Ever since granular adsorbent media such as bone char and granular activated carbon (GAC) replaced powdered activated carbon (PAC), the amount of air in a bed of dry GAC has adversely affected the performance of many adsorption systems. Too many operators of liquid phase adsorption systems are unaware of this property.
Addressing air in the bed of dry GAC
ParaGuard silver-impregnated powder-activated-carbon pleated cartridges offer high flow rates, efficient filtration and high dirt-holding capacity. They reduce chlorine, viruses, bacteria, cysts, volatile organic compounds, disinfection byproducts, endotoxins, natural organic matter and other sub-micron particles. Standard and custom sizes are available.
Activated carbon (AC) is a common component in many water treatment devices. It removes a wide variety of organic-based contaminants, as well as some inorganic contaminants such as free chlorine and monochloramine. It is common to use AC ahead of reverse osmosis and ion exchange resins to prevent oxidation and organic fouling and to decrease maintenance frequency.
Activated Carbon Properties
Activated carbon properties determine filtration performance
In 1986, California voters approved an initiative to address growing concerns about exposure to toxic chemicals. That initiative became the Safe Drinking Water and Toxic Enforcement Act of 1986, better known Proposition (Prop) 65. The act requires the state to publish a list of chemicals known to cause cancer, birth defects or other reproductive harm. This list, which must be updated at least once a year, has grown to include approximately 800 chemicals since it was first published in 1987.
Aiming for Arsenic
Preemptive testing can prevent costly penalties in California
Many adverse ecological effects have been attributed to pharmaceutical and personal care products (PPCPs) and endocrine-disrupting compounds (EDCs), but it is not clear what risk they pose to human health. In the past, water was known to contain these chemicals, but the exact amount was difficult to quantify. Recently, these chemicals have gained much more attention.
Treatment solutions for chemicals affecting human health
Activated carbon is commonly used in point-of-use (POU) and point-of-entry (POE) water applications. Activated carbon is predominantly used to remove organic-based contaminants and inorganic contaminants like free chlorine and monochloramine from water. Other water treatment processes such as reverse osmosis or ion exchange are better suited for other inorganic chemicals that may be present in water.
Factors impacting contaminant removal
As more companies tout “green” and eco-friendly products, Dennis Roberts of Filtrex Technologies, along with other industry insiders in the Water Quality Assn. (WQA) task force, take on the complicated challenge of creating green product standards.
Controlling VOC contamination with activated carbon
At this point, many of you probably have learned that the U.S. Department of Commerce (DOC) has announced a significant preliminary increase of anti-dumping duties on steam-activated carbon imported from China. Domestic manufacturers can expect to see duties increase from 4.8% to as much as 14 to 228%.
Following the announcement, U.S. Customs and Border Protection will require importers to post a deposit in the amount of the duties.