Introduction
(Hi-Reduction) is a very simple yet efficient technique for reducing organic carbon and nitrogen in contaminated waters. Hi-Reduction involves treating organic-bearing wastewater with heat and a reducing agent such as sulfur dioxide (SO2). The heat and SO2 react chemically with organic-containing pollutants, and in the process, the pollutants are broken down into simpler forms such as inorganic carbon, nitrogen oxide, and water. The Hi-Reduction process has several advantages over other conventional and advanced pollutant removal methods including low operational and maintenance costs, relatively quick and efficient treatment, and superior removal of nitrogen, carbon, and other pollutants.
Background
The origin of Hi-Reduction is not known with certainty, but it is believed to have been developed as a result of research into wastewater treatment technologies from the 19th century, when a need for improved methods was realized. Hi-Reduction first gained public attention in the 1950s and 1960s, when it was widely adopted in municipal wastewater treatment systems. Since then, Hi-Reduction has been used in a variety of industrial processes, including drinking water, industrial wastewater, process water, pulp and paper, petrochemical, and food and beverage production.
Function and Mechanism of Operation
In the Hi-Reduction process, a reducing agent (generally SO2) is combined with heated wastewater in a reaction tank. The heat and SO2 react chemically with pollutants in the wastewater, resulting in the conversion of some of the organic pollutants into simpler forms such as inorganic carbon, nitrogen oxide, and water. The process of Hi-Reduction is relatively simple and cost-effective, and it results in superior removal of nitrogen, carbon, and other pollutants.
The mechanism of operation of the Hi-Reduction process can be broken down into three stages: first, the reaction between the SO2 and the contaminated wastewater; second, the oxidation and reduction of organic pollutants; and third, the release of oxidized or reduced products from the reaction tank.
In the first stage, the SO2 is injected into the wastewater, where it reacts with the organic pollutants and forms sulfite anions (SO32-) and hydrogen ions (H+). The sulfite anions are more reactive than the hydrogen ions and react more readily with the organic matter in the wastewater, forming carbonate anions (CO3 2-) and sulfide anions (S2-). In the second stage, the carbonate and sulfide anions are further oxidized or reduced depending on the reaction conditions. For example, if the reaction occurs in an aerobic condition, the carbonate and sulfide anions will undergo oxidation, generating carbon dioxide and hydrogen sulfide, respectively. On the other hand, if the reaction occurs in an anaerobic condition, both carbonates and sulfides will be reduced, generating inorganic carbon and nitrogen oxide, respectively. In the third stage, the oxidized or reduced products such as carbon dioxide, hydrogen sulfide, inorganic carbon, and nitrogen oxide are released from the reaction tank.
Advantages
The Hi-Reduction process has several distinct advantages over other conventional and advanced wastewater treatment methods. Firstly, Hi-Reduction is a simple and cost-effective process, and it requires minimal operational and maintenance costs. Secondly, it is a relatively quick and efficient treatment process, and it can reduce the levels of organic pollutants in wastewater by more than 90%. Thirdly, Hi-Reduction is generally superior to other techniques in removing nitrogen, carbon, and other pollutants from wastewater. Finally, Hi-Reduction does not generate any toxic byproducts or sludge, and it does not require any hazardous chemicals or energizing sources.
Conclusion
In conclusion, Hi-Reduction is a simple, cost-effective, and relatively quick technique for reducing organic carbon and nitrogen in contaminated waters. It has several distinct advantages over other conventional and advanced wastewater treatment methods, and it is generally superior to other processes in removing nitrogen, carbon, and other pollutants from wastewater. Hi-Reduction is a popular technique that is widely adopted in municipal and industrial wastewater treatment systems, and it holds tremendous potential as a successful tool for pollutant clean-up.
