{"id":{"repo_id":"vt","oai_identifier":"oai:vtechworks.lib.vt.edu:10919/35259"},"canonical_url":"https://search.dev.ndltd.org/etd/vt/oai:vtechworks.lib.vt.edu:10919/35259","repository":{"repo_id":"vt","name":"Virginia Tech","base_url":"https://vtechworks.lib.vt.edu/oai/request"},"display":{"title":"Effect of Calcium on Arsenic Release From Ferric and Alum Sludges and Lagoons","abstract":"The dewatering of arsenic-containing residuals is a process that has received little study in the past. Arsenic that has been removed from water by sorption to ferric or aluminum hydroxides can accumulate in residuals to concentrations many times higher than in the source water. The first part of this study evaluates the effectiveness of lime conditioning as a method for immobilizing this arsenic. As the pH is increased with addition of caustic soda or soda ash, soluble arsenic concentration increases dramatically. However, as the pH is increased with lime, very little arsenic is released back into the water. On the basis of previous research this phenomenon might be attributed to the formation of a calcium arsenate solid. However, this study indicates it is more likely that the soluble calcium neutralizes the negative surface charge on the hydroxide solids at high pH and enhances arsenic sorption compared to when calcium was absent. In many cases arsenic-containing residuals are stored in lagoons and allowed to reside there for months or even years. Many parameters may affect the soluble arsenic concentration and speciation in these lagoons. The second portion of this study gives some baseline conditions for these lagoons, both with and without microbial activity and biological organic matter. In these practical situations it appears that lime can assist in keeping arsenic sorbed to the solids and prevent its release to the environment.","abstract_html":"The dewatering of arsenic-containing residuals is a process that has received little study in the past. Arsenic that has been removed from water by sorption to ferric or aluminum hydroxides can accumulate in residuals to concentrations many times higher than in the source water. The first part of this study evaluates the effectiveness of lime conditioning as a method for immobilizing this arsenic. As the pH is increased with addition of caustic soda or soda ash, soluble arsenic concentration increases dramatically. However, as the pH is increased with lime, very little arsenic is released back into the water. On the basis of previous research this phenomenon might be attributed to the formation of a calcium arsenate solid. However, this study indicates it is more likely that the soluble calcium neutralizes the negative surface charge on the hydroxide solids at high pH and enhances arsenic sorption compared to when calcium was absent. In many cases arsenic-containing residuals are stored in lagoons and allowed to reside there for months or even years. Many parameters may affect the soluble arsenic concentration and speciation in these lagoons. The second portion of this study gives some baseline conditions for these lagoons, both with and without microbial activity and biological organic matter. In these practical situations it appears that lime can assist in keeping arsenic sorbed to the solids and prevent its release to the environment.","abstract_has_math":false,"creators":["Parks, Jeffrey Lynn"],"institution":"Virginia Tech","degree_name":"Master of Science","degree_level":"masters","degree_discipline":"Environmental Planning","degree_department":"Environmental Engineering","school":null,"contributors":[],"advisors":[],"committee_chairs":["Edwards, Marc A.","Novak, John T."],"committee_members":[],"year":2001,"date_issued":"2001-09-18","date_published":"2001-09-18","updated_at":"2026-07-22T22:20:21Z","subjects":["Calcium","Arsenic","Leachability","Ferric","Sludge","Alum","Drinking Water"],"languages":[],"rights":["In Copyright"],"rights_urls":["http://rightsstatements.org/vocab/InC/1.0/"],"identifier_entries":[{"key":"dc:identifier.other","label":"Dc Identifier Other","values":["etd-10022001-110024"],"render_values":[{"text":"etd-10022001-110024","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/10919/35259","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.committeechair","label":"Committee Chair","values":["Edwards, Marc A.","Novak, John T."]},{"key":"dc:contributor.department","label":"Department","values":["Environmental Engineering"]},{"key":"dc:creator","label":"Author","values":["Parks, Jeffrey Lynn"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2014-03-14T20:46:14Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2014-03-14T20:46:14Z","2004-10-03"]},{"key":"dc:date.issued","label":"Date","values":["2001-09-18"]},{"key":"dc:publisher","label":"Institution","values":["Virginia Tech"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Environmental Planning"]},{"key":"thesis:degree_level","label":"Degree Level","values":["masters"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Master of Science"]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["Virginia Polytechnic Institute and State University"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Calcium","Arsenic","Leachability","Ferric","Sludge","Alum","Drinking Water"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:rights","label":"Dc Rights","values":["In Copyright"]},{"key":"dc:rights.uri","label":"Rights URI","values":["http://rightsstatements.org/vocab/InC/1.0/"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.other","label":"Dc Identifier Other","values":["etd-10022001-110024"]},{"key":"dc:identifier.uri","label":"Identifier URI","values":["http://hdl.handle.net/10919/35259"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["The dewatering of arsenic-containing residuals is a process that has received little study in the past. Arsenic that has been removed from water by sorption to ferric or aluminum hydroxides can accumulate in residuals to concentrations many times higher than in the source water. The first part of this study evaluates the effectiveness of lime conditioning as a method for immobilizing this arsenic. As the pH is increased with addition of caustic soda or soda ash, soluble arsenic concentration increases dramatically. However, as the pH is increased with lime, very little arsenic is released back into the water. On the basis of previous research this phenomenon might be attributed to the formation of a calcium arsenate solid. However, this study indicates it is more likely that the soluble calcium neutralizes the negative surface charge on the hydroxide solids at high pH and enhances arsenic sorption compared to when calcium was absent. In many cases arsenic-containing residuals are stored in lagoons and allowed to reside there for months or even years. Many parameters may affect the soluble arsenic concentration and speciation in these lagoons. The second portion of this study gives some baseline conditions for these lagoons, both with and without microbial activity and biological organic matter. In these practical situations it appears that lime can assist in keeping arsenic sorbed to the solids and prevent its release to the environment."]},{"key":"dc:description.degree","label":"Dc Description Degree","values":["Master of Science"]},{"key":"dc:title","label":"Title","values":["Effect of Calcium on Arsenic Release From Ferric and Alum Sludges and Lagoons"]}]}],"canonical_facts":{"dc:contributor.committeechair":["Edwards, Marc A.","Novak, John T."],"dc:contributor.department":["Environmental Engineering"],"dc:creator":["Parks, Jeffrey Lynn"],"dc:date.accessioned":["2014-03-14T20:46:14Z"],"dc:date.available":["2014-03-14T20:46:14Z","2004-10-03"],"dc:date.issued":["2001-09-18"],"dc:description.abstract":["The dewatering of arsenic-containing residuals is a process that has received little study in the past. Arsenic that has been removed from water by sorption to ferric or aluminum hydroxides can accumulate in residuals to concentrations many times higher than in the source water. The first part of this study evaluates the effectiveness of lime conditioning as a method for immobilizing this arsenic. As the pH is increased with addition of caustic soda or soda ash, soluble arsenic concentration increases dramatically. However, as the pH is increased with lime, very little arsenic is released back into the water. On the basis of previous research this phenomenon might be attributed to the formation of a calcium arsenate solid. However, this study indicates it is more likely that the soluble calcium neutralizes the negative surface charge on the hydroxide solids at high pH and enhances arsenic sorption compared to when calcium was absent. In many cases arsenic-containing residuals are stored in lagoons and allowed to reside there for months or even years. Many parameters may affect the soluble arsenic concentration and speciation in these lagoons. The second portion of this study gives some baseline conditions for these lagoons, both with and without microbial activity and biological organic matter. In these practical situations it appears that lime can assist in keeping arsenic sorbed to the solids and prevent its release to the environment."],"dc:description.degree":["Master of Science"],"dc:identifier.other":["etd-10022001-110024"],"dc:identifier.uri":["http://hdl.handle.net/10919/35259"],"dc:publisher":["Virginia Tech"],"dc:rights":["In Copyright"],"dc:rights.uri":["http://rightsstatements.org/vocab/InC/1.0/"],"dc:subject":["Calcium","Arsenic","Leachability","Ferric","Sludge","Alum","Drinking Water"],"dc:title":["Effect of Calcium on Arsenic Release From Ferric and Alum Sludges and Lagoons"],"dc:type":["Thesis"],"thesis:degree_discipline":["Environmental Planning"],"thesis:degree_level":["masters"],"thesis:degree_name":["Master of Science"],"thesis:institution_name":["Virginia Polytechnic Institute and State University"]},"updated_at":"2026-07-22T22:20:21Z"}