生物质利用方式对富营养水体中碳氮磷含量及其比例的影响

生物质常被添加至富营养水体中以调节碳氮比(C/N)，促进脱氮，但不清楚生物质的粒径和投加方式对富营养水体中营养物质浓度和比例的影响。通过机械粉碎制得20~40、40~80、80~160目稻壳颗粒，并选取直接投加和无纺布包裹投加2种投加形式，以不添加稻壳或无纺布包裹砖块作为对照组。以超纯水为水样研究不同粒径和投加方式下稻壳的3 d碳氮磷释放特性；以成都市府河下游河段水样为研究对象，考察了不同粒径和投加方式下稻壳的21 d静态脱氮特性。结果表明，在超纯水中，稻壳释放出COD_Mn(5.5~16.5 mg·L⁻¹)、TP(0.18~0.45 mg·L⁻¹)、TN(0.39~0.95 mg·L⁻¹)、COD_Mn/TN(8.5~19.7)、COD_Mn/TP(27.9~37.5)，前四者均呈现出80~160目>40~80目>20~40目的规律，仅COD_Mn和COD_Mn/TN呈现直接投加>无纺布包裹投加的规律。在静态脱氮实验中，21 d后，添加了稻壳的水样COD_Mn含量由28.1 mg上升至71.7~143.0 mg，TP含量由1.2 mg下降至0.2~0.5 mg，COD_Mn/TN由0.9上升至8.5~16.5，COD_Mn/TP由24.2上升至170以上，这4个参数的变化情况与稻壳的碳氮磷释放规律相同；TN含量由30.04 mg下降至7.64~8.68 mg，低于对照组(13.2~13.9 mg)，但粒径和投加方式仅对实验初期水中氮的存在形态有影响。粒径决定稻壳的比表面积，投加方式决定稻壳的间隙，并影响微生物的附着效果，进而影响稻壳的碳氮磷释放效果。在实际应用时可根据情况，采用不同的生物质粒径和投加方式，以调节水中营养物质浓度和比例。

Effects of biomass utilization on carbon,nitrogen and phosphorus contents and their proportion in eutrophic water

Biomass is often added to eutrophic water to adjust the ratio of carbon to nitrogen ratio (C/N) and promote denitrification. However, the effects of particle size and dosing mode on the nutrient concentrations and their proportion in the eutrophic water are not clear. In this study, rice husk with the particle size of 20~40, 40~80 and 80~160 mesh was prepared by mechanical grinding, and two modes such as directly and non-woven fabrics-wrapped dosing were used to conduct the experiments with control groups of adding nothing or bricks wrapped with non-woven fabric. The carbon, nitrogen and phosphorus release characteristics of rice husk under the conditions of different grain sizes and dosing modes in 3 days were studied by using ultra-pure water as water samples, while the static nitrogen removal characteristics of rice husk with different grain sizes and dosing modes in 21 days were studied by using water samples from the lower reaches of Fuhe River in Chengdu. The results showed that in the ultra-pure water, rice husk released CODMn of 5.5~16.5 mg·L−1, TP of 0.18~0.45 mg·L−1 and TN of 0.39~0.95 mg·L−1, CODMn/TN ratio of 8.5~19.7, CODMn/TP ratio of 27.9~37.5, and the first four indices showed the order: 80~160 mesh >40~80 mesh >20~40 mesh, while only CODMn and CODMn/TN showed the order: direct addition > non-woven fabric-wrapped addition. In the static nitrogen removal experiments with rice husks-dosed water samples after 21 days, CODMn increased from 28.1 mg to 71.7~143.0 mg, TP decreased from 1.2 mg to 0.2~0.5 mg, CODMn/TN increased from 0.9 to 8.5~16.5, CODMn/TP increased from 24.2 to more than 170, which showed the same trends as above rice husk release experiments in ultra-pure water; TN decreased from 30.04 mg to 7.64~8.68 mg, which was lower than that of the control group (13.2~13.9 mg), but the particle size and dosing modes of rice husks only affected N species at the beginning of the experiment. The particle size of rice husks determined its specific surface, the dosing modes determined the gap between rice husks, they affected the attachment effect of microorganisms, and then the release of carbon, nitrogen and phosphorus. In actual application, the various combination of the biomass particle size and non-woven fabric-wrapping can be used to adjust the concentration and proportion of nutrients in water.