| The problem of black-odorous water bodies in China has become more and more serious,and it has increasingly attracted more and more attention from the society to this environmental problem.At present,there is a large amount of literature on the causes of black-odorous water bodies and the research on black odorous substances.Oily sludge contaminated by petroleum products will not only have a serious impact on water quality at the beginning of entering the water body,but also after it enters the river channel and becomes a river sediment,it will become an important endogenous pollution.Compared with other common river sediments,oily sludge have adverse effects on microbial activities in the sludge and in the water due to the toxic and hazardous substances carried in the petroleum products contained therein,thus affecting the water quality conditions.And the oily sediment will also hinder the exchange of material between the two phases of sediment and water,and even the mud layer will be formed,which will further deteriorate the environmental conditions in the water.Therefore,it is particularly important to clear the influence of oily sludge on the black-odor of water quality and the influence of various physical conditions on the release of oily sediment,and find a suitable treatment and disposal method,for the treatment of black odorous water contaminated by petroleum products in the future.In view of the changes in physical and chemical properties of oily sludge in the process of evolution of oil-bearing sludge into gradual other sediments into oil-bearing sediments,under laboratory conditions,in-situ oil-bearing sediment in contaminated rivers is used as test mud.The known black body odor-induced principle is to select the indicators to be tested,and to measure Fe ions,organic matter(COD/TOC),sulfide content,oil content,oil-bearing petroleum hydrocarbon species,and total nitrogen total phosphorus in oily sludge.After clarifying the physical and chemical properties of the oil-bearing sediment,simulate the river environment,and control the water body temperature,water body flow rate and sediment content as a single factor variable,in the water BODS,CODCr,NH3-N,TP,water color,oil The amount and the sulfide content are used as indicators to measure the black odor of the water body.Explore the effects of various factors on the black odor process in water.At the same time,multi-factor orthogonal experiments were carried out to clarify the significance of the influence of each single factor on the black odor caused by water.After clarifying the process of the influence of oily sludge on water quality change,the feasibility of using the mixed composting method to harmlessly treat the oily sediment is explored,so as to determine the scientific treatment method of the toxic and hazardous waste generated by the dredging method to treat the black odorous water body.In the analysis experiment of bottom mud source,it was found that the oil-bearing river bottom sediment of a black-smelting river section of Panjin City,Liaoning Province had a large difference in oil-free sediment properties.The oil content of the oil-bearing sediment taken in the black odor river section is 26.83±1g/kg,and the oil content in the oil-free sediment is not detected.The organic matter content is 117.26±1g/kg,which is 4.74g/kg lower than that of the oil-free sediment.The sulphide content is 8.52mg/kg,the content is 5.30mg/kg higher than the oil-free sediment,the total nitrogen content is 2.86mg/kg,the content is 2.36mg/kg lower than the oil-free sediment,and the total phosphorus content is 1.91mg/kg.It is 0.42 mg/kg lower than the oil-free sediment content,and the Fe ion content is 5.77 mg/kg lower than the oil-free sludge content 3.40 mg/kg.The content of various pollutants in the oily sediment is much higher than the water quality standard.Among them,the oil content and the sulfide content are different compared with the common river sediment.The single-factor control river simulation experiment has the following conclusions:1)The sediment content of the sediment has an influence on the formation of black and odorous water.The oil content and sulfide content in the oily sediment are quite different from those without oil.The experimental results show that the experimental group with oil-bearing sediments formed a black odorous water body on the 26th day,and the control group without oil sludge was laid until the end of the experiment.The black odor water formed has a maximum chroma of 920 degrees,which is 770 degrees larger than the highest chroma of the control group.The odor threshold of the experimental group was up to 493,which was 384 higher than the maximum calculated odor threshold of the control group.Other organic matter and nitrogen and phosphorus contents are also quite different.2)The temperature of the water body is positively correlated with the formation of the black odorous water body caused by the release of the sediment.When the other conditions are the same,the higher the temperature of the water body,the earlier the black body odor occurs,and the higher the black odor.In the high temperature group with a water temperature of 30?,a black odorous water body was forned on the 24th day,two days earlier than the normal temperature group,and the low temperature group of the water body temperature of 15? did not form a black odorous water body until the end of the experiment.During the experiment,the highest color of the water in the high temperature group was 960 degrees,40 degrees higher than the normal temperature group and 330 degrees higher than the low temperature group.The high temperature group calculates the odor threshold up to 488,which is 202 higher than the maxinum calculated odor threshold of the low temperature group.After the end of the main experiment,the low temperature group experiment was continued in situ.On the 45th day after the follow-up,the water body turned black,but it still did not smell.The color of the water body was 890 degrees,the oil content of the water body was 4.8 mg/L,and the calculated smell threshold was 33.It proves that the temperature has a significant inhibitory effect on the formation of black odor in water.3)The influent flow rate is negatively correlated with the black odorous water body caused by the release of the sediment.Keeping the other conditions the same,the data indexes of the slow group with the inflow runoff velocity of 5.5*10-7m3/s are consistent with the experimental data under the constant temperature and constant current conditions.The inflow runoff velocity was 7.83*10-6 m3/s in the fast group,and no black odorous water body was formed until the end of the experiment.The highest chroma was 72 degrees,the maximum CODer content in the water was 169.3 mg/L,and the maximum oil content was 0.89 mg/L.The results of multi-factor orthogonal comparison experiments show that all three influencing factors have significant effects on the black odor caused by water bodies.Among them,the significant order of the influence of various factors on the blackening of water bodies is:water body temperature>the oil content of the sediment>runoff velocity;for the effect of water body odor,the significant order of the influence of various factors on the odor of the water body is:oil content of the sediment>runoff velocity>water body temperature.The feasibility of treating oily sludge by composting was discussed by using a mixture of straw and two organic fertilizers to treat river sediments contaminated by petroleum products.The whole process of composting was carried out for 120 days,and the total petroleum hydrocarbon content,temperature,C/N/P ratio and functional microbial quantity in the process of stacking were dynamically monitored,and the changes of petroleum composition before and after the heap were determined,The results showed that the total petroleum hydrocarbon content of the composting group decreased from 26.83±1g/kg to 17.22±0.74g/kg,and the degradation rate reached 36%.The heap reached the highest temperature of 52? on the 50th day;the C/N/P ratio changed.The downward trend;the functional microbial activity of the whole compost is high,and the hydrocarbon degrading bacteria and the aromatic degrading bacteria are increased by nearly four orders of magnitude compared with that before the stacking.After composting treatment,the physical and chemical indicators in the sediments reached the application standard in the "Sludge Disposal of Agricultural Sludge in Urban Sewage Treatment Plants"(CJ-T309-2009). |
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