Comparison of corrosivity of polymeric sulfate ferric and ferric chloride as coagulants in water treatment

Abstract

CHAPTER 1. INTRODUCTIONElectrical power is the backbone of modem society. Most power is generated by using coal combustion as the primary source of heat. Coal contains sulfides, which are oxidized into various sulfur oxides during combustion, mainly sulfur dioxide (S02). S02 Emission ReductionThe Clean Air Act (CAA) Amendments of 1990 require substantial reductions in power plant S02 emissions for control of acid rain [ 1]. As a result from this strict restriction on S02 emission, it is necessary for the power plants to resort to clean coal technologies that are superior to the technologies in common use today. 1These technologies can be new combustion processes -such as fluidized bed combustion -that allow removal of pollutants, or prevent them from forming, while the coal bums. Also, they can be new pollution control facilities -like advanced scrubbers -that clean pollutants from flue gases before they exit a plant's smokestack. Other clean coal technologies can convert coal into fuel forms that can be cleaned before being burned. For example, a clean coal plant may convert coal into a gas that has the same environmental characteristics as clean-burning natural gas. Typical S02 reduction measures are introduced as follows: Fluidized Bed with Sorbent AdditionFluidized-bed combustion (FBC) system bums coal in a fluidized bed in the presence of chemicals such as limestone or dolomite, to facilitate the capture of S02, while the conventional boilers only simply bum coal. Two kinds of FBCs, atmospheric fluidized-bed combustion (AFBC) and pressurized fluidized-bed combustion (PFBC), have already been

Feasibility investigation of oily wastewater treatment by combination of zinc and PAM in coagulation/flocculation

“…However, these inorganic coagulants are easy to form smaller flocs with low settling speed. In addition, the corrosive coagulants usually result in a large amount of hazardous sludge with residual metal, and increase the treating load [12]. The organic polyacrylamide has the excellences of lower dosage and rapid settling speed for flocs, but with limited effect by oneself [13,14].…”

Effective Removal of Microorganisms and Biostimulants of Wastewater by the Application of Various Electrolytes

“…However, there are special challenges to using ferric chloride. Corrosion is one of the associated disadvantages of ferric chloride [20,21]. Aluminium on the other hand in the natural bodies such as ponds and lakes does not reach values likely to have a big impact on the biodiversity.…”

Preparation of a novel inorganic polymer coagulant from oil shale ash

“…However, the formation of metal hydrolysis species of them is uncontrolled, and the dose of the coagulant is large. To avoid the drawbacks and improve the coagulation efficiency, several polymer inorganic coagulants have been developed, such as poly-aluminum sulfate, poly-ferric sulfate and poly-aluminum chloride [13][14][15][16][17], and moreover, the coagulation performance of polymer inorganic coagulants is generally better than that of conventional coagulants in the same dosage and a similar pH value. Both iron and aluminum-based coagulants have obviously merits and demerits for water and wastewater treatment.…”