Research And Application Of Water-based Ink Wastewater Treatment

An ink manufacturer needs to carry out project reconstruction and expansion due to market development,and changes the original production formula and production scale.The generated wastewater is treated by the existing“coagulation sedimentation-hydrolysis acidification-BIOFOR biofilter”combination process,can not meet the relevant emission standards.Therefore,this subject studies the characteristics of wastewater generated after the expansion and expansion of the enterprise,and conducts small-scale experiments to apply the experimental results to the upgrading of the enterprise wastewater treatment process.Finally,the pretreatment process of“Fenton oxidation+coagulation sedimentation”was used to decolorize the wastewater,improve the biodegradability of the wastewater,and then carry out secondary biological treatment through the combined process of“UASB+A/O+BIOFOR biofilter”,Meet the standard discharge.Ink wastewater has attracted the attention of many water treatment researchers because of its high salt content,high chroma,high pollutant concentration and difficult biodegradation.Through the experimental study on decolorization of wastewater and pretreatment of improving biochemical properties of wastewater,this paper explores the best application conditions of the treatment scheme,and then through the operation and debugging of the biochemical treatment unit,ensures the higher pollutant treatment efficiency of the whole wastewater treatment system and the stability of the effluent to meet the standards.For the characteristics of high total salt content in ink wastewater,the project uses three-effect evaporator to remove salt,which reduces the total salt content from155136 mg/L to 800 mg/L;For the high chroma and difficult biodegradation characteristics of wastewater,the project first performs preliminary decolorization of ozone-activated carbon,then decolorizes with Fenton oxidation,and improves the biodegradability of wastewater.The experiment showed that under the conditions of Fe²⁺dosage of 3g/L,hydrogen peroxide dosage of 5ml/L,pH of 4 and reaction time of 120min,the chromaticity of wastewater and the removal rate of CODcr were 71.8%and 57.8%respectively;Then the wastewater is further decolorized by coagulation precipitation and the suspended substances in the wastewater are removed.In the experiment,under the conditions of PAC dosage of 300mg/L,PAM dosage of 5mg/L,pH of 8 and reaction time of 90min,the chromaticity and removal rate of CODcr of coagulation precipitation were 75.7%and 66.9%respectively.In the actual operation of the process,the chromaticity of Fenton oxidation wastewater and the removal rate of CODcr were 60.0%and 30.7%respectively.The removal rates of CODcr and chromaticity were 65.4%and 24%,respectively.After pretreatment,the B/C value of wastewater was increased from 0.124 to0.379.Then the pollutants can be removed by culturing and domesticating microorganisms in biochemical treatment unit and adjusting the optimum water temperature,pH value,dissolved oxygen and nutrients for their growth and reproduction:?1?In the initial stage of the UASB anaerobic tank,the water temperature is controlled at 25°C to 30°C,the pH value is 7.0-8.0,and the volumetric load is between 0.2-0.5 kg CODcr/?m³·d?for sludge cultivation and domestication.Then,according to the growth state of anaerobic sludge,the removal rate of pollutants,the concentration of VFA,etc.,the volumetric load is gradually increased until the design standard is reached.The removal rate of CODcr and chromaticity of the anaerobic tank reaches 71.5%and 73%,respectively;?2?The A/O tank was stifled to stimulate the microbial activity of sludge,and then the sludge was cultured and domesticated by adjusting the dissolved oxygen and other factors to achieve the designed treatment effect.The final removal rates of CODCr and ammonia nitrogen in A/O cell were 90.1%and 89.1%respectively;?3?During the operation of BIOFOR biofilter,backwashing should be carried out regularly to maintain the microbial activity in the filter.The removal rates of CODCr and ammonia nitrogen in the final biofilter were 68.7%and 40.6%respectively;After 2-4 months of commissioning and operation,under the conditions of inlet CODcr concentration of 10000mg/L,ammonia nitrogen concentration of 150mg/L,and chroma of 1600 times,the combined process of"Fenton oxidization-coagulation-sedimentation-uasb-a/o-biofor biological filter"was adopted to treat the effluent,and the concentration of effluent was reduced to 45mg/L for CODcr,ammonia nitrogen7.5mg/L,and chroma was 15 times,which reached the discharge standard of wastewater stably.In addition,the treatment cost of each ton of water is 13.82 yuan on the premise of only calculating the cost of medicine,electricity and labor.It provides a good process reference for the same type of wastewater treatment project.