Ability to reduce arsenic

In all cases the RO units were capable of reducing the arsenic in the water from the highest influent arsenic level of 35 ppb down to non-detect. There have been other installations of the KP-5 RO on individual private well dwellings; the highest influent arsenic levels observed were between 700 to 800 ppb of arsenic. The KP-5 RO unit was able to reduce the arsenic by nearly 99%, with drinking water arsenic levels testing between 5 to 10 ppb over several different sampling phases.

Additional significance of this performance is the capability of RO devices to consistently achieve this level of reduction with varying inlet water chemistries like pH, pressure, TDS levels, and other interfering agents like vanadium and silicates. This consistent reduction capability is continuously achieved between sights and fluctuations in annual water chemistry with out modifying or adding any system pre treatment.

It has been noted that the majority of the arsenic in Nevada, Arizona and Southern California is in the arsenate (arsenic 5) form, with trace amounts appearing as arsenite (arsenic 3) form. Because there are trace amounts of arsenite in the water, the KP-5 uses a specialty pre filter that oxidizes any of the arsenite to arsenate in order to increase the RO reduction capability.

Performance Indication Device

RO units used for this program are equipped with a total dissolved solids (TDS) monitoring faucet to determine if the unit is working properly. Reverse osmosis is the only point of use water treatment device that directly monitors the quality of each individual POU unit. If the metering faucet senses that the TDS level through the RO membrane is above the programmed level, the faucet will indicate to the user that it is time to service the RO membrane. The system indicator does not mean that the system is not removing any of the incoming water contaminants. Rather, the RO system is still removing minimally 80% of the incoming water contaminants; however, it is signaling to the user that it is time to service the unit.

There is also a timer meter on the faucet. This timer is strictly based upon the passage of time and not the performance of the reverse osmosis system. The time is based upon the recommended general maintenance that is required of the RO units annually.

It is important that the performance indicator does not turn the POU device off. As indicated through the pilot study, homeowners become accustomed to using the auxiliary tap for their cooking and drinking needs. If the device were to turn off, the homeowner would then be forced to use regular untreated tap water until such time that the POU device can be serviced. In this scenario, not only is the homeowner drinking water out of compliance with the safe drinking water act, but also is breaking the routine of using the auxiliary tap for their cooking and drinking needs.

Education outreach

There were three public outreach programs that were very beneficial for the success of the POU program

The combination of these three outreach programs enabled the community to become more directly involved with the POU program.

However the one document that provided significant assistance in the success of the program was the program hand that was provided to the homeowner during the installation. This handout answered many questions that the home owner had regarding the program. It also provided contact numbers for the homeowner in the event there was a problem with the RO unit.

Use of Arsenic Test kits

Through the duration of the program a couple different arsenic test kits were used. There was one test kit that showed statistical accuracy between results obtained in the field and those obtained through wet lab analysis. This kit, the ITS Arsenic Quick II Test Kit, part number 481303 performed very well. Initial discussions indicate that these test kits will play a part in the monitoring compliance program for the State POU program. Briefly, this test kit will be used to supplement the current monitoring program, being used to evaluate the POU units in the first and second year. The normal wet lab samples will be collected in the third year.

Community acceptance of POU treatment

For Michael's Ranch, 100% of the community agreed that point of use was the best financial solution for the community and were in favor of implementation. Based upon the financial impact alone, they decided to move forward with the POU program for the community. Michael's Ranch has incorporated the use of POU RO for arsenic compliance in to the communities CCR. Now as the remaining 20 units are built, the homes are being fitted with RO units during construction.

The large community, Black Canyon City, decided to move forward with centralized treatment as the water district determined they did not want to perform the additional monitoring, time and maintenance requirements for the 750 private, public and commercial dwellings.

Even though Black Canyon City did not move forward with the POU program, they agreed the POU approach was beneficial, and less costly than the centralized treatment. In one case, a participant had commented that they had signed up for the pilot program in order to find all the reasons why NOT to have POU treatment, but by the end of the program was in favor of it.

Based upon the results of the study, some parameters can be applied when a community is considering point of use treatment for water compliance;

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