There are two different types of water; they are: soft water and hard water.
Treatment of hard water: this often seen in ground water. The hardness of water is caused by the presence of calcium and magnesium ion in water. The hardness of water can be done by addition of calcium hydroxide or ion exchange process. In ion exchange process, hard water is reduced to the minimum.
BASIC WATER treatment process
These include processes that help to achieve water treatment. These treatment processes include: biological, physical and chemical process. The most common processes include; both chemical and physical processes. Biological is employed in the treatment of waste water; (This is applied in the recycling of used industrial water). Pathogen removal from portable water is done by slow sand filtration. Also, biological activated carbon process is biological process use in removing organic contaminants from portable water. pollution of water
The chemical process in water treatment include: oxidation, coagulation and disinfestations.
The physical processes include: flocculation, sedimentation, filtration, adsorption and ultra-violet light dis-infestations. These processes depend on the type of contaminant to be removed.
Oxidation: chemical oxidation is used in water treatment to remove inorganic contaminants. The contaminants exist as ions in water. They include: iron (ii) ion (Fe2+), manganese ion (Mn2+) and arsenic ion (As3+).
This aids in removal of particles by coagulation. The chemical used in this process is called OXIDANT. The most widely used oxidants are; chlorine and potassium permanganate. They are deposited as granular substances for dissolution. When air or oxygen is used; ozone is formed in the process. The selection of oxidant depends on the type of process requirement, cost, chemical safety and operational complexity.
Coagulation: in the dissolution of substances in water; some substances don’t dissolve easily. Therefore, the process of decreasing the stability of colloids is known as coagulation. This is exhibited by most organic and inorganic compounds suspended water. They tend to increase the turbidity of water. These are called colloidal materials. Due to the electrical charges colloidal materials have on their surface; they tend to settle for a longer time.
Coagulation is done by adding salts and cationic polymers to the water.
Disinfection: this process is use in the removal of pathogens in water. These pathogen causes water borne diseases. This is in contrast to sterilization. Sterilization is the total killing of the pathogen. The effectiveness of disinfection is by testing of the presence or absence of Coliform bacteria. Coliform bacteria are not pathogenic but a good indicator of contamination. Most times, chlorine is considered an effective disinfectant due to the kind of residues it produces. Note: a residual distribution system helps to prevent re-growth of microbes.
Sedimentation and clarification: clarification of water involves contaminant removal by gravity sedimentation. The most important types of clarifiers’ uses in this process are: gravity sedimentation, up-flow sludge blanket and down flow contact clarification.
Filtration: this is the process of removing particles from solvents. Direct filtration is a conventional system without a clarifier. This is employed in treating high quality water source; having low turbidity and organic contaminants. For low contaminant loading on filters, an up-front process is required. Filtration can be at constant pressure system and constant volume system.
Pressure filtration system is raw material is fed into a gravity filter. This kind of system can be design to contain two filters, a static mixer and piping design. This facilitates flocculation.
Slow sand filtration: this is used by some firms to remove the turbidity and micro-organisms. A slow and sand filter is consisting of filter bed of sand that is few inches deep. The bed is placed over a drainage system to remove contaminants.
Adsorption: this is the accumulation of gases on the surface of solid. This means that the accumulated materials can still be removed from the surface of solid by some reaction types of reaction. These solid materials are called adsorbent. Example of adsorption is the catalysis of dehydrogenation of alkenes to alkanes. Examples of adsorbents includes, metal oxides, activated carbons, aluminum and many more.