Applications Of Semi-coke On Conditioning And Concentrated Dewatering Of Sludge

With the development of economy, urban sewage emissions is increasing. And the sludge production has been also improve. Composition of sludge is complicated,containing pathogenic microorganisms, parasite eggs and poisonous heavy metals. If not handled properly, it is likely to cause secondary pollution to the environment.Meanwhile, the sludge also contains many rich in organic matter, after appropriate treatment can be used as fertilizer, the production of biogas and other energy materials.It becomes urgent problems in the environmental pollution control to clean up how to properly deal with the disposal of sludge.High moisture content of the sludge is the core issue of restricting its effective resource utilization. In this paper, the factors influencing sludge conditioning and concentrated dewatering based on semi-coke and chemical flocculant on sludge conditioning and concentrated dewatering were explored using gravity concentrated dewatering method, selecting of a suitable semi-coke and chemical flocculants condition sludge. In the end, the form of sludge resource utilization was discussed with the method of slurry experiment. The main contents are as follows:(1) Sludge conditioning and concentrated dewatering by using semi-coke can significantly improve the performance of sludge concentrated dewatering. The effect of semi coke conditioning sludge concentration dewatering was explored using gravity concentrated dewatering method. It was found that the optimum adding amount of semi-coke derived from the pyrolysis of Yunnan brown coal with a particle size of 75-125μm was 3.0 g YN-800-2.5semi-coke As a result, the water content of concentrated sludge decreased to 87.71%,the rate of sedimentation increased to 1.55mL/min There is a apparent correlation between the water content of concentrated sludge and the quality parameters of semi-coke(FCad, Vad, O/C, H/C, Specific surface area and Pore volume). The moisture content of concentrated sludge increased with increasing Vad, H/C, and O/C of the semi coke, while the moisture content of concentrated sludge decreased with increasing FCad of semi coke. The moisture content of concentrated sludge exhibited negative correlation with the BET specific surface area and pore volume of semi coke. For the semi-coke with particle size of75-125 μm, when the BET specific surface area and pore volume were larger than21.1085 m2/g and 13.968 mm3/g, respectively, the dewatering performance of semi-coke was relatively satisfactory. The mechanism could be explained by the weakened hydrophilic properties of sludge and the adsorption of sludge on semi-coke.(2) The chemical flocculant effect on conditioning and concentrated dewatering of sludge was explored by the method of gravity concentrated dewatering. The results showed that: When the sludge is modified by a single chemical flocculant combined with semi coke, the effect of the organic polymer flocculant PAM with 0.3 mg/L on the concentrated dewatering of the sludge is the best, the sludge settlement rate is 1.55ml/min, the moisture content of concentrated sludge is 87.71%, the supernatant turbidity is 0.75 NTU; With FeCl3+PAM、PFS+PAM and FeCl3+PFS combined with semi coke for sludge conditioning, the effect of the 7.5% FeCl3+0.1mg/L PAM on the concentrated dewatering of the sludge is the best, the sludge settlement rate is 1.53mL/min, the moisture content of concentrated sludge is 86.83%, the supernatant turbidity is 1.08 NTU.(3) The sludge directly mixed with semi-coke to prepare sludge semi-coke slurry.The influence factors such as the type and dosage of additives, sludge proportion, etc.on slurryability of sludge semi-coke slurry has been studied by slurryability experimental methods. The results showed that: sludge semi-coke slurry which produced by DCS-1 and DCS-2 both have good fluidity and rheological properties,shear-thinning properties. Under the same conditions, sludge semi-coke slurry produced by 0.6% DCS-2 has better results in terms of its apparent viscosity, stability and pseudoplastic characteristics. There was a good linear relationship between the sludge and fixed incorporation sticky sludge concentration semi-coke slurry(φ=66.2530-0.2127α, R=0.9948). With increasing sludge proportion, the slurry properties of sludge semi-coke slurry deteriorates. Sludge semi-coke slurry is pseudoplastic fluid properties. Sludge can effectively enhance the semi-coke slurry sludge shear thinning properties, and with the increase of sludge proportion, the shear thinning effect is more obvious.