| Paint wastewater is intermittently discharged, which quality and quantity have a large fluctuation. The wastewater is little, but the pollutant composition is very complex, which includes a variety of toxic, difficult biochemical degradation of organic polymer compound and has high concentration.There are many solid in the wastewater.In this experiment, the wastewater was from a paint company, when replacing production needed cleaning equipment,the process of packaging production demanded to washing filter cloth, wastewater was generated from cleaning equipment and washing filter cloth. As the wastewater produced by typical architectural paint company, choosing the economical and practical treatment process through the experiment provided certain reference significance and guide meaning to similar enterprises.In the experiment of micro-electrolysis of iron-carbon and biological contact oxidation process, micro-electrolysis of iron-carbon improved the biodegradability of the wastewater and removed the part of COD and NH3-N, and provided the favorable conditions for follow up biological treatment. Biological contact oxidation removed COD and NH3-N, the treated wastewater met emission standards. In the experiment of micro-electrolysis of iron-carbon,static and dynamic small-scale experiment were respectively studied. Effects of iron-carbon ratio, solid to liquid ratio, p H on COD removal efficiency and water quality changes in a running cycle were studied in microelectrolysis of iron-carbon process, the corresponding optimum operating parameters were determined. Effects of residence time on the COD removal efficiency and The effects of water quality changes on different heights of sample was studied. p H change, the change of turbidity, COD removal, water quality changes in a running cycle were studied in the biological contact oxidation. On this basis, the preliminary design of paint wastewater treatment engineering was did.1.In the static experiment of micro-electrolysis of iron-carbon, results were as follows:(1) The COD removal efficiency had not greatly changes when iron-carbon ratio changed from 1:1 to 6:1. it was not a positive correlation between them. COD removal efficiency reached maxium with iron-carbon ratio of 2:1 and 2.5:1, it was 43.71%. It was determined 2:1 in this experiment.(2) The lower p H, the higher removal efficiency of COD. The maximum removal rate of COD reached to 57.14%. In order to avoid the effect of low p H on the follow up biochemical processing. The raw water p H was not adjusted in the micro-electrolysis experiment.(3) The higher solid-liquid ratio, the higher removal efficiency of COD. The economic factors should be considered on actual project, so the solid-liquid ratio could not too high, it was determined 100:1 in this experiment.(4) In a running cycle, the time period of iron carbon micro-electrolysis reaction was the time of the COD removal. Changes in p H and COD removal efficiency curves were similar.(5) In a running cycle, with increasing of residence time, the NH3-N removal efficiency becoming better and better in the micro-electrolysis experiment, reached 33.5% within120 min.2. The results showed in the dynamic experiment of micro-electrolysis of iron-carbon:(1) The COD removal efficiency was nearly maxium with residence time of 30 min, it was 52.14%, increasing residence time didn’t improve COD removal efficiency significantly,it reached 55.04% with 120 min. Turbidity dropped rapidly within the first 30 min, which from310 NTU to 55 NTU, it dropped from 310 NTU to 17 NTU within 120 min.(2) With the increasing of the height of sample from top to bottom, efflent COD graudally decreased, p H gradually increased.2. Intermittent biological contact oxidation experiment results showed:(1) Treatment effect improved sinifcantly with biological contact oxidation in progress.The COD removal efficiency was only 27.66%~42.31% from 11 d to 19 d and increased to53.01%~70.50% from 20 d to 22 d.(2) In a running cycle(8h), the COD removal efficiency increased gradually along with increasing time of the biological reaction. The optimum reaction time was 8h.(3)Effluent p H was in the range of 6.12~8.40, effluent p H and COD attained the primary discharging standard of "Integrated Wastewater Discharge Standard"(GB8978-1996). |
PDF Full Text Request