Ozone Drinking Water Treatment for Algae Related Issues

Algae in lakes and reservoirs can create issues for drinking water plants including toxins, bad taste and unpleasant odors in the water. While there are a number of treatment methods used to deal with this problem, ozone treatment of the water has emerged as a proven and cost effective method.

Depending on where and how the ozone is applied to the process, the ozone can serve two purposes: primary disinfection and removal of algae related compounds that pose health or aesthetic risks to the drinking water plants customers.

The city of Oregon in Ohio was concerned about algae related issues from their intake in Lake Erie due to cyanobacteria that can produce microcystin, a toxin. Toledo had experienced a severe issue with this toxin that resulted in a 2014 temporary ban on the use of water from their drinking water plant. This cause Oregon to look for solutions before they experienced a similar problem.

In Oregon’s process, water from lake Erie will be treated with ozone and then go through biological filtration. The approach will remove algae-related toxins. The process works because ozone breaks down the toxins into molecules that are quickly digested by the biology living in the filter.

The process was first tested at the pilot scale for several months to prove that it worked well. The full scale system is expected to be in operation by the algae season of 2017. Other advantages include reduced use of chlorine, improved disinfection and reduced disinfection byproducts. Ozone also eliminates trace organic compounds.

The project is expected to cost $14 million, with funds mainly coming from the Ohio Environmental Protection Agency’s Water Supply Resolving Loan Account. Oregon’s water rates will increase about $2 to $3 more a month for the improved quality and safety.


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.


Ozone Drinking Water Authority Wilfred LePage Passes

Wilfred LePage, age 83 of Monroe, MI died Monday, January 27, 2014 in his home after a year long period of declining health.

Following service with the Marines during the Korean Conflict, he studied at Wayne State University. While in college he entered his career field of drinking water purification at the Mount Clemens Water Filtration Plant. In 1959 he accepted a supervisory position with the Monroe Water Department from which he retired in 1995.

Wilfred rose to international prominence in the water industry. He authored and published numerous technical papers largely on the application of ozone to drinking water treatment and, following invasion of the water system by the non-indigenous zebra mussel, on mussel mitigation. He traveled extensively at home and abroad while presenting his work.

He held leadership positions in several technical and scientific societies and received numerous high honors including the water industry’s coveted George Warren Fuller Award for his innovative work with ozone.


Drinking Water Utilities Treatment Practices Based On Recent Disinfection Rules

The Long Term 2 Enhanced Surface Water Treatment Rules, know as LT2ESWTR was promulgated in 2006 obligating large drinking water utilities to comply with the rules by 2012. The rule was designed to prevent cryptosporidium, a difficult to kill pathogen from entering the drinking water supply. An incident in Milwaukee resulted in thousands of people becoming ill and others to die. It was considered a serious threat that was not treated by the standard disinfection method of chlorination.

The AWWA has reported on both the monitoring results and treatment methodologies employed by these utilities in the August issue of the associations journal.

The LT2ESWTR required utilities to first monitor their water for the presence of cryptosporidium. Based on these results, utilities were placed in bins associated with the observation of cryptosporidium being in present in the source water. The more pathogen found, the more aggressively the utility had to treat its water. Reservoirs ad lakes showed the lowest occurrence with 3.2% of samples showing the organism while rivers and other flowing water sources showed up to 11% of samples with the pathogen. The average was about 6.4% of all surface water sources had the organism.

If utilities fell into the higher risk bins, i.e. they observed higher levels of cryptosporidium, they were required to use EPA methods referred to the microbial tool box. Utilities assigned in the higher risk bins used a variety of methods to treat the water. These methods begin at the water source where plans to control the watershed are intended to prevent the organisms from entering the source water. Various filtration methods were employed by the utilities to filter out the organisms. Finally, some utilities upgraded their disinfection processes to inactivate the organism. One of the more popular methods was ultraviolet light or UV.

Unfortunately, the AWWA survey only looked at 38 utilities with 24 actually reporting results. So the study did not provide good statistical information on how the various methods are being used. For example, the particular utilities contacted had not used ozone, although ozone is used to control cryptosporidium, especially were water temperature is higher and their are other reasons for using ozone. For example, in reservoirs and lakes, algae can create significant taste and odor challenges for a water utility while also having to deal with cryptosporidium. So employing ozone water treatment in these cases can provide both taste and odor removal as well as pathogen reduction.

The Milwaukee outbreak lead to a detailed study of the drinking water systems in this country that use surface water. A well designed plan involving considerable public comment resulted in an enhancement of the safety of drinking water. Although the process took over a decade, the results will be enjoyed for many years to come.


Middleton Adds Ozone Water Treatment in Plant Rennovation

A $20 million project to retrofit the Middleton Water Treatment Plant is expected to be completed this fall. The original plant went online in 1976. The upgrade is expected to extend the plant operations for another 20 to 30 years of life while permitting it to meet new Safe Drinking Water Act by 2015. The renovation and addition involves construction filtration, ozone treatment and sludge dewatering buildings.

Treating the water uses both chemical and mechanical processes. The water enters a flash mixer where it gets an initial dose of chemicals to coagulate and precipitate out solids. The water also gets a dose of ozone. The flow of the water is slowed, allowing heavy solids to settle out. The water is pumped through sand and carbon filters. The sand removes particles and the carbon absorbs organic materials. The water from the filters then passes into a clear well to be disinfected with chloramine before being sent out into the water system.

One of the most significant upgrades is an ozone treatment plant built at the front of the building.
When this form of treatment is up and running, the pond water will first be treated with ozone, which removes organic materials and kills parasites. The ozone also aids in the precipitation and sedimentation process, and helps eliminate harmful byproducts from other disinfectants.


China Drinking Water Quality

Original article published in Caixin’s Century Weekly by Gong Jing and Liu Hongqiao. Reprinted at Chinadialogue.net. Authors won the “Journalist of the Year” and “Young Journalist of the Year” categories at chinadialogue and The Guardian’s China Environmental Press Awards. A month after their article was published, the housing ministry was forced to release previously unpublished information about urban water quality and officials announced they would be spending 410 billion yuan (about £40 billion) on improving water quality in urban areas by 2016.

What is the quality of Chinese drinking water? In the second half of 2009, the Chinese housing ministry carried out a nationwide survey of more than 4,000 water-treatment plants in cities at county level and above. Nearly four years later, it still hasn’t made any of this data public. However, several industry insiders have told us the results of this survey indicate only around half of the water meets standards. More than 30 years of rapid industrialisation has caused extensive pollution of water sources.

In 1985, drinking water sources in China’s cities and towns were considered clean. By 2006, water sources had seriously deteriorated. The main pollutants in water sources for towns and cities had changed from microorganisms to soluble organic pollutants and heavy metal ions.

Many academics believe that China’s water pollution situation is even more serious than Europe’s during its period of industrialisation, and that pollution from rare earth metals is a particular problem in China. The “leakage” of heavy metal ions from smelting plants is a danger that has not yet been properly appreciated.

Wang Zhansheng, a professor at Tsinghua University’s School of Environment, believes that the harm done to the human body from dirty drinking water is of two kinds – the kind that can be seen, and the kind that cannot. The former is generally the harm that comes from contamination by microorganisms. It can cause sudden acute illness. Fortunately, Chinese people have a habit of drinking boiled water, which can kill microorganisms, so this is a less urgent problem.

The harm that cannot be seen is a more pressing issue. “Organic compounds can build up in the human body, and eventually they damage your health. In serious cases it can lead to cancer, birth defects and mutations,” said Wang.

The 2009 survey found that water-treatment plants that used surface water as the source of their tap water did not meet standards. Many had levels of fluorine, arsenic, iron and manganese that exceeded limits.

Wang said that a significant proportion of these organic compounds are environmental hormones, also known as endocrine disruptors. Environmental hormones pose four kinds of dangers: they can impair the immune system, affect fertility, cause cancer or interfere with the nervous system.

Liu Wenjun, head of the Institute of Drinking Water Safety Research at Tsinghua University, believes that public officials at all levels fail to understand the connection between drinking water and public health. Most know little about the long-term dangers of organic compounds because it may take 10 or 20 years before they cause sickness. It is also difficult to prove that this sickness came from drinking water in the first place.

Another misconception is that they believe that having a water dispenser in their home is a total solution. But there’s no escape from water pollution. A large number of studies have shown that, of the harmful substances found in water, only a third enters the body through drinking. The other two thirds are absorbed through the skin or inhaled – while bathing, washing and brushing your teeth.

The need for treatment

With only half of water sources reaching standards, the fact the water-treatment plants are using outdated technology has become the first hurdle to regaining control. he first conventional water treatment technology appeared in Belgium in 1902. The process involved flocculation (adding aluminium polychloride), filtration (through quartz sand and pebbles, for example) and sterilisation. In 2004, the US National Academy of Engineering said that water-treatment technology was one of the most important inventions of the twentieth century.

Liu Wenjun told Caixin reporters that New York, and many cities in Canada and Europe, are still using this simple technology to supply drinkable water. “The thing is that all these cities that are still using conventional technology are using water sources that are basically unpolluted. Most of China’s water sources are polluted, so this conventional technology is not suitable,” Liu said.

Conventional water purification methods aim to kill microorganisms. If the water is polluted with heavy metal ions or organic compounds, conventional technology can’t do anything. In the opinion of Song Lanhe, chief engineer at the housing ministry’s water monitoring unit, Japan and most European countries have been able to overcome relatively serious environmental pollution by using advanced water-treatment methods, such as ozone and activated carbon technology, to eliminate all kinds of organic and inorganic compounds.

Yet despite the severity of pollution of water sources, by the end of 2009, of the more than 4,000 water-treatment plants at or above country level, 98% were still using conventional technology. At present, only cities such as Beijing, Shanghai, Guangzhou, Shenzhen, Hangzhou and Zhengzhou are using advanced technology.

Beijing – which has the best quality tap water – has been heavily investing for 10 or more years to transform its water supply system, and still isn’t finished: the water is still not drinkable. And the outmoded network of water pipes in most cities and towns cannot be compared to Beijing’s infrastructure. Producing drinkable water is way beyond their reach.

The method of treatment is not the only consideration. After the water leaves the treatment plant, it flows into the urban network of water pipes, where it finally ends up coming out of household taps. On the way there are a lot of dangers: the outdated network of pipes as well as secondary water supplies can compromise water quality.

In 2002 and 2003, the housing ministry surveyed the network of water pipes in hundreds of cities and found it was universally sub-standard. “Outmoded pipe systems badly leak water, and secondary pollution is also likely to occur,” according to Song Lanhe. From 2000 to 2003, there were 4,232 cases of secondary pollution occurring in the pipe systems of 184 large- to medium-sized cities.

Liu Wenjun has been studying the problem of secondary pollution in the water pipe network for many years. His opinion is that outmoded pipe systems easily corrode, form scale, allow microorganisms and bacteria to breed, and react with nutrients in the water, creating secondary pollution. Occasionally it can even be seen with the naked eye – the water becomes yellow or black and may give off a bad smell.

Compared with developed nations, secondary water supply is a challenge unique to China. In China’s towns and cities, most buildings of six or more floors are high-rises. In order to provide normal water pressure for those homes, and at the same time avoid putting too much pressure on the fragile pipe network, all urban water supply companies chose a pipe network model where pressure is applied at the end: water is pumped to water tanks on the roofs of high-rises or cisterns in the basement. From here it flows into people’s homes and is thus a major potential source of secondary pollution; a dead mouse or bird can contaminate a building’s entire water supply.

The maintenance of these water tanks and cisterns is thus a major issue. Property rights generally belong to the residents, but residents certainly don’t have the skills to manage them. Usually it’s the property management of an estate that looks after them, but they don’t have the necessary specialised skills.

According to Song Lanhe, it is the urban buildings department that generally manages urban water-treatment plants. Theoretically, however, the secondary water supply facilities should be taken care of by the Department of Health. Water-treatment plants are unwilling “to meddle in others’ affairs” and so the Department of Health is also usually powerless to manage them. They are mainly involved in issuing sterilisation permits. In the end there is virtually no management of all these urban secondary water supply facilities, and no one to take responsibility.

But the secondary water supply is not without advantages. When an accident or disaster happens in a city and the power and water supplies are cut off, secondary water tanks can provide residents with water for a period of time, and they can also be used by firefighters as an emergency water source. Song sees their use as an urban management issue. If managed well, it’s a blessing; if managed badly, it’s a disaster.

The importance of clean drinking water was well expressed by a professional in the drinking water industry, who emphasised three points:

For the government, improving water supply is the most fundamental way of improving people’s lives, more fundamental than fixing roads, building high-speed railways or constructing high rises.

In the past few decades, it has become the most neglected way of improving people’s lives.

For every person, tap water is like air – you can’t choose it and you can’t escape from it.


Laughlin, NV Treats Drinking Water with Ozone to Reduce Disinfection By products and Control Taste and Odor Issues

Big Bend Water District (BBWD) is the supplier of potable water to the community of Laughlin, the sole source of which is the Colorado River. “The BBWD has over 15,000 acre feet per year as an allotment, but historically Laughlin rarely uses more than 5,000 acre feet of that allotment. BBWD can treat a maximum of 15 million gallons per day. Over a 12-month period, the average per-day flow through the treatment plant is three to four million gallons a day. Intake for the BBWD is located in the Colorado River just north of the Laughlin Bridge; most of the water in the river is a result of snow melt in the Rocky Mountains.

The job of the treatment plant is to remove impurities from the water and make it safe for drinking. The BBWD uses ozone as a disinfectant at the facility. Ozone is generated on-site and prevents the formation TTHMs, which the EPA limits in water.
Trihalomethane – or TTHM – is a by-product of chlorine, when it is used to disinfect drinking water. Ozone can remove some of the precursor compounds that form TTHM and reduces the total amount of chlorine that can form them. While more expensive to generate than other oxidants the tradeoff is a lot less taste and odor issues and much lower TTHMs. BBWD treats with chlorine, the EPA requires the district to maintain a disinfectant residual in the system because it is a surface water system.


Milwaukee Now a Leader In Water Testing and Treatment

20 years ago Cryptosporidium passed through a Milwaukee water treatment plant. The microorganism caused an estimated 400,000 cases of gastrointestinal illness and at least 69 deaths. It was the largest waterborne desease outbreak recorded in U.S. history.

Since the outbreak, the city’s water utility, which draws its supply from Lake Michigan, has invested $417 million in improvements to infrastructure, monitoring and treatment.

Beginning in 2004, Milwaukee Water Works launched an aggressive program to monitor for emerging contaminants including estrogen and testosterone, flame retardants, pesticides, explosives and pharmaceuticals. Milwaukee Water Works tests for more than 500 chemicals annually, and posts its monitoring results online. The majority of water systems in the US focus only on a standard list of 91 contaminants regulated by the U.S. Environmental Protection Agency.

Since the Cryptosporidium outbreak of 1993, Milwaukee has made numerous improvements to its drinking water treatment. An $11 million project extended the Howard Avenue water intake 4,200 feet to a distance of two miles off Lake Michigan’s shoreline, beyond the path of contamination from the city’s industrial harbor. The water enters a nine-step treatment process that includes ozone disinfection, sedimentation and filtration.

At the other end of the city’s water system, the Milwaukee Metropolitan Sewerage District tested a state-of-the-art sewage filtration system. The goal was to catch emerging contaminants resistant to removal by conventional wastewater treatment along with phosphorus, a nutrient that contributes to algae blooms and fish kills.

As a result of the improvements, Milwaukee has become a leading municipality with respect to drinking water treatment.


The City of Manistique Win Besting Water Using Ozone Treatment

During the 64th Annual U.P. Water Treatment System Operator’s Training, which is associated with the American Water Works Association. Manistique competed against 11 other communities in a drinking water taste off. Manistique’s water supply is drawn from the Indian River – something which sets Manistique apart form many of the other communities in the taste competition. It’s very hard for a surface water treatment plant to compete against groundwater systems. Manistique is the first surface water plant to win the competition in the U.P.

Last year the city upgraded it’s water treatment plant to use ozone and granular activated carbon filtration in order to meet new drinking water quality rules making it the first in the U.P. One of the primary uses for ozone water treatment is taste and odor improvement. What makes ozone especially attractive for this application is that it can simultaneously improve water taste while also imrpoving disinfection and removing other water impurities. This is the case in Manistique.


Sand Hills Opens New Ozone Drinking Water Treatment Plant

New Jersey American Water has built a new water treatment plant in Short Hills, NJ to meet the standards of the Safe Drinking Water Act including the control of disinfection by-products. The new plant was built alongside two older plants, one that was built in 1929 and the second built in 1958. The 1958 plant remained online during construction.

The new facility cost $78 million to build, which was funded by a grant from the New Jersey Environmental Infrastructure Trust, and created 200 jobs. It can produce 14 million gallons of water a day that meets or exceeds state and federal standards.

The new plant has ozone water treatment and allows New Jersey American Water to comply with the by-products disinfection rule and improves taste and odor for the facility’s customers. Raw water is pumped from the reservoir and ozone gas is added to the raw water as needed. A coagulant is added to the water to remove natural organic matter suspended in the water. After that, the water is mixed is rapid mixed with paddle mixers to form floc and then goes on to the Dissolved Air Flotation basins. Tiny bubbles float the floc to the surface and form a sludge blanket which is removed by using a mechanical scrapper. Once it leaves the DAF basin it enters filters which remove any remaining suspended solids from the water. A disinfectant and corrosion inhibitor are then added before the water leaves the plant to the distribution system.