Radium removal by HMO and manganese greensand

Abstract

In December 2000, the US Environmental Protection Agency published the final radionuclides rule. The standard of 5 pCi/L for combined radium (Ra) 226 and 228 will affect more than 500 US systems and 1.4 million people in 177 cities in the Midwest. The best available technology for Ra removal includes ion exchange, lime softening, and reverse osmosis. However, hydrous manganese oxide and manganese greensand filtration is capable of removing up to 80% of Ra. For plants designed to remove iron and manganese by a manganese greensand filtration system, the cost of removing Ra is minimal. Results of pilot‐ and full‐scale studies are reported from Bellevue Sanitary District 1 in Brown County, Wis.; Knoxville, Iowa; Garretson and Elk Point, S.D.; Marcus, Iowa; and Savage, Lakeville, and Hinckley, Minn. Also discussed are the relationship between total dissolved solids and Ra removal and the disposal of water containing Ra, which is a major concern.

Natural speciation of Ni, Zn, Ba, and As in ferromanganese coatings on quartz using X-ray fluorescence, absorption, and diffraction

“…The geochemical affinity of Ra for Mn oxides is well documented and some authors estimate that 0.5% of Mn oxides in an oxidized aquifer would suffice to control Ra mobility (Herczeg et al, 1988). This affinity has been used in pilot-and full-scale experiments for Ra removal from contaminated waters by manganese green sand (Qureshi and Nelson, 2003). Because of the extremely low amount of Ra in natural solid samples (concentrations related inversely to the half-life), studies on Ra interactions with mineral surfaces have remained of a macroscopic nature (e.g., leaching experiments, sequential filtrations), and no structural investigations have been performed.…”

“…Here, focus is placed on the structural chemistry of metal(loid)s-containing ferrihydrite and vernadite formed naturally at the surface of quartz grains from sand filters used in groundwater treatment plants. These samples were chosen because oxide-coated silica sand commonly is used for water purification due to its high hydraulic conductivity and low cost (e.g., Cheremisinoff, 1995;Babel and Kurniawan, 2003;Qureshi and Nelson, 2003;Vaishya and Gupta, 2003;Hu et al, 2004a,b) and studied in the laboratory especially for application in household arsenic removal systems (Thirunavukkarasu et al, 2001(Thirunavukkarasu et al, , 2003Bose and Sharma, 2002;Yuan et al, 2002;Vaishya and Gupta, 2004;Gupta et al, 2005;Jessen et al, 2005;Kundu and Gupta, 2005;Leupin and Hug, 2005;Newcombe et al, 2006). Fundamental understanding of the structure of the sorbent phases and of the partitioning and retention mechanisms of toxic elements (here, Ni, Zn, As, and Ba, an analogue for Ra) should benefit the design and use of engineered field systems.…”

Importance of pipe deposits to Lead and Copper Rule compliance

“…Only a small subset of the abundant geochemical references demonstrating manganese as an effective scavenger of lead and other metals can be cited here (Kwon et al, 2013;Puppa et al, 2013;Rout et al, 2013;Wang et al, 2012;Eren et al, 2011;Kwon et al, 2010;Zhao et al, 2010;Feng et al, 2007;Tonkin et al, 2004;Dong et al, 2003;O'Reilly & Hochella, 2003;Ohta & Kawabe, 2001;Pretorius & Linder, 2001;Kiratisevee et al, 2000;Tessier et al, 1996;Manceau et al, 1992). Manganese media have found direct application to the removal of both arsenic (Chang et al, 2012;Ouvrard et al, 2005;Chakravarty et al, 2002) and radium (Qureshi & Nelson, 2003;Mott et al, 1993;Brinck et al, 1978), further verifying the ability of manganese solids to accumulate contaminants of potential health concern. As such, manganese could function similarly to iron if present in drinking water flowing through pipes.…”

Pilot Study of Radionuclide Removal: Using Conventional Iron‐ and Manganese‐removal Equipment

“…The 226 Ra was removed most efficiently with the manganese greensand filtration equipment (98%) with removal that is based on the use of potassium permanganate. Manganese dioxide forms a fresh coating on the greensand granulates and acts as an efficient adsorbent (Qureshi & Nelson, 2003; Valentine et al, 1990). Strong acid cation resins, which are normally used to remove Fe, Mn, and hardness from water, have been observed to remove more than 80% of 226 Ra (Vesterbacka et al, 2003; Clifford, 1990).…”

“…Although most removals were incomplete, they were often sufficient to meet regulatory requirements (0.2 Bq/L for 210Pb and 0.1 Bq/L for 210 Po). The removal of 210 Pb and 210 Po by conventional water treatment methods has been found to be difficult because these nuclides are primarily bound to particles of various sizes (Vesterbacka et al, 2005b; 2003; Lehto et al, 1999).…”