| Acrylic fiber wastewater contains large amounts of biorefractory organics and toxic or hazardous substances, such as N, N- dimethylacetamide(DMAC), AN(acrylonitrile), vinyl acetate, monomer and polymers, amines, nitriles and alcohols.The complex components and high concentration of pollutants contribute to recognized problem in water treatment industry.Currently, the treatment effect of industrial wastewater with high concentration of biorefractory organics is not ideal `through physical chemical or biochemical treatment alone.Using a combination of both series to degradate pollutants is the general process of wastewater treatment plant.However, due to the conditions of wasterwater and restrictions of the pretreatment process, the physical chemical part has some capacity limitations in improving the biodegradability of wastewater, so the focus of wastewater treatment depends on the biochemical process.1970 s, scholars began to separate and breed some special high-performance composite microbes targeted certain contaminants to treat wastewater, these degrading bacteria decomposed organics faster and stronger, having unique features and benefits in the biological treatment of industrial wastewater.It is a promising wastewater treatment technology.Highly effective bacteria has been put into use in treating petrochemical, coking, printing and dyeing wastewater and other industries about liquid propellant, but research referring to acrylic fiber wastewater treatment has been reported rarely.Therefore, under the high environmental standards, exploration and research about acrylic fiber wastewater biochemical treatment effects reinforced by highly effective bacteria is necessary,and the experiments have important practical significance.In this paper, the raw water in regulating tank right after adsorption by activated sludge was biochemical tested through adding efficient outsourcing bacterial enzyme additive in Jilin Chemical Fiber wastewater treatment plant.The decontamination effect was investigated in small scale SBR reactor about the dosage of bacterial enzyme additive, the different ratio of carrier filling, adding alkalinity and source of phosphorus or not, and increasing dissolved oxygen.The experiment also investigated acrylic fiber wastewater biochemical treatment strengthened by highly effective bacteria combining with fillers in the new plexiglass efficient continuous flow reactor. Basing on the propagation of bacteria, the study focused on four influencing factors including temperature, nutrients, dissolved oxygenand alkalinity) in biochemical treatment of acrylic fiber wastewater.At the same time,the research on denitrification effects was conducted and measures were taken in practical new-builded biochemical engineering in chemical fiber plant.The results provided direction for transformation of biochemical pool.Study reached the following conclusions:(1)Dosing highly effective bacteria and adding fillers to the SBR reactor,both COD and ammonia had a good treatment effect through the synergy, the removal rate could reach 50% and 95%, respectively.But different dosage of highly effective bacteria had little influence on effluent in biochemical system, due to the limited small scale test device probably; the COD treatment effect in the reactor filled with different proportions of filler was positively correlated with the loading level of carrier while the ammonia removal showed a downward trend with the increase in the amount of carrier; Within a certain range, the decontamination effect of the reactor would be improved with the increasing of the dissolved oxygen concentration, especially for the COD removal efficiency;Adding a certain amount of sodium bicarbonate and sodium dihydrogen phosphate solution to the reactor for alkalinity and phosphorus source adjustment would play a very good effect of lowering ammonia, but both dosing or not had no significant effect in terms of COD removal.(2) The certain strengthening effect was showed in acrylic fiber wastewater biochemical treatment by adding highly effective bacteria and carrier,and the maintaining stability of the wastewater treatment system was better reflected. Combined with the basic law of microbial growth and reproduction, the relevant measures( raising the temperature of biochemical systems to 30 ℃, dosing 500 ml sterilized pure milk every 24 hours and refluxing 15 L nitrification liquid from SBR reactor) were taken in the experimental reactor to culture high concentrations of microbial strains within the biochemical system, basing on the maintaining mixed solution pH(7.5-8.0) and giving adequate DO(4 mg / L). The concentration of ammonia in reactor effluent could be reduced to the average of 11.8 mg / L, the removal rate was about 90% in culturing phase. The degradation of ammonia reached a new level. The concentration of mixed liquor suspended solids in reactor was 400-500 mg / L, maintaining a stable level, and carrier biomass achieved 0.03-0.04 g / cm3.(3)Four factors( temperature, nutrients, dissolved oxygen and alkalinity)were determined in the wastewater treatment process to the optimal process conditions through single factor experiments. The concentration of COD in reactor effluent remained at 280 mg / L or less, with an average of 242.5mg / L; the degradation of ammonia was good, maintaining in the 5mg / L or less, the removal rate increased steadily to 95% or more while the experimental condition was controled as follows: T( 25-27 ℃), 125 mL sterilized pure milk, DO <2mg / L, alkalinity(bicarbonate) adding 0.5g / L, the phosphorus source(sodium dihydrogen phosphate) adding 0.0389 g / L, HRT(24h).The reactor ran the preferred operating state and proceed biochemical good results under conditions of optimal parameters.(4) In the five grids of each test corridor in aeration tank new biochemical pool, the first and the second grid proceeded C oxidation about degradation of COD mainly,the ammonia removal efficiency was significantly increased with the reduce of the organic load and the strengthening of nitrification from the third grid;Through taking some measures(returning sludge or effluent, adding alkalinity, raising the temperature,increasing the aeration)along the hydraulic flow paragraph, the results showed that the biochemical effect of the sludge backing to the 3rd grid was better than to the first grid, the reflux liquid effluent contributed to strengthening the degradation of ammonia, adding alkalinity and raising the temperature could improve ammonia removal,increasing the DO concentration enhanced the activity of denitrifying bacteria, thereby enhancing the ammonia removal.The using of highly effective bacteria in acrylic fiber wastewater strengthened biological treatment and applying to the actual project provide a new method to improve the acrylic fiber wastewater treatment effect.Efficient bacteria have a good prospect in water treatment industry. It is necessary to do deep research. |
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