MBBR is widely used in municipal and industrial wastewater treatment. Industrial wastewater includes petrochemical, printing and dyeing, leather, pharmaceutical, paper, industrial park integrated wastewater, etc. Municipal sewage includes projects such as raising, lifting, and raising materials; MBBR Widely used in all grades of water, including small, medium, large and extra large sewage plants, the application is not limited by scale, MBBR is now used for integrated equipment engineering; MBBR can be applied to both onshore sewage plants and Semi-underground, full underground sewage treatment plant.

The typical engineering application of MBBR in China has the following characteristics:

1) Strengthening nitrogen and phosphorus removal: The sluge-film composite process can realize the simultaneous enhancement of nitrogen and phosphorus removal. The TP of the biochemical section of a sewage treatment plant in Shandong can be <1mg/L, the TP removal rate of the biochemical section is over 90%, and the ammonia nitrogen and TN  are stablely up to standard; municipal renovation projects have all reached the first-class grade A standard, some projects have achieved S- IV water standards; a sewage treatment plant in Shandong uses Bardenpho five-stage + MBBR process, and the effluent NH3-N is reduced from 1.55mg/L to 0.54. Mg/L, ammonia nitrogen removal rate is as high as 99.3%, effluent TN is reduced from 23.23mg/L to 8.04mg/L, removal rate is increased by 23.5%, breaking the limit of TN removal by the original A2/O process;

2) High-load-occupied province: In most cases, the original pool has been upgraded, and even the cross-level bidding, lifting, and bidding are simultaneously carried out, and the amount can be increased by more than 100%. In the retrofitting of a sewage treatment plant in Zhejiang, The amount of water is increased from 5wt/d to 10wt/d, and the amount is increased by 100%. The expansion of a sewage treatment plant in East China is carried out in 2018. The water volume is expanded from 10wt/d to 12wt/d, and the capacity is expanded by 20%. It is also used for pretreatment of industrial wastewater. Organic matter removal, the load is 2-3 times higher than the traditional process; Wang Xiaoyun et al [12] used a two-stage MBBR series process to treat organic wastewater from a semiconductor plant, with a volumetric load of 12.5kg BOD5/(m3·d), total HRT=  12h, the COD removal rate can reach 60%-85% under the condition of 30% fill rate; MBBR decontamination efficiency and load rate are significantly better than ordinary activated sludge method;

3) Strong anti-shock load capacity: Due to the presence of some or all of the MBBR microorganisms, especially the nitrifying bacteria group, the nitrifying bacteria group is less affected by the impact, can resist strong impact, and exceeds the design load (including The coefficient of variation) can quickly restore the effect after the impact; Qian Xiaohui and others used MBBR to treat the chemical park wastewater. When the influent COD increased from 130 mg/L to 845.5 mg/L, the effluent COD increased from 97.1 mg/L to 132.1. Mg/L, after which it has been stable; when the water volume increased from 15971m3/d to 27891m3/d, the effluent COD increased from 80.5mg/L to 119.1mg/L, and then remained stable, indicating that though the MBBR water inflow and water quality change drastically,it can maintain a good effluent quality; a sewage treatment plant in Shandong has a high proportion of industrial wastewater in the influent water, and the water quality and quantity change greatly, and it is often subjected to impact. After the impact, the ammonia nitrogen can not be restored to the standard for several weeks, and it takes several months to recover. After the three-stage MBBR series retrofitting, the treatment effect is stable and up to standard, and is not affected by the fluctuation of water inflow;

4) Tolerant to low temperature, poor nutrition, high toxicity, high chloride ion and other extreme water quality: MBBR biofilm sluge retention time is long, generally more than 30d, which is conducive to the enrichment of nitrifying bacteria, especially for high-efficiency bacteria under special water quality conditions. Screening; North and Yangtze River sewage plants suffer from low temperature, MBBR can achieve low temperature treatment at 6 °C, the lowest can achieve 3 °C; Wuxi Lucun sewage treatment plant is the first application of MBBR process in domestic large sewage treatment plant, Wang Putian et al [3] added SPR-I suspension carrier in the aerobic section of A2O. After the completion of the reform, the effluent water quality was stable, the COD and NH3-N removal rate reached 85%, and the low water temperature (<12 °C) in winter was very high. The good treatment effect improves the problem of poor treatment effect of activated sludge in winter; the practice of Urad Zhongqi also shows that the denitrification capacity of MBBR process at 6 °C water temperature is still considerable, and the total nitrogen removal rate can reach 90%; In one of a Shanxi  water plant, the nitration load of the suspension carrier at 6-8 °C can reach 0.15-0.20kgN/m3/d [16]; the deep denitrification process of the sewage plant is influent or the southern sewage plant, the water concentration is low or often in a state of poor nutrition. , MBBR can be used for lower C/N Water treatment or micro-polluted water treatment, such as deep treatment of effluent from secondary sedimentation tank, enhancing TN removal; high chloride ion content in coastal urban seawater backflow irrigation, MBBR can meet the denitrification treatment of chloride ion over 5000-10000mg/L; Both are difficult to handle in the activated sludge process, and MBBR show excellent performance and solves related problems;

5) Sustainable upgrading: Due to the different effective specific surface area and fill rate of the suspension carrier used in MBBR, the fill rate can be increased by 10-68% through the replacement of the suspension carrier or the dosage; a wastewater treatment plant in Shandong will carry out a the first-class grade A standard and the MBBR SPR-I suspension carrier was used. In 2015, the suspension carrier was added during the original pool, and the original pool was increased by 22%.

6) Investment province: MBBR investment mainly comes from suspension carrier, and the amount of suspension carrier is related to various factors such as water quantity, water quality, water output standard and temperature. The MBBR water investment index is weak, and municipal sewage is from 100-800 yuan. / (m3 / d), the typical value is 200-500 yuan / (m3 / d); and the life expectancy is more than 15 years, no need to replace the suspended carrier, no follow-up additional costs;

7) Low operating cost: MBBR suspended carrier fluidization requires no additional aeration, normal aeration can meet the requirements of suspension carrier fluidization, and as the suspension carrier fill rate increases, the suspension carrier can cut the bubble to increase gas-liquid contact. The area and the presence of the suspension carrier prolong the bubble overflow time, improve the oxygen transfer efficiency, and reduce the aeration energy consumption; optimizing the pool type can eliminate the agitator in the circulating flow  type, which can further reduce the operating energy consumption [9- 10].

The MBBR retrofiting has the following characteristics:

1) Mosaic modification: Through the implementation of the sluge-film composite MBBR process, MBBR can be combined with A2/O, SBR, oxidation ditch, Biolake and the deformation process of the above activated sludge process to realize inlaid transformation without new construction and expansion; Dai Zhigang transformed the CASS process of a sewage treatment plant in Hohhot into SBR+MBBR process, and achieve that COD, BOD5, NH3-N and TN can reach Grade A standard in the biological pool; Shijian will transform the Obel Oxidation Ditch into a filling zone. The fill rate is 10%-20%. When the influent water is TP 4.67mg/L and the internal reflux ratio is 75%, only the biological dephosphorization of the oxidation ditch can meet the first-class A standard, and no auxiliary chemical phosphorus removal is needed. It can be combined with various pool types. , including round, square, long strip, ring groove type, etc.;

2) Flexible aeration method: mainly adopts perforated tube aeration, and can also be combined with microporous aeration and catenary exposure, which does not affect the process; Li Yuqing carries out the first-class A standard upgrade of Chaoyang Wastewater Treatment Plant, and MBBR Combined with the hanging chain exposure of the original project, the nitrogen removal rate after the transformation is increased by more than 15%;

3) The project implementation period is short: generally each group of pools is 7-14d, mainly due to the simple construction and installation, MBBR transformation of less or no civil construction, MBBR components are mostly prefabricated, can be directly installed, can achieve non-stop water transformation;

4) Convenient operation and management: MBBR application implements the concept of inlay, can continue the operation and management experience of the existing operators on the process, and the process has no special maintenance requirements, and the operation management is simple.

The underground sewage plant has the advantages of good social and environmental benefits, land occupation and low noise, and is the development trend of the sewage plant. At present, the mainstream process of domestic underground sewage plants are MBR and MBBR, but the investment cost of MBR is up to twic than that of MBBR and the operation and maintenance are cumbersome. In addition, MBBR can solve the problem of upgrading the underground sewage plant through the filling of the packing. Since the original pool can realize the retrofitting, the construction does not need to reserve the long-term civil construction, saving the initial investment cost, and having both environmental protection benefits and long-term economic benefits. . Qingdao High-tech Zone is a newly built underground sewage treatment plant with a design scale of 18wt/d. MBBR is used to effectively reduce the pool capacity of the biochemical pool.

At present, MBBR is mainly used for centralized treatment of sewage, but it is still in its infancy for decentralized sewage treatment such as rural domestic sewage. The integrated equipment based on MBBR can adapt to the characteristics of dispersed sewage treatment, occupying land, impact resistance, low temperature resistance, low sludge production, simple operation and maintenance, etc., and has been applied in some areas, and has achieved good results. Source pollution treatment has gradually moved from the device age to the effect era.