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CN-121990690-A - Sewage treatment method based on microalgae thin-layer fountain photobioreactor

CN121990690ACN 121990690 ACN121990690 ACN 121990690ACN-121990690-A

Abstract

The invention belongs to the technical field of sewage treatment, and in particular relates to a sewage treatment method based on a microalgae thin-layer fountain photobioreactor, which comprises the following steps that S1, microalgae cells are inoculated into the thin-layer fountain photobioreactor and are cultured to a logarithmic growth phase, so that high-activity microalgae seed liquid is obtained; S2, introducing the sewage to be treated into the thin-layer fountain photobioreactor containing the high-activity microalgae seed liquid in the step S1, so that the microalgae cell concentration is maintained at 0.01-5.0 g/L, S3, dynamically adjusting the transparent material and the liquid layer thickness of the surface sealing degree (namely the sealing film ratio) of the thin-layer fountain photobioreactor according to the sewage turbidity and the treatment stage, and supplementing water in real time according to the evaporation condition to maintain the stable operation of the system, S4, cooperatively adjusting and controlling parameters such as the water pump flow, the pH value of the culture liquid, the liquid layer thickness and the like of the thin-layer fountain photobioreactor, and continuously operating until the effluent reaches the discharge standard. The method obviously strengthens the gas-liquid mass transfer and the light energy utilization of the microalgae culture liquid through a thin-layer fountain structure, effectively overcomes the light limiting effect in high-turbidity sewage, combines the dynamic adjustment of the sealing film ratio, realizes the cooperative control of temperature, evaporation and light receiving conditions, realizes the COD removal rate of more than or equal to 90%, the ammonia nitrogen removal rate of more than or equal to 95% and the total phosphorus removal rate of more than 99% under the condition of no need of exogenous carbon source and complex pretreatment, and synchronously completes the microalgae high-density culture and biomass recycling recovery. The system has the characteristics of low operation cost, easy amplification and wide applicability, and provides a technical scheme with industrialization potential for high-efficiency and low-carbon treatment of the culture sewage and the like.

Inventors

  • ZHU CHENBA
  • WANG JIALIN
  • ZHANG MINGJING
  • LUO WENJUN
  • LI CHENGZE
  • WANG WENZHAO
  • GUO XIAOYU
  • HU CHEN
  • JIAO NIANZHI

Assignees

  • 厦门大学

Dates

Publication Date
20260508
Application Date
20260126

Claims (10)

  1. 1. The sewage treatment method based on the microalgae thin-layer fountain photobioreactor is characterized by comprising the following steps of: S1, inoculating microalgae cells into a thin-layer fountain photobioreactor, and culturing until the growth period of the microalgae cells is logarithmic, thereby obtaining high-activity microalgae seed liquid. The thin-layer fountain photobioreactor comprises a reactor main body, a microalgae culture cavity is formed in the reactor main body, a culture solution circulating device for conveying culture solution in the microalgae culture cavity to a high position and enabling the culture solution to fall back after being scattered at the high position and a transparent material which covers the surface of the thin-layer fountain photobioreactor and can adjust the sealing degree (namely the sealing film ratio) are arranged on the reactor main body, the culture solution circulating device comprises a water pump, a liquid delivery pipe and a water outlet piece, the liquid delivery pipe end is connected to a water outlet of the water pump, and the water outlet piece is connected to the upper end of the liquid delivery pipe; S2, introducing the sewage to be treated into the thin-layer fountain photobioreactor containing the high-activity microalgae seed liquid in the step S1, so that the concentration of microalgae cells is maintained at 0.01-5.0 g/L; S3, dynamically adjusting the sealing film ratio and the liquid layer thickness of the thin-layer fountain photobioreactor according to the turbidity and the treatment stage of the sewage, and supplementing water in real time according to the evaporation condition so as to maintain the stable operation of the system; and S4, cooperatively regulating and controlling the water pump flow, the pH value of the culture solution and the liquid layer thickness parameter of the thin-layer fountain photobioreactor, and continuously running until the effluent reaches the discharge standard.
  2. 2. The sewage treatment method according to claim 1, wherein the surface of the thin-layer fountain photobioreactor is provided with a device for adjusting the sealing film ratio, and the device is used for controlling one or more of the gas exchange rate, the water evaporation rate and the temperature inside and outside the reactor.
  3. 3. The method according to claim 1, wherein the target thickness of the culture solution in the step S3 is dynamically set according to the initial turbidity of the introduced sewage, wherein the liquid layer thickness is controlled to be 0.1-2.0 cm when the initial turbidity of the sewage is not less than 200 NTU, and is controlled to be not less than 2.0 cm when the initial turbidity of the sewage is less than 200 NTU.
  4. 4. The wastewater treatment method according to claim 1, wherein the fountain pump flow rate in step S4 is in the range of 0.1-100L/min.
  5. 5. The wastewater treatment method according to claim 1, wherein the temperature of the culture solution in step S1 to step S4 is controlled to 20 ℃ to 45 ℃.
  6. 6. The method according to claim 1, wherein the pH of the culture solution in the step S4 is 9.0-12.0.
  7. 7. The method for treating sewage according to any one of claims 1 to 6, wherein the efficient purification of sewage and the recycling of microalgae are realized by cooperatively controlling a plurality of technical parameters of sealing membrane ratio, liquid layer thickness, water pump flow, pH and temperature.
  8. 8. The wastewater treatment method according to claim 1, wherein the microalgae in step S1 are one or more of chlorella, nannochloropsis, and spirulina having high ammonia nitrogen resistance.
  9. 9. The method for treating sewage according to claim 1, wherein 0.01-5.0 g/L of photosynthetic bacteria is added to the reactor after the sewage is introduced in the step S2.
  10. 10. The wastewater treatment method according to claim 1, wherein the sealing ratio in step S1 is 60%.

Description

Sewage treatment method based on microalgae thin-layer fountain photobioreactor Technical Field The invention relates to the technical field of sewage treatment, in particular to a sewage treatment method based on a microalgae thin-layer fountain photo-bioreactor. Background With the continuous growth of global population and the change of dietary structure, the increase of the consumption demand of livestock and poultry products promotes the large-scale development of the breeding industry, and simultaneously, the discharge of industrial and domestic sewage is continuously increased. Various types of sewage (including livestock and poultry raising sewage, aquaculture tail water and the like) are usually rich in nutrient salts such as nitrogen and phosphorus, heavy metals and high-concentration suspended matters (the turbidity is often higher than 500 NTU), and direct discharge is easy to cause water eutrophication and ecological unbalance. The current sewage treatment technology is mainly divided into three major categories, namely a physical method, a chemical method and a biological method. Although the techniques such as grating, precipitation and filtration in the physical method can effectively remove suspended matters and part of colloid, the removal effect on soluble pollutants (especially nutrient salts such as nitrogen, phosphorus and the like) is limited. The chemical method can effectively precipitate phosphorus and remove part of colloid and heavy metal by adding coagulant, precipitant and the like, but has the problems of high medicament cost, easy generation of chemical sludge, secondary pollution and the like. Under the background that the physical and chemical treatment processes are difficult to remove the soluble nutrient salts efficiently and the problems of cost and secondary pollution are easy to bring, the traditional biotechnology represented by an activated sludge method and a biomembrane method also faces significant challenges. In the process of removing nutrient salts such as nitrogen, phosphorus and the like and organic pollutants, the process generally depends on sufficient and stable available carbon sources in sewage, and the problem of unbalanced carbon nitrogen ratio (C: N is often lower than 5:1) of actual aquaculture sewage often exists, so that the pollutant removal efficiency is reduced, and extra exogenous carbon is often required to be added to maintain the treatment effect, so that the running cost is further increased and the potential secondary pollution risk is brought. Meanwhile, a large amount of colloid particles, refractory organic matters and microbial aggregates exist in the culture sewage, so that the water body is in a high turbidity state (usually higher than 500 NTU) for a long time, the mass transfer and metabolism efficiency in the traditional biological treatment process is weakened, the effective utilization capacity of the light-dependent treatment process on light energy is obviously reduced, and the application of various biological strengthening and recycling technologies in engineering practice is limited. The microalgae technology is paid attention to because of the potential of high-efficiency pollutant removal and biomass recycling, and can absorb CO 2 through photosynthesis and synthesize organic matters, so that inorganic carbon sources are supplemented for the sewage denitrification process in situ, and the problem of unbalanced carbon-nitrogen ratio is solved. However, the large-scale application of the technology still faces multiple constraints that the traditional photo-bioreactor is often high in cost due to complex structure and large occupied area, the microalgae are in a light limiting state due to serious light attenuation when the thicker culture liquid layer (> 5.0 cm) is used for treating high-turbidity sewage, so that the density of the microalgae in a culture system is generally low, meanwhile, the utilization of CO 2 in the microalgae growth and the air is further limited due to insufficient mixing and mass transfer efficiency, and in addition, a large amount of water is required to be treated in the subsequent harvesting process due to the low biomass density, and the whole cost is high due to the fact that the technology of high energy consumption such as high-speed centrifugation is not needed. The superposition of these problems severely restricts the overall economy and engineering popularization potential of the technology. It is worth noting that single microalgae systems are susceptible to factors such as substrate inhibition, poison accumulation and the like in complex sewage environments, and metabolic activity is often limited. In recent years, bacteria and microalgae are introduced to construct a bacteria-algae cooperation system, and the functional complementation of different microorganisms on carbon, nitrogen and organic matter metabolic pathways is utilized, so that the cooperative reinforcement of pollutant