Grantee Research Project Results

Simultaneous Removal of Inorganic Pollutants by Sorbents for Small Drinking Water Systems

EPA Grant Number: F13E10814
Title: Simultaneous Removal of Inorganic Pollutants by Sorbents for Small Drinking Water Systems
Investigators: Gifford, James McKay
Institution: Arizona State University
EPA Project Officer: Packard, Benjamin H
Project Period: August 21, 2014 through August 21, 2016
Project Amount: $84,000
RFA: STAR Graduate Fellowships (2013) RFA Text |  Recipients Lists
Research Category: Fellowship - Civil Engineering , Academic Fellowships

Objective:

This research proposes to develop the science and technology of sorption processes for simultaneous removal of such inorganic pollutants as hexavalent chromium, arsenic and nitrate. It seeks to develop testing protocol and evaluation methodology, create new sorbents and mechanistically understand how the simultaneous removal occurs.

Approach:

A protocol will be developed for evaluating simultaneous removal capacity using batch equilibrium testing, packed-bed column testing and pilot well-head testing of existing sorbents in waters containing mixtures of pollutants. New sorbents will be created by forming metal nanoparticles made of iron hydroxide or titanium dioxide within the porous structure of anion exchange resins. The synthesis of these sorbents will be optimized using the testing protocol and other physical characterization. Mechanistic explanations will describe how simultaneous removal occurs in the metal nanoparticle-infused sorbents.

Expected Results:

It is suspected that existing sorbents have limited capacity to remove multiple pollutants, indicating a need for new, better-performing, options. It is expected that metal nanoparticles will add a high capacity to remove a second pollutant without a significant loss in capacity for the original target pollutant of the anion exchange resin. This will demonstrate that simultaneous removal of pollutants can be cumulative or synergistic and need not be competitive. The model describing the pollutant removal should indicate how diffusion or the number of reactive sites limits the new sorbents. It could then predict the performance of any metal-infused ion exchange sorbent given specific water quality parameters, allowing preliminary screening of treatment options without expensive laboratory or pilot testing.

Potential to Further Environmental/Human Health Protection

Small rural communities face challenges in providing clean drinking water due to few source water options, lack of specialized personnel and the need to meet multiple treatment objectives. These very small systems represent around 80% of contaminant level violations, but the people they serve are entitled to a clean water supply. A single, simple-to-use sorbent process with simultaneous treatment capacity may reduce human exposure to inorganic contaminants in these small communities.

Supplemental Keywords:

drinking water, simultaneous removal, small systems

Progress and Final Reports:

2015

Final