{"id":31003,"date":"2026-06-27T10:55:58","date_gmt":"2026-06-27T02:55:58","guid":{"rendered":"https:\/\/shchimay.com\/what-causes-foam-buildup-in-recycled-paper-mill-process-water-a-diagnostic-guide-by-shanghai-chimay\/"},"modified":"2026-06-27T10:55:58","modified_gmt":"2026-06-27T02:55:58","slug":"what-causes-foam-buildup-in-recycled-paper-mill-process-water-a-diagnostic-guide-by-shanghai-chimay","status":"publish","type":"post","link":"https:\/\/shchimay.com\/zh\/what-causes-foam-buildup-in-recycled-paper-mill-process-water-a-diagnostic-guide-by-shanghai-chimay\/","title":{"rendered":"What Causes Foam Buildup in Recycled Paper Mill Process Water? A Diagnostic Guide by Shanghai ChiMay"},"content":{"rendered":"<hr \/>\n<p>title: &ldquo;What Causes Foam Buildup in Recycled Paper Mill Process Water? A Diagnostic Guide by Shanghai ChiMay&rdquo;<br \/>\ndate: 2026-06-26<br \/>\ntype: \u7591\u95ee\u6807\u9898\u578b<\/p>\n<hr \/>\n<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-1'><a class=\"ez-toc-link ez-toc-heading-1\" href=\"https:\/\/shchimay.com\/zh\/what-causes-foam-buildup-in-recycled-paper-mill-process-water-a-diagnostic-guide-by-shanghai-chimay\/#What_Causes_Foam_Buildup_in_Recycled_Paper_Mill_Process_Water_A_Diagnostic_Guide_by_Shanghai_ChiMay\" title=\"What Causes Foam Buildup in Recycled Paper Mill Process Water? A Diagnostic Guide by Shanghai ChiMay\">What Causes Foam Buildup in Recycled Paper Mill Process Water? A Diagnostic Guide by Shanghai ChiMay<\/a><ul class='ez-toc-list-level-2'><li class='ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-2\" href=\"https:\/\/shchimay.com\/zh\/what-causes-foam-buildup-in-recycled-paper-mill-process-water-a-diagnostic-guide-by-shanghai-chimay\/#Why_Foam_Is_a_Persistent_Problem_in_Recycled_Paper_Mills\" title=\"Why Foam Is a Persistent Problem in Recycled Paper Mills\">Why Foam Is a Persistent Problem in Recycled Paper Mills<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-3\" href=\"https:\/\/shchimay.com\/zh\/what-causes-foam-buildup-in-recycled-paper-mill-process-water-a-diagnostic-guide-by-shanghai-chimay\/#Cause_1_Surfactant_Overload_from_Deinking_Chemistry\" title=\"Cause 1: Surfactant Overload from Deinking Chemistry\">Cause 1: Surfactant Overload from Deinking Chemistry<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-4\" href=\"https:\/\/shchimay.com\/zh\/what-causes-foam-buildup-in-recycled-paper-mill-process-water-a-diagnostic-guide-by-shanghai-chimay\/#Cause_2_Microbial_Slime_Breakdown_Releasing_Organics\" title=\"Cause 2: Microbial Slime Breakdown Releasing Organics\">Cause 2: Microbial Slime Breakdown Releasing Organics<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-5\" href=\"https:\/\/shchimay.com\/zh\/what-causes-foam-buildup-in-recycled-paper-mill-process-water-a-diagnostic-guide-by-shanghai-chimay\/#Cause_3_Dissolved_Air_Supersaturation_from_Pump_Cavitation\" title=\"Cause 3: Dissolved Air Supersaturation from Pump Cavitation\">Cause 3: Dissolved Air Supersaturation from Pump Cavitation<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-6\" href=\"https:\/\/shchimay.com\/zh\/what-causes-foam-buildup-in-recycled-paper-mill-process-water-a-diagnostic-guide-by-shanghai-chimay\/#Cause_4_pH-Driven_Fatty-Acid_Emulsification\" title=\"Cause 4: pH-Driven Fatty-Acid Emulsification\">Cause 4: pH-Driven Fatty-Acid Emulsification<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-7\" href=\"https:\/\/shchimay.com\/zh\/what-causes-foam-buildup-in-recycled-paper-mill-process-water-a-diagnostic-guide-by-shanghai-chimay\/#Building_a_Diagnostic_Workflow\" title=\"Building a Diagnostic Workflow\">Building a Diagnostic Workflow<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-8\" href=\"https:\/\/shchimay.com\/zh\/what-causes-foam-buildup-in-recycled-paper-mill-process-water-a-diagnostic-guide-by-shanghai-chimay\/#Why_Defoamer_Alone_Is_Not_the_Answer\" title=\"Why Defoamer Alone Is Not the Answer\">Why Defoamer Alone Is Not the Answer<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-9\" href=\"https:\/\/shchimay.com\/zh\/what-causes-foam-buildup-in-recycled-paper-mill-process-water-a-diagnostic-guide-by-shanghai-chimay\/#Sensor_Configuration_for_Foam_Diagnostics\" title=\"Sensor Configuration for Foam Diagnostics\">Sensor Configuration for Foam Diagnostics<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-10\" href=\"https:\/\/shchimay.com\/zh\/what-causes-foam-buildup-in-recycled-paper-mill-process-water-a-diagnostic-guide-by-shanghai-chimay\/#Conclusion\" title=\"Conclusion\">Conclusion<\/a><\/li><\/ul><\/li><\/ul><\/nav><\/div>\n<h1 id=\"what-causes-foam-buildup-in-recycled-paper-mill-process-water-a-diagnostic-guide-by-shanghai-chimay\"><span class=\"ez-toc-section\" id=\"What_Causes_Foam_Buildup_in_Recycled_Paper_Mill_Process_Water_A_Diagnostic_Guide_by_Shanghai_ChiMay\"><\/span>What Causes Foam Buildup in Recycled Paper Mill Process Water? A Diagnostic Guide by Shanghai ChiMay<span class=\"ez-toc-section-end\"><\/span><\/h1>\n<p><strong>Key Takeaways:<\/strong><br \/>\n&#8211; Foam in recycled paper mill process water is rarely a single-cause problem; it is the visible symptom of underlying surfactant, fiber, and microbial dynamics interacting in closed water loops<br \/>\n&#8211; The four most common diagnostic patterns are surfactant overload (deinking residues), microbial slime breakdown, dissolved air supersaturation, and pH-driven fatty-acid emulsification<br \/>\n&#8211; Online monitoring of pH, conductivity, ORP, and suspended solids provides the diagnostic fingerprint needed to differentiate root causes within hours rather than days<br \/>\n&#8211; Shanghai ChiMay multi-parameter sensors deliver the correlated chemistry data that defoamer dosing systems need to operate efficiently and avoid over-treatment<br \/>\n&#8211; The <strong>Confederation of European Paper Industries (CEPI)<\/strong> has reported that mills running real-time foam-related chemistry monitoring reduce defoamer consumption by <strong>22-35%<\/strong> while improving foam control reliability<\/p>\n<h2 id=\"why-foam-is-a-persistent-problem-in-recycled-paper-mills\"><span class=\"ez-toc-section\" id=\"Why_Foam_Is_a_Persistent_Problem_in_Recycled_Paper_Mills\"><\/span>Why Foam Is a Persistent Problem in Recycled Paper Mills<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>Recycled paper mills are far more foam-prone than virgin fiber mills. The reason is structural: recovered paper carries a legacy of printing inks, sizing agents, adhesives, coating residues, and surfactants from prior life cycles. Combine this with closed water loops that concentrate dissolved organics, and the result is process water with a strong tendency to entrain air and stabilize foam blankets. The operational consequences are real: foam interferes with flotation deinking, masks level sensors, disrupts wire pit operation, and can carry over into finished sheet defects.<\/p>\n<p>The first step in solving foam problems is correctly diagnosing what is causing them. This guide walks through the four dominant diagnostic patterns and the monitoring data that confirms each one.<\/p>\n<h2 id=\"cause-1-surfactant-overload-from-deinking-chemistry\"><span class=\"ez-toc-section\" id=\"Cause_1_Surfactant_Overload_from_Deinking_Chemistry\"><\/span>Cause 1: Surfactant Overload from Deinking Chemistry<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>Deinking flotation cells deliberately introduce surfactants to detach ink particles from fiber. When surfactant carryover into the wet end exceeds the system&rsquo;s tolerance, foam stability rises sharply.<\/p>\n<p><strong>Diagnostic fingerprint:<\/strong><br \/>\n&#8211; Conductivity drift upward over <strong>24-72 hours<\/strong>, indicating dissolved organics accumulation<br \/>\n&#8211; pH drift toward the <strong>8.0-9.5<\/strong> range as deinking chemistry compounds<br \/>\n&#8211; ORP shifting toward more reducing values as oxidizable surfactants accumulate<br \/>\n&#8211; Foam blanket is white, glossy, and persistent<\/p>\n<p><strong>Root cause and intervention:<\/strong> The mill is operating deinking chemistry at higher dose than necessary, or filtrate from deinking is being recycled into chemistry-sensitive zones. Shanghai ChiMay multi-parameter sensors installed on the flotation overflow and on the wet-end white water silo confirm the chemistry transit pattern and guide either dose reduction or selective filtrate isolation.<\/p>\n<h2 id=\"cause-2-microbial-slime-breakdown-releasing-organics\"><span class=\"ez-toc-section\" id=\"Cause_2_Microbial_Slime_Breakdown_Releasing_Organics\"><\/span>Cause 2: Microbial Slime Breakdown Releasing Organics<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>Closed water loops in recycled paper mills harbor microbial colonies. When biocide dosing falls out of balance, slime breakdown releases extracellular polymeric substances into the bulk water, dramatically increasing foam-stabilizing surfactant load.<\/p>\n<p><strong>Diagnostic fingerprint:<\/strong><br \/>\n&#8211; ORP drops sharply (often <strong>80-150 mV<\/strong>) over <strong>6-12 hours<\/strong> as biocide depletes<br \/>\n&#8211; Conductivity may remain stable, distinguishing this from surfactant overload<br \/>\n&#8211; pH may drift slightly acidic as microbial activity produces organic acids<br \/>\n&#8211; Foam is yellowish, sticky, and accompanies visible slime patches on tank walls<\/p>\n<p><strong>Root cause and intervention:<\/strong> Biocide rotation is incomplete or dose is inadequate for current bioload. Real-time ORP monitoring is the highest-value diagnostic signal because it falls before microbial counts spike. Shanghai ChiMay 4-in-1 multi-parameter sensors capture ORP simultaneously with pH, conductivity, and temperature, allowing the control room to distinguish slime-driven foam from chemistry-driven foam within minutes.<\/p>\n<h2 id=\"cause-3-dissolved-air-supersaturation-from-pump-cavitation\"><span class=\"ez-toc-section\" id=\"Cause_3_Dissolved_Air_Supersaturation_from_Pump_Cavitation\"><\/span>Cause 3: Dissolved Air Supersaturation from Pump Cavitation<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>Mechanical foam is often misdiagnosed as a chemistry problem. When pumps cavitate or when piping geometry entrains air, the water becomes supersaturated and air comes out of solution at low-pressure points\u2014often visibly at chest tanks and wire pits.<\/p>\n<p><strong>Diagnostic fingerprint:<\/strong><br \/>\n&#8211; Foam appears suddenly when a specific pump is running and disappears when it stops<br \/>\n&#8211; ORP, pH, and conductivity remain stable; the chemistry tells you it is not a chemistry problem<br \/>\n&#8211; Dissolved oxygen may show elevated readings against process expectation<br \/>\n&#8211; Foam is fine-textured, short-lived, and reforms cyclically with pump operation<\/p>\n<p><strong>Root cause and intervention:<\/strong> Hydraulic fix, not a chemistry fix. Confirming this pattern with a Shanghai ChiMay DO transmitter on the suspect line and seeing that conductivity, pH, and ORP are stable saves the mill from chasing chemical solutions to a mechanical problem\u2014a common and costly mistake.<\/p>\n<h2 id=\"cause-4-ph-driven-fatty-acid-emulsification\"><span class=\"ez-toc-section\" id=\"Cause_4_pH-Driven_Fatty-Acid_Emulsification\"><\/span>Cause 4: pH-Driven Fatty-Acid Emulsification<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>Recovered paper carries residual sizing agents and pitch derived from wood resin acids. When wet-end pH drifts into the <strong>5.5-6.5<\/strong> range, these fatty acids partially ionize and form emulsified droplets that stabilize foam blankets at the chest and headbox.<\/p>\n<p><strong>Diagnostic fingerprint:<\/strong><br \/>\n&#8211; pH measurement drifts below the operating target (often by <strong>0.5-1.0 unit<\/strong>)<br \/>\n&#8211; Conductivity may rise modestly due to acid carryover<br \/>\n&#8211; Foam blanket is creamy, with visible droplet structure under close inspection<br \/>\n&#8211; Pitch deposits begin appearing on stationary surfaces within <strong>48-72 hours<\/strong> of pH excursion<\/p>\n<p><strong>Root cause and intervention:<\/strong> pH control loop is inadequate or alum\/sulfate dosing has shifted the chemistry balance. The Shanghai ChiMay in-line <a href=\"\/tag\/pH-Meter\" target=\"_blank\"><strong><a href=\"\/tag\/ph-meter\/\" target=\"_blank\"><strong>ph meter<\/strong><\/a><\/strong><\/a> provides the closed-loop control signal needed to hold pH at the target setpoint, typically <strong>7.0-7.5<\/strong> for recycled paper machines, preventing the fatty-acid emulsification cascade.<\/p>\n<h2 id=\"building-a-diagnostic-workflow\"><span class=\"ez-toc-section\" id=\"Building_a_Diagnostic_Workflow\"><\/span>Building a Diagnostic Workflow<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>A practical diagnostic workflow for paper mill operators looks like this:<\/p>\n<ol>\n<li><strong>Observation<\/strong>: foam character (color, persistence, texture, location)<\/li>\n<li><strong>Quick read<\/strong>: check pH, conductivity, ORP, and DO on the relevant Shanghai ChiMay sensor panel<\/li>\n<li><strong>Pattern match<\/strong>: compare the chemistry fingerprint to the four diagnostic patterns above<\/li>\n<li><strong>Targeted intervention<\/strong>: dose adjustment, hydraulic correction, or biocide rotation based on which pattern fits<\/li>\n<\/ol>\n<p>The combined diagnostic stack typically resolves foam events in under <strong>2 hours<\/strong> when monitoring is in place, compared to <strong>8-24 hours<\/strong> when relying on grab samples and trial-and-error defoamer dosing.<\/p>\n<h2 id=\"why-defoamer-alone-is-not-the-answer\"><span class=\"ez-toc-section\" id=\"Why_Defoamer_Alone_Is_Not_the_Answer\"><\/span>Why Defoamer Alone Is Not the Answer<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>Many mills default to increasing defoamer dose when foam appears. The <strong>TAPPI Wet End Chemistry Subcommittee<\/strong> has documented that excessive defoamer dosing causes its own problems: paper machine sheet defects, downstream deposit formation, and runaway dosing costs. Defoamer is a tactical intervention; the strategic solution is online chemistry monitoring that catches the foam root cause early enough to fix the underlying chemistry or hydraulics.<\/p>\n<p>Mills with real-time chemistry monitoring on closed water loops typically reduce defoamer consumption by <strong>22-35%<\/strong> while improving foam control reliability\u2014a substantial operating cost saving on top of the quality benefits.<\/p>\n<h2 id=\"sensor-configuration-for-foam-diagnostics\"><span class=\"ez-toc-section\" id=\"Sensor_Configuration_for_Foam_Diagnostics\"><\/span>Sensor Configuration for Foam Diagnostics<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>The recommended Shanghai ChiMay sensor configuration for diagnostic-grade foam monitoring includes:<\/p>\n<ul>\n<li><strong>In-line <a href=\"\/tag\/pH-Meter\" target=\"_blank\"><strong><a href=\"\/tag\/ph-meter\/\" target=\"_blank\"><strong>ph meter<\/strong><\/a><\/strong><\/a><\/strong> at the white water silo and at the headbox feed<\/li>\n<li><strong>In-line <a href=\"\/tag\/Conductivity-Meter\" target=\"_blank\"><strong><a href=\"\/tag\/conductivity-meter\/\" target=\"_blank\"><strong>conductivity meter<\/strong><\/a><\/strong><\/a><\/strong> at the same two points<\/li>\n<li><strong>4-in-1 multi-parameter sensor<\/strong> at the cloudy filtrate line, capturing pH, ORP, conductivity, and temperature<\/li>\n<li><strong>Suspended solids sensor<\/strong> at the deinking flotation overflow<\/li>\n<li><strong>DO transmitter<\/strong> at the chest tank pump discharge, optional, useful for cavitation diagnostics<\/li>\n<\/ul>\n<p>The full suite reports to a unified controller and provides the diagnostic fingerprint required to differentiate all four foam causes without ambiguity.<\/p>\n<h2 id=\"conclusion\"><span class=\"ez-toc-section\" id=\"Conclusion\"><\/span>Conclusion<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>Foam in recycled paper mill process water is a chemistry signal first and a chemistry signal second. The four dominant causes\u2014surfactant overload, microbial slime breakdown, dissolved air supersaturation, and pH-driven fatty-acid emulsification\u2014each leave a distinctive fingerprint in pH, conductivity, ORP, and DO data. Mills equipped with continuous chemistry monitoring resolve foam events faster, use less defoamer, and protect product quality more reliably than mills relying on visual inspection and reactive chemistry dosing. The Shanghai ChiMay sensor portfolio is engineered specifically for this diagnostic role in modern recycled paper mill operation.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>title: &ldquo;What Causes Foam Buildup in Recycled Pape&#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":[158,134429,11579,134481],"translation":{"provider":"WPGlobus","version":"2.12.0","language":"zh","enabled_languages":["en","zh","es","de","fr","ru","pt","ar","ja","ko","it","id","hi","th","vi","tr"],"languages":{"en":{"title":true,"content":true,"excerpt":false},"zh":{"title":false,"content":false,"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:\/\/shchimay.com\/zh\/wp-json\/wp\/v2\/posts\/31003"}],"collection":[{"href":"https:\/\/shchimay.com\/zh\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/shchimay.com\/zh\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/shchimay.com\/zh\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/shchimay.com\/zh\/wp-json\/wp\/v2\/comments?post=31003"}],"version-history":[{"count":0,"href":"https:\/\/shchimay.com\/zh\/wp-json\/wp\/v2\/posts\/31003\/revisions"}],"wp:attachment":[{"href":"https:\/\/shchimay.com\/zh\/wp-json\/wp\/v2\/media?parent=31003"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/shchimay.com\/zh\/wp-json\/wp\/v2\/categories?post=31003"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/shchimay.com\/zh\/wp-json\/wp\/v2\/tags?post=31003"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}