Nitrogen with no carbon left to remove it
Advanced nitrogen removal handles the stream that defeats a conventional anoxic tank. Nitrate and nitrite, in water with almost no organic carbon. Total nitrogen goes stably below 25 mg/L, in a packaged unit that bolts onto a plant you already own.
What is advanced nitrogen removal?
Advanced nitrogen removal is the polishing stage that takes total nitrogen out of water after the main biological treatment has done what it can.
It is built for one specific case. Low to medium strength streams, nitrogen present mainly as nitrate or nitrite, and little or no carbon left to drive denitrification.
The clearest example is nanofiltration permeate in a leachate plant. The membrane passes the nitrate and holds back the organics. What comes out is exactly the water a conventional anoxic tank cannot treat.
Nitrogen is easy. Nitrogen without carbon is not.
Denitrification is a bacterial process that eats carbon. Take the carbon away and the biology stops.
Nanofiltration does its job well, and that is the problem. It passes nitrate and rejects most of the organic load. The permeate reaches the back of the plant with nitrogen and nothing to reduce it.
So the plant chooses between an operating cost that never ends and a permit it cannot reliably hold. Neither is a solution. The stage that follows removes the choice.
Where Bac-FerM sits
Bac-FerM is a bacterial fermentation and membrane process for advanced biological nitrogen removal. It sits after nanofiltration, on the branch heading to discharge rather than to water recovery.
That split matters. A leachate plant has two outlets, not one. A nitrogen route that must meet a discharge limit, and a water recovery route through reverse osmosis and concentrate treatment. Upstream of both, short-cut nitrification and denitrification has already taken out the bulk of the nitrogen at lower aeration and carbon cost.
Effluent total nitrogen is held stably below 25 mg/L, from a feed carrying up to 200 mg/L as nitrate or nitrite.
Stability is the number that matters. A process that reaches a limit occasionally is not compliant. A process that holds it every day is.
Designed to be added, not designed in
Most nitrogen problems appear on plants already built. A limit tightens, a feed changes, or the biology was always marginal and the site lived with it.
The unit ships as an integrated package and installs at the tail end of the existing system. Only minor modification is required. That is usually the difference between a retrofit that gets approved and one that stays in a drawer.
Where it is applied
Leachate advanced treatment
The nanofiltration permeate branch of a landfill or waste-to-energy leachate plant. Nitrate passes the membrane; the carbon does not.
Plants facing a tightened nitrogen limit
Sites whose biological stage was sized for an older standard, and now need polishing rather than a rebuild.
Industrial effluent low in carbon
Nitrate streams from processes that never carried much organic load. Dosing carbon is the only conventional answer.
Frequently asked questions
What is advanced nitrogen removal?
It is a polishing stage that removes total nitrogen after the main biological treatment has done what it can. It targets low to medium strength streams where nitrogen is mainly nitrate or nitrite, and where little or no carbon remains to drive conventional denitrification.
Why is nanofiltration permeate so hard to denitrify?
Because nanofiltration lets nitrate through and holds most of the organic load back. What arrives is water with nitrogen but almost no carbon. A conventional anoxic tank has nothing to work with, so plants dose methanol, glucose or acetate continuously.
What effluent total nitrogen can be achieved?
Total nitrogen is stably reduced to below 25 mg/L. The unit is designed for feed streams carrying less than 200 mg/L of total nitrogen, present mainly as nitrate or nitrite.
Can it be added to an existing plant?
Yes. It is a packaged, integrated unit that sits at the tail end of an existing treatment system. It needs only minor modification to what is already there.
How much operator attention does it need?
It ships as an integrated skid and is straightforward to run. Nitrogen polishing normally consumes operator time on a leachate plant. The package is meant to take that back.
Is it patented?
Yes. The advanced nitrogen removal technology is covered by Chinese patent ZL 2015 2 0657462.6. The short-cut nitrification and denitrification stage upstream of it is covered by ZL 2014 2 0469160.6.
Send us your nitrogen figures
Start here
If your plant doses carbon to hold a nitrogen limit, the arithmetic is worth redoing. Send the feed and effluent numbers, and we will tell you what a polishing stage changes.
Useful to include
- Flow to the nitrogen polishing stage
- Total nitrogen in, and the split between nitrate and nitrite
- COD available at that point
- The discharge limit you have to hold
- Carbon source and dose rate, if you are dosing today
Contact us directly
- info@jing-yu.com
- Phone
- +86 21 6593 0816
- Office hours
- Monday to Friday, 9:00 to 18:00 Shanghai time (GMT+8)