A practical soil washing method for use in a Cd-contaminated paddy field, with simple on-site wastewater treatment

Tomoyuki Makino, Yuji Maejima, Ikuko Akahane, Takashi Kamiya, Hiroyuki Takano, Shinichi Fujitomi, Toshiyuki Ibaraki, Anitha Kunhikrishnan, Nanthi Bolan

Research output: Contribution to journalArticlepeer-review

20 Citations (Scopus)

Abstract

Heavy metal contamination in rice paddies is a serious problem in monsoon Asia, and these fields require appropriate restoration measures. Although soil washing is a promising remediation technology, high cost for the treatment on soil washing leachate (wastewater) is one of the critical problems. This study sought to develop a simple method for the restoration of paddy fields by soil washing, with simplified wastewater treatment. Ferric chloride solution (FeCl3) was used as a washing chemical to extract Cd from a soil, which produced the wastewater containing Cd and other metals. Three alkali materials (NaOH, MgO, and CaCO3) were tested to treat the wastewater and determined MgO is optimal. In an on-site experiment, the target pH for wastewater treatment was controlled between 8 and 9 by using MgO. All metals in the wastewater could be effectively removed, reaching levels substantially lower than those permitted by Japanese standards. The treated wastewater could be discharged to agricultural canal. Therefore, our novel simplified method effectively removed heavy metals from the wastewater produced by on-site soil washing and contribute drive down the cost.

Original languageEnglish
Pages (from-to)3-9
Number of pages7
JournalGeoderma
Volume270
DOIs
Publication statusPublished - 2016 May 15
Externally publishedYes

Keywords

  • Heavy metal contamination
  • Paddy soil
  • Soil treatment
  • Soil washing
  • Wastewater treatment

ASJC Scopus subject areas

  • Soil Science

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