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المحاضرة 3-2

الكلية كلية الهندسة     القسم  الهندسة البيئية     المرحلة 4
أستاذ المادة محمد عبد مسلم عبد الله الطفيلي       04/07/2018 08:40:27
SECTION - 5 (WASTEWATER TREATMENT)
(CHEMICAL UNIT PROCESSES)

Those processes used for the treatment of wastewater in which change is brought about by means of or through chemical reactions are known as chemical unit processes. In the field of wastewater treatment, chemical unit processes usually are used in conjunction with the physical unit operation and the biological unit processes.


ROLE OF CHEMICAL UNIT TREATMENT PROCESSES
The principal chemical unit processes used for wastewater treatment include:
1. chemical coagulation
2. chemical precipitation
3. chemical oxidation
4. chemical neutralization

APPLICATION OF CHEMICAL UNIT PROCESSES
Applications of chemical unit processes for the management and treatment of wastewater are reported in Table N-1.




FUNDAMENTAL OF CHEMICAL COAGULATION
Colloidal particles found in wastewater typically have a net negative surface charge and its state of hydration. The size of colloids (about 0.01 to 1 ??m) is such that the attractive body forces between particles are considerably less than the repelling forces of the electrical charge. Under these stable conditions Brownian motion keeps the particles in suspension. Brownian motion (i .e. random movement ) is brought about by the constant thermal bombardment of the colloidal particles by the relatively small water molecules that surround them.
Coagulation is the process of destabilizing colloidal particles so that particle growth can occur as a result of particle collisions.

The term "chemical coagulation" includes all of the reactions and mechanisms involved in the chemical destabilization of particles and in the formation of larger particles, through flocculation process (aggregation of particles in the size range from 0.01 to 1 ??m.
The term flocculation" is used to describe the process whereby the size of particles increases as result of particle collisions.


المادة المعروضة اعلاه هي مدخل الى المحاضرة المرفوعة بواسطة استاذ(ة) المادة . وقد تبدو لك غير متكاملة . حيث يضع استاذ المادة في بعض الاحيان فقط الجزء الاول من المحاضرة من اجل الاطلاع على ما ستقوم بتحميله لاحقا . في نظام التعليم الالكتروني نوفر هذه الخدمة لكي نبقيك على اطلاع حول محتوى الملف الذي ستقوم بتحميله .