Over the years, water quality has noticeably deteriorated worldwide. This decline in water quality stems from the extreme demand on very limited natural resources. Various principles of filtration are used in many applications to improve the general quality of the water that is being treated. Along with screen filters, coagulation/filtration, neutralizing filters, oxidizing filters, clairifying filters and carbon filters are other treatment methods that may be used.
Various filter technologies stretch limited natural resources for drinking water
Most reverse osmosis systems waste as much as 20 gallons just to produce one gallon of product water. The new technology called "ZeroWaste" eliminates this problem by returning the concentrate water from the reverse osmosis system back to the home's plumbing, resulting in 100 percent efficiency.
The borough of West Mifflin, Penn., is a community located about nine miles southeast of downtown Pittsburgh. For years, the West Mifflin Sanitary Sewer Municipal Authority (WMSSMA) hauled liquid from its New England STP (a 1.2 mgd plant) to the Thompson Run facility (a 4.5 mgd plant), where it was processed on a belt press for dewatering. However, the hauling and associated labor proved very costly, and it was not always easy to coordinate dewatering schedules for both plants.
Additionally in the late 1990s, the WMSSMA faced a requirement to achieve higher cake solids and provide odor control that would respect nearby homes and businesses. Moreover, space constraints and staffing reductions necessitated a simple-to-operate installation.
No one wants to drink radium, nitrates or arsenic. However, if not for some technologically advanced methods of removing these contaminants, we all might be sipping on some very unhealthy water.
As the residential point-of-use (POU) reverse osmosis (RO) industry approaches its 35th anniversary, it is time for a reality check on the industry's progress to date as well as a look ahead to new technologies or improvements that the industry may introduce for POU RO systems in 2003.
Looking for Answers in 2003 and Beyond
While high concentrations of arsenic are found mostly in the Western region of the United States, parts of the Midwest and New England show levels of arsenic
that exceed the newly approved U.S. Environmental Protection Agency (EPA) standard of 10 parts per billion (ppb). Individuals not willing to wait for their water system's compliance with the arsenic standard currently are looking for treatment systems to use in their homes. POU and even point-of-entry (POE) treatment systems are an attractive solution for these individuals. The process should begin with a basic understanding of arsenic contamination and the element's chemistry, a complete water quality analysis of the application-specific water and the knowledge of available technologies.
Thanks to a new membrane filtration system, National Raisin Company, Fowler, Calif., not only has been able to cut its wastewater costs, but it also has opened up a potentially lucrative source of additional income.
Water works engineers are now turning to a new generation of pneumatic valve actuators that are capable of executing the instructions of electronic control systems with the necessary precision to accurately control effluent flow. Surprisingly simple but rugged in construction, this new breed of actuators also is meeting the need to reduce downtime, as some of the first ones to debut in 1981 are still in operation without needing a spare (new) part.
Reverse Osmosis - Anion-Filtration Water Plant Run by a Single Automation Platform with Fieldbus Communications
A new 3.0 mgd water treatment plant on North Carolina's Cape Hatteras is believed to be the first in the United States to apply Foundation fieldbus for device-level control communications. The plant, built by the Dare County Water Department near the famous Cape Hatteras Lighthouse, has been operating without a problem since startup more than two years ago. Fieldbus has been widely applied in all process industries including electric power generation, an industry also cautious to adapt new technology.
A study published as part of the EPA's Environmental Technology Verification (ETV) Program verifies the performance of a Fyne Process membrane filtration plant tested on high organic-laden surface water in Barrow, Ark. The plant was able to remove significant levels of organics--precursors to disinfection byproducts such as trihalomethanes (THM) and haloacetic acids (HAA)--producing water that easily met the disinfection byproduct standards set by the EPA's stringent Stage 1 D/DBP Rule.