Arsenic

Arsenic is naturally distributed throughout the Earth's biosphere. It enters drinking water supplies from natural deposits in the earth or from agricultural and industrial practices. Consumption of arsenic contained in water and food is very dangerous to human health. According to study by the National Academy of Sciences, arsenic in drinking water causes bladder, lung and skin cancer, and may cause kidney and liver cancer. The study also found that arsenic harms the central and peripheral nervous systems, as well as heart and blood vessels, and causes serious skin problems. It also may cause birth defects and reproductive problems.

In order to protect consumers served by public water systems from the effects of long-term, chronic exposure to arsenic, the U.S. Enviromental Protection Agency estalished higher arsenic standard for drinking water at 10 parts per billion (from 50 ppm since 1942). As result of that, water systems must comply with this standard since January 23, 2006, providing additional protection to an estimated 13 million Americans.

The new EPA arsenic standard, sets new challenges before water systems , especially the small operator of a ground water well site. In many of these cases, the water is pump directly from the gound to the serving water tanks and water distribution systems. These systems will now require water treatment solution. Whether you need small water treatment plant or media absorbtion equipment, ORCA Water Technologies can find the right solution for you.

Arsenic Removal Solutions Offering Large System Technology at Small System Affordability

Where there is Arsenic in water, there are usually other contaminants.  ORCA's experienced personnel know how to evaluate treatability options based on the specific characteristics of your well.
We provide state-of-the-art network and data processing technologies to keep our customers in touch with the their water systems. Let us find the best solution for you...

Technology Complete Automation Remote Access Real-time Data Collection and Monitoring Alarm Notification On-line Technical Support INTERNET, LAN, modem lines Mobile Device Interface Analysis of Historic Trends

Applications Arsenic Removal TOC Removal Turbidity Removal Radium Removal Iron Removal Manganese Removal Color Removal

Coagulation for Arsenic Removal

Coagulation and precipitation of arsenic using iron as a coagulant is a well-known basic technology for arsenic removal. Various forms of iron (e.g. ferric chloride) are added to water, and the pH is adjusted to an optimal level to form iron floc. As part of the coagulation process, arsenic is co-precipitated with the iron. The mixing process helps to build the floc into larger particles that can then be removed by various forms of particle removal (settling, filtration etc.). Some equipment trains use flocculation tanks and clarifiers with or without post filtration to remove the precipitated iron and arsenic particulate. Other process trains use only chemical coagulation, mixing, and media filtration. The KEMLOOP process is based on chemical coagulation, a proprietary mixing loop to optimize the coagulation process, and granular media filtration with no intermediate solids separation process.

It is widely accepted in the scientific community that the precipitation of arsenic (V) with iron or similar coagulants is readily removed by this process, while arsenic (III) is not removed as easily to the low concentrations required to meet drinking water regulations. Water that contains arsenic (III) is often pre-treated with an oxidization step to convert the arsenic (III) to arsenic (V).

How ORCA KEMLOOP Filtration System Removes Arsenic?

The KEMLOOP system uses chlorine (fed as calcium hypochlorite) as a pretreatment step to to oxidize any arsenic (III) to arsenic (V), and iron present in the water supply. A solid contact chlorinator designed to use calcium hypochlorite tablets is incorporated in the standard treatment system or chemical pump feeding liquid chlorine. Total residual chlorine is targeted to a range of 0.5 to 1.0 mg/L. Ferric chloride is added to augment the naturally occurring iron in the groundwater and optimize the iron dose. The typical target range is 1.5 to 3.0 mg/L of iron. The actual dose is optimized during startup/shakedown testing. Sulfuric acid is added, if needed, to adjust the pH to an optimal level, as determined during shakedown testing at the site. This chemically treated water (feed water) enters the "mixing loop", which is unique in the KEMLOOP treatment system. This mixing loop consists of approximately 200 feet of 2.5 inch PVC pipe.

The chemically treated water flows through the mixing loop, where precipitation and coagulation of the iron and arsenic occurs without the need for a separate mixing tank. The coagulated water exits the mixing loop and is applied directly to one of the two-granular media filter modules. The water enters the top of the operating filter and flows through the granular media filter, exiting at the bottom of the module. The granular media filter removes the precipitate, including arsenic, iron, and any other precipitated constituents. The two filter module system operates with the filters in parallel, one filter module is in active operation, and one unit is in standby mode. When backwash of a filter module is required, the standby filter is brought on line, and the backwash cycle for the "dirty" filter module is initiated. Once the backwash cycle is complete, the clean filter module becomes the standby unit.