| With the development of economy, more and more highway had been constructed in Mountainous region of China, which resulted that a lot of tunnels were constructed in recent year. However, the tunnels mostly located in eco-environmental vulnerable area, such as drinking water source region, drinking water conservation region. At the same time, eco-environment could be contaminated by the tunnel construction wastewater which did not treated. Therefore, the research for properties and treatment technique of tunnel construction wastewater is very necessary.This thesis's research content is a single part of Shanxi province communications department task which is mountain area highway tunnel construction wastewater treatment technology research. Papers based in prophase investigation data from task group to production wastewater of the tunnel construction in mountainous area and using cement as disposal reagents. Through adding other coagulant to cement, we researched mixed ratio and tested the whole flow, educed the conclusion as follows:1. Single coagulation experiments show that the minerals contained in cement are factors of forming coagulation precipitate; The different label water cement to the treatment effect of little impact; The main effect factors of coagulation precipitate is component of the content of C3S.2. Experiments of cement and different coagulants cooperating show that the cement adding coagulant is superior combinations processing, and the tiptop removal rate is cement adding A12(SO4)3.3. Experiments of cement adding Al2(SO4)3 mixing ratio show that, on the mountain tunnel construction wastewater, when cement adding Al2(SO4)3 mixing ratio is at 25:1, the removal rate of COD is at about 70%; At 15:1～30:1, the removal of nitrobenzene at about 50%; At 25:1～45:1, the removal of petroleum at 25 percent to 30 percent. For 1 liter preparing treatment water sample, selecting the mass ratio of cement and vitriolic at 25:1 as combinations medicament, reaction conditions for 1.25 gram, A12(SO4)3 for 0.05 gram, precipitate time for 1 hour and rotating speed for 150r per minute can achieve the best effect. Adding sand filter after sedimentation, removal efficiency of petroleum and nitrobenzene increased, while the removal rate of COD declined.4. After the whole flow treating with the three different mixing ways of no agitation, mechanical agitation and air agitation, the removal rate of pollutant indexes stayed stabilization on the whole. 5. Cement's main minerals in the water can create the sedimentation with flocculation effect. In cement hydration and hardening process, hydration products can remove colloid impurities from water through adsorption electricity neutralization, adsorption bridges, capturing with a variety of action such as net volume. Al2(SO4)3 could promote the minerals of cement to dissolve, having greater influence to cement hydration rate.6. Quartz sand selected as filter material, having the adsorption ability to nitrobenzene, can adsorb dissolve oil of wastewater on the surface, so it could apart the oil from water. Due to its intercepting and agglomeration function, quartz sand has a good impact to dispose scattered oil from water, too. |
PDF Full Text Request