Hanford and Oak Ridge underground storage tank waste filtration process evaluation

The filters tested for these applications were selected based on the ability to tolerate high radiation fields. The filters used were constructed primarily of stainless steel and can be welded. These filters were among those recommended for testing of these waste streams and the Mott filters currently installed in the SRS In-Tank Precipitation facility

Oak Ridge National Laboratory Melton Valley Storage Tanks Waste filtration process evaluation

The purpose of this filter study was to evaluate cross-flow filtration as effective solid-liquid separation technology for treating Oak Ridge National Laboratory wastes, outline operating conditions for equipment, examine the expected filter flow rates, and determine proper cleaning.The Gunite Tanks at the Oak Ridge National Laboratory contain heels which are a mixture of sludge, wash water, and bentonite clay. The tanks are to be cleaned out with a variety of flushing techniques and the dilute mixture transferred to another storage tank. One proposal is to transfer this mixture into existing Melton Valley Storage Tanks (MVST), which already contain a large amount of sludge and supernate. The mixed aqueous phase will then be transferred to new MVST, which are prohibited from containing insoluble solids. To separate the solid from the liquid and thereby prevent solids transfer into the new MVST, a technique is needed that can cleanly separate the sludge and bentonite clay from the supernate. One proposed method for solid liquid separation is cross-flow filtration. Cross-flow filtration has been used at the Savannah River and West Valley sites for treatment of tank waste, and is being tested for applicability at other sites. The performance of cross-flow filters with sludge has been tested, but the impact of sludge combined with bentonite clay has not. The objective of this test was to evaluate the feasibility of using cross-flow filters to perform the solid liquid separation required for the mixture of Gunite and MVST tank wastes

Cross-Flow Filtration of Department of Energy Hanford Waste Streams Using Sintered Metal Mott and Graver Filters at the Savannah River Technology Center

Treatment processes have been proposed that will utilize cross-flow filtration to filter supernate and concentrated sludge waste streams at a Department of Energy plant in Hanford, Washington. Two waste processing applications have been identified as candidates for this technology. The first of the Hanford applications involves filtration of the decanted supernate from sludge leaching and washing operations. This process requires the concentration and removal of dilute fines from the bulk of the supernate. The second application involves filtration to wash and concentrate the sludge during out-of-tank processing of a relatively concentrated solids feed stream

Unit bar architecture in a highly‐variable fluvial discharge regime: Examples from the Burdekin River, Australia

Unit bars are relatively large bedforms that develop in rivers over a wide range of climatic regimes. Unit bars formed within the highly-variable discharge Burdekin River in Queensland, Australia, were examined over three field campaigns between 2015 and 2017. These bars had complex internal structures, dominated by co-sets of cross-stratified and planar-stratified sets. The cross-stratified sets tended to down-climb. The development of complex internal structures was primarily a result of three processes: (i) superimposed bedforms reworking the unit bar avalanche face; (ii) variable discharge triggering reactivation surfaces; and (iii) changes in bar growth direction induced by stage change. Internal structures varied along the length and across the width of unit bars. For the former, down-climbing cross-stratified sets tended to pass into single planar cross-stratified deposits at the downstream end of emergent bars; such variation related to changes in fluvial conditions whilst bars were active. A hierarchy of six categories of fluvial unsteadiness is proposed, with these discussed in relation to their effects on unit bar (and dune) internal structure. Across-deposit variation was caused by changes in superimposed bedform and bar character along bar crests; such changes related to the three-dimensionality of the channel and bar geometry when bars were active. Variation in internal structure is likely to be more pronounced in unit bar deposits than in smaller bedform (for example, dune) deposits formed in the same river. This is because smaller bedforms are more easily washed out or modified by changing discharge conditions and their smaller dimensions restrict the variation in flow conditions that occur over their width. In regimes where unit bar deposits are well-preserved, their architectural variability is a potential aid to their identification. This complex architecture also allows greater resolution in interpreting the conditions before and during bar initiation and development

The Future of Psychopharmacological Enhancements: Expectations and Policies

The hopes and fears expressed in the debate on human enhancement are not always based on a realistic assessment of the expected possibilities. Discussions about extreme scenarios may at times obscure the ethical and policy issues that are relevant today. This paper aims to contribute to an adequate and ethically sound societal response to actual current developments. After a brief outline of the ethical debate concerning neuro-enhancement, it describes the current state of the art in psychopharmacological science and current uses of psychopharmacological enhancement, as well as the prospects for the near future. It then identifies ethical issues regarding psychopharmacological enhancements that require attention from policymakers, both on the professional and on the governmental level. These concern enhancement research, the gradual expansion of medical categories, off-label prescription and responsibility of doctors, and accessibility of enhancers on the Internet. It is concluded that further discussion on the advantages and drawbacks of enhancers on a collective social level is still needed