Ozone Helps Milwaukee Achieve High Drinking Water Quality

The City of Milwaukee’s drinking water gets high marks when it comes to “quality”. The Environmental Protection Agency requires every public water supplier around the country to publish its annual report.

Technology has influenced the utility’s ability to get ahead of the requirement curve. More than 150 instruments continuously monitor the entire water treatment process. The water treatment protocol has also become more sophisticated. The most important part of the process was the shift from chlorine to ozone as the primary disinfectant. Ozone water treatment was prompted by the 1993 outbreak of Cryptosporidium. It sickened hundreds of thousands, killed some people and forced residents to boil their water.

Chlorine, at practical dosages, does not kill Cryptosporidium. Ozone is an effective treatment for this organism and, it also removes emerging contaminants such as pesticides, pharmaceuticals and personal care products that are present in the city’s source water.

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Bio Treatment with Ozone Reduces Wastewater Sludge

Biological treatment plus ozone can reduce the amount of sludge coming from wastewater treatment plants by a factor of 10. The process was developed by the Water Research Institute (WRI) of the Italian National Research Council.

Biological processes are said to offer the cheapest way to treat industrial wastewater but pollutants from industries such as leather, textiles and pharmaceuticals are not easily broken down by microbes. WRI scientists have reportedly developed a technology where the microbial biomass, which breaks down wastes, grows mainly as granules and the process is known as SBBGR (Sequencing Batch Biofilter Granular Reactor).

The granules are trapped in pores between plastic support material in a reactor and the microbes are stressed so less sludge is produced. This is because the microbes are not given suitable conditions to proliferate, so fewer microbes and less waste results.

Removing one kilo of wastewater through a biological system produces half a kilo of sludge, which then needs to be disposed of. This technology produces only 50g of sludge. A treatment plant using this technology could be 10 times smaller than usual.

Integrating ozone with the reactor allows effluents from leather and textile processing to be treated. Ozone is a powerful oxidiser and can break down most organic compounds. In the new system, ozone does not completely break down the pollutants but transforms them into more biodegradable compounds. This means less ozone is needed, reducing treatment costs.

At a pilot-scale facility for treating tannery wastewater, the final effluent from the process looked like tap water. In Italy alone, leather processing has a turnover of around €5bn (£4bn) — around 1,500 companies are involved and about 20,000 workers employed.

Sludge output in Europe is said to be on the rise; 5.5 million tonnes of dry solids came from plants in 1992, increasing to 10 million by 2007, and each tonne of dry solids costs between €350 and €750 to dispose of.

Ozone has also be used for direct sludge reduction in the activated sludge process by damaging the activated sludge and allowing it to be cannibalized by the rest of the biomass.

Read more: http://www.theengineer.co.uk/sectors/energy-and-environment/news/process-reduces-sludge-from-wastewater-treatment-plants/1012508.article#ixzz1vR13tLXF

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US Rivers Require Continued Environmental Protection

American Rivers today released its annual list of America’s Most Endangered Rivers. American Rivers named the Potomac River, known as ‘the nation’s river’ as it flows through the capital, the most endangered in the country. While the Potomac is cleaner than it used to be, the river is still threatened by urban and agricultural pollution– and it could get much worse if Congress rolls back critical clean water safeguards.

Before the Clean Water Act was enacted in 1972, the Potomac was highly polluted. As a result of Clean Water Act, the Potomac and rivers across the country are cleaner and safer for drinking, boating, and fishing.

American Rivers called on Congress to kill any legislation that weakens the Clean Water Act or prevents the Environmental Protection Agency and the U.S. Army Corps of Engineers from restoring protections for small streams and wetlands under the Act. American Rivers also called on the Obama Administration to finalize guidance clarifying the scope of the Clean Water Act and issue a rule-making to ensure that all waters get the protections Americans expect and deserve.

Ozone water treatment plays an important role in treating both wastewater that flows into rivers as well as treating the water for drinking that comes out of the rivers. Increased use of ozone as well as other advanced water treatment technologies can enhance river water quality and protect public health.

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Indian City Looks to Ozone Drinking Water Treatment

The Hyderabad Metropolitan Water Supply and Sewerage Board (HMWS&SB) is considering switching over to ozone water treatment from chlorination to improve water quality. Ozone is a more effective disinfectant and oxidant than chlorine and does not produce as many byproducts that have been found to be potentially damaging to human health. Ozone can also improve the aesthetics of the water by removing color, taste and odor compounds.

The Water Board supplies 340 million gallons per day (MGD) of water. The Water Board has proposed to use ozone technology to convert raw water into safe drinking water. Ozone is used extensively to treat drinking water in the US, Europe and Japan.

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MBR Ozone System for Water Reuse in Seafood Processing

Pescados Industrializados of Mazatlan, Mexico, a tuna cannery, has installed a new MBR system with down stream ozone treatment. The primary purpose of the MBR is to treat wastewater from the plant to comply with effluent regulations of the Mexican government. 30% of the effluent is further polished using ozone, AC, RO for reuse in the cannery. Ozone water treatment is used in this case to disinfect the water and provide partial oxidation of wastewater components. Removal of micro organisms protects the AC/RO units from biofouling. Ozone has been used extensively in wastewater disinfection because it does not form undesirable disinfection byproducts.

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