Batch Test Screening of Industrial Product/Byproduct Filter Materials for Agricultural Drainage Water Treatment

Abstract

Filter treatment may be a viable means for removing the nitrate (NO 3 − ), phosphate (PO 4 3− ), and pesticides discharged with agricultural drainage waters that cause adverse environmental impacts within the U.S. on local, regional, and national scales. Laboratory batch test screening for agricultural drainage water treatment potential was conducted on 58 industrial product/byproduct filter materials grouped into six categories: (1) high carbon content media; (2) high iron content media; (3) high aluminum content media; (4) surfactant modified clay/zeolite; (5) coal combustion residuals; and (6) spent foundry sands. Based on a percent contaminant removal criteria of 75% or greater, seven industrial products/byproducts were found to meet this standard for NO 3 − alone, 44 met this standard for PO 4 3− , and 25 met this standard for the chlorinated triazine herbicide, atrazine. Using a 50% or greater contaminant removal criteria, five of the industrial product/byproduct filter materials exhibited potential for removing NO 3 − , PO 4 3− , and atrazine together; eight showed capability for combined NO 3 − and PO 4 3− removal; 21 showed capability for combined PO 4 3− and atrazine removal; and nine showed capability for combined NO 3 − and atrazine removal. The results of this study delineated some potential industrial product/byproduct filter materials for drainage water treatment; however, a complete feasibility evaluation for drainage water treatment of any of these filter materials will require much more extensive testing.

The Impact of Selected Pretreatment Procedures on Iron Dissolution from Metallic Iron Specimens Used in Water Treatment

“…Thus, material selection for an application should be site-specific. It cannot be simply stated that SW is better or worse than GI like it is currently done in the Fe 0 remediation literature [83][84][85]. For example, Allred [84] recently evaluated the suitability of 58 industrial aggregates (products and by-products), including 8 Fe 0 specimens as filter materials for the treatment of agricultural drainage water.…”

“…By doing so, the specificity of Fe 0 , making it applicable for decades, is not addressed [46][47][48][49][50]. The approach used by Allred [84] is commonplace in the recent literature and was introduced already in the 1990s [6,88,89], resulting in disqualifying Fe 0 for water treatment [89] or recommending it [6,88]. Since then, a legitimate scepticism on the efficiency of Fe 0 for water treatment is available within the remediation community [90,91].…”

“…The Fe 0 materials tested by Allred [84] were from three different origins and included a carbon reduced iron, a hydrogen reduced iron, a porous iron composite, two scrap iron specimens and three sulfur modified iron (SMI) specimens. The results revealed (i) that all eight materials were very efficient at removing PO4 3-(>94%) and (ii) that only the SMI specimens achieved more than 50% NO3 - The approach used by Allred [84] is commonplace in the recent literature and was introduced already in the 1990s [6,88,89], resulting in disqualifying Fe 0 for water treatment [89] or recommending it [6,88]. Since then, a legitimate scepticism on the efficiency of Fe 0 for water treatment is available within the remediation community [90,91].…”

“…In particular, the established suitability of commercial iron nails [94] for decentralized safe drinking water supply is presented as a proof of the potential of Fe 0 -based systems to assure universal access to safe drinking water [10,96,97]. The Fe 0 materials tested by Allred [84] were from three different origins and included a carbon reduced iron, a hydrogen reduced iron, a porous iron composite, two scrap iron specimens and three sulfur modified iron (SMI) specimens. The results revealed (i) that all eight materials were very efficient at removing PO 4 3-(>94%) and (ii) that only the SMI specimens achieved more than 50% NO 3 removal and the two reduced irons exhibited the worst efficiency for atrazine.…”

The Suitability of Pozzolan as Admixing Aggregate for Fe0-Based Filters

“…Meanwhile it has been intensively demonstrated that pure sand filters (biosand filters) just partly address biological contamination [72][73][74][75][76]. Amending biosand filters with Fe 0 is progressively established as an affordable and applicable alternative to more sophisticated systems [77,78]. The more important feature is that in-situ-generated ferrous and ferric oxides are contaminant collectors [17,19,36] besides impairing the permeability [20,24].…”