Sigma offers a range of chemical treatment systems. All systems are specific to the application and may comprise of a variety of systems such as:
o pH Adjustment System
o Chemical Dosing Systems
o Coagulation & Flocculation Systems
o Electro Coagulation
pH adjustment is provided in the event there are variances in the inlet feed water quality. A pH controller automatically regulates the pH in a pH adjustment tank. The pH shall be adjusted to optimum effectiveness for coagulation & flocculation process. A acid/caustic pump, automatically pumps the chemical based on a preset value of the pH desired programmed in the controller. An inline or submersible pH probe will sense the pH of the water/wastewater and relay it to the controller, which then proportionally controls the acid/caustic dosing pump.
Following pH adjustment, coagulant and flocculent injection is practiced. In the precipitation process, chemical precipitants, coagulants, and flocculants are used to increase particle size through aggregation. The precipitation process can generate very fine particles that are held in suspension by electrostatic surface charges. These charges cause clouds of counter-ions to form around the particles, giving rise to repulsive force that prevent aggregation and reduce the forces of the particles. Sigma uses tailor made organic coagulants and flocculants that are non-sensitive to pH and very effective at low dosages. Generic coagulants and flocculants are also used in several applications.
In certain applications, Pre-oxidation of refractory organics may be required. Polyphenolics such as the tannins and similar multi ring compounds are stable complex structures. This makes it a difficult candidate to break down. Cleaving the rings of the functional benzene rings will provide broken down simpler organic compounds that are easier for the biological microorganisms to use as a substrate. Strong oxidant such as hydrogen peroxide shall be used to provide the high oxidation potential. A relatively small amount of peroxide can cleave organic molecules, reducing toxicity to acceptable levels, or making the molecules more easily managed. Using a catalyst in a favorable pH range dissociates the hydrogen peroxide forming the hydroxyl radical, which has twice the oxidation potential compared to oxidants such as chlorine. A proprietary catalyst blend is used by Sigma to perform advanced oxidation. Partial oxidation of organic contaminants results in more polar (charged) substances which are more amenable to adsorption onto coagulants and flocculants.