Veolia Water Systems Offers Arsenic Removal Solutions

Saint-Maurice Cedex, France — Arsenic is a semi-metallic element occurring both naturally and as a result of human activities. Recent studies have shown that long-term exposure to arsenic causes skin disorders as well as internal organ cancers. Therefore, the WHO and USA EPA have lowered the standard maximum level of arsenic in drinking water from 50 to 10 ppb.

To address this growing concern in public health, Veolia Water Systems has developed several proven technological solutions adapted to a wide range of municipal and industrial applications, such as greenfield projects and upgrade or retrofit of existing treatment works. Since arsenic is often present among other contaminants, Veolia Water Systems offers combined solutions that remove arsenic as well as iron, manganese, heavy metals and micropollutants. Depending on the arsenic concentration in raw water, its chemical form (As III or As V) and the presence of other contaminants, Veolia Water Systems selects the most appropriate solution to meet each specific requirement. From standard solutions to tailor-made engineered systems, all technologies are fully compliant with the latest regulations and provide additional benefits including a small footprint, no sludge production, and easy maintenance.

• Filtraflo™ and Filtraflo™ As:
  Filtraflo™ filter is an advanced filtration solution where a coagulant, such as ferric chloride, precipitates arsenic within the filtration media (sand). This two-stage process is well adapted to remove high As V concentrations from raw water, with high turbidity.

  Filtraflo™ As is an innovative filtration process based on the adsorption of arsenic on granular ferric hydroxide. It removes both As III and As V from raw water containing low concentrations of arsenic (< 200 ppb) without chemical pre-oxidation. Noteworthy is the fact that there is no risk of residual iron.

  Both Filtraflo™ and Filtraflo™ As are ideal for medium to large treatment facilities. In existing plants, they can be easily installed downstream of the sand/dual media filters.

• Opafer™:
  Based on the Filtraflo™ As solution, Veolia Water Systems has also designed a range of small scale, compact, skid-mounted units. Having a short manufacturing lead time, the Opafer™ units are suitable for temporary or permanent use and can be adapted on site to meet different flow rates and arsenic concentration levels.

  This Opafer™ system does not require any cleaning or regeneration; only a simple loosening on a regular basis. Once saturated, the media is replaced to maintain treatment capacity and can be disposed of at special waste sites.

• Mangaflo™ Plus:
  The Mangaflo™ Plus process, patented since 2002, features a triple-media filtration system comprising of a bottom layer of manganese dioxide, a middle layer of sand and anthracite and a top layer of granular ferric hydroxide. It offers an innovative combined treatment solution, well adapted to As III and As V removal and suitable for variable concentrations of arsenic, iron and manganese. No chemical dosing, minimum sludge production and no risk of residual iron are some of its other benefits.

• Metclean™:
  The Metclean™ technology utilizes the adsorption process (typically on quartz sand granules), within a fluidised bed reactor, to remove a wide range of metals from solutions. Veolia Water Systems' experience includes As and Cd, Cr, Hg, Mo, Ni, Se, Zn, Cu, V, Ba and Sr.

  Treatment efficiency is as high as 99% in a one-process step, and the waste product resulting from the treatment is a granule with a dry solids content of 80-90%. The savings in waste disposal costs and the small footprint of the Metclean™ process make it a very cost-effective solution for several applications including potable water contaminated by arsenic and nickel, groundwater contamination due to leaching of metals, industrial effluents from metal treatment industries, wood preservation, tanning, and flue gas desulphurisation wastewater from power plants.

• Actiflo® / Multiflo™ Trio:
  The Actiflo® and Multiflo™ Trio technologies treat high concentrations of arsenic (500 – 2 000 ppb) with other heavy metals. They are based on enhanced coagulation and flocculation, using a proprietary system (Turbo Mix™) to optimise chemical dosing, mixing and floc formation. This first stage is either combined with lamella settling and sludge recirculation (Multiflo™ Trio), or followed by ballasted floc settling (Actiflo®).

  In the Multiflo™ Trio streamlined process, sludge recirculation optimizes chemical dosing and further improves sludge settling and thickening. This is a robust and proven technology that is easy to build and operate. It is suitable for removal of suspended solids and color, as well as for softening.

  The unique features of Actiflo® is the use of microsand as a floc ballast, which is permanently recycled, providing the following additional benefits: very large contact surface area enhancing the coagulation/flocculation, further improved by the Turbo Mix™; unrivalled hydraulic load (up to 70 m/hr), leading to very short retention time and extremely compact solutions; strong buffer capacity, providing flexibility in terms of raw water variability as well as rapid start-up and shut-down sequences.

SOURCE: Veolia Water Systems