SYSTEMS AND METHODS TO PREVENT CONTAMINATION OF POTABLE WATER WITH LEAD AND/ OR IRON, AND TO EXTEND THE USEFUL LIFE OF THE POTABLE WATER SYSTEM, WHILE REDUCING MAINTENANCE AND CAPITAL COSTS

Abstract

Provided are systems and methods for preventing corrosion, and lead and iron contamination in potable water piping systems comprising lead, non-electrically conducting, and/or iron pipes. A sacrificial/potential anode, made of a material, such as a metal or metal alloys less noble than iron, e.g., zinc, aluminum, magnesium, and/or alloys thereof, is electrically attached to the potable water piping system. Alternatively, an active cathodic corrosion prevention system may be used. The active cathodic corrosion protection system comprises an independent source of DC power, a voltage controller and a non-sacrificial or a sacrificial/potential grounding anode. The negative terminal of the voltage controller is connected to the potable water piping system. The interior surface of the lead and/or iron pipe is maintained at a voltage and/or potential above the reduction potential of the redox reactions between the disinfection chemicals and the interior surfaces of the lead and iron pipes.

Claims

1. A corrosion prevention system for a potable water piping system, wherein the potable water piping system comprises at least one iron main, possibly one section of non-conductive pipe, and at least one section of lead pipe, the corrosion prevention system comprising: a. iron mains and at least one sacrificial/potential anode electrically connected to at least one section of lead pipe, b. whereby an interior surface of the section of lead pipe is maintained at a voltage above the reduction potential of the redox reaction between iron and the protective concentration of disinfection chemicals, wherein the lead pipe is electrically connected to the iron main.

2. The corrosion prevention system of claim 1, wherein the sacrificial/potential anode is comprised of a metal less noble than iron.

3. The corrosion prevention system of claim 2, wherein the sacrificial/potential anode is comprised of zinc, an alloy thereof, or a metal or metal alloy less noble than zinc.

4. The corrosion prevention system of claim 1, further comprising a DC power source electrically connected to at least one section of iron main connected to a lead pipe.

5. A corrosion prevention system for a potable water piping system, wherein the potable water piping system comprises at least one iron main, possibly one section of non-conductive pipe, and at least one section of lead pipe, the corrosion prevention system comprising: a. at least one insoluble anode, and/or a sacrificial/potential anode b. a power source electrically connected to the insoluble anode, and/or sacrificial/potential anode c. a voltage controller electrically connected to the insoluble anode, the power source, and the lead pipe, d. whereby an interior surface of the lead pipe is maintained at a voltage above the reduction potential of iron, wherein the lead pipe and the iron main are electrically connected

6. The corrosion prevention system of claim 5, wherein the insoluble anode is comprised of graphite.

7. The corrosion prevention system of claim 5, wherein the power source comprises a battery or a solar cell and a voltage controller.

8. The corrosion prevention system of claim 5, wherein the power source comprises an AC/DC rectifier-converter.

9. A method for preventing corrosion of a lead pipe in a potable water piping system, wherein the potable water piping system comprises at least one iron main and possibly a section of non-conductive pipe, electrically bypassed by an electrical jumper, comprising: a. electrically connecting means for corrosion protection to the lead pipe; b. whereby the interior surface of the lead pipe is maintained at a voltage above the reduction potential of iron.

10. The method of claim 9, wherein the means for corrosion protection comprises at least one sacrificial/potential anode.

11. The method of claim 10, wherein the sacrificial/potential anode is comprised of a metal less noble than iron.

12. The method of claim 11, wherein the sacrificial/potential anode is comprised of iron, zinc, or an alloy thereof.

13. The method of claim 9, wherein the means for corrosion protection comprises a voltage controller, a DC power source, wherein the voltage controller is electrically connected to the power source and the iron and lead distribution system. x

14. The method of claim 13, wherein the power source comprises an AC/DC rectifier converter

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Embodiments are illustrated by way of example and not limited to the figures of the accompanying drawings, in which like references indicate similar elements and in which:

[0019] FIG. 1 illustrates a passive corrosion prevention system according to one embodiment of the invention.

[0020] FIG. 2 illustrates an active corrosion prevention system according to one embodiment of the invention Note that an electrical conductor is used to bridge a non-conducting section such as a break and/or a plastic repair.

[0021] FIG. 3 illustrates the use of fire hydrants and /or other above ground metal components as points of electrical connection to the distribution system.

DETAILED DESCRIPTION

[0022] The following detailed description includes references to the accompanying drawings, which form a part of the detailed description. The drawings show illustrations in accordance with example embodiments.

[0023] The systems and methods disclosed herein for preventing corrosion of lead and/or iron piping comprise electrically attaching a dedicated cathodic corrosion protection system to the lead and/or iron pipes. The passive cathodic protection system may comprise a sacrificial anode or multiple anodes made of, zinc metal, zinc alloy, or a lesser noble metal such as aluminum or magnesium, or alloys thereof. The sacrificial/potential anode is in contact with the ground and electrically connected to the lead and/or iron pipes. The sacrificial/potential anode maintains the lead and/or iron pipes at a voltage above the pipes' respective reduction potentials, thus preventing the external corrosion of the lead and/or iron pipes. If the sacrificial/potential anode creates a cathodic potential high enough to make the redox reaction between the protective concentration of disinfection chemicals cathodic, then the interior of the pipes will be protected from corrosion.

[0024] Alternatively, an active cathode corrosion protection system supplied by an independent electrical energy source may be used. The positive terminal of the active system is connected to ground by either a conducting non-sacrificial anode or a sacrificial anode. The negative terminal is connected to the lead and/or iron pipes. The voltage between the grounding anode and the lead and/or iron pipes is maintained at a level at, or above, the pipes' respective reduction potential, and the cathodic potential of the redox reaction between the pipe interior surface and the disinfectant chemicals. It must be understood that the necessary cathodic potential to make the redox reaction between the pipe interior and the disinfectant chemicals is dependent on the concentration of the chemicals and the temperature of the system.

[0025] FIG. 1 shows an example embodiment of a lead pipe corrosion prevention system according to the present invention. Iron main 110 provides potable water from a water source. Lateral 120 provides water from iron main 110 to a lead pipe 170, possibly through service connection 130. The delivery system is comprised of iron main 110 and lateral 120, and is generally underground, as indicated by the cross hatches. If lateral 120 is plastic, a conducting jumper 140 is used between the iron main 110 and lead pipe 170 in order to maintain electrical continuity throughout the delivery system. Note that, for clarity, only a portion of the ground is shown crosshatched.

[0026] The present invention adds sacrificial anode 180, which is electrically connected to the lead piping by, e.g., electrical conductor 190 and clamps 200. While electrical conductor 190 and clamps 200 are provided as an example, any means of electrically connecting sacrificial/potential anode 180 to the lead piping may be used, and one of ordinary skill in the art will recognize other such connections. At least part of sacrificial/potential anode 180 is grounded, as indicated by the cross hatches in FIG. 1. Furthermore, while FIG. 1 only shows one sacrificial anode 180, more than one sacrificial anode may be used. Sacrificial anode 180 is comprised of zinc, a zinc metal alloy, or a more cathodic metal or alloy. One of ordinary skill in the art will recognize other materials that may be used. Sacrificial anode 180 maintains the lead pipe at a voltage above the reduction potential of iron and thus the reduction potential of lead and the reduction potential of the redox reaction between the disinfectant chemicals and lead and iron. Consequently, both the exterior and the interior, of both the iron and the lead pipes are protected from corrosion Thus, both the iron and the lead in the deliver water, added from the delivery system are reduced to a level of little concern, perhaps ppts. Thus, the health problems caused by lead contamination of potable water by the delivery pipes are prevented.

[0027] The ground medium provides the electrical return leg of the electrolytic circuit. The required size of sacrificial anode 180 depends on the size and length of the distribution system. The required number and location of sacrificial anodes 180 is dependent on, whether, or not, the lead pipe is electrically connected to the iron main. The iron main acts as a sacrificial/potential anode for the lead pipe. If the lead pipe is not electrically connected to the iron main, a separate sacrificial/potential anode connected to the lead pipe is required to protect the lead pipe from both external and internal corrosion.

[0028] FIG. 2 illustrates an alternate embodiment of the present invention, an active cathodic corrosion protection system for both the iron and lead pipes. This system is substantially the same as the system described in FIG. 1, but with a DC voltage from an independent power source controlled at a voltage above the reduction potentials of the iron and the cathodic redox potential of the iron and disinfectant chemicals, is impressed on the lead or iron pipes. In this system, iron main 110 and lateral 120 are substantially the same as described with respect to FIG. 1. In this system, however, either an electrically conducting insoluble anode or a sacrificial/potential anode 210 is used to contact ground. Insoluble anode 210 may be made of an insoluble material, such as graphite. One of ordinary skill in the art will recognize other suitable materials for insoluble anode 210. Insoluble anode 210 is electrically connected to a DC power source 220 and voltage controller 230. DC power source 220 is electrically connected to the variable voltage controller 230. The DC power source 220 may be any source of direct current power, of appropriate voltage, including but not limited to a storage battery or an AC/DC rectifier converter. The variable voltage controller's 230 negative terminal is electrically connected to the lead or iron pipe, for example, the negative terminal of variable voltage controller 230 may be electrically connected to the lead pipe. Variable voltage controller 230 will permit the cathodic voltage to be raised or lowered to control the concentration of lead and/or iron in the potable water at point of delivery. The cathodic voltage may be increased to protect greater areas of the distribution system, as well as for changes in the protective concentration of disinfecting chemicals

[0029] Multiple sacrificial/potential anodes and/or DC voltage sources may be connected to any part or parts of the electrically connected potable water distribution system so as to, maintain a desired uniform voltage throughout the entire potable water distribution system.

[0030] Fire hydrants, control valves, and flow meters are above ground components that can be utilized as connection points; FIG. 3 to diagnose the electrical continuity of the distribution system, to bridge electrical breaks with surface jumper cables, and to install this cathodic corrosion protection system. By utilizing above ground surface components, the corrosion protection can be installed without excavating to gain access to the underground pipes of the distribution system. This is of major significance when the water mains are located under streets or, other infrastructures.

[0031] Similar systems may be used to limit or prevent corrosion of iron pipes. A passive corrosion prevention system for iron pipes includes the components described in FIG. 1, but the sacrificial/potential anode is comprised of zinc metal, zinc metal alloy, or a lesser noble metal such as aluminum or magnesium, or alloys thereof.

[0032] An active corrosion prevention system for iron pipes includes the components described in FIG. 2, but the voltage is controlled at a voltage above the reduction potential of iron.

[0033] The present invention prevents the excessive lead and/or iron contamination of the potable water, while extending the service life of the iron mains and lead laterals by using cathodic corrosion protection techniques for protecting the exterior surfaces of the lead and iron pipes and potential to control the reaction protect at great savings over the

[0034] Additional benefits of this invention include: 1) the cathodic potential will prevent pinhole corrosion of any copper tubing in the distribution system and in the final plumbing; 2) water loss will be reduced; 3) the cost to maintain the potable water distribution system will be reduced; and 4) the use and cost of water purification chemicals will be reduced by eliminating the need for corrosion inhibitors, and less disinfection agent.

[0035] Additional Notes:

[0036] The protection methods are implemented by electrically connecting to a fire hydrant or multiple hydrants, valves, or flow meters.

[0037] Bypass breaks and non-conducting repairs to the iron mains by installing electrical conductors between hydrants located on opposite ends of the break, thus restoring electrical continuity of the underground system without disturbing the ground surface.

[0038] Bypass electrical continuity breaks in lead laterals by installing metallic jumpers between a fire hydrant and a water meter on the lateral.

[0039] Detect the local level of cathodic corrosion protection by measuring the electrical potential between a hydrant and the ground

[0040] Connect the protective power source to a hydrant to boost a decayed protective voltage to protection levels.

[0041] Reduce maintenance and capital costs and extend the useful life of the potable water system by implementing these claims that also reduces the iron and lead contamination in the delivered potable water to regulatory levels. (we are assuming that the water purification plant is delivering water with lead content that meets regulatory specifications.)

[0042] The corrosion protection system prevents the potable water from being contaminated with lead and iron by the existing water distribution system when this process is implemented. The system maintenance and capital costs are reduced by using surface components such as fire hydrants to electrically detect and correct existing underground electrical faults. Further, fire hydrants are conveniently available throughout the system and can be used to monitor the system's protective voltage, and to provide a local connection to the distribution system to boost any decayed protective voltage. Once preexisting conditions are corrected, my method will deliver potable water without adding lead or iron for a very long time. My methods rejuvenate existing systems and protect new and future systems from decay due to corrosion.

[0043] Although the invention has been described in terms of particular embodiments, one of ordinary skill in the art, in light of the teachings herein, will be able to generate additional embodiments and modifications without departing from the spirit of, or exceeding the scope of, the claimed invention. This invention is not limited to using the particular elements, materials, or components described herein, and other elements, materials, or components will be equivalent for the purposes of this invention. Accordingly, it is understood that the drawings and the descriptions herein are proffered only to facilitate comprehension of the invention and should not be construed to limit the scope thereof.