两种缓释肥料在海水中的养分释放特性及强化石油烃生物降解

STUDY ON NUTRIENT RELEASE CHARACTERISTICS OF TWO SLOW-RELEASE FERTILIZERS IN SEAWATER AND THEIR ABILITIES TO ENHANCE BIODEGRADATION OF PETROLEUM HYDROCARBONS

通过沙土柱实验考察了硫包衣尿素和甲醛尿素2种缓释肥料在不同pH值和盐度的海水介质中养分的释放特性,并利用摇瓶培养实验考察了这两种肥料对SZ36-1原油生物降解作用的影响.结果表明,在实验设置的pH(7.00—8.00)和盐度(24.00—32.00)范围内,pH值对硫包衣尿素和甲醛尿素肥料氮素释放性能有较大影响,其中,近中性的海水介质有利于硫包衣尿素中氮素的释放,弱碱性环境更有利于甲醛尿素的释放;而盐度对两种肥料的氮素释放均无明显影响.两种缓释肥料都能够持续释放氮素而维持石油烃降解菌QPH-2的生长,并促进原油中各组分包括烷烃和芳烃明显降解.其中,添加硫包衣尿素体系中各烷烃组分的降解率为13.94%—59.02%,芳烃类组分降解率为9.60%—32.33%;添加甲醛尿素体系中各烷烃组分的降解率为11.56%—49.65%,芳烃类组分降解率为13.49%—41.67%.

The nitrogen nutrient release efficiencies of two slow-release fertilizers,a sulfur-coated urea and a formaldehyde urea,were measured in different pH and salinity seawater by sand soil column experiments.And their ability to enhance biodegradation of SZ36-1 crude oil was also determined in shake flasks.The results showed that pH value of seawater had significant effect on the nitrogen release of both sulfur coated urea and formaldehyde urea in the pH range of 7.00—8.00.The nitrogen release efficiency of sulfur coated urea was higher in neutral seawater,while that of formaldehyde urea was higher in alkalescent seawater.However,in the test set salinity range of 24.00—32.00,the salinity of seawater had weak effects on the nitrogen release for two fertilizers.On the other hand,both fertilizers could release nitrogen persistently and maintain the growth of the hydrocarbon-degrading strain QPH-2,thus promote biodegradation of various alkanes and aromatic hydrocarbons.In the degradation system added with sulfur coated urea,the degradation rates of the alkanes and aromatic hydrocarbons ranged from 13.94% to 59.02% and from 9.60% to 32.33%,respectively;while in the degradation system added with formaldehyde urea,those rates ranged from 11.56% to 49.65% and from 13.49% to 41.67%,respectively.