How to Remove Lead from Water
Civilizations have used lead for industrial purposes for centuries. While it is a durable metal, it is also flexible at low temperatures. These characteristics were ideal for shaping everything from pipes to plates in the Roman Empire. Ingesting lead poses dangerous health risks. In children, low-level lead poisoning can cause stunted growth and learning disabilities. High concentrations of this heavy metal may result in kidney failure, high blood pressure, and cognitive issues in adults. For this reason, the 1974 Safe Drinking Act states that there is no safe level of lead in the public water supply. Therefore, industries need to understand how to remove lead from water.
Lead and Industrial Water
Many industries use lead during production processes. The metal is part of the creation of glass, ceramics, circuit boards, and batteries. Manufacturing plants often release water as a byproduct of their operations. If this water contains lead, the plant must consider the proper industrial water treatment solution for its situation.
The EPA divides water-discharging industrial plants into two categories. Direct dischargers are plants that send effluent directly into local waterways. Indirect dischargers send their water to water treatment plants. In either case, the company must decide how to remove lead from water.
Common Forms of Industrial Water Treatment
Even companies that release their water to treatment plants will typically need lower lead levels before discharging it. Factors such as initial lead levels, water temperatures, and pH levels affect the abilities of standard removal techniques. Other considerations for adopting a lead treatment solution include cost and water volume.
Chemical precipitation is a frequent pre-treatment for lead removal. Adding a fundamental solution to increase the pH draws some of the dissolved lead out as a precipitate. The factory can then remove the solid lead compound through sedimentation or a filtering process. While this process is relatively inexpensive, it will not altogether remove the metal. After precipitation, the industrial water will require further treatment to reach safe levels.
In adsorption, water flows through a substance chosen for its ability to draw out lead ions. Activated charcoal and biomass are effective solutions for pulling ionic lead out of a solution. For most industrial sites, adsorption provides an economical water treatment option. However, manufacturing processes that produce high lead levels may find frequent media changes inconvenient and expensive.
Lead ions carry a positive charge. An ionic exchange treatment uses this property to capture the contaminant. Water streams pass over a polymer resin that contains anionic chemical groups. These negatively charged ions bind the lead. After the treatment, lead levels in the water are often low enough for safe discharge. As with adsorption, factories with high lead levels may find the cost of frequent resin renewal prohibitive.
Advances in material science have developed physical techniques for filtering lead from water. Pressurized water passes through membranes with specially designed pores. These small openings block lead ions and divert them in a separate stream. Running water through a series of membranes will reduce the lead count to acceptable levels without adding extra chemicals to the water stream. Factories that use this technique can produce clean effluent, but they will also have to deal with the reject stream with an even higher lead concentration.
As the world looks for freshwater sources, researchers have discovered new applications to desalination techniques. In electrodialysis, water enters a porous material. An electric wave then creates streams of clean water and contaminated water. The plant can discharge the treated water and collect the toxic stream for disposal. This technique is in its early stages, but it may provide another economical means for filtering lead from water.
Monitoring Industrial Water Treatment Solutions with SCADA
At High Tide Technologies, we specialize in designing and implementing SCADA solutions for water collection, treatment, and distribution systems. In an industrial setting, SCADA sensors can provide data about contaminant levels before and after treatment. This knowledge offers an advanced warning about changing a treatment’s substrate material and insight into the treatment’s effectiveness. For more information about the benefits of a SCADA system, contact us today.