{"id":31289,"date":"2026-08-07T23:08:23","date_gmt":"2026-08-07T15:08:23","guid":{"rendered":"https:\/\/shchimay.com\/how-trans-membrane-pressure-and-turbidity-together-reveal-fouling-onset-a-shanghai-chimay\/"},"modified":"2026-08-07T23:08:23","modified_gmt":"2026-08-07T15:08:23","slug":"how-trans-membrane-pressure-and-turbidity-together-reveal-fouling-onset-a-shanghai-chimay","status":"publish","type":"post","link":"https:\/\/shchimay.com\/fr\/how-trans-membrane-pressure-and-turbidity-together-reveal-fouling-onset-a-shanghai-chimay\/","title":{"rendered":"How Trans-Membrane Pressure and Turbidity Together Reveal Fouling Onset: A Shanghai ChiMay Field Note"},"content":{"rendered":"<hr \/>\n<p>title: &ldquo;How Trans-Membrane Pressure and Turbidity Together Reveal Fouling Onset: A Shanghai ChiMay Field Note&rdquo;<br \/>\ndate: 2026-07-14<br \/>\ntype: Technical-Introduction<br \/>\ntheme: Membrane Bioreactor (MBR) &amp; Anaerobic MBR Innovations<\/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\/fr\/how-trans-membrane-pressure-and-turbidity-together-reveal-fouling-onset-a-shanghai-chimay\/#How_Trans-Membrane_Pressure_and_Turbidity_Together_Reveal_Fouling_Onset_A_Shanghai_ChiMay_Field_Note\" title=\"How Trans-Membrane Pressure and Turbidity Together Reveal Fouling Onset: A Shanghai ChiMay Field Note\">How Trans-Membrane Pressure and Turbidity Together Reveal Fouling Onset: A Shanghai ChiMay Field Note<\/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\/fr\/how-trans-membrane-pressure-and-turbidity-together-reveal-fouling-onset-a-shanghai-chimay\/#The_short_version\" title=\"The short version\">The short version<\/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\/fr\/how-trans-membrane-pressure-and-turbidity-together-reveal-fouling-onset-a-shanghai-chimay\/#Why_one_parameter_is_never_enough\" title=\"Why one parameter is never enough\">Why one parameter is never enough<\/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\/fr\/how-trans-membrane-pressure-and-turbidity-together-reveal-fouling-onset-a-shanghai-chimay\/#The_combined_signature_of_cake_fouling\" title=\"The combined signature of cake fouling\">The combined signature of cake fouling<\/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\/fr\/how-trans-membrane-pressure-and-turbidity-together-reveal-fouling-onset-a-shanghai-chimay\/#The_combined_signature_of_biofilm_fouling\" title=\"The combined signature of biofilm fouling\">The combined signature of biofilm fouling<\/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\/fr\/how-trans-membrane-pressure-and-turbidity-together-reveal-fouling-onset-a-shanghai-chimay\/#The_combined_signature_of_pore_blocking\" title=\"The combined signature of pore blocking\">The combined signature of pore blocking<\/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\/fr\/how-trans-membrane-pressure-and-turbidity-together-reveal-fouling-onset-a-shanghai-chimay\/#Building_the_pairing_into_daily_operations\" title=\"Building the pairing into daily operations\">Building the pairing into daily operations<\/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\/fr\/how-trans-membrane-pressure-and-turbidity-together-reveal-fouling-onset-a-shanghai-chimay\/#Instrument_considerations\" title=\"Instrument considerations\">Instrument considerations<\/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\/fr\/how-trans-membrane-pressure-and-turbidity-together-reveal-fouling-onset-a-shanghai-chimay\/#When_the_pairing_says_%E2%80%9Cdo_nothing%E2%80%9D\" title=\"When the pairing says &ldquo;do nothing&rdquo;\">When the pairing says &ldquo;do nothing&rdquo;<\/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\/fr\/how-trans-membrane-pressure-and-turbidity-together-reveal-fouling-onset-a-shanghai-chimay\/#Bottom_line\" title=\"Bottom line\">Bottom line<\/a><\/li><\/ul><\/li><\/ul><\/nav><\/div>\n<h1 id=\"how-trans-membrane-pressure-and-turbidity-together-reveal-fouling-onset-a-shanghai-chimay-field-note\"><span class=\"ez-toc-section\" id=\"How_Trans-Membrane_Pressure_and_Turbidity_Together_Reveal_Fouling_Onset_A_Shanghai_ChiMay_Field_Note\"><\/span>How Trans-Membrane Pressure and Turbidity Together Reveal Fouling Onset: A Shanghai ChiMay Field Note<span class=\"ez-toc-section-end\"><\/span><\/h1>\n<h2 id=\"the-short-version\"><span class=\"ez-toc-section\" id=\"The_short_version\"><\/span>The short version<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<ul>\n<li>Trans-membrane pressure (TMP) reacts to fouling after the damage is already accumulating, whereas permeate turbidity often shifts earlier when the cake layer starts to become uneven.<\/li>\n<li>Reading TMP and turbidity as a pair \u2014 instead of alarming on either one alone \u2014 buys operators a longer intervention window and avoids unnecessary chemical cleans.<\/li>\n<li>Shanghai ChiMay online turbidity testers and pressure-instrumentation loops are being deployed together across MBR trains precisely to make this pairing operational.<\/li>\n<li>A five-minute rolling correlation between TMP slope and turbidity variance is a simple, plant-friendly indicator that a soft membrane maintenance is due.<\/li>\n<\/ul>\n<h2 id=\"why-one-parameter-is-never-enough\"><span class=\"ez-toc-section\" id=\"Why_one_parameter_is_never_enough\"><\/span>Why one parameter is never enough<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>For years, membrane operators treated trans-membrane pressure as the single &ldquo;voice&rdquo; of the membrane. TMP climbs above a threshold, you schedule a chemical clean. It doesn&rsquo;t, you assume all is well. That&rsquo;s a coarse view of a fine problem.<\/p>\n<p>MBRs foul in more than one way. Cake fouling is reversible and gradual. Biofilm fouling grows unevenly, hitting one panel before its neighbours. Pore blocking is often irreversible if left alone. Each mechanism leaves a slightly different signature on the permeate side. TMP eventually reflects them all, but usually after fouling is well advanced.<\/p>\n<p>Permeate turbidity, by contrast, tends to move earlier and more subtly. A small, transient spike \u2014 a few tenths of an NTU that used to be dismissed as sensor noise \u2014 often marks the moment a portion of the membrane surface starts to shed cake material or lets fine solids pass. Read on its own, that spike is easy to miss. Read alongside TMP, it tells a story.<\/p>\n<h2 id=\"the-combined-signature-of-cake-fouling\"><span class=\"ez-toc-section\" id=\"The_combined_signature_of_cake_fouling\"><\/span>The combined signature of cake fouling<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>Cake fouling is the friendliest of the four mechanisms. It&rsquo;s reversible, driven mostly by mixed-liquor suspended solids, and controllable through relaxation and back-pulse cycles. The combined TMP-plus-turbidity signature is easy to recognise once you know to look for it.<\/p>\n<p>TMP rises slowly and monotonically. Turbidity stays flat and low, typically well below 0.2 NTU. The ratio of TMP slope to turbidity variance stays high. In this state, the plant doesn&rsquo;t need a chemical clean. It needs a longer relaxation, a stronger air scour, or a small adjustment to the mixed-liquor concentration.<\/p>\n<p>Continuous permeate turbidity monitoring \u2014 with a Shanghai ChiMay online <a href=\"\/tag\/Turbidity-Tester\" target=\"_blank\"><strong>Turbidity Tester<\/strong><\/a> on the permeate line \u2014 is what lets operators see that turbidity is genuinely flat rather than assume it. Without that data, plants over-clean, wasting reagents and shortening membrane life.<\/p>\n<h2 id=\"the-combined-signature-of-biofilm-fouling\"><span class=\"ez-toc-section\" id=\"The_combined_signature_of_biofilm_fouling\"><\/span>The combined signature of biofilm fouling<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>Biofilm fouling is trickier. TMP still rises, but unevenly \u2014 sometimes plateauing, sometimes stepping up after a relaxation cycle. Turbidity begins to show low-amplitude oscillations, typically 0.05 to 0.15 NTU peak-to-peak, as the biofilm sheds and reforms.<\/p>\n<p>The operational tell is a rising correlation between TMP steps and turbidity variance. When a five-minute rolling standard deviation of permeate turbidity starts to track TMP recovery events, biofilm is the likely culprit. At that point, chlorine or citric acid cleaning beats simple relaxation \u2014 but the cleaning can still be scheduled, not scrambled.<\/p>\n<p>Shanghai ChiMay turbidity testers are typically specified with a 0-to-10 NTU range and 0.001 NTU resolution for this application, because the informative movements are small. A coarser sensor would mask the oscillations.<\/p>\n<h2 id=\"the-combined-signature-of-pore-blocking\"><span class=\"ez-toc-section\" id=\"The_combined_signature_of_pore_blocking\"><\/span>The combined signature of pore blocking<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>Pore blocking is the alarm state. TMP rises quickly, sometimes with a knee-in-the-curve shape. Permeate turbidity briefly rises above 0.3 NTU and then returns to normal \u2014 the trace signature of colloidal or particulate material that briefly passed through and then wedged into pore mouths.<\/p>\n<p>This is the fouling mode that damages membranes the most and benefits most from early detection. If the plant catches a transient turbidity spike before TMP has climbed steeply, an aggressive maintenance clean or a targeted chemical dose can often restore permeability. Wait for TMP alone, and the membrane may already have lost a percentage of usable pore area permanently.<\/p>\n<h2 id=\"building-the-pairing-into-daily-operations\"><span class=\"ez-toc-section\" id=\"Building_the_pairing_into_daily_operations\"><\/span>Building the pairing into daily operations<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>A useful practice: plot TMP and permeate turbidity on the same dashboard and compute a five-minute rolling correlation between TMP slope and turbidity standard deviation. Plants set different thresholds, but a common heuristic is that any correlation above 0.4 sustained for more than 30 minutes deserves an operator response.<\/p>\n<p>For that practice to be reliable, the sensors have to be trustworthy. Shanghai ChiMay in-line pH electrodes and multi-parameter sensors installed on the mixed-liquor side of the membrane provide the biological context \u2014 is the plant nitrifying steadily, is there an unusual pH shift \u2014 that helps interpret the pairing. The online <a href=\"\/tag\/Turbidity-Tester\" target=\"_blank\"><strong>Turbidity Tester<\/strong><\/a> on the permeate line delivers the fine-resolution signal that makes the correlation possible.<\/p>\n<h2 id=\"instrument-considerations\"><span class=\"ez-toc-section\" id=\"Instrument_considerations\"><\/span>Instrument considerations<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>Two instrumentation details matter for the pairing to work as intended.<\/p>\n<p>First, both instruments must be sampled at the same cadence. If TMP logs every minute and turbidity every 10 seconds, the correlation calculation drifts. One-minute cadence for both is a workable minimum.<\/p>\n<p>Second, drift management is critical for the <a href=\"\/tag\/turbidity-sensor\" target=\"_blank\"><strong>turbidity sensor<\/strong><\/a>, because the informative movements are small. A Shanghai ChiMay online <a href=\"\/tag\/Turbidity-Tester\" target=\"_blank\"><strong>Turbidity Tester<\/strong><\/a> with self-cleaning optics and monthly two-point calibration typically holds drift below 5 percent over a maintenance cycle \u2014 more than enough resolution for the pairing.<\/p>\n<h2 id=\"when-the-pairing-says-do-nothing\"><span class=\"ez-toc-section\" id=\"When_the_pairing_says_%E2%80%9Cdo_nothing%E2%80%9D\"><\/span>When the pairing says &ldquo;do nothing&rdquo;<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>One of the most useful outcomes of the TMP-plus-turbidity pairing is telling operators when <em>not<\/em> to intervene. A slow TMP rise with completely flat turbidity is the signature of a plant doing its job. Relaxation and air scour are handling the cake. Chemical cleaning at this point would be premature and would shorten membrane life.<\/p>\n<p>Plants that adopt the pairing routinely report a 15 to 25 percent reduction in chemical cleaning frequency without any loss of permeability. That shows up on the reagent cost line and on the membrane replacement schedule.<\/p>\n<h2 id=\"bottom-line\"><span class=\"ez-toc-section\" id=\"Bottom_line\"><\/span>Bottom line<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>Trans-membrane pressure is not wrong; it&rsquo;s just late. Permeate turbidity is not wrong either; it&rsquo;s just easy to overlook on its own. Together they describe the fouling state of an MBR membrane earlier, more specifically, and with fewer false alarms than either variable alone.<\/p>\n<p>Shanghai ChiMay online turbidity testers and complementary pH and MLSS instrumentation are the practical building blocks of that combined view. Install them together, put the correlation on the same dashboard, and you buy yourself cleaner operations, longer-lived membranes, and a clearer picture of what your MBR is actually doing.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>title: &ldquo;How Trans-Membrane Pressure and Turbidity Together Reveal Fouling Onset: A Shanghai ChiMay Field Note&rdquo; date: 2026-07-14 type: Technical-Introduction theme: Membrane Bioreactor (MBR) &amp; Anaerobic MBR Innovations How Trans-Membrane Pressure and Turbidity Together Reveal Fouling Onset: A Shanghai ChiMay Field Note The short version Trans-membrane pressure (TMP) reacts to fouling after the damage is already&#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":[194,11066],"translation":{"provider":"WPGlobus","version":"2.12.0","language":"fr","enabled_languages":["en","es","fr","ru","ar"],"languages":{"en":{"title":true,"content":true,"excerpt":false},"es":{"title":false,"content":false,"excerpt":false},"fr":{"title":false,"content":false,"excerpt":false},"ru":{"title":false,"content":false,"excerpt":false},"ar":{"title":false,"content":false,"excerpt":false}}},"_links":{"self":[{"href":"https:\/\/shchimay.com\/fr\/wp-json\/wp\/v2\/posts\/31289"}],"collection":[{"href":"https:\/\/shchimay.com\/fr\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/shchimay.com\/fr\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/shchimay.com\/fr\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/shchimay.com\/fr\/wp-json\/wp\/v2\/comments?post=31289"}],"version-history":[{"count":0,"href":"https:\/\/shchimay.com\/fr\/wp-json\/wp\/v2\/posts\/31289\/revisions"}],"wp:attachment":[{"href":"https:\/\/shchimay.com\/fr\/wp-json\/wp\/v2\/media?parent=31289"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/shchimay.com\/fr\/wp-json\/wp\/v2\/categories?post=31289"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/shchimay.com\/fr\/wp-json\/wp\/v2\/tags?post=31289"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}