The dewaterability of excess sludge significantly improved upon pretreatment with Fenton's reagent in this study. After 0.9 g/L of Fe and 5.0 g/L of HO were added to the sludge, and reacted for 2 h at pH = 4, the specific resistance to filtration (SRF) of the excess sludge decreased from an initial value of 29.74 × 10 m/kg to 6.49 × 10 m/kg. The factors that affected this improvement in sludge dewaterability as evaluated by SRF reduction showed the following order: HO > pH > Fe > reaction time. Furthermore, the hydrolysis performance of the sludge under the optimal reaction conditions was investigated. The results indicated that the concentration of soluble chemical oxygen demand in the supernatant increased almost 14 times compared to raw sludge, and the contents of soluble protein and soluble polysaccharide were more than 8 and 17 times higher, respectively, than for the untreated situation. However, the amounts of ammonia nitrogen (NH-N) and phosphate (PO-P) released from the sludge showed different trends: NH-N increased by 200%, while PO-P decreased by 82%. The production of volatile fatty acids (VFAs) from the treated sludge showed that total VFAs increased by 66%, and iso-butylacetic acid was the dominant product among the total VFAs.
Flame retardants modified asphalt with SBS flame retardant SMA hybrid material was prepared, flame retardant performances of SMA mixture was studied by the cone calorimeter. The results show that adding 12% flame retardant with SBS modified asphalt in preparation of flame retardant SMA mixture, the peak heat release rate values than the non-flame retardant asphalt mixture decreased by 4.02 kW/m2, and the heat release rate values were significantly reduced, the total heat and the amount of smoke of flame retardant asphalt mixture released less than the non-flame retardant asphalt mixture.
Overlay new cement concrete pavement on the old cement concrete pavement following different treatment schemes, survey pavement cracking phenomenon after the opening of the new pavement , analysis the crack resistance of the various programs, accumulate experience for the cement concrete pavement repair technical solutions.
Through a large number of laboratory tests,authors study the preparation technology of exposed-aggregate cement concrete pavement, such as the spraying time, spraying dose of exposed-aggregate agent and the flush time. According to the tests results, the spraying time of exposed-aggregate cement concrete declines constantly with the increase of temperature and the appropriate spraying dose of exposed-aggregate agent is determined. The higher the temperature the earlier the flush time. There is a bigger time interval, more than 10h for normal temperature between the earliest and latest flush time.
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