Marana Project

So just to fill everybody in, my senior research project is being held with Dr. Ed Glenn of the Environmental Research Lab. In Marana, they've recently set up a water-purification system that purifies water from the Colorado River using a reverse-osmosis (RO) filter or a vibrating membrane separation (Vsep) filter. The problem is that both of these filters create saline reject water. The RO filter creates a concentrate of about 3 parts per thousand (ppt), and the Vsep filter produces a brine of 17 ppt. At the moment, the Marana filtering plant has no use for the saline water and is just simply putting the salt-water concentrates into evaporation ponds. The evaporation ponds are costly and not only waste the water, but also require some subsequent method of disposing of the salt. Through the ERL I am trying to find a good economical solution to this problem. I will be experimenting with halophytes (salt-tolerant plants) particularly Atriplex hortensis, which is commonly known as French spinach, that was introduced to the United States in the early 1500's and that can grow on saline water. In the lab, through a series of experiments in the greenhouse, I will be figuring out the ideal irrigation salinity to support the growth of French spinach and determining how effective it would be to grow the spinach on the concentrates created by the RO and Vsep filters. In addition, I will also be experimenting with fish and shrimp to see how well the fish (Tilapia hybrids) and Pacific white shrimp (Litopenaeus vannamei) survive and grow in the concentrates, and to determine if it is worth producing these high-value organisms using the concentrates.

As to what I have accomplished so far... At this moment I have already met all the faculty of the Environmental Research Lab. I have been cleaning out the greenhouse to make room for our halophyte experiments. This has included clearing weeds from the nursery area, re-potting plants, and harvesting seeds of other halophyte species (dwarf saltwort Salicornia biglovii, iodine bush Allenfolfea occidentalis, and saltwort Batis maritima) within the greenhouse. These seeds will be used for future experiments. I have also been helping out Desiree Soliz, one of Ed Glenn's doctoral students in data collection and analyses on another species Atriplex canescens. I have been analyzing data with Statistix, a program of statistical software. Today I got to go down to the water filtration plant at Marana, where we gathered data about the moisture content of the soil through the use of a neutron probe. The probe contains radioactive material, so I can't use it directly without first taking a class and being certified first. We also gathered soil samples from the ground which will be sent to a lab to be analyzed. I have also been reviewing literature on halophyte agronomy, halophyte physiology, and reverse osmosis and vibrating membrane separation filtration processes.