Water and Wastewater Treatment: Historical Perspective of Activated Carbon Adsorption and its Integration with Biological Processes

Activated carbon is broadly defined to include a wide range of amorphous carbonbased materials prepared in such a way that they exhibit a high degree of porosity and an extended surface area [1]. Moreover, all non-carbon impurities are removed and the surface is oxidized. Although today the term ‘activated carbon’ is taken for granted, a long time elapsed before it became generally adopted. The use of activated carbon in its current form has only a short history. On the other hand, according to records, the use of carbon itself dates back to ancient times. The earliest known use of carbon in the form of wood chars (charcoal) by the Egyptians and Sumerians was in 3750 BC [2]. At that time, charcoal was used for various purposes such as reduction of ores in the manufacture of bronze, domestic smokeless fuel, and medicinal applications [3]. In Egyptian papyri dating from 1550 BC we find the first citation of the use of charcoal for the adsorption of odorous vapors – from putrefying wounds and the intestinal tract. The ancient Greeks used charcoal to ease the symptoms of food poisoning [4]. The beneficial effect was due to the adsorption of the toxins emitted by ingested bacteria, thereby reducing their toxic effects. Hindu documents dating from 450 BC refer to the use of sand and charcoal filters for the purification of drinking water. Recent studies of the wrecks of Phoenician trading ships led to the discovery that drinking water was stored in charred wooden barrels in order to keep the water fresh [4]. In the time of Hippocrates (ca. 460 –370 BC) and Pliny the Elder (AD 23–79) wood chars were employed for medicinal purposes [5]. In about 157 BC carbons of vegetable and animal origin were applied in the treatment of many diseases [2]. A Sanskrit text around 200 AD recommends the use of filtration of water through coal after storing it in copper vessels and exposing it to sunlight, providing probably one of the earliest documents describing the removal of compounds from water in order to disinfect it [6].