Pilot Study On PAEs Removal In Drinking Water With Ozone-Sorbent Combine Processes

Phthalate acid esters (or Phthalate esters, write PAEs for short)are an important compound in the environment hormone substances. With the development of plastics industry and widely use of plastic products, PAEs have been poured into the environment as pollutants in the environment everywhere. Nowadays, main method in drinking water treament as follow:photocatalytic oxidation, activated carbon, ozone/activated carbon process.At present, activated carbon is the most common kind of packing in drinking water treatment technology. Activated carbon can be cost-effective way to remove smell, taste, color, chlorinated organic compounds, pesticides, radioactive organic compounds and other synthetic organic compounds, and the production process is convenient. Zeolite is a family of which have connected channels, and frame-like structure of water content aluminum silicate minerals. Zeolite is now more widely used in the water environment field, and more for the selective adsorption to remove organic contaminants, ammonia nitrogen, heavy metals, reducing fluorine content and the elimination of radioactive substances, and also has some use in water filter. Zeolite price is low, about several hundred dollars per ton, while the activated carbon according to different kinds of applications, different quality and price per ton on a few thousand to ten thousand dollars. Thus, making use of zeolite in dringking water treatment is feasible. Although using zeolite alone is economic, but the removal of low molecular weight PAEs is not efficiency, so combine the two kinds of filler is considerable. Because ozone / activated carbon process is more mature, so based on the use of this, combine zeolite and activated carbon to reduce costs, ensure the processing performance, which play a positive role in terms of costs on reducing the water plant run cost.The design and operation of the control parameters, the depth of the treated effluent quality and production costs of "ozone - sorbent process" have directly with the local water quality, climate and water plants existing production processes. For the proposed water plant in Chongqing will use the "ozone - combine sorbent" process, it is necessary to make a pilot experiment before construction of the process system. The equipment is settled in GaoJia garden plant, the scale is 24m3/d. Inflow of the process is the water from coagulation, sedimentation and filtration of the water after conventional process, that is access to V-filter of GaoJia garden plant, water before the chlorination. In this paper, four different molecular weight, molecular polarity of PAE have been chosen as a target material to study the ozone - biological activated carbon and ozone - zeolite / activated carbon packing process. In order to get removal effective of these four kinds of PAE and relevant process parameters. High concentration of PAE water have been examined in the two processes. Paper made the following main conclusions:1) The effective height of the carbon layer is 100cm, the optimum operation parameters is as follows: the ozone dosage—2~3mg / L, the ozone contact time—15min, the empty bed contact time(EBCT) of activated carbon—9min. Take DEHP as an example, inflow 18. 06μg / L, outflow 6. 7μg / L, removal rate is 62. 9%, which satisfy the comand of the dringking water;under the parameter combinations: ozone dosage 3mg / L, ozone contact time 15min, empty bed contact time of activated carbon 9min, the removal effective of the PAEs is good, while the conventional water indicators such as turbidity, CODmn, UV254, ammonia can also meet drinking water health standards;2) Dosing different ozone in two places:ozone tow and activated carbon filter, compare the treatment efficiency. As excellent adsorption ability of activated carbon, outflow did not show large differences, thus it is not necessary to use multi-point dosing in the actual production;3) The optimum combination of filler filling ratio: 30% zeolite +70% activated carbon, in which filling ratio, provides better removal effects. Take 150cm combination fillers as an example, the influent concentration of DEHP is 15. 28μg / L, the effluent is 5. 68μg / L, removal rate is 62. 8%;4) Under the influent are 60μg / L and 100μg / L, the activated carbon column and the combination column had good removal rates of DMP and DBP , the removal ratio close to 100%. With the increase of empty bed contact time, the removal of PAEs have shown an upward trend for the removal with the activated carbon filter and the combination filter column. Compared with the activated carbon filter and the combination filter column, both the removal of high molecular PAEs(DEHP and DOP) were not ideal, activated carbon columns on the removal of DEHP and DOP filter slightly better than filler column combination.