Study On Residual Sludge Reducing From Alkali-minimization And Dyeing-Printing Wastewater Biological Treatment

Usually, the treatment of alkali minimization and dyeing—printing wastewater is the combination of aerobic and anaerobic bio-treatment. During the process, with the growth of the microorganism, the residual sludge is the certain byproduct. The sludge is hard to dehydrate and even after dehydration, the volume of the sludge is still very large and consumes large management and disposal fee. In this thesis, we mainly study the residual sludge from the bio-treatment of alkali minimization and dyeing— printing wastewater.First, we study the reason of the hard-dehydration of the sludge and the effect of sludge conditioner on the specific resistance of the sludge so as to reduce the volume of the sludge by physical-chemical adjustment. From the result we can see that the dehydration of the sludge is very hard and the main reason of the high specific resistance is the polymer and their hydrolyzaion product. The key to improve the dehydrate characteristic of the sludge is the destabilization of the grain. The combination of PAM of cation and Fecl₃ can improve the specific resistance and dehydrate characteristic of the sludge.After adsorption, the pollutant becomes an important part of the sludge and biodegradation of the pollutant begins from the adsorption. Under the experimentation condition, the adsorption characteristic of activated sludge to particular sludge accord with the Langmuir and Frundlich equation.We first study the reducing of the sludge after hydrolysis and acidogenosis in captive test. As the test show, both the residual sludge itself and the sludge inoculating mature hydrolysis and acidogenosis bacteria can realize reducing under anaerobic condition. And the hydrolysis and acidogenosis is the main key. The test also shows that after inoculating mature hydrolysis and acidogenosis bacteria, the reducing of the sludge is better. Endogenesis metabolization is an important way to realize reducing of the sludge and degradation of organisms adsorbed by the sludge through hydrolysis and acidogenosis effect of the microorganisms is another important factor.In the continuous A₁/A₂/O dynamic sludge reducing system, the reducing of the sludge is realized by the recycle of sludge to A₁ part. Dynamic test shows that recycle of sludge to A₁ part can efficiently realize the reducing of the sludge. Under the condition that volume loading of A₁ is 2.54 kgCOD_cr/m³ · d and water input is 25L/d, in the continuous 6 months, the residual sludge from the system is 95.9% peeled. At the same time, the specific yield coefficient of the sludge in O part decreases about 54.5%. The system runs properly under the condition that volume loading of A₁ part is about 2.54 kgCOD_cr/m³ · d and HRT is about 7.56 hours. The recycle of sludge to A₁part improves the elimination efficiency of CODcr and chroma while the SS of each part increased and the pH is not affected. By recycle of sludge to A1 part, the release of N and P can compensate the maladjustment of C:N:P of the alkali minimization and dyeing—printing wastewater and save the fee of nutrition.The basic aim of the alkali minimization and dyeing—printing wastewater system is to achieve the standard drainage and the reducing of the sludge certainly includes the degradation of particular pollutants of the sludge. After the hydrolyzatio and acidification in A1 part, the B/C of the alkali minimization and dyeing—printing wastewater is greatly improved. From the value of dynamic parameter of part A and O, we can see that the degradation of the water in aerobic part is far better than in anaerobic part. By the combination of GC/MS and LC/MS, we make primary estimation and analysis of degradation law of particular pollutants.In the last, we make microbiology analysis of the sludge reducing system and we get two predominant microorganism: TA1 and TO2 from aerobic and anaerobic sludge, which have high degradation efficiency on TA. And we analyze various condition that affect the characteristic of the predominant microorganism.From the view of cleaner production and making use...