The Preparation And Application Of Livestock Sewage Sludge Activated Carbon

In order to realize resource utilization, the livestock sewage sludge was used to prepare sludge activated carbon (LAC) via chemical activation and microwave heating. Meanwhile, the physiochemical properties of this material were also studied in this paper. In order to test the absorption capacity of sludge activated carbon, it was used to treat livestock wastewater.A serial of single factor experiments were carried out to decide on the optimal preparation conditions through iodine value and yield rate. The livestock sewage sludge activated carbon was characterized using BET specific surface area, pore size distribution, SEM photography, surface functional groups, and iodine value. Finally, the activated carbon was used to treat livestock wastewater through focusing on the concentration of absorbent, and removal of COD and chrominance and odor.The results show that potassium hydroxide is the best activator among the three kinds of activator (including zinc chloride, phosphoric acid and potassium hydroxide). For potassium hydroxide, the optimal conditions for the preparation of LAC are as follows:Potassium hydroxide concentration:8 mol/L; activated power:480 w; activated time:14 min. Under the optimal conditions, the yield rate of activated carbon was 28.90%, the iodine value of LAC was 711.48 mg/g, the BET specific surface area of LAC was 684.65 m2/g. The main functional groups of LAC include-OH, C-O, C= O, C-O-C, CH2-and N-H. The Pore structure of LAC is mainly composed of mesoporous, the average pore size is 38.20 nm, and microporous isn’t found. Therefore, this carbon is more suitable for the adsorption of macro-molecular substances.Next the LAC prepared under the optimal conditions was used to treat the livestock sewage from the livestock sewage treatment factory in Sichuan Agricultural University. The results from the absorption experiments show under the conditions of dosage of LAC 0.4 g/L and adsorption time 3 hours, the maximum removal rate of COD reaches 76.94%, the chroma falls below 20 from 100, and its deodorant effect is obvious.Under the optimum conditions for preparing the LAC, the discharged liquid tar mixed with a small amount of water is about 2.80 g/(g·LAC), the emitted flue gas is about 4.28 L(g·LAC). The preliminary cost for preparing LAC is 8600Yuan/ton.