The Effects Of Alkalinity On Start-Up And Predominant Community Fermation Of Anaerobic Baffled Reactor

In this dissertation, An Anaerobic Baffled Reactor (ABR) with seven compartments was employed as experimental equipment and the molasses wastewater was elected as experimental objective. Under the condition of inlet COD up to 1000 mg/L, organic load up to 0.8 kg/m3·d, Hydraulic Retention Time (HRT) up to 30 h, temperature around 35±1℃, sludge inoculation between 15 and 25 gMLSS/L, the effects of alkalinity on the start-up and operation of the reactor, and formation of predominant community in ABR was investigated. The alkalinity of inlet water was adjusted by the addition of NaHCO3. In the experiment, we determined the spatial niche of acedogenic hydrogenogens and studied its important function in anaerobic treatment system.The experimental results suggested that the reactor system was sensitive to environmental changes without the regulation of inlet water alkalinity. And the microbial community was not highly separated. The failure of formation of granular activated sludge, due to the low activity of sludge, led to the failure of the start-up.Under the circumstance of alkalinity regulation; the alkalinity of inlet water was elevated with the increase of COD concentration. Finally with the inlet COD up to 4000 mg/L, organic load up to 3.2 kg/m3·d, and initial alkalinity up to 2000 mg/L, the reactor could be successfully started up and the removal rate of COD reached up to 93%. In steady stage, the main fermentation type of the system was propionic-acid type. The granular sludge appeared in the 40th day during start-up and became grown up in every compartment in 90 days. The sludge granules in the fore-three compartments were loose and brown flocculant microparticles around 2mm diameter and the middle of granules were filled with white gelatinous materials. While the sludge granules in the last two compartments were mainly made up of elliptical or global black bright granula with diameter around 1.5 mm. The sludge granules in the fourth and fifth compartments were mainly flat-elliptical and its diameter was around 1.5mm.The community in the reactor was separated sufficiently by different compartments when the reactor was started up by means of adjusting the...