Sun, 24 Sep 2017 19:55:42 GMT

ONLINE SUBMISSION
USER:
PASSWORD:
         
GUIDE FOR AUTHORS
Forgot your password?
Enter your e-mail to receive an e-mail with your account information.
CONTENTS
Current Issues
ALL Issues
Subscription
Online First
Journal Citation
ABOUT JCUG
Committee
Journal Honor
JCUG
Contact us

Nitrate Removal by a Permeable Reactive Barrier of Fe0: A Model-based Evaluation

Qinghua Wu*1,2, Chunmiao Zheng3, Jiafa Zhang1, Fawang Zhang4
1. Changjiang River Scientific Research Institute, Wuhan 430010, China2. Institute of Hydrogeology and Environmental Geology, Chinese Academy of Geological Sciences, Shijiazhuang 050061, China3. Department of Geological Sciences, University of Alabama, Tuscaloosa, Alabama,USA4. Institute of Karst Geology, CAGS, Guilin 541004, China

Permeable reactive barrier (PRB) filled with zero valent iron (ZVI, Fe0) can be an effective option to remove nitrate from contaminated groundwater. The long-term performance of such PRBs, however, might be compromised by the problem of declining reactivity and permeability, which could cause a decrease in the nitrate removal efficiency. In this study we explored suitable model formulations that allow for a process-based quantification of the passivation effect on denitrification rates and tested the model for a 40 years long operation scenario. The conceptual model underlying our selected formulation assumes the declining reactivity of the ZVI material through the progressing passivation caused by the precipitation of secondary minerals and the successive depletion of the ZVI material. Two model scenarios, i.e., the base model scenario which neglects the explicit consideration of the passivation effect and one performed with the model in which the impact of the passivation effect on denitrification was considered, were compared.  The modeling results illustrate that nitrate removal in the model of considered passivation  started to be incomplete after 10 years, and the effluent nitrate concentration of PRB rose up to 86% of the injected water concentration after 40 years, in contrast to the base scenario, corresponding well with the field observations of successively declining nitrate removal efficiencies. The model results also showed that the porosity of the PRB increased in both models. In order to improve and recover the reactivity of ZVI, pyrite was added to the PRB, resulting in completely nitrate removal and lower consumption of ZVI.

 

PDF下载

Keywords:groundwater, PRB, Zero Valent Iron, PHT3D, Denitrification

DOI:
10.1007/s12583-016-0924-2
CLC number:
U469.72
Download Full Text:
Click Here
Downloaded:
124