| The quantity of the sewage treatment plant emissions of dewatered sludge is more and more, the dewated sludge contains a lot of nutrients, the main train of solving dewatered sludge in fundamentally is able to make full use of the nutrients.This topic choose the dewatered sludge of 80% moisture content as object, using the method of microwave in combination with other additives, aims to research on its utilization way.This research mainly divided into four parts: the first is to use microwave combined sodium hydroxide and hydrogen peroxide to consider microwave thermal effect; The second is microwave combined Ca(OH)2 and solid content factors to consider sludge production of foaming agent; The third is do orthogonal experiment to get the optimized process; The fouth is multiple extraction experiments on the influence of foaming agent production.As the increase of microwave time, sludge been fast drying, dissolubility content increased as high as 14.55%, increased by 40%; Soluble protein content was as high as 935 mg/L, increased 3.7 times; Effective phosphorus and fat content decreased, total phosphorus content was 15~19 g/kg, the total amount of carbon and total nitrogen, basically remain unchanged, maintained at 400 g/kg and 31~35 g/kg, respectively. Add sodium hydroxide to sludge the pH increased, ammonia release a increased quantity; Soluble content increased from 8.93% to 12.26%, increased by 37%; Soluble protein content increased to 200.3 mg/L, increased by 76%; Effective phosphorus content maintain in 0.5~0.6 g/kg. As the add of hydrogen peroxide, the soluble content increased from 12.26% to 13.6%; Effective phosphorus content decreased by 20%, fat content lower 33%, the total carbon in 410~420 g/kg.Microwave time around 15 min was best to production foaming agent, at this point, the TC, the TOC and protein concentration value in the foam fluid achieved the maximum, protein concentration of 56.77 mg/L, increased by 50%; Foaming power and stability time reached higher levels of 7.57 times and 5 h, respectively; Organic matter protein content in sludge after extraction reached minimum value of 32.37% and 10.67%, respectively. Microwave power near 700 W was best to production of foaming agent, at this point, the TC, the TOC and protein concentration value in foam fluid achieved the highest, protein concentration of 56.77 mg/L; Foaming power and stability time reached at the highest level of 7.57 times and 5 h, respectively; Organic matter and protein content in sludge after extraction reached the low value of 32.37% and 10.67%, respectively. Ca(OH)2 addition amount near 15(g/2000mL) was best to production of foaming agent, at this point, protein concentration achieved the highest value 62.88 mg/L, increased by 20%; Foaming power and stability time to reach the highest level of 9.36 times and 5 h, respectively; Organic matter content in sludge after extraction dropped to the lowest 30.05%. Solid content amount near 5(%/2000mL) was best to production of foaming agent, foaming power and stability time in the highest of 5.92 times and 5 h, respectively; The excessive water volume and subsidence distance were low, moisture content of sludge was in the lowest 77.11%.Orthogonal test analysis found that microwave time at 13 min, microwave power at 700 W, Ca(OH)2 addition amount at 17(g/2000ml) and solid content at 6(%/2000mL) get white foam, small diameter and density of foam foaming agent, the foaming power and stability time at the highest 11 times and 4 h, respectively; Under the optimal scheme, TOC and protein concentration value was 1819.5 mg/L and 8.75 mg/L, respectively, compared with other solutions in a high state.Five consecutive extraction experiments of the same samples found that the TOC and protein concentration value of foam fluid were reduced gradually, the organic matter and protein content in sludge after extraction also gradually reduce, reduced by 63% and 70%, respectively; Foaming power and stability time of foam fluid was largest at the first extraction of 7.07 times and 3 h, respectively; Multiple extraction had little influence on the production of foaming agent, but it could provide theoretical support for the resource utilization of sludge. |
