Self Evaluation Quiz - Water Treatment Processes

Explanation
Coagulation is the correct answer because it refers to the process of destabilizing colloidal particles by charge neutralization in water treatment. During coagulation, chemicals known as coagulants are added to the water, which neutralize the charges on the colloidal particles and cause them to come together and form larger, more easily settleable particles called flocs. This process helps in the removal of impurities and suspended particles from the water, making it clearer and safer for consumption.

Explanation
Slow sand filtration is a water treatment process that uses naturally occurring biological activity to clean drinking water. In this process, water is passed through a bed of fine sand, where microorganisms present in the sand help to remove impurities and pathogens from the water. The sand acts as a physical filter, while the microorganisms in the biofilm on the sand surface break down organic matter and help to remove bacteria and other contaminants. This natural biological activity makes slow sand filtration an effective and sustainable method for water treatment.

Explanation
The purpose of screening during water intake for treatment is to protect pumps and conduits from blockage. Screening helps to remove large debris and particles from the raw water, preventing them from entering the pumps and conduits and causing blockages. This ensures the smooth flow of water through the treatment system and prevents damage to the equipment. Removing odour-producing compounds, preventing scaling and corrosion, and removing disease-causing organisms are also important objectives in water treatment, but they are not directly related to the purpose of screening during water intake.

Explanation
Aeration is a process that involves introducing air into water to increase the oxygen content. It is primarily used to enhance the biological processes in water treatment systems. However, aeration does not remove solids from water. Instead, it helps to oxidize dissolved metals and volatile organic compounds, and also aids in the removal of certain gases. Therefore, aeration is not an effective method for removing solids from water, unlike filtration, sedimentation, and screening, which are specifically designed for this purpose.

Explanation
Plain sedimentation refers to the process of settling of particulate matter in water without the use of chemicals. It is a natural process where the solid particles in water, such as sand, silt, and clay, gradually settle down due to gravity. This process occurs when the velocity of the water decreases, allowing the particles to settle at the bottom. Plain sedimentation is commonly used in water treatment systems and is an important step in the removal of suspended solids from water.

Explanation
The World Health Organisation (WHO) is not responsible for establishing drinking water standards for public health protection worldwide. Instead, it provides guidance and recommendations on water quality and safety, but the responsibility for setting and enforcing drinking water standards lies with individual countries or regions.

Explanation
The given statement is false. In water treatment, the characteristics of raw water are indeed considered before selecting a treatment method. The quality and composition of the raw water, including its pH level, turbidity, presence of contaminants, and other factors, play a crucial role in determining the appropriate treatment method. Different treatment processes such as filtration, coagulation, disinfection, and others are chosen based on the specific characteristics of the raw water to ensure effective and efficient treatment.

Explanation
In a conventional water treatment plant, the range of unit processes and operations is typically arranged in series. This means that the water flows through each unit process one after the other, with each process addressing a specific aspect of water treatment. This arrangement ensures that the water undergoes multiple treatment steps, such as coagulation, flocculation, sedimentation, filtration, and disinfection, in a sequential manner. By arranging the processes in series, the treatment plant can effectively remove impurities and contaminants from the water, making it safe for consumption. Therefore, the statement is true.

Explanation
Intake structures for water treatment are not always required to operate under gravity to reduce cost. In some cases, it may be more cost-effective to use pumps or other mechanical means to move water into the treatment facility. The choice of whether to operate under gravity or not depends on various factors such as the location, topography, and available resources. Therefore, the statement that intake structures for water treatment are always required to operate under gravity to reduce cost is false.

Explanation
A floating or pontoon type intake structure for abstracting raw water can be classified as a variable intake structure because it can be adjusted or moved to different locations depending on the water conditions and requirements. This allows for flexibility in the intake process and ensures that the structure can effectively capture water from different depths or areas as needed.