The water quality standards used in agricultural irrigation are different from those for drinking water. Generally speaking, agricultural irrigation water does not need to meet the high standards of drinking water, but it must meet the growth needs of crops and cannot cause adverse effects on soil and plants.

At present, the coagulants used in the market are mainly divided into three categories: inorganic coagulants, organic coagulants and polymer coagulants. Each type of coagulant has its own unique chemical properties and application scenarios.

The top five famous water treatment plants: 1. Tokyo Water Treatment Plant (Japan), 2. Singapore NEWater Plant (Singapore), 3. London Thames Water Treatment Plant (UK), 4. New York Brooklyn Water Treatment Plant (USA), 5. Abu Dhabi Sulaibiya Water Treatment Plant (UAE).

The main types of water treatment plants are: 1. Drinking water treatment plants, 2. Sewage treatment plants, 3. Industrial water treatment plants, 4. Seawater desalination plants.

According to the lowest and highest costs, the total cost of building a small water treatment plant is about 170,000-485,000 US dollars. If operation and maintenance costs are taken into account, the total expenditure in the first year will increase to between $270,000 and $630,000.

The prices of aluminium sulfate (alum) and polyaluminium chloride are relatively low and suitable for large-scale applications. Although polyacrylamide (PAM) has a good flocculation effect, it is more expensive and is suitable for scenarios with high requirements for flocculation effect volume.

According to the Indian Water Works Association (IWWA), the cost of building a medium-sized drinking water treatment plant (with a daily processing capacity of 100,000 cubic meters) is approximately between 5 billion and 7 billion Indian rupees (approximately US$67 million to US$94 million).