Study On Treatment Process Of The High Density And Difficultly Biodegradable Mixed Fixing And Developing Waste Liquid

Photosensitive wastewater has a high concentration of pollutants,complex components,large chroma,and a certain degree of toxicity.Direct discharge or non-compliance discharge can cause serious pollution to water bodies and the environment.The waste water used in this study belongs to photographic wastewater,which has been defined as the developer mixed wastewater for the photography industry.The wastewater that used by this study has been subjected to silver extraction work.At present,there is no widely used and mature treatment method for such waste water in China.This study explored the treatment process of the fixed developer mixed wastewater produced by the photographic industry,screened the flocculants in the pretreatment stage,and found the optimal flocculation conditions;the biological treatment process explored the biological treatment process,and studied under the different residence time and temperature condition that the effect of biological treatment process on wastewater treatment effect;advanced treatment stage to explore the effect of US/Fenton and its combination system on wastewater treatment,analysis of experimental results,adsorption treatment stage to explore different size of activated carbon and its dosage to wastewater.The best experimental conditions was selected through the experiment?pH value,adsorption time?.The whole experimental study provides data reference and theoretical basis for mixed fixing and developing waste liquid of the photography industry treatment method and its application in the treatment of photosensitive waste water.The conclusions obtained in this paper are summarized as follows:1.Polyaluminum chloride?PAC?and anionic polyacrylamide?APAM?were selected as pre-stage flocculants through experiments.The optimal dosing amounts of PAC and APAM were 2 g/L and 0.05 g/L,respectively.pH=7 was the optimal pH value.The COD removal rate and decolorization rate for wastewater were 29.59%and 21%,respectively.2.Biological treatment wastewater selected hydrolytic acidification and delayed aeration process.After the analysis of the test results,the HRT of hydrolysis acidification was 24h,and the HRT of delayed aeration was 12h.Under this operating condition,the COD removal efficiency of biological treatment wastewater was 57.34%,and the decolorization rate was33.54%.The activated sludge method has little effect on the effect of waste water at different temperatures.The reason for the analysis is that the temperature can be formed into the biological population at each temperature.3.Comparing the wastewater treatment effect of US,Fenton and its combination system,it can be concluded from the treatment effect that the US-Fenton system can significantly improve the treatment of wastewater pollutants.Through experimentation,when the wastewater pH value was 5,the H₂O₂ dosage was 200 mmol/L,the n?H₂O₂?/n(Fe²⁺)was 12:1,the ultrasonic time was 50 min,the ultrasonic power was 160 W,the US-Fenton system was applied to the wastewater.The treatment of effect the US-Fenton system applied to the wastewater reached the best,and the COD removal rate and decolorization rate of wastewater were 85.21%and 89%,respectively.4.Experimental study on the effect of removal of pollutants in wastewater by the particle size of activated carbon and its dosage.The effect of 3-30 meshes of 4-8 meshes,10-18meshes,and 20-30 meshes of three particle sizes is the most effective.Well,at the dosage of10 g/L,COD is very close due to the best results of the three particle sizes,taking into account the economy and operability,selecting 4-8 mesh particle size activated carbon.5.When the pH value of the wastewater is 3,the adsorption time is 30min,the effect of activated carbon on COD and color removal is best.The removal rate of COD is 78.51%and the decolorization rate is 77.27%.Adsorption isotherms of activated carbon with three particle sizes are in accordance with the Freundlich adsorption isotherm.By calculation,all three particle sizes are easily adsorbed,and 20-30 mesh have a strong adsorption capacity.6.After the developer wastewater is treated with flocculation/biochemistry/US-Fenton/activated carbon,the COD of the wastewater is reduced from 8000 mg/L to 73 mg/L,and the removal rate is 99.09%;the chroma from 2000 to 25,the removal rate Up to 98.75%,the treated wastewater meets Level 1 standards of other pollutant discharge units in Table 4 of?Integrated wastewater discharge Standard??GB8978-1996?,the removal effect is significant,which greatly reduces the content of pollutants in the wastewater.