for Pesticide Removal

The Acomb Landing water treatment plant with an output capacity of 35ML/day drinking water processes raw water from the River Ouse as part of Yorkshire Water. The principal contractor, AECOM, is working to update the plant to remove micro pollutatns, primarily pesticides. They have decided to use ozone water treatment combined with activated carbon to remove these contaminants.

Ozone is effective in breaking down complex micro pollutants, such as pesticides, into safer compounds.


Natrona County Uses Ozone To Treat Drinking Water

Natrona County’s drinking water is taken from the North Platte River and is treated at the Central Wyoming Regional Water System (RWS) with the primary disinfectant being ozone. The facility produces up to 25 million gallons of water per day. RWS uses chloramines as their secondary disifectant to keep bacteria from growing in the delivery system, including the pipes in your house.

At the RWS plant, after raw water is drawn from a well field that’s under the influence of the river, water is filtered and then ozone is used as their primary disinfectant.

Ozone is used because it’s better at killing giardia and other protozoan parasites like cryptosporidium (crypto) than chlorine. Protozoan parasites have hard outside surfaces. When chlorine is used in the process it requires longer contact times to kill bacteria.

Both RWS’ water plants is located low in the valley by the river. Once water is processed, it’s pumped uphill to high capacity tanks for storage. RWS operates 22 tanks. The system of high capacity tanks sits above the populations they serve and employ gravity to provide water pressure.

RWS’ water plant uses closed-system computers to operate their plants. Operators are able to gather information in real time from water flow and chemical analysis sensors, and use the computers to operate valves, introduce chemicals and automatically fill tanks. Supervisory control and data acquisition (SCADA) systems are common in the industry. Because their SCADA systems are closed systems, there’s no remote access to them from the Internet and operators must be on site to manage the plant.

The cost of the RWS facility in the range of $40-$50 million not including tanks or the distribution system. Tanks start at more than $1 million. Add the cost of miles and miles of underground lines, lift pumps, taps and other plumbing to the cost of the water plant and the total cost is much higher.


Ambient Ozone Measurement for Ozone Water Treatment

The use of ozone water treatment systems requires the measurement of ambient ozone levels as a safety measure. OSHA sets a 40 our exposure limit to ozone in spaces where people are present of 0.10 or less. Emissions from the ozone system or the down stream processes can exceed the OSHA levels. If this occurs, the ozone system should be shut down and the source of the ozone isolated. Normally, an ozone system will be interlocked with the ambient ozone monitor.

There are basically two different types of ambient ozone monitors: electrochemical and UV. The electrochemical sensors are less expensive and if there is not source of interference for these units, they are a good choice. They can see interference, especially from other oxidants that might be present, for example chlorine or one of its variants.

UV sensors are very accurate for low level ozone measurement, but much more expensive than electrochemical sensors. UV monitors are essentially UV spectrophotometers operating at 254 nm where ozone absorbs UV. They can also be affected by interferences, especially by aromatic hydrocarbons that also absorb UV at the 254 nm region. So, if these organic compounds are present UV monitors may not be a good choice for the application.

Because ambient ozone monitors are used for measuring ppb levels of ozone, it is a very challenging applications. Sometimes it is difficult to find the interference or to determine if there is an interfering compound. So, it is important to test the sensors against a known zero gas and calibrated ozone containing gas.

In general, electrochemical sensors are widely deployed for a variety of industrial and municipal drinking water applications. If problems develop a UV monitor might be a good option for checking the environment if calibration of the electrochemical sensors does not indicate the nature of the high ozone readings.


Burleson, TX Faces Water Taste and Odor Challenge

Burleson, TX residents are having taste and odor problems with their drinking water which is purchased from Fort Worth. While the water has been determined to be safe to drink, officials have acknowledged that it does have an “earthy smell and taste”.

Tests indicated an increase in the levels of a substance called geosmin in Lake.
Geosmin is a type of bicyclic alcohol produced by actinobacteria and released when those organisms die. City officials have said that colder-than-usual temperatures in December and January killed off the actinobacteria and released the geosmin into Lake Benbrook. Geosmin levels there are the highest seen in years.

Fort Worth uses ozone as a primary disinfectant which has the side benefit of removing taste and odor compounds like geosmin from the water. To combat the increased level of geosmin, the water department has increased the dose of ozone injected into the water. In addition city has also started blending the water from Lake Benbrook with water from Cedar Creek Lake.

Many factors such as seasonal variations and weather can result in changes in the level of taste and odor compounds in surface water sources such as lakes an reservoirs. It is difficult to predict these changes and develop counter measures. Ozone has been found to be one of the more effective and economical agents for this purpose since it not only removes the taste and odor compounds, but also disinfects the water.