Ozone Water Treatment System Design Requires Understanding of Water Quality and Treatment Objectives

Spartan Environmental Technologies principal business is supplying ozone water treatment systems. We numerous inquiries where the customer does not have a thorough understanding of their water quality. For the design of any type of water treatment system, the starting point is a good understanding of water quality, its potential vairations and the treatment objective.

A first step is the collection of represntative water samples that correspond to various periods of operation. Such an analysis should include pH, alkalinity, TDS, TSS, inorganics (anions/cations), specific metals and organics (TOC, color, BOD and COD). If disinfection is a key objective an analysis of micro organisms should be included.

Depending on the water source to be tested, seasonal variations might be important, e.g. for surface water treatment. If such variations occur, water quality sampling should be done in different seasons to corrspond to these variations.

Treatment objectives include removal of which contaminants and to what levels. In many industrial applications COD reduction is a key objective. In drinking water and bottled water applications disinfection is the key objective. The identification of what test will be used to measure the key parameter.

A water treatment company can use the water quality data and treatment objective to make an initial assessment into the application of various technologies. In the case of Spartan, this means ozone, peroxide or advanced oxidation systems using ozone/peroxide.

If the initial assessment indicates that teh chosen technology appears to be a feasible option, lab and pilot testing are usually indicated. For ozone a basic ozone demand test is often a first step. In this test ozone is added to a water sample and the decay of the ozone over time is measured. Pilot testing is on a slightly larger scale and often involves continuous flow of water to be treated through key unit operations. For ozone systems this would invlove all of the steps in ozone generation, ozone water mixing, the inclusion of key down stream unit operations, e.g. filtration, and the necessary instruments and testing procedures to determine of the treatment objective is being met.

A competent water treatment company will not begin to discuss water treatment system costs without at least a through discussion of water quality and treatment objectives.

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Sequester to Affect Water Funding According to the EPA

The Safe Drinking Water Act and the Clean Water Act include revolving loan funds to help states finance drinking water purification and sewage treatment facilities—both of which are essential to the country’s public-health infrastructure. The Environmental Protection Agency reports that:

Reductions under sequestration would impact states’ ability to meet drinking water public health standards and to reduce the nitrogen and phosphorus pollution that contaminate drinking water supplies, cause toxic algae blooms, and deprive waters of oxygen that fish need to survive.

This reduction would result in the elimination of more than 100 water quality protection and restoration projects throughout the United States.

Drinking water and wastewater treatment are already underfunded, as are other major infrastructure projects. The Environmental Protection Agency estimates that they have capital needs of at least $31.6 billion per year.

Investment in water treatment infrastructure is important because new sources of water are of lower quality. Cities and states have already tapped into the low hanging fruit of high quality water sources and now are looking at lower quality surface water sources or recaliming wastewater. Both types of water require more intensive treatment with technologies like ozone, UV and membranes.

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Maersk Uses Ozone UV for Ballast Water Treatment

A.P. Moller-Maersk (Maersk) has indicated that ballast water treatment system (BWTS) based on mechanical filtration and disinfection with UV and ozone represents a good solution for container vessel retrofits. Both ozone water treatment and UV are excellant disinfection technologies for a wide range of applications.

Maersk says that the containerization of the BWTS is a viable way of overcoming space problems in crowded engine rooms as well as it gives the advantage of easy and short installation time.

The system works in fresh, brackish, or salt water and can provide flow rates up to 500 cubic meters per hour in a 20-foot container or and up to 3,000 cubic meters per hour in a configuration with two 40-foot containers placed on top of each other.

The International Maritime Organisation (IMO) has called on ship owners to adopt treatment technologies to prevent the spread of invasive species, although the 2004 convention on the issue has not yet received enough support to go into force.

Maersk Line is the global containerized division of the A.P. Moller – Maersk Group. The first Maersk Line vessel sailed in 1904 and has become the world’s largest ocean carrier.

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Emmons County ND Uses Ozone Pretreatment for a UF/RO Drinking Water Treatment Plant

The South Central Regional Water District utility knew that water from these wells contained high levels of dissolved solids, hardness, and sulfates, as well as arsenic content beyond the safety standards established by the Environmental Protection Agency (EPA).

A treatment solution was developed ozone pretreatment, ultrafltration (UF) and reverse osmosis (RO) to treat nearby Missouri River water. In operation since May 2012, the new Emmons County Water Treatment Plant demonstrates the successful use of ozone as a primary disinfection and pretreatment for the downstream UF and RO membrane technologies with no compatibility issues.

Ozone is finding wide application in surface water treatment because it is economical and effective. Over 1.5 billion gallons of drinking water is treated with ozone every day.

Ozone is a stronger oxidizer than other water treatment chemicals, potentially creating challenges for UF and RO membranes. The new Emmons County water treatment plant validates ozone pretreatment for UF and RO membranes with good operating performance and membrane stability.

The new water treatment plant draws raw water from the Missouri river. Ozone is the primary disinfectant for removal of organics. Ozone is generated on site with a high degree of automation making it a safe and low maintenance treatment option.
Ozone-oxidized water enters sedimentation basins with coagulant dosage.

The water settles for 30 minutes before passing through screen flters to the ultrafltration systems for pathogen and solids removal down to the 0.03 micron level. DOW™ Ultrafltration SFD-2860 membranes were used due to their ozone-resistant PVDF chemistry and fber integrity.

The ultrafltered water then enters the RO system to remove tastes and odors, followed by chloramines dosing prior to distribution. The RO system provides a ratio of 60% permeate to 40% UF fltrate to meet the hardness target of six grains per gallon.

The residual ozone dosage shows no compatibility issues on the UF membrane, and RO performance is stable with minimal pressure drop.

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Muttenz Switzerland to Treat Groundwater with Advanced Oxidation

The groundwater in Muttenz, Switzerland will be purified using a combination of advanced oxidation, adsorption and ultrafiltration. The water is subject to organic trace substances and occasionally impacted by Rhine filtrate.

Difficult to treat compounds will be oxidized using ozone and hydrogen peroxide. The ozone and peroxide react to form hydroxyl radicals that are fast reacting and non specific oxidants that will break down virtually all organic molecules. Technologies like ozone peroxide combination that produce these radicals are geneerally referred to as advanced oxidation processes.
In the next phase powdered active carbon (PAC) will absorb the residual substances and finally ultrafiltration will be employed to filter out the activated carbon in combination with the adsorbed contaminants. Such a combination ensures that micro-pollutants, which are otherwise difficult to degrade, can be safely removed or reduced. This fact has already been confirmed by the operational results from the pilot plant at the location.

Muttenz is the first plant in Switzerland to be equipped with this particular process technology. The new drinking water treatment plant will produce about 5 MGD of ground water and is expected to start operation in December 2014.

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Grey Water Reuse – A Low Cost Option for Sustainability

A recent paper published in the AWWA Journal (Olmos & Lodge, 105:2,February 2013, pp 41-42) discusses achieving zero water use and reasonable payback periods for a housing development in Davis California. Net zero water use as defined here is that annula water use equal annual rain fall. This would make the development sustainable from teh stand point of water.

The study concluded that such an objective can be obtained by increasing teh efficiency of indoor water use and landscape water conservation. principle savings came from reducing the need to heat water for indoor use. Simple residential greywater systems for landscape irrigation showed relatively short payback periods, about 1-3 years. Improving the efficient use of potable water for landscape irrigation has alonger payback period.

This February issue of the journal also discusses other water conservation and resue applications in San Francisco. The city published a guide to designing greywater water treatment systems. For a one or two unit residence directly using washing machine effluent, no permit is required for installing a grey water system if the water comes directly from the washing machine and does not require a change in the buildings plumbing.

Treatment of residential grey water, at least from the washing machine, seems to be a low cost and easy way to make an immediate impact on the sustainability of water resoruces

In larger greywater projects, for example large buildings, more extensive treatment may be required, especially if the water is going to be stored for some period of time since this could lead to biological growth. Ozone has been found to be effective in these types of water reuse situations.

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Ann Arbor Michigan Uses Ozone for Primary Disinfection

Ann Arbor’s Drinking Water Treatment Plant’s primary source of water comes from the Huron River. Ann Arbor is one of only seven facilities using an inland river as a drinking water source in Michigan. About 85 percent of the water comes from the river, while 15 percent comes from wells located at the city’s airport. The plant pumps on average more than 15 million gallons of water per day to some 125,000 city water customers.

Because the city uses surface water as it primary source, the water goes through a complete treatment process that consists of rapid mixing for quick dispersion of chemicals being added, flocculation to give the chemical reaction time it needs, settling to allow the removal of solids by gravity, and filtration.

The city also softens the water using lime, removing calcium and magnesium. Ozone is used as the primary disinfectant and chloramines as a secondary disinfectant. Fluoride is added to the water for dental protection, and phosphate is added to stabilize the water.

City officials are evaluating replacing portions of the plant that date back to the 1930s, and which could cost tens of millions of dollars.

Spartan periodically posts information about water plants around the world that use ozone. Most people, and even some water professionals, are not aware of the widespread use of ozone in drinking water treatment as well as other applications.

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