{"id":30866,"date":"2026-05-28T12:13:41","date_gmt":"2026-05-28T04:13:41","guid":{"rendered":"https:\/\/chimaytech.net\/understanding-water-age-and-its-impact-on-drinking\/"},"modified":"2026-05-28T12:13:41","modified_gmt":"2026-05-28T04:13:41","slug":"understanding-water-age-and-its-impact-on-drinking","status":"publish","type":"post","link":"https:\/\/chimaytech.net\/vi\/understanding-water-age-and-its-impact-on-drinking\/","title":{"rendered":"Understanding Water Age and Its Impact on Drinking Water Quality"},"content":{"rendered":"<div id=\"ez-toc-container\" class=\"ez-toc-v2_0_50 counter-hierarchy ez-toc-counter ez-toc-light-blue ez-toc-container-direction\">\n<div class=\"ez-toc-title-container\">\n<p class=\"ez-toc-title\">Table of Contents<\/p>\n<span class=\"ez-toc-title-toggle\"><\/span><\/div>\n<nav><ul class='ez-toc-list ez-toc-list-level-1 ' ><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-1\" href=\"https:\/\/chimaytech.net\/vi\/understanding-water-age-and-its-impact-on-drinking\/#Key_Takeaways\" title=\"Key Takeaways\">Key Takeaways<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-2\" href=\"https:\/\/chimaytech.net\/vi\/understanding-water-age-and-its-impact-on-drinking\/#Introduction\" title=\"Introduction\">Introduction<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-3\" href=\"https:\/\/chimaytech.net\/vi\/understanding-water-age-and-its-impact-on-drinking\/#Defining_Water_Age_in_Distribution_Networks\" title=\"Defining Water Age in Distribution Networks\">Defining Water Age in Distribution Networks<\/a><ul class='ez-toc-list-level-3'><li class='ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-4\" href=\"https:\/\/chimaytech.net\/vi\/understanding-water-age-and-its-impact-on-drinking\/#Measurement_Approaches\" title=\"Measurement Approaches\">Measurement Approaches<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-5\" href=\"https:\/\/chimaytech.net\/vi\/understanding-water-age-and-its-impact-on-drinking\/#Factors_Influencing_Water_Age\" title=\"Factors Influencing Water Age\">Factors Influencing Water Age<\/a><\/li><\/ul><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-6\" href=\"https:\/\/chimaytech.net\/vi\/understanding-water-age-and-its-impact-on-drinking\/#Water_Quality_Impacts_of_Extended_Residence_Time\" title=\"Water Quality Impacts of Extended Residence Time\">Water Quality Impacts of Extended Residence Time<\/a><ul class='ez-toc-list-level-3'><li class='ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-7\" href=\"https:\/\/chimaytech.net\/vi\/understanding-water-age-and-its-impact-on-drinking\/#Disinfectant_Decay_Dynamics\" title=\"Disinfectant Decay Dynamics\">Disinfectant Decay Dynamics<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-8\" href=\"https:\/\/chimaytech.net\/vi\/understanding-water-age-and-its-impact-on-drinking\/#Microbial_Regrowth_Risks\" title=\"Microbial Regrowth Risks\">Microbial Regrowth Risks<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-9\" href=\"https:\/\/chimaytech.net\/vi\/understanding-water-age-and-its-impact-on-drinking\/#Chemical_Changes_During_Distribution\" title=\"Chemical Changes During Distribution\">Chemical Changes During Distribution<\/a><\/li><\/ul><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-10\" href=\"https:\/\/chimaytech.net\/vi\/understanding-water-age-and-its-impact-on-drinking\/#Optimization_Strategies\" title=\"Optimization Strategies\">Optimization Strategies<\/a><ul class='ez-toc-list-level-3'><li class='ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-11\" href=\"https:\/\/chimaytech.net\/vi\/understanding-water-age-and-its-impact-on-drinking\/#Hydraulic_Management_Approaches\" title=\"Hydraulic Management Approaches\">Hydraulic Management Approaches<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-12\" href=\"https:\/\/chimaytech.net\/vi\/understanding-water-age-and-its-impact-on-drinking\/#Operational_Monitoring_Integration\" title=\"Operational Monitoring Integration\">Operational Monitoring Integration<\/a><\/li><\/ul><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-13\" href=\"https:\/\/chimaytech.net\/vi\/understanding-water-age-and-its-impact-on-drinking\/#Regulatory_Compliance_Considerations\" title=\"Regulatory Compliance Considerations\">Regulatory Compliance Considerations<\/a><ul class='ez-toc-list-level-3'><li class='ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-14\" href=\"https:\/\/chimaytech.net\/vi\/understanding-water-age-and-its-impact-on-drinking\/#Federal_Requirements\" title=\"Federal Requirements\">Federal Requirements<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-15\" href=\"https:\/\/chimaytech.net\/vi\/understanding-water-age-and-its-impact-on-drinking\/#International_Standards\" title=\"International Standards\">International Standards<\/a><\/li><\/ul><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-16\" href=\"https:\/\/chimaytech.net\/vi\/understanding-water-age-and-its-impact-on-drinking\/#Conclusion\" title=\"Conclusion\">Conclusion<\/a><\/li><\/ul><\/nav><\/div>\n<h2><span class=\"ez-toc-section\" id=\"Key_Takeaways\"><\/span>Key Takeaways<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<ul>\n<li>Water age in distribution networks ranges from <strong>1-72 hours<\/strong>, directly affecting disinfectant decay<\/li>\n<li>Chlorine residual decreases by <strong>30-40%<\/strong> for every 24 hours of increased residence time<\/li>\n<li><strong>Microbial regrowth<\/strong> accelerates when water age exceeds <strong>48 hours<\/strong>, increasing health risks<\/li>\n<li>ChiMay&#39;s inline pH meters enable real-time monitoring that correlates water quality with hydraulic residence time<\/li>\n<li>Utilities implementing hydraulic modeling tools report <strong>25% reduction<\/strong> in water quality complaints<\/li>\n<\/ul>\n<h2><span class=\"ez-toc-section\" id=\"Introduction\"><\/span>Introduction<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>Water age\u2014the time elapsed between water treatment and delivery to customers\u2014represents one of the most critical parameters affecting drinking water quality. While treatment plants produce water that meets or exceeds regulatory standards, the distribution network itself can become a source of water quality degradation through processes that occur during transit.<\/p>\n<p>According to the <strong>World Health Organization (WHO) 2024 Water Quality Guidelines<\/strong>, <strong>25-35%<\/strong> of water quality violations in developed countries originate from distribution system issues rather than treatment failures. This statistic highlights the importance of understanding and managing water age as part of comprehensive drinking water management strategies.<\/p>\n<h2><span class=\"ez-toc-section\" id=\"Defining_Water_Age_in_Distribution_Networks\"><\/span>Defining Water Age in Distribution Networks<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<h3><span class=\"ez-toc-section\" id=\"Measurement_Approaches\"><\/span>Measurement Approaches<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p>Water age is typically calculated using <strong>hydraulic water quality models<\/strong> that combine flow patterns with pipe geometry and topology. The <strong>EPANET<\/strong> modeling software, developed by the <strong>U.S. Environmental Protection Agency (EPA)<\/strong>, enables utilities to simulate water age under varying operational conditions.<\/p>\n<p>Calculation methodologies include:<\/p>\n<ul>\n<li><strong>Hydraulic residence time<\/strong>: Time for a particle to travel from source to measurement point<\/li>\n<li><strong>Age distribution analysis<\/strong>: Statistical characterization of ages across the network<\/li>\n<li><strong>Tracer studies<\/strong>: Chemical marker deployment to validate model predictions<\/li>\n<\/ul>\n<p>Accurate water age calculation requires validated hydraulic models. The <strong>American Water Works Association (AWWA)<\/strong> recommends calibrating models against <strong>minimum 12 months<\/strong> of operational data to ensure predictive accuracy within <strong>\u00b115%<\/strong>.<\/p>\n<h3><span class=\"ez-toc-section\" id=\"Factors_Influencing_Water_Age\"><\/span>Factors Influencing Water Age<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p>Multiple operational and infrastructure variables affect water age throughout distribution systems:<\/p>\n<table border=\"1\" cellpadding=\"5\" cellspacing=\"0\">\n<thead>\n<tr>\n<th>Factor<\/th>\n<th>Impact on Water Age<\/th>\n<th>Typical Variation<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>Network configuration<\/td>\n<td>Storage tank cycling time<\/td>\n<td>4-72 hours<\/td>\n<\/tr>\n<tr>\n<td>Pipe diameter<\/td>\n<td>Flow velocity variations<\/td>\n<td>0.1-3.0 m\/s<\/td>\n<\/tr>\n<tr>\n<td>Demand patterns<\/td>\n<td>Peak vs. off-peak residence time<\/td>\n<td>200%+ differences<\/td>\n<\/tr>\n<tr>\n<td>Tank operating strategies<\/td>\n<td>Drawdown\/refill cycles<\/td>\n<td>6-48 hours<\/td>\n<\/tr>\n<tr>\n<td>System layout<\/td>\n<td>Dead-end locations<\/td>\n<td>72+ hours<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>ChiMay&#39;s paddle wheel inserted flow meters provide essential data for validating water age calculations by measuring actual flow velocities at strategic locations. These measurements enable continuous model refinement and anomaly detection.<\/p>\n<h2><span class=\"ez-toc-section\" id=\"Water_Quality_Impacts_of_Extended_Residence_Time\"><\/span>Water Quality Impacts of Extended Residence Time<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<h3><span class=\"ez-toc-section\" id=\"Disinfectant_Decay_Dynamics\"><\/span>Disinfectant Decay Dynamics<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p>Chlorine and chloramine residuals\u2014critical for maintaining microbial safety\u2014degrade continuously during distribution. The <strong>EPA Disinfection By-Product Rules<\/strong> require utilities to maintain residual levels that protect public health while minimizing DBP formation.<\/p>\n<p>Chlorine decay follows <strong>first-order kinetics<\/strong>, with decay rates influenced by:<\/p>\n<ul>\n<li><strong>Water temperature<\/strong>: Decay rates increase <strong>100%<\/strong> for every 10\u00b0C temperature rise<\/li>\n<li><strong>pH levels<\/strong>: Higher pH accelerates chlorine decay by <strong>20-30%<\/strong><\/li>\n<li><strong>Natural organic matter (NOM)<\/strong>: Reacts with chlorine, consuming residuals<\/li>\n<li><strong>Pipe materials<\/strong>: Corrosion and biofilm formation increase chlorine demand<\/li>\n<\/ul>\n<p>The <strong>Journal of Water Supply: Research and Technology &#8211; AQUA<\/strong> reports that chlorine residuals can decrease from <strong>2.0 mg\/L at treatment<\/strong> to <strong>&lt;0.2 mg\/L<\/strong> in distribution sections with <strong>48+ hours<\/strong> residence time, potentially falling below protective thresholds.<\/p>\n<p>ChiMay&#39;s residual chlorine transmitters provide continuous monitoring capabilities that enable utilities to track disinfectant decay throughout their networks, correlating residual levels with calculated water age.<\/p>\n<h3><span class=\"ez-toc-section\" id=\"Microbial_Regrowth_Risks\"><\/span>Microbial Regrowth Risks<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p>Extended residence time creates conditions favorable for microbial colonization in distribution systems. The <strong>International Society for Infectious Diseases (ISID)<\/strong> identifies <strong>biofilm formation<\/strong> as the primary mechanism for water quality deterioration in aging networks.<\/p>\n<p>Risk factors include:<\/p>\n<ul>\n<li><strong>Opportunistic pathogens<\/strong>: <em>Legionella<\/em>, <em>Mycobacterium avium complex<\/em>, <em>Pseudomonas aeruginosa<\/em><\/li>\n<li><strong>Heterotrophic plate count (HPC) bacteria<\/strong>: Increase exponentially when water age exceeds <strong>48 hours<\/strong><\/li>\n<li><strong>Taste and odor issues<\/strong>: Geosmin and 2-methylisoborneol production<\/li>\n<\/ul>\n<p>The <strong>Centers for Disease Control and Prevention (CDC)<\/strong> documented <strong>28 waterborne disease outbreaks<\/strong> in the U.S. between 2015-2020, with <strong>18%<\/strong> attributed to distribution system issues associated with extended water age.<\/p>\n<h3><span class=\"ez-toc-section\" id=\"Chemical_Changes_During_Distribution\"><\/span>Chemical Changes During Distribution<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p>Water chemistry evolves during transit through distribution networks, potentially creating compliance issues:<\/p>\n<ul>\n<li><strong>Lead leaching<\/strong>: Increases when pH adjustments degrade over time<\/li>\n<li><strong>Corrosion control<\/strong>: Orthophosphate inhibitors degrade, affecting lead and copper corrosion rates<\/li>\n<li><strong>Disinfection by-product (DBP) formation<\/strong>: Trihalomethanes (TTHM) and haloacetic acids (HAA5) increase with residence time<\/li>\n<\/ul>\n<p>The <strong>EPA Lead and Copper Rule Revisions (LCRR)<\/strong> require utilities to assess and address lead exposure risks throughout distribution systems, with particular attention to areas where water age exceeds <strong>24 hours<\/strong>.<\/p>\n<p>ChiMay&#39;s inline pH meters enable continuous monitoring of pH stability throughout networks, providing early warning when chemical treatments degrade due to extended residence time.<\/p>\n<h2><span class=\"ez-toc-section\" id=\"Optimization_Strategies\"><\/span>Optimization Strategies<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<h3><span class=\"ez-toc-section\" id=\"Hydraulic_Management_Approaches\"><\/span>Hydraulic Management Approaches<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p>Utilities employ multiple strategies to minimize water age and maintain quality:<\/p>\n<p><strong>Tank Management Optimization<\/strong>: Implementing <strong>variable-level setpoints<\/strong> and <strong>floating operation modes<\/strong> reduces residence times by <strong>30-40%<\/strong> compared to conventional fill-and-draw cycles.<\/p>\n<p><strong>Dead-end Flushing Programs<\/strong>: Scheduled directional flushing removes stagnant water from terminal pipe segments. The <strong>AWWA<\/strong> recommends flushing frequencies of <strong>quarterly<\/strong> for systems with average water age &gt;<strong>48 hours<\/strong> in dead ends.<\/p>\n<p><strong>System Pressure Regulation<\/strong>: Maintaining optimal pressures reduces dead-end stagnation and minimizes infiltration\/exfiltration events. Smart pressure management valves reduce pressure-related water age variations by <strong>25%<\/strong>.<\/p>\n<h3><span class=\"ez-toc-section\" id=\"Operational_Monitoring_Integration\"><\/span>Operational Monitoring Integration<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p>Effective water age management requires integration of hydraulic modeling with real-time monitoring:<\/p>\n<ul>\n<li><strong>SCADA system integration<\/strong>: Connects model predictions with operational data<\/li>\n<li><strong>Geospatial visualization<\/strong>: Maps water age distributions across service territories<\/li>\n<li><strong>Predictive analytics<\/strong>: Anticipates quality degradation events before occurrence<\/li>\n<\/ul>\n<p>The <strong>Smart Water Networks Forum (SWAN)<\/strong> estimates that utilities implementing integrated monitoring systems reduce water quality incidents by <strong>60%<\/strong> and achieve <strong>$1.8 million<\/strong> average annual savings through proactive management.<\/p>\n<p>ChiMay&#39;s 4-in-1 multi-parameter sensors provide comprehensive monitoring capabilities, simultaneously measuring pH, ORP, conductivity, and temperature. This integrated data enables correlation of water quality parameters with hydraulic residence time.<\/p>\n<h2><span class=\"ez-toc-section\" id=\"Regulatory_Compliance_Considerations\"><\/span>Regulatory Compliance Considerations<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<h3><span class=\"ez-toc-section\" id=\"Federal_Requirements\"><\/span>Federal Requirements<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p>U.S. water utilities must comply with multiple regulations influenced by water age:<\/p>\n<ul>\n<li><strong>Total Coliform Rule<\/strong>: Requires monitoring for microbial contamination in distribution systems<\/li>\n<li><strong>Stage 2 DBP Rule<\/strong>: Controls disinfection by-products formed during distribution<\/li>\n<li><strong>Lead and Copper Rule<\/strong>: Addresses corrosion control throughout the distribution network<\/li>\n<li><strong>Revised Total Coliform Rule<\/strong>: Includes operational evaluations triggered by water age-related quality issues<\/li>\n<\/ul>\n<p>The <strong>EPA&#39;s Revised Total Coliform Rule (RTCR)<\/strong> requires utilities to conduct <strong>distribution system evaluations (DSE)<\/strong> when water quality violations occur, with particular attention to hydraulic residence time and water age.<\/p>\n<h3><span class=\"ez-toc-section\" id=\"International_Standards\"><\/span>International Standards<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p>Various jurisdictions have established water age guidelines:<\/p>\n<table border=\"1\" cellpadding=\"5\" cellspacing=\"0\">\n<thead>\n<tr>\n<th>Jurisdiction<\/th>\n<th>Maximum Recommended Water Age<\/th>\n<th>Compliance Approach<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>United Kingdom<\/td>\n<td>72 hours<\/td>\n<td>Water quality monitoring programs<\/td>\n<\/tr>\n<tr>\n<td>Australia<\/td>\n<td>48 hours<\/td>\n<td>Hydraulic modeling requirements<\/td>\n<\/tr>\n<tr>\n<td>Canada<\/td>\n<td>72 hours<\/td>\n<td>Distribution system maintenance plans<\/td>\n<\/tr>\n<tr>\n<td>EU<\/td>\n<td>Varies by member state<\/td>\n<td>Risk assessment frameworks<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<h2><span class=\"ez-toc-section\" id=\"Conclusion\"><\/span>Conclusion<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>Water age represents a critical factor affecting drinking water quality throughout distribution networks. Understanding and managing hydraulic residence time enables utilities to maintain water quality, protect public health, and achieve regulatory compliance.<\/p>\n<p>Challenges include balancing operational constraints with quality objectives, requiring sophisticated modeling tools and continuous monitoring capabilities. ChiMay&#39;s sensor portfolio provides essential data for these management efforts, enabling utilities to correlate water quality parameters with hydraulic characteristics.<\/p>\n<p>The future of water age management lies in integration\u2014combining hydraulic modeling, real-time monitoring, and predictive analytics to create distribution networks that deliver consistent, high-quality water to customers while minimizing operational costs and infrastructure investments.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Key Takeaways Water age in distribution networks ranges from 1-72 hours, directly affecting disinfectant decay Chlorine residual decreases by 30-40% for every 24 hours of increased residence time Microbial regrowth accelerates when water age exceeds 48 hours, increasing health risks ChiMay&#39;s inline pH meters enable real-time monitoring that correlates water quality with hydraulic residence time&#8230;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"_kad_post_transparent":"","_kad_post_title":"","_kad_post_layout":"","_kad_post_sidebar_id":"","_kad_post_content_style":"","_kad_post_vertical_padding":"","_kad_post_feature":"","_kad_post_feature_position":"","_kad_post_header":false,"_kad_post_footer":false},"categories":[1],"tags":[],"translation":{"provider":"WPGlobus","version":"2.12.0","language":"vi","enabled_languages":["en","es","de","fr","ru","pt","ar","ja","ko","it","id","hi","th","vi","tr"],"languages":{"en":{"title":true,"content":true,"excerpt":false},"es":{"title":false,"content":false,"excerpt":false},"de":{"title":false,"content":false,"excerpt":false},"fr":{"title":false,"content":false,"excerpt":false},"ru":{"title":false,"content":false,"excerpt":false},"pt":{"title":false,"content":false,"excerpt":false},"ar":{"title":false,"content":false,"excerpt":false},"ja":{"title":false,"content":false,"excerpt":false},"ko":{"title":false,"content":false,"excerpt":false},"it":{"title":false,"content":false,"excerpt":false},"id":{"title":false,"content":false,"excerpt":false},"hi":{"title":false,"content":false,"excerpt":false},"th":{"title":false,"content":false,"excerpt":false},"vi":{"title":false,"content":false,"excerpt":false},"tr":{"title":false,"content":false,"excerpt":false}}},"_links":{"self":[{"href":"https:\/\/chimaytech.net\/vi\/wp-json\/wp\/v2\/posts\/30866"}],"collection":[{"href":"https:\/\/chimaytech.net\/vi\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/chimaytech.net\/vi\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/chimaytech.net\/vi\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/chimaytech.net\/vi\/wp-json\/wp\/v2\/comments?post=30866"}],"version-history":[{"count":0,"href":"https:\/\/chimaytech.net\/vi\/wp-json\/wp\/v2\/posts\/30866\/revisions"}],"wp:attachment":[{"href":"https:\/\/chimaytech.net\/vi\/wp-json\/wp\/v2\/media?parent=30866"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/chimaytech.net\/vi\/wp-json\/wp\/v2\/categories?post=30866"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/chimaytech.net\/vi\/wp-json\/wp\/v2\/tags?post=30866"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}