2018-06-27 Meeting Minutes (EMC)

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Chair Bennett said he has a lot of questions on this, and Director Kucharski has informed him there is some information available about the design of the ponds, and there are some lab scale tests slated. He asked for an update. Director Kucharski explained they are essentially going through the final designs for the R-1 system, which includes the SAT ponds. There are other R-1 elements going in. The design still needs to be completed, put out to bid, and then constructed. The system is supposed to be up and running in about two years. Regarding the SAT ponds, there are studies regarding the phosphorus removal capability of the blue rock. From the testing done so far, he is not aware of anything that precludes or changes the anticipated removal (which is somewhat in excess of 90%) of the phosphorus. Right now the distribution system for the SAT is being designed—how the wastewater will be gotten into the SAT in such a way that there isn’t oversaturation or channel flow. The geology needs to be looked at, and at some point in the future the blue rock will need to be removed and replaced. The designers are looking at about a 30-year saturation time before replacement of the blue rock will be necessary. They will also be able to monitor what comes through the SAT. There will be wells going down so they can sample any flow of the wastewater through the SAT material. Once it’s down in the lava, it is really unknown where it will go other than eventually downhill. All of these elements are being studied. However, there has not been any indication that the ability of the blue rock to absorb the phosphorus has changed. The preliminary design will be coming out, and if there is something he can share with the EMC in executive session, he will. Chair Bennett explained to the commissioners what Soil Aquifer Treatment ponds are. The design Director Kucharski was talking about actually isn’t the pond. It is soil treatment, where the reclaimed water is put in contact with the soil. As he understands it, it is a required design feature for the R-1 upgrade should there not be sufficient reuse. The R-1 would be disposed of in settling basins. They’ll be along the highway and just south of Kealakehe Parkway. Director Kucharski said they will be at the base of where the County regional park is supposed to be. Chair Bennett said the standing water in the ponds creates a bird attraction, which is not desired by the airport. The philosophy is that the phosphorus, which is difficult to remove in the wetlands, can be absorbed by the blue rock, which is high in iron and manganese. The phosphate is to be bound and prevented from leaching into the groundwater. He is concerned that the groundwater is shallow and brackish seawater, not fresh. The groundwater rises and falls with the tide every day, so it is intimately connected to the ocean. The ocean is already nitrogen enriched, and its productivity is limited by low levels of phosphorus. The nitrogen is very soluble and flows with the water. Phosphorus is not very soluble and does not leach through the soil because the soil will bind it. However, the capacity is not infinite, so he questions how well the matrix will work. It may be efficient in the beginning but will start to drop off. At what point does the efficiency drop from 90% to 50%? That information is not known.