| Nowadays,concentrated landfill leachate from two-stage DTRO?Disk-Tube Reverse Osmosis?treatment process and food waste?FW?are two kinds of high concentrated organic wastewater,which are difficult to treat in the field of environment.The treatment and disposal of concentrated leachate is a troublesome issue due to high concentration of pollutants,complicated treatment,process,investment and operation cost etc.,accounting for landfill leachate volume 8%?30%.FW was characterized by high organic matter content,rich in nitrogen,phosphorus and other nutritional elements,and resource recycling and reuse value was desirable strategy.On the other hand,high moisture content?70-85%?,fat content and perishable,smelly and breeding ground for pathogens resulting in the spread of the disease.Thus,the FW collection,transportation and processing are troublesome,and also polluted the surrounding environment and groundwater.It can be seen that the development of economical and efficient treatment method for concentrated landfill leachate and FW is the urgent task.Recently,a novel bioevaporation process which treats highly concentrated organic wastewater has successful developed.In the bioevaporation process,water contained in wastewater itself is evaporated by metabolic heat released from aerobic microbial degradation of organic matters contained in the highly concentrated organic wastewater itself so that simultaneous removal of organic matter and water is achieved.In this study,FW and concentrated leachate was together introduced into BS for repeated batch-fed co-bioevaporation.By the combination of FW and concentrated leachate,the nutritional properties was adjusted to achieve co-treatment of the two waste streams generated from urban area for bioevaporation process.In this study,a total of 4 series of co-bioevaporation trials were conducted under different operational parameters?Table 1?.Firstly,4 trials of different mixing ratios of concentrated leachate and FW(COD of 40,80,120 and 160 g L-1)were carried out to investigate the feasibility of repeated batch-fed co-bioevaporation.Afterwards,the key factors of co-bioevaporation were explored under the preferable mixing ratio.In order to determine the optimal initial MC of BS for co-bioevaporation,the belt-pressed sludge?MC of around 82%?was air-dried and biodried to obtain the BS with MC of 52.77%,40.81%,33.92%and 17.92%,respectively.The VS were almost the same?in the range of 38.32-41.31%?.Different additions?85%,90%,95%,and 100%?were carried out to investigate the effect of addition in repeated batch-fed co-bioevaporation process.In addition,AFR was controlled at 0.02,0.035 and 0.05 m3 kg TS-1 h-1 in each trial to study the effect of air-flow in co-bioevaporation process.Results showed that the co-bioevaporation basically achieved the simultaneously effective removal of water and organic matter contained in FW and concentrated leachate,especially for 120 g L-1 of COD of mixture of FW and concentrated leachate,in which water was evaporated by means of the heat produced from aerobic degradation of theirs organic matters.The initial MC range of BS of 30-45%?the corresponding initial MC range of sludge bed of 35-50%?was preferable for bioevaporation by providing adequate MC and interstices to facilitate the oxygen transport and microbial activity.90%was chosen as the better addition for balancing the co-bioevaporation performance and practical application.High addition with more VS added was almost similar to add more water,and the more metabolic heat was not large enough to completely evaporate the more added water.A moderate air-flow rate of 0.035 m3 kg TS-1 h-1 showed the best performance.Lower temperature achieved by excessive aeration delayed fermentation and resulted in reduced water loss,but less water was removed with much VS consumption due to lower aeration.Under these optimum operating conditions,96.7%of the total added water was removed by consuming 96.5%of total VS contained in FW and concentrated leachate during five cycle co-bioevaporation. |
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