Facts about Lead In Drinking Water

 

  • The EPA Action Level for Lead is 15 parts per billion (PPB)
  • You can NOT see, smell or taste lead in drinking water.
  • Your skin does not absorb lead while bathing or washing
  • Boiling water does NOT reduce lead content
  • The mechanism of lead removal from water is with filtration, ion exchange or a combination in most applications.
  • Homes / buildings built before 1986 are more likely to have lead pipes, fixtures and solder. If your house is of this age you should remove the aerator from all faucets (every 3 months) and clean out any metal particles that may be present.
  • More lead leaches from hot water plumbing than cold water plumbing
  • Corrosion is the main cause for lead leaching into drinking water from the sources stated below. Corrosion in water is a dissolving or wearing away of metal caused by a chemical reaction between water and plumbing. In order to keep corrosion in check requires that the pH of the water to be  7.0 or above (no higher than 8.5). There should be some alkalinity in the water to hold the pH stable.

Where does Lead in Drinking Water Come from?

  • Lead can be found in some brass or chrome-plated faucets.
  • Water pipes constructed of lead.
  • Connection water line from the city supplied water main to the house piping.
  • Corrosion of older fixtures
  • Solder used to join the plumbing

Factors that affect the amount of lead found in drinking water are:

  • The chemistry of the water (acidity and alkalinity) and the types and amount of minerals in the water source (pH  level)
  • The amount of lead the water comes in contact with.
  • The temperature of the water.
  • The amount of wear in the pipes.
  • How long the water stays in the pipes.
  • The presence of protective scales or coating inside the piping and plumbing materials.

Corrective Actions for Reducing Lead in Drinking Water

  • Remove lead pipes, lead fixtures and lead solder present in the water delivery system.
  • Maintain a proper range of pH (between 7.0 and 8.5) to address any corrosion issues found in the water delivery system to all points of use. Coating the water delivery system with a phosphate designed for water treatment is one example.
  • Install a point of use treatment device to remove the lead.     

WATER TREATMENT FOR THE REMOVAL OF LEAD

Important Message

Most jug style water filters are ineffective in lead removal. Most of these devices use loose granular activated carbon which is not designed for removing Lead. Some jug water filters do use a activated carbon block that contains ion exchange resin (should be NSF rated) which can reduce the lead level in drinking water.

Effective Treatment Technologies for Lead Reduction

Reverse Osmosis (RO)

Treatment Removal: Membrane technology separates the bad ions from the good ions based on the size of the contaminates. Most RO membranes remove down to .001 micrometers in size. All bad ions are send to drain. 

Advantages
  • Reduces lead by 96 to 98%
  • Only treatment that provides a physical barrier ( membrane) between the lead and consumer
  • Remove many other types of contaminates along with lead
Disadvantages
  • Higher initial cost compared to other treatment media’s
  • 25% to 35% of  the water being treated is rejected to drain. The RO waste water would most likely require treatment to collect the rejected lead from the waste stream .     

Ion Exchange Resin (Strong Acid Cation Resin)

Treatment Removal: The mechanism of lead removal is by ion exchange which can only remove soluble lead. This is because lead carbonate is virtually completely insoluble and almost all water supplies contain at least some alkalinity which can liberate carbonates from the water. 

Advantages
  • Can reduce lead by 95% in most applications
  • Can be put into throw away filter cartridges
  • Low cost
  • Can be mixed with block activated carbon in a filter cartridge for removal of both soluble and insoluble lead. Please note that these types of filters require replacement on a regular bases.
Disadvantages
  • In some cases ion exchange may not be suitable as a single technology for removal of lead ( due to  factors such as what ionic form the lead is present in)
  • Lead can Fluff off the ion exchange resin( not  during times of high flow rates sometimes causing higher lead levels present in the treated water then what is found in the untreated  water.
  • It is important to remember that an ion exchange column is designed to remove only ions and with lead, the real story is that these types of contaminants are frequently not in an ionic form or may interact with and then precipitate in the resin.

Some Activated Carbon Block (The Filter’s label will state if it is designed to remove lead)

Treatment Removal: The filter uses the activated carbon to remove the insoluble lead by filtration and remove the soluble lead by ion exchange

Advantages
  • Can remove both soluble and insoluble lead from water
  • Filters particles down to 0.6 micron in size
  • Comes in throw away filter cartridges
Disadvantages
  • Not all Activated Carbon Block Filters are designed for Lead removal, please check label.
  • Activated Carbon by itself can not remove soluble lead from the water.

Redox Treatment Media (KDF-55)

Treatment Removal: Redox process allows the lead to plate onto the copper portion of the media. The lead replaces the zinc which goes into solution as ions.

Advantages
  • Can Reduce Soluble Lead by 95%.
  • When combined with Activated Carbon media it will also reduce the amount of insoluble lead.
  • The treatment Media tightly holds onto the lead and the lead will not fluff off the media.
  • It can used in Filter Cartridges for point of use applications so there is no waste water.
  • Can also  remove Chlorine.
Disadvantages
  • High initial cost.
  • In larger applications the media  will require a High volume of backwash water to clean media

Choosing the Correct Treatment

We have had very good results using the following technologies out in the field since they can be installed at most point of use applications

  • Activated Carbon Block Lead Removal Filters
  • KDF-55/Activated Carbon Filters

RO’s work very well but due to the reject water issue is this technology is not feasible in some applications.

About Water Resources

Water Resources is a local company that has been helping businesses, communities and homeowners solve water quality issues for 20 years. We provide and service water treatment equipment to correct all types of water quality issues. If we can be of any assistance or provide you with any technical guidance please feel free to contact us at 609-268-7965.