Importance of a Dosing Pump in a Water Treatment Plant

Water Treatment Plant

Pumps are an integral part of any industrial plant. Manufacturing plants usually have different kinds of pumps in use in almost all aspects of the manufacturing process. These include those pumps which bring water to a specific equipment, where a liquid has to be filtered, and where cleaning has to be done. Industrial pumping equipment is also used to deliver exact measurements of chemicals or components to a liquid.

Mixing Exact Doses

There are different types of mixing processes. There are tubs of solid ingredients mixed together in batches, or where thick viscous fluids are combined in a giant mixer. There are also some liquids which have to mixed while they flow in and out of a large tank. These require a constant measurement of liquid flow, along with an a consistent inflow of another liquid, measured precisely to maintain a constant ratio.

One of the most common use of a dosing pump is in a sewage treatment plant. The sewage flows continuously throughout the day. While it flows in, it is measured, and at the same time, chemicals are also measured and added to the flow of water, going to the tanks. The dosing pumps have pistons inside which control the amount of mixture being added to the flow. For operational purposes, there are two sets of pumps for each treatment plant. This redundancy allows one pump to take over when the other pump is under maintenance or repair.

Feeding the Chemicals

Man checking pump
For water treatment plants, the inflow and chemical feeds are not constant over the course of a day. The water inflow is usually slower at night, which would necessitate less chemicals used. The pumps are programmed to deliver less chemicals into the stream when the inflow is less. The dosing pump has to measure the chemicals exactly and dole out what is needed. The whole procedure makes use of automated controls built into the system, or it is part of the pump assembly.

The dosing chemicals ensure help to clean the water in several ways. It balances the pH levels, and can remove impurities. Phosphates in the water can induce algal bloom, which inhibits the amount of sunlight entering the water. Algae also uses up the oxygen in the water and lowers the its nutrient qualities, which can affect livestock drinking from the stream.

Chemical dosing is important as not all pollutants are cleaned with the use of filter beds. These are designed to trap solids, however, there are sediments which remain with the water, keeping it dirty. In addition, the filter beds cannot be cleaned and discharged without first being treated. The solids and sludge it traps are poisonous and harmful to aquatic life.

The pump capacity is measured against the peak requirements. The dosing increases as needed when the water flow is faster with heavier volume during the daytime. The dosing pump has to keep up with the demand. The water flow results in a diurnal cycle for the dosing pump as well.

Pumps and equipment are designed to fit the needs of the treatment plants. The variable water flow, and the constant adjustment in chemicals can be calibrated and automated with the use of measuring equipment and sensors. Dosing pumps help ensure that the proper mix and quantity of chemicals are used in a treatment plant. Other plants which require continuous flow mixing also use these pumps and methods.