{"id":3642,"date":"2026-10-15T15:01:53","date_gmt":"2026-10-15T07:01:53","guid":{"rendered":"http:\/\/www.hewilson.com\/blog\/?p=3642"},"modified":"2026-10-15T15:01:53","modified_gmt":"2026-10-15T07:01:53","slug":"how-efficient-are-mbr-membrane-bioreactor-systems-in-removing-nitrogen-and-phosphorus-4a74-16eef8","status":"publish","type":"post","link":"http:\/\/www.hewilson.com\/blog\/2026\/10\/15\/how-efficient-are-mbr-membrane-bioreactor-systems-in-removing-nitrogen-and-phosphorus-4a74-16eef8\/","title":{"rendered":"How efficient are MBR Membrane Bioreactor Systems in removing nitrogen and phosphorus?"},"content":{"rendered":"

Hey there, if you\u2019ve spent any time in wastewater treatment, you know how tricky it is to get nitrogen and phosphorus levels low enough to meet today\u2019s strict regulations. I\u2019m Jake, and I\u2019ve been part of the MBR game for over a decade\u2014my company supplies these systems, so I\u2019ve talked to hundreds of plant operators pulling their hair out over nutrient removal. The question I get most? \u201cHow efficient are MBRs at getting rid of nitrogen and phosphorus anyway?\u201d Let\u2019s break this down without the boring jargon overload. MBR Membrane Bioreactor Systems<\/a><\/p>\n

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First, let\u2019s recap what MBRs actually do, super quick. Unlike traditional activated sludge (AS) systems that use sedimentation tanks to separate bacteria from cleaned water, MBRs swap that out for tiny membrane filters\u2014think 0.04-micron holes, way smaller than what\u2019s in a coffee filter. That means you keep way more active bacteria in the tank, no more worrying about sludge carryover in the final effluent. But when it comes to nitrogen and phosphorus, it\u2019s not just the membranes themselves\u2014most of the heavy lifting is done by the bacteria living in the MBR tank. That\u2019s the part I want to focus on because that\u2019s where the efficiency lives.<\/p>\n

Nitrogen is the big two-part problem, right? You\u2019ve got ammonia (NH3), which is super toxic to aquatic life, and then other nitrogen compounds like nitrites (NO2-) and nitrates (NO3-), which cause algal blooms that kill fish and mess up ecosystems. Traditional systems usually handle nitrification (turning ammonia to nitrates) pretty well, but denitrification (turning nitrates into harmless nitrogen gas that floats away) is where they fall short\u2014they can\u2019t hold enough slow-growing denitrifying bacteria because they lose so much sludge in the sedimentation step.<\/p>\n

MBRs fix that. The membranes keep every single bacteria cell in the tank, so you can have a mixed culture that\u2019s packed with nitrifiers and denitrifiers. The average MBR I\u2019ve installed removes 95%+ of total nitrogen (TN) most days. Wait, let me be real here\u2014some operators hit 99% if they tweak the tank\u2019s oxygen levels right, but 92-97% is the sweet spot for steady, reliable performance, way above what you get with a traditional AS system (which usually hovers around 70-85% TN removal). Why? Because the solids retention time (SRT) in MBRs is way longer\u2014we\u2019re talking 15-30 days, compared to 5-10 days in traditional systems. Those slow-growing nitrifiers (like Nitrosomonas and Nitrobacter) need that extra time to multiply and do their job, and MBRs don\u2019t flush them out. No more chasing ammonia spikes when your sedimentation tank is finicky.<\/p>\n

But nitrogen isn\u2019t just about bacteria\u2014you also need the right tank setup. A lot of our clients use a modified MBR with an anoxic zone before the aerobic (oxygen-rich) zone. In the anoxic zone, there\u2019s no oxygen, so denitrifying bacteria can feed on the organic matter in the wastewater and turn nitrates into gas. We size that zone based on your incoming wastewater load\u2014if you\u2019ve got a lot of food processing runoff with high organic content, we\u2019ll make that zone a bit bigger. If it\u2019s municipal sewage, we can scale it back. That flexibility is a big part of why MBRs are so efficient here.<\/p>\n

Now phosphorus\u2014this is the other headache. Traditional systems almost always rely on chemical phosphorus removal, where you add metal salts like alum or iron chloride that bind to phosphorus and make it fall out as sludge. The problem is that adds operational costs, you end up with more waste sludge, and sometimes you still miss the mark on limits. Biological phosphorus removal (BPR) is the alternative\u2014certain bacteria (called polyphosphate-accumulating organisms, or PAOs) suck up way more phosphorus than they need and store it as granules, which you can remove when you waste some sludge.<\/p>\n

Here\u2019s where MBRs really shine for phosphorus. Because MBRs have super stable SRT and mixed liquor suspended solids (MLSS) levels (we run 8,000-12,000 mg\/L, way higher than the 2,000-4,000 mg\/L in traditional AS), PAOs thrive. No sludge loss means you keep all your hard-working PAOs around, and you can operate an anaerobic zone (no oxygen, no nitrate) before the anoxic\/aerobic zones to fuel their phosphorus uptake. The average MBR we supply removes 85-95% of total phosphorus (TP) when we combine biological and a little chemical polishing, compared to 50-70% for traditional systems that only do BPR. And if your plant needs to hit super strict limits (like 0.05 mg\/L TP for sensitive areas), we can tweak the chemical dose to be way more efficient than traditional systems\u2014we only add what\u2019s needed, no over-dosing because the effluent quality is so consistent.<\/p>\n

But wait, I don\u2019t want to paint MBRs as perfect. There are scenarios where efficiency drops, and it\u2019s not the system\u2019s fault\u2014it\u2019s operator error or a bad design. For example, if an MBR is run with too short an SRT (under 10 days), you\u2019ll flush out the nitrifiers and PAOs, and nutrient removal plummets. I\u2019ve seen a plant in the Midwest that tried to cut costs by lowering SRT to 7 days, and their ammonia levels jumped from 0.2 mg\/L to 12 mg\/L in two weeks. We fixed it by adjusting the SRT and tweaking the zone sizes, and it went back to 96% TN removal in a month. Another common mistake is not managing membrane fouling\u2014if you don\u2019t clean the membranes on schedule, the tank can get short on oxygen, which messes with both nitrification and PAO activity. Fouling doesn\u2019t just hurt the flow; it kills the bacteria that do the nutrient work.<\/p>\n

Also, let\u2019s talk real-world data, not just lab tests. A municipal MBR we installed in Florida a few years ago serves 120,000 people, and their average TN removal is 94% and TP is 91%\u2014they\u2019ve held that steady for 5 years, even during peak tourist season when their incoming wastewater load doubles. Before they switched to MBR, their old AS system only hit 82% TN and 72% TP, and they were in violation of nutrient limits every other month. That\u2019s the kind of result that makes our clients happy. Another client is a food processing plant in California with super high nitrogen levels from their wastewater; their MBR removes 97% TN consistently, which is way below the state\u2019s strict coastal limits.<\/p>\n

Compare that to newer traditional systems that try to add biological nutrient removal (BNR)\u2014they often need more space, right? Because they need bigger anoxic and aerobic zones to hold enough sludge. MBRs are way more compact, so you can get the same or better nutrient removal in half the footprint. That\u2019s a huge win for plants that are already tight on space, or for new plants that don\u2019t want to build a giant facility.<\/p>\n

Now, what about cost? I know that\u2019s a big question when operators are looking at MBRs vs. traditional systems. The upfront cost is higher, but the operational savings add up fast. Because MBRs have less waste sludge (you don\u2019t waste as much sludge since you\u2019re keeping almost all of it), you spend less on sludge disposal. And you use less chemical for phosphorus removal, since biological removal is doing most of the work. Our clients usually see a payback period of 3-5 years, which is shorter than you\u2019d think. Plus, with regulations getting stricter every year, MBRs future-proof your plant\u2014you don\u2019t have to do a huge retrofit in 10 years to hit new nutrient limits.<\/p>\n

But here\u2019s the thing I always tell people: MBR efficiency for nutrients isn\u2019t a one-size-fits-all. It depends on your wastewater type, your local limits, how well you operate the system, and how we design it. We don\u2019t just show up and drop a standard MBR tank\u2014we test your incoming wastewater, calculate the TN and TP loads, size the anoxic\/anaerobic zones, set the right SRT and MLSS levels, and even help with operator training. That\u2019s why we\u2019ve got such a high success rate, because we don\u2019t just sell equipment\u2014we partner with our clients.<\/p>\n

I\u2019ve talked to operators who were skeptical about MBRs at first, after hearing horror stories about high energy costs or membrane replacement. But the ones who\u2019ve stuck with it say the consistent nutrient removal is worth every penny. Last month, a client in Texas told me that since switching to our MBR, they haven\u2019t had a single nutrient violation, and their energy bill went down 18% because the system\u2019s aeration is optimized for the bacteria, not wasting air like traditional systems.<\/p>\n

So, to wrap this up: MBRs are way more efficient than traditional systems at nitrogen and phosphorus removal, with average 92-99% TN removal and 85-95% TP removal when designed and operated right. The key is the membrane\u2019s ability to retain slow-growing nutrient-eating bacteria, which solves the biggest flaw of traditional systems. They\u2019re compact, future-proof, and lower operational costs long-term\u2014if you don\u2019t cut corners on design and operation.<\/p>\n

<\/p>\n

If you\u2019re dealing with nutrient violations, tired of high chemical costs, or need to upgrade your wastewater plant to meet stricter rules, we can help. We\u2019ll do a free assessment of your current system, walk you through how an MBR would work for your specific needs, and answer all your questions no jargon included. Reach out to our team to chat through your project\u2014we\u2019re here to help you get your nutrient levels where they need to be, without the headache.<\/p>\n

Packaged Sewage Treatment Plant<\/a> References:<\/p>\n

    \n
  1. State of the Art of Membrane Bioreactors for Wastewater Treatment. International Water Association, 2019.<\/li>\n
  2. Nutrient Removal in Membrane Bioreactors: A Review. Water Research, 2021, Vol. 198, p. 117125.<\/li>\n
  3. Full-Scale Performance of MBR Systems for Municipal Wastewater: Nutrient Removal and Operational Parameters. Journal of Membrane Science, 2020, Vol. 602, p. 117892.<\/li>\n
  4. Biological vs. Chemical Phosphorus Removal in MBRs: Cost and Efficiency Comparisons. Water Environment Research Foundation, 2018.<\/li>\n
  5. Operational Best Practices for MBR Nutrient Removal: A Guide for Plant Operators. Membrane Technology Association, 2022.<\/li>\n<\/ol>\n
    \n

    Shandong Lingke Environmental Technology Co., Ltd.<\/a><\/p>\n

    Address: 100 Meters South of the Intersection of County Road 042 and National Highway 309, Changle County, Weifang City, Shandong Province
    E-mail: aileenlin@sdlingkegroup.com
    WebSite:     https:\/\/www.lkecotech.com\/<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"

    Hey there, if you\u2019ve spent any time in wastewater treatment, you know how tricky it is … How efficient are MBR Membrane Bioreactor Systems in removing nitrogen and phosphorus?<\/span>Read more<\/a><\/p>\n","protected":false},"author":971,"featured_media":3642,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[3605],"class_list":["post-3642","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-industry","tag-mbr-membrane-bioreactor-systems-466b-17ab76"],"_links":{"self":[{"href":"http:\/\/www.hewilson.com\/blog\/wp-json\/wp\/v2\/posts\/3642","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/www.hewilson.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.hewilson.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.hewilson.com\/blog\/wp-json\/wp\/v2\/users\/971"}],"replies":[{"embeddable":true,"href":"http:\/\/www.hewilson.com\/blog\/wp-json\/wp\/v2\/comments?post=3642"}],"version-history":[{"count":0,"href":"http:\/\/www.hewilson.com\/blog\/wp-json\/wp\/v2\/posts\/3642\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/www.hewilson.com\/blog\/wp-json\/wp\/v2\/posts\/3642"}],"wp:attachment":[{"href":"http:\/\/www.hewilson.com\/blog\/wp-json\/wp\/v2\/media?parent=3642"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.hewilson.com\/blog\/wp-json\/wp\/v2\/categories?post=3642"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.hewilson.com\/blog\/wp-json\/wp\/v2\/tags?post=3642"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}