Organic matter makes up a significant part of the soil, therefore water-soluble organic compounds are present in all water supplies. Organic matter is reported on a water analysis as carbon, as it is in the TOC (total organic carbon) determination. The following is a list of organics, which regulated under the Safe Drinking Water Act of 1986.
Polynuclear aromatic hydrocarbons (PAH)多环芳烃
Polychlorinated bi phenyls (PCB)多氯联苯
Ethylene dibromide (EDB)二溴化乙烯
Organics come from three major sources: (1) the breakdown of naturally occurring organic materials, (2) domestic and commercial chemical wastes, and (3) chemical reactions that occur during water treatment processes. The first source is comprised of humic materials, microorganisms, and petroleum-based aliphatic and aromatic hydrocarbons. Organics derived from domestic and commercial chemical wastes include wastewater discharges, agricultural runoff, urban runoff, and leaching from contaminated soils. Organic contaminants formed during water treatment include disinfection by-products such as THM抯 (Trihalomethanes), or undesirable components of piping assembly such as joint adhesives.
Activated carbon is generally used to remove organics, color, and taste-and-odor causing compounds. The contact time and service flow rate dictate the size of the carbon filter. When removing organics, restrict flow rates to 2 gpm per square foot of the filter bed. Reverse osmosis will remove 98 to 99% of the organics in the water. Ultrafiltration (TJF) and nanofiltration (NF) have both been proven to remove organics. Anion exchange resin also retains organics, but periodically needs cleaning.