Studies On The Effects Of Rare Earth On Aerobic Granular Sludge

There is abundant rare earth in our country, the field where rare earth can apply to becomes wider along with the technique develops. Rare earth can enhance the activity of enzyme, increase the amount of microorganism. The major content of this article comprise three parts: The first is effect of rare earth on activated sludge, the second is effect of rare earth on formation of aerobic granular sludge, and the last is study on treatment of beer wastewater by aerobic granular sludge. The article can lead the research that the effect of rare earth on activated sludge and application of rare earth on biological treatment, and it increased theory of aerobic granular sludge treating on treating high strength organic wastewater. The main researches included as follows:1) The effect of rare earth on degradation kinetic of activated sludge, EPS in activated sludge, and microbial morphology were researched. Result indicated right strength of rare earth can improve V_max of degradation kinetic, enhance the activity of enzyme, increase the amount of EPS, amend the ratio of Protein/Amylose, improve surface of activated sludge, stimulate life of microorganism. But high strength rare earth were inhibitory and toxicity. It caused enzyme destroyed, depressed the activity of enzyme, reduced the ratio of Protein/Amylose, wrecked structure of zoogloea, and it is bad to sludge depositing.2) Effect of rare earth on formation of aerobic granular sludge in two same SBR was studied while La³⁺ was added to one SBR, the nutriment was beer wastewater, the process was divided to three periods according air flow rate and volume loading. Result indicated that aerobic granular sludge which La³⁺ was added formed 7days earlier than aerobic granular sludge which was cultivated commonly. In first period the effect of rare earth is unconspicuous, however in second period it is most conspicuous. The shape of sludge, MLSS, SVI, ability of COD removal became more different between the two SBR during second period. The SOUR of aerobic granular sludge cultivated adding La³⁺ was more 20% than aerobic granular sludge cultivated commonly, the percent of water is lower 0.5%, the speed of sedimentation is faster 2%. aerobic granular sludge cultivated adding La³⁺ was solider than cultivated commonly, the kinds of microorganism is more, the volume of microorganism is smaller, the distance of interstice is shorter.3) Effect of treatment of beer wastewater by aerobic granular sludge was good, the effluent water can meet "Discharge Standard of Pollutants for beer industry (GB19821-2005)". Through the orthogonal tests, the optimal technique for operation was flowing process of unlimited aeration, anaeration 1h, aeration 4h. DO, MLSS and pH can influence the effect of treatment of beer wastewater, especially TN removal. In one operation cycle COD and NH3-N is removed mostly after 3h of aeration, the characteristic of operation cycle showed that microorganism is hunger in residual time in one operation cycle, and it helped aerobic granular sludge morecompact. In one operation cycle the concentration of NO₂^- was decrease, howeverNO₃^- wasn't increased abundantly, it indicated that aerobic granular sludge had the ability of simultaneous nitrification and denitrification (SND).