{"id":40712,"date":"2025-09-25T17:01:59","date_gmt":"2025-09-25T09:01:59","guid":{"rendered":"https:\/\/stark-water.com\/?p=40712"},"modified":"2025-09-25T17:02:01","modified_gmt":"2025-09-25T09:02:01","slug":"century-egg-wastewater-treatment","status":"publish","type":"post","link":"https:\/\/stark-water.com\/pt\/blogue\/century-egg-wastewater-treatment\/","title":{"rendered":"Tratamento de \u00e1guas residuais da Century Egg: Neutralize o pH 14 da salmoura com seguran\u00e7a"},"content":{"rendered":"<p><strong>Century egg wastewater treatment<\/strong>&nbsp;deals with extremely caustic brine (often near pH 14), high salinity, suspended solids, proteins and oil\/grease from washing and peeling. This guide explains two proven process trains, safe pH control, design ranges you can bench-test, and what to monitor from start-up to steady state.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Why Century Egg Wastewater Treatment  Is Challenging<\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Very high pH<\/strong>\u00a0from NaOH\/Ca(OH)<sub>2<\/sub>\u00a0marinade \u2014 must be neutralized under control (never by dilution).<\/li>\n\n\n\n<li><strong>High salinity (brine)<\/strong>\u00a0\u2014 osmotic stress inhibits anaerobic\/aerobic biology if the strongest streams are not segregated.<\/li>\n\n\n\n<li><strong>Organics<\/strong>\u00a0\u2014 proteins\/peptides and marinade residues drive COD\/BOD.<\/li>\n\n\n\n<li><strong>SS &amp; FOG<\/strong>\u00a0\u2014 shell fines and grease often require front-end clarification or DAF.<\/li>\n<\/ul>\n\n\n\n<figure class=\"wp-block-image size-large\"><img fetchpriority=\"high\" decoding=\"async\" width=\"1024\" height=\"683\" src=\"https:\/\/stark-water.com\/wp-content\/uploads\/2025\/09\/century-egg-wastewater-treatment1-1024x683.webp\" alt=\"century egg wastewater treatment1\" class=\"wp-image-40728\" title=\"\" srcset=\"https:\/\/stark-water.com\/wp-content\/uploads\/2025\/09\/century-egg-wastewater-treatment1-1024x683.webp 1024w, https:\/\/stark-water.com\/wp-content\/uploads\/2025\/09\/century-egg-wastewater-treatment1-300x200.webp 300w, https:\/\/stark-water.com\/wp-content\/uploads\/2025\/09\/century-egg-wastewater-treatment1-768x512.webp 768w, https:\/\/stark-water.com\/wp-content\/uploads\/2025\/09\/century-egg-wastewater-treatment1-18x12.webp 18w, https:\/\/stark-water.com\/wp-content\/uploads\/2025\/09\/century-egg-wastewater-treatment1-600x400.webp 600w, https:\/\/stark-water.com\/wp-content\/uploads\/2025\/09\/century-egg-wastewater-treatment1.webp 1536w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/><figcaption class=\"wp-element-caption\">century egg wastewater treatment1<\/figcaption><\/figure>\n\n\n\n<h2 class=\"wp-block-heading\">Century Egg Wastewater Treatment Process Options<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\">Option 1 \u2014 pH Adjustment \u2192 Coag\/Floc \u2192 Anaerobic \u2192 Aerobic \u2192 Clarification<\/h3>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>Equalization (EQ)<\/strong>: buffer flows\/loads; mixer + level control; conductivity probe recommended.<\/li>\n\n\n\n<li><strong>Neutralization<\/strong>: acid dosing (HCl or food-grade CO<sub>2<\/sub>) with dual pH probes and interlocked pumps; target pH 6.8\u20137.5 before coagulation.<\/li>\n\n\n\n<li><strong>Coagulation\/Flocculation<\/strong>: PAC\/FeCl<sub>3<\/sub>\u00a0+ polymer; add\u00a0<strong>DAF<\/strong>\u00a0when FOG is high or quick solids capture is needed.<\/li>\n\n\n\n<li><strong>Anaerobic (UASB\/AnMBR)<\/strong>: high-rate COD removal and biogas; keep feed salinity within acclimated limits.<\/li>\n\n\n\n<li><strong>Aerobic polishing (A\/O, SBR or MBR)<\/strong>: close BOD\/SS; nitrification if ammonia is present.<\/li>\n\n\n\n<li><strong>Secondary Clarifier \/ Membrane<\/strong>: achieve solids limit; optional sand\/carbon filters for final polishing.<\/li>\n<\/ol>\n\n\n\n<p><em>Strengths:<\/em>&nbsp;low OPEX (biogas credit), good for medium\u2013large flows.&nbsp;<em>Watch-outs:<\/em>&nbsp;longer HRT, biology needs salinity control.<\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img decoding=\"async\" width=\"1024\" height=\"683\" src=\"https:\/\/stark-water.com\/wp-content\/uploads\/2025\/09\/century-egg-wastewater-treatment2-1024x683.webp\" alt=\"century egg wastewater treatment2\" class=\"wp-image-40727\" title=\"\" srcset=\"https:\/\/stark-water.com\/wp-content\/uploads\/2025\/09\/century-egg-wastewater-treatment2-1024x683.webp 1024w, https:\/\/stark-water.com\/wp-content\/uploads\/2025\/09\/century-egg-wastewater-treatment2-300x200.webp 300w, https:\/\/stark-water.com\/wp-content\/uploads\/2025\/09\/century-egg-wastewater-treatment2-768x512.webp 768w, https:\/\/stark-water.com\/wp-content\/uploads\/2025\/09\/century-egg-wastewater-treatment2-18x12.webp 18w, https:\/\/stark-water.com\/wp-content\/uploads\/2025\/09\/century-egg-wastewater-treatment2-600x400.webp 600w, https:\/\/stark-water.com\/wp-content\/uploads\/2025\/09\/century-egg-wastewater-treatment2.webp 1536w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/><figcaption class=\"wp-element-caption\">century egg wastewater treatment2<\/figcaption><\/figure>\n\n\n\n<h3 class=\"wp-block-heading\">Option 2 \u2014 Brine Segregation Line + Physicochemical Mainstream + Aerobic MBR<\/h3>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>Brine-only line<\/strong>: collect the strongest marinade separately; do\u00a0<strong>dedicated neutralization<\/strong>\u00a0in a small, high-torque tank; controlled blending or partial desalination if TDS remains excessive.<\/li>\n\n\n\n<li><strong>Mainstream line<\/strong>: wash water + light brine \u2192 neutralization \u2192 coag\/floc \u2192\u00a0<strong>DAF<\/strong>.<\/li>\n\n\n\n<li><strong>MBR<\/strong>: compact aerobic polishing with consistent low SS; no separate clarifier required.<\/li>\n<\/ol>\n\n\n\n<p><em>Strengths:<\/em>&nbsp;small footprint, faster start-up, robust to shift changes.&nbsp;<em>Trade-off:<\/em>&nbsp;higher CAPEX (membranes) and moderate OPEX.<\/p>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th>Item<\/th><th>Option 1<\/th><th>Option 2<\/th><\/tr><\/thead><tbody><tr><td>Pegada<\/td><td>Medium\u2013large<\/td><td>Small<\/td><\/tr><tr><td>Start-up Speed<\/td><td>Slower (seed\/acclimation)<\/td><td>Fast<\/td><\/tr><tr><td>Salinity Tolerance<\/td><td>Needs careful control<\/td><td>Good (split-stream)<\/td><\/tr><tr><td>OPEX<\/td><td>Low (biogas credit)<\/td><td>Medium<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<h2 class=\"wp-block-heading\">Safe Neutralization of pH-14 Brine<\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Instrumentation<\/strong>: dual pH probes (duty\/standby), static or flash mixer, interlocked dosing pumps; high\/low pH trips overflow back to EQ.<\/li>\n\n\n\n<li><strong>Acid choice<\/strong>: HCl is compact and precise; CO<sub>2<\/sub>\u00a0is safer and reduces overshoot (forms bicarbonate). Use corrosion-resistant materials and ventilation.<\/li>\n\n\n\n<li><strong>Control concept<\/strong>: coarse pH trim in EQ, fine trim in a dedicated neutralization tank just before coag\/floc.<\/li>\n\n\n\n<li><strong>Safety<\/strong>: reaction is exothermic; add acid to water; provide secondary containment and eyewash\/shower as standard EHS practice.<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\">How to Estimate Acid Demand (Titration \u2192 Full-Scale)<\/h2>\n\n\n\n<ol class=\"wp-block-list\">\n<li>Take a well-mixed 1 L sample.<\/li>\n\n\n\n<li>Titrate with HCl of known normality to pH 7.0; record the volume used:\u00a0<strong>V_HCl<\/strong>\u00a0(litres).<\/li>\n\n\n\n<li>For 1.0 N HCl: acid equivalents per litre =\u00a0<strong>V_HCl \u00d7 1.0<\/strong>.<\/li>\n\n\n\n<li>Per m\u00b3 requirement = (acid equivalents per litre) \u00d7\u00a0<strong>1000<\/strong>. If using 10 N HCl, divide the result by\u00a0<strong>10<\/strong>\u00a0to get litres per m\u00b3.<\/li>\n<\/ol>\n\n\n\n<p><strong>Worked example (step-by-step):<\/strong>&nbsp;A 1 L sample needs&nbsp;<strong>0.20 L<\/strong>&nbsp;of&nbsp;<strong>1.0 N HCl<\/strong>&nbsp;to reach pH 7.0.<\/p>\n\n\n\n<p>Acid equivalents = 0.20 \u00d7 1.0 =&nbsp;<strong>0.20 mol\/L<\/strong>.<br>Per m\u00b3 = 0.20 \u00d7 1000 =&nbsp;<strong>200 mol<\/strong>&nbsp;H\u207a equivalent.<br>Using&nbsp;<strong>10 N HCl<\/strong>: volume per m\u00b3 = 200 \u00f7 10 =&nbsp;<strong>20 L\/m\u00b3<\/strong>.<br>Add 10\u201320% control margin; let the PID loop fine-trim.<\/p>\n\n\n\n<p><em>Nota:<\/em>&nbsp;If you need to convert a supplier\u2019s mass-percent HCl to normality, use the SDS values for&nbsp;<strong>wt%<\/strong>&nbsp;e&nbsp;<strong>density<\/strong>.<br>Approximation for HCl (monoprotic):&nbsp;<code>N \u2248 (density \u00d7 wt% \u00d7 10) \/ 36.46<\/code>&nbsp;(density in g\/mL; wt% as %). Example: 31% HCl at 1.15 g\/mL \u2192 N \u2248 (1.15 \u00d7 31 \u00d7 10) \/ 36.46 \u2248 9.8 N.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Typical Design Ranges (Bench-Test Before Final Design)<\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>EQ HRT<\/strong>: 6\u201312 h.<\/li>\n\n\n\n<li><strong>Coag\/Floc<\/strong>: flash mix \\(G\u00b7t\\) \u2248 300\u20131000; floc \\(G\u00b7t\\) \u2248 20,000\u201380,000; optimize by jar tests.<\/li>\n\n\n\n<li><strong>DAF<\/strong>: surface loading \\( \\mathrm{SLR} = Q\/A \\) = 5\u201310 m\u00b3\u00b7m\u207b\u00b2\u00b7h\u207b\u00b9; recycle 10\u201330%.<\/li>\n\n\n\n<li><strong>UASB\/AnMBR<\/strong>: organic loading \\( \\mathrm{OLR} = Q \\times \\mathrm{COD}_{in}\/V \\) = 1\u20136 kg COD\u00b7m\u207b\u00b3\u00b7d\u207b\u00b9; acclimate for salinity.<\/li>\n\n\n\n<li><strong>MBR<\/strong>: MLSS 6\u201312 g\u00b7L\u207b\u00b9; SRT 12\u201325 d; monitor TMP and set CIP triggers.<\/li>\n\n\n\n<li><strong>Final pH<\/strong>: typically 6\u20139; COD\/BOD\/SS to meet your permit or local Standard A\/B equivalents.<\/li>\n<\/ul>\n\n\n\n<figure class=\"wp-block-image size-large\"><img decoding=\"async\" width=\"1024\" height=\"683\" src=\"https:\/\/stark-water.com\/wp-content\/uploads\/2025\/09\/century-egg-wastewater-treatment3-1024x683.webp\" alt=\"century egg wastewater treatment3\" class=\"wp-image-40725\" title=\"\" srcset=\"https:\/\/stark-water.com\/wp-content\/uploads\/2025\/09\/century-egg-wastewater-treatment3-1024x683.webp 1024w, https:\/\/stark-water.com\/wp-content\/uploads\/2025\/09\/century-egg-wastewater-treatment3-300x200.webp 300w, https:\/\/stark-water.com\/wp-content\/uploads\/2025\/09\/century-egg-wastewater-treatment3-768x512.webp 768w, https:\/\/stark-water.com\/wp-content\/uploads\/2025\/09\/century-egg-wastewater-treatment3-18x12.webp 18w, https:\/\/stark-water.com\/wp-content\/uploads\/2025\/09\/century-egg-wastewater-treatment3-600x400.webp 600w, https:\/\/stark-water.com\/wp-content\/uploads\/2025\/09\/century-egg-wastewater-treatment3.webp 1536w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/><figcaption class=\"wp-element-caption\">century egg wastewater treatment3<\/figcaption><\/figure>\n\n\n\n<h2 class=\"wp-block-heading\">Operation &amp; Monitoring<\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Online: pH (dual), conductivity (salinity), DO in aerobic tanks, ORP in anaerobic, DAF interface level, MBR TMP.<\/li>\n\n\n\n<li>Routine lab: COD, BOD<sub>5<\/sub>, SS, oil\/grease; record chemical usage and sludge volumes.<\/li>\n\n\n\n<li>Sludge: dewater (belt\/plate); segregate brine-rich streams for licensed disposal.<\/li>\n<\/ul>\n\n\n\n  <section id=\"faq\">\n    <h2>FAQ<\/h2>\n    <details>\n      <summary>Do we need a separate tank for the strongest brine?<\/summary>\n      <p>Sim. <strong>Segregation<\/strong> protects biology from salt shock and significantly shortens the overall HRT. A small neutralization tank dedicated to the brine line is best practice.<\/p>\n    <\/details>\n    <details>\n      <summary>HCl vs CO\u2082 \u2014 which is better for neutralization?<\/summary>\n      <p>HCl offers tight control with a small footprint. CO\u2082 is inherently safer and reduces overshoot; many plants use CO\u2082 for bulk trim and a small HCl dose for precise setpoint control.<\/p>\n    <\/details>\n    <details>\n      <summary>How do we choose between Option 1 and Option 2?<\/summary>\n      <p>If land is available and long-term OPEX matters most, choose Option 1 with anaerobic energy recovery. If space is tight, flows vary or rapid commissioning is needed, Option 2 with brine split + MBR is preferred.<\/p>\n    <\/details>\n  <\/section>\n\n  <section id=\"notice\">\n    <h2>Engineering Notice (Read Before You Design)<\/h2>\n    <p>\n      Os valores acima s\u00e3o <strong>typical ranges<\/strong> from bench practice. Always verify with <strong>titration<\/strong>, <strong>jar tests<\/strong> and, where feasible, a small pilot before full-scale design. Do not substitute dilution for treatment. Install dual pH probes, dosing interlocks, ventilation, secondary containment and eyewash\/shower per standard EHS practice.\n    <\/p>\n  <\/section>\n\n\n\n  <footer class=\"cta\">\n    <p><strong>Ready to size your system?<\/strong> Send flow (average\/peak), brine share (% of total), current pH\/COD\/BOD\/SS and target discharge limits. We\u2019ll return a PFD, tank sizes and a budgetary quote.<\/p>\n    <p>Related: <a href=\"\/pt\/solucoes\/\">Water &#038; Wastewater Solutions<\/a> - <a href=\"\/pt\/categoria-produto\/estacao-de-tratamento-de-aguas\/\">Treatment Plants<\/a> - <a href=\"\/pt\/contact-us\/\">Contact Stark Water<\/a><\/p>\n  <\/footer>\n\n\n\n<section id=\"refs\">\n  <h2>References &#038; Further Reading<\/h2>\n  <ul>\n    <li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Acid%E2%80%93base_titration\" rel=\"noopener\" target=\"_blank\">Acid\u2013Base Titration (bench method for neutralization demand)<\/a><\/li>\n    <li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Dissolved_air_flotation\" rel=\"noopener\" target=\"_blank\">Dissolved Air Flotation (DAF) \u2014 principle &#038; applications<\/a><\/li>\n    <li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Upflow_anaerobic_sludge_blanket_digester\" rel=\"noopener\" target=\"_blank\">UASB \u2014 high-rate anaerobic digestion<\/a><\/li>\n    <li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Membrane_bioreactor\" rel=\"noopener\" target=\"_blank\">Membrane Bioreactor (MBR) \u2014 overview &#038; performance<\/a><\/li>\n  <\/ul>\n<\/section>","protected":false},"excerpt":{"rendered":"<p>Century egg wastewater treatment&nbsp;deals with extremely caustic brine (often near pH 14), high salinity, suspended solids, proteins and oil\/grease from [&hellip;]<\/p>","protected":false},"author":1,"featured_media":40732,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"_joinchat":[],"footnotes":""},"categories":[1],"tags":[],"class_list":["post-40712","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-water-treatment-industry-information"],"acf":[],"_links":{"self":[{"href":"https:\/\/stark-water.com\/pt\/wp-json\/wp\/v2\/posts\/40712","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/stark-water.com\/pt\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/stark-water.com\/pt\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/stark-water.com\/pt\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/stark-water.com\/pt\/wp-json\/wp\/v2\/comments?post=40712"}],"version-history":[{"count":3,"href":"https:\/\/stark-water.com\/pt\/wp-json\/wp\/v2\/posts\/40712\/revisions"}],"predecessor-version":[{"id":40734,"href":"https:\/\/stark-water.com\/pt\/wp-json\/wp\/v2\/posts\/40712\/revisions\/40734"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/stark-water.com\/pt\/wp-json\/wp\/v2\/media\/40732"}],"wp:attachment":[{"href":"https:\/\/stark-water.com\/pt\/wp-json\/wp\/v2\/media?parent=40712"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/stark-water.com\/pt\/wp-json\/wp\/v2\/categories?post=40712"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/stark-water.com\/pt\/wp-json\/wp\/v2\/tags?post=40712"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}