CN-116534995-B - Extracellular respiration type anaerobic ammonia oxidation process without need of nitrite

Abstract

An extracellular respiratory ANAMMOX process without nitrous oxide belongs to the field of water treatment, and overcomes the defects of difficult nitrous oxide supply, limited physiological denitrification limit due to accumulation of byproducts and the like. The method comprises the following steps of 1, constructing a conventional ANAMMOX system, 2, introducing an extracellular electron acceptor subjected to embedding treatment of a bacterial extracellular polymer, domesticating and exciting direct transfer of ammonia nitrogen electrons to the cell surface, and extracting the selected bacterial extracellular polymer from residual sludge of a sewage treatment plant, wherein the principle of treating waste by waste is met. And step 3, treating ammonia-containing sewage by adopting the extracellular respiration type ANAMMOX reactor constructed in the step 2. The invention provides an extracellular electron acceptor screening and treatment process and a detailed ANAMMOX electron outward transmission path in detail, proves the denitrification feasibility under the condition of no nitrous oxide supply, greatly expands the application scene of the ANAMMOX process, and is beneficial to the direct implementation of single ANAMMOX in main stream town wastewater.

Inventors

• ZHANG LI
• Dou quanhao
• Fan running
• YANG JIACHUN

Assignees

• 北京工业大学

Dates

Publication Date

20260512

Application Date

20230521

Claims (3)

1. 1. An extracellular respiration type anaerobic ammonia oxidation process without nitrous is characterized in that an extracellular electron acceptor is introduced based on the anaerobic ammonia oxidation process, an extracellular respiration type anaerobic ammonia oxidation system without nitrous is constructed, the direct removal of single ammonia nitrogen is realized, and no nitrate by-product is generated; The method comprises the following steps: step 1, constructing an anaerobic ammonia oxidation system for synchronously supplying NO 2 - -N and ammonia nitrogen: feeding inoculated sludge into a reactor, and then adding sewage into the reactor, wherein the inoculated sludge meets at least one of the following conditions: A. the volume of the inoculated sludge accounts for 20-40% of the total volume of the reactor; B. The total suspended matters in the initial mixed solution formed after stirring are 5000-6000 mg/L; C. In an initial mixed solution formed after stirring, the mass ratio of volatile suspended matters to total suspended matters is 0.4-0.6, so that sufficient organic microorganisms are ensured to be contained in sludge, wherein in the step, the sewage contains NO 2 - -N、NH 4 + -N and a medium solution containing trace elements, the concentration of NO 2 - -N is 30-80mg/L, the concentration of NH 4 + -N is 1.2-1.3 times that of NO 2 - -N, deionized water is utilized to prepare a trace element nutrient solution containing 5-20 mg/LPO 4 3- -P、50-80mg/LCaCl 2 、500-1000 mg/LKHCO 3 , and the pH of the sewage is controlled to be 7.0-7.5; Adding an extracellular electronic receptor substance on the basis of the anaerobic ammonia oxidation system prepared in the step 2, wherein the adding amount of the extracellular electronic receptor substance is 50-100mg/L in terms of mass ratio to sludge in a reactor, and the mass concentration of inflow NO 2 - -N is 5-10 mg/L every 3-4 days until the mass of inflow NO 2 - -N is 0mg/L, so as to finally construct an extracellular respiration type anaerobic ammonia oxidation process without nitrite; step 3, treating the ammonia-containing sewage; The extracellular electron acceptor substance comprises ferric oxide (Fe 2 O 3 ), ferroferric oxide (Fe 3 O 4 ), manganese dioxide (MnO 2 ), wurtzite (gamma FeO (OH)) or humus, and is added after being embedded and pretreated by bacterial Extracellular Polymer (EPS) to ensure a complete and convenient electron transmission channel between anaerobic ammonia oxidizing bacteria and extracellular acceptors.
2. 2. The process for the anaerobic ammonium oxidation by extracellular respiration without the need of nitrous oxide according to claim 1, wherein the mass concentration of the external electron acceptor substance to be embedded in the EPS supernatant is 20-50 mg/mlEPS supernatant.
3. 3. The extracellular respiratory anaerobic ammonia oxidation process according to claim 1, wherein: NH 4 + -N releases electrons through an electron off-transport pathway within the bacterial body to bacterial extracellular receptors, rather than NO 2 - -N; The detailed electron transfer path is that the anaerobic ammonia oxidizing bacteria mediate trans-anaerobic enzyme transfer through Rieske/cytb bc1, rely on cytoplasmatic migration of the heme cytochromes and cell surface electron transition, and transport NH 4 + -N oxidation electrons to the outside of cells directly.

Description

Extracellular respiration type anaerobic ammonia oxidation process without need of nitrite Technical Field The invention belongs to the technical field of water treatment, and in particular relates to an extracellular respiration type anaerobic ammonia oxidation process without nitrous oxide Background In view of the increasingly serious water pollution problem worldwide, more and more researches are focused on developing efficient, energy-saving and low-carbon biological denitrification technologies. Anaerobic ammonia oxidation (ANAMMOX) is a subverted technology in the field of sewage denitrification, and the novel technology effectively overcomes the defects of high oxygen supply energy consumption, large carbon source demand, high treatment cost and the like in the traditional denitrification technology (nitrification-denitrification), and greatly promotes the energy conservation and emission reduction process of sewage denitrification treatment. Under strict anaerobic conditions, anaerobic ammonia oxidizing bacteria (AnAOB) take HCO 3- or CO 2 as a carbon source, nitrite (NO 2- -N) is used as an electron acceptor on an anaerobic enzyme membrane structure, ammonia nitrogen (NH 4+ -N) is directly converted into N 2, and then denitrification is completed. According to the existing model of ANAMMOX biochemistry, the detailed process of ANAMMOX nitrogen conversion is the reduction of nitrite (NO 2- -N) to Nitric Oxide (NO) by nitrite reductase (NIR). Then hydrazine synthetase (HZS) catalyzes the condensation of NO and ammonia nitrogen (NH 4+ -N) to generate a chemical reducing agent which is the strongest in nature, namely hydrazine (N 2H4; E' 0= -700 mV). Finally, hydrazine Dehydrogenase (HDH) oxidizes N 2H4 to N 2. Simultaneously, N 2H4 releases four low potential electrons and establishes membrane potential through an electrorespiratory complex contained in ANAMMOX through a series of intracellular electron transfer paths and returns to the anaerobic enzyme body to provide electrons for NO 2- -N reduction and N 2H4 synthesis, thereby forming a complete intracellular electron circulation path. As inorganic autotrophy is long, the electrons consumed in the CO 2 immobilization process are compensated by the oxidation of a nitrite oxidoreductase (NXR) catalytic portion of NO 2- -N to NO 3- -N. However, ANAMMOX, which relies on intracellular electron transport, still has a number of attendant problems. First, the ANAMMOX for intracellular electron transfer must use NO 2- -N in the wastewater as an electron acceptor. NO 2- -N is hardly present in actual sewage because NO 2- -N is very easily oxidized or reduced to other forms. therefore, rare NO 2- -N in sewage becomes the biggest obstacle to the popularization of the ANAMMOX process. Second, oxidation of NO 2- -N to NO 3- -N to compensate for the electron vacancies in the intracellular electron transport chain also results in the accumulation of 11% nitrogen-containing byproducts (as compared to the NH 4+ -N content of the feed water), thus defining a denitrification physiological limit of ANAMMOX of only 89%. Thus, there is a need to develop an extracellular respiratory ANAMMOX pathway that is distinguished from the NO 2- -N electron acceptor, thus addressing the NO 2- -N supply limitation and scavenging all the NO 3- -N by-product limitations. Shi et al (2016) provide a design concept for extracellular electron transfer pathways based on Shewanella (Shewanella) and Geobacillus (Geobabacter) that ① specific microorganisms can breathe using metal minerals as terminal electron sinks to directly cross the barrier of intracellular electron acceptors, ② microbial cell membranes are a physical barrier to electron exchange and can be overcome by transfer pathways consisting of redox proteins (e.g., c-type cytochromes) and structural proteins (e.g., microbial nanowires and other cellular structures) that are expected to occur in the same or different species and participate in electrons crossing the whole cell domain, allowing the exchange of intracellular produced electrons with extracellular electron acceptors. However, due to the unique cellular structure of AnAOB, it is still largely unknown whether this process fits into the ANAMMOX system, which makes its feasibility still challenging from basic research to industrial application. Based on this, the present study is based on the original functional species of the ANAMMOX system and a known enzyme library, by stimulating the novel non-nitrosylated ANAMMOX pathway in situ to drive efficient extracellular respiratory nitrogen metabolism and provide detailed extracellular electron transfer pathways and molecular mechanisms. The invention develops an extracellular respiratory anaerobic ammonia oxidation process without nitrous for the first time, and fundamentally solves the bottlenecks of blocked supply of ANAMMOX electron acceptors, accumulation of byproducts and the like. Disclosure of Inve