Research On The Treatment Effect For Domestic Wastewate By Pre-denitrification BAF And Microorganism Characteristics

BAF(Biological Aerated Filter) is a new technique of water treatment has the merits of high-efficiency, energy-saving, small site area,Furthermore the operato and management of it are convenient. On the basis of enhanced Primary Treatment, BAF use particle packing and biofilm in the combined packing as treatment medium for Pollutants Removal in a unit reactor.In the process, bio-metabolism, bio-flocculation, physical filtration,physical adsorption by biofilms and packing biofilms and classify predation of food chain in the reactorThe experimental use BAF with pre-denitrification to treat domestic sewage primarily,the paper analyzes the removal efficiency of the organic matter and nitrogen, the rule of removing pollutants meanwhile strive.to obtain the optimal operating parameters so as to providing evidence for Promote biological aerated filter with pre-denitrification in wastewater treatment field.subsequently, internal structures microbial characteristics and microorganism population distribution in BAF with pre-denitrification is stated. Also, anaerobic denitrification bacteria was screened from the sludge of anaerobic reactorsThe experimental results show that the performance of BAF with pre-denitrification for sewage treatment is excellent.Under the hydraulic load of 1.69m/h-2.54m/h(do not include reflux),the reflux ratio of 200%,air/water ratio of 5:l,the the mean value of effluent COD NH4+-N is 20.5mg/L,0.89 mg/L,the average removal percent of COD and NH4+-N is 90.87%,94.41%.The effluent quality is acceptable and meets the municipal greywater standard. The experimental results also show that most of COD and NH4+-N is reduced in the anoxic zone.The objective of the experiments is to study the influence of hydraulic load,reflux ratio,capacity load,influent temperature and pH.The experimental results show that it will get high pollutants removal efficiency under the hydraulic load of 2.04m/h (do not include reflux),the reflux ratio of 200%,the COD capacity load less than 8 kg/(m3-d).Ceramic pellets were packed in the BAF with Pre-denitrification Process as a filler. anaerobic microbes adhered to its surface which formed a more perfect Food chain. At different packing height, microorganism's species in contrast with amounts. That is, Along the direction of stream flow, the amount of microorganism keep coming down, inversely, the kinds of microorganism are increasing constantly. In addition, fond on observing the growth of microorganisms by the methods of microscopic examination and scanning electron microscope,we can not only learn internal operating environment and changing situation of water quality in BAF with pre-denitrification,but also guide the couse of biofilm culturing.