Grantee Research Project Results

2013 Progress Report: Small, Safe, Sustainable (S3) Public Water Systems through Innovative Ion Exchange

EPA Grant Number: R835334
Title: Small, Safe, Sustainable (S3) Public Water Systems through Innovative Ion Exchange
Investigators: Boyer, Treavor H. , Zhang, Qiong
Institution: University of Florida , University of South Florida
EPA Project Officer: Packard, Benjamin H
Project Period: August 16, 2012 through August 15, 2016 (Extended to August 15, 2017)
Project Period Covered by this Report: August 16, 2012 through August 15,2013
Project Amount: $499,361
RFA: Research and Demonstration of Innovative Drinking Water Treatment Technologies in Small Systems (2011) RFA Text | Recipients Lists
Research Category: Drinking Water , Water

Objective:

The main objective of this project is to identify and test ion exchange processes that can treat groups of chemical contaminants and evaluate their sustainability. The specific objectives of this project are to: (1) identify combined anion and cation exchange processes that can treat groups of chemical contaminants in an environmentally friendly way; (2) develop an ion exchange process model that includes multi-contaminant treatment and regeneration efficiency; (3) demonstrate the performance of the ion exchange treatment and regeneration processes through pilot-scale testing at a small public water system (PWS); and (4) evaluate the environmental, human health, and economic impacts of the ion exchange treatment and regeneration processes through life cycle assessment (LCA) and life cycle cost analysis (LCCA).

Progress Summary:

Project progress is on track with research objectives and timeline to accomplish research activities. Laboratory ion exchange experiments are under way that evaluate contaminant removal by combined anion and cation exchange process and subsequent regeneration (research objective 1) and data collection is under way to allow for LCA and LCCA of ion exchange unit process (research objective 4). Activities for research objectives 1 and 4 have focused on regeneration because regeneration is considered to be the major barrier to improving the sustainability of the ion exchange unit process. Laboratory experiments as part of research objective 1 investigated the regeneration efficiency of anion exchange resin exhausted with nitrate and cation exchange resin exhausted with calcium. Sodium chloride (NaCl), potassium chloride (KCl), sodium bicarbonate (NaHCO₃), and potassium bicarbonate (KHCO₃) were tested as regeneration chemicals. Chloride showed higher regeneration efficiency than bicarbonate for polystyrene anion exchange resin, while bicarbonate showed higher regeneration efficiency than chloride for polyacrylic anion exchange resin. Potassium showed higher regeneration efficiency than sodium for all cation exchange resins. As part of research objective 4, the life cycle environmental impacts of the regeneration chemicals was determined using cradle-to-gate comparative LCA. The increasing environmental burden of regeneration chemicals was NaCl < KCl < NaHCO₃ < KHCO₃.

Future Activities:

The following activities will take place during the next reporting period: continue laboratory ion exchange experiments (research objective 1), begin development of ion exchange process model (research objective 2), and continue data collection and work on LCA and LCCA of ion exchange unit process (research objective 4). The laboratory experiments as part of research objective 1 will investigate the selectivity of bicarbonate-form anion exchange resin for various anionic contaminants and potassium-form cation exchange resin for various cationic contaminants. NaCl, KCl, and NaHCO₃ will be used in regeneration experiments; KHCO₃ will not be used in future work because of high life cycle environmental impacts. The ion exchange process model as part of research objective 2 will be developed to include regeneration efficiency and composition of the waste regeneration solution. The LCA and LCCA of ion exchange unit process as part of research objective 4 will be refined based on new data collection and results from research objective 1.

Journal Articles:

No journal articles submitted with this report: View all 37 publications for this project

Supplemental Keywords:

Nitrate, softening, regenerant brine, salinity, life cycle assessment, LCA, mining, freshwater toxicity, sodic soil, wastewater nitrification

Relevant Websites:

Professor Boyer’s research website, listing published journal articles and presentations:

http://www.ees.essie.ufl.edu/homepp/boyer/ Exit

http://scholar.google.com/citations?user=vhn_98oAAAAJ Exit

Progress and Final Reports:

Original Abstract

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.