厌氧消化(Anaerobic digestion)由多种微生物共同作用，使污染物分解为氢气与甲烷，具有负荷高，污泥量少，运行费用低，并可回收能源等特点，应用前景广阔。但是，厌氧消化也存在着种种缺陷，酸化、氨抑制、磷酸盐积累等都可造成系统稳定性下降，严重时甚至会导致系统崩溃。为避免此类情况的发生，运用简便、快捷的检测方法，对可能损害系统的因素进行实时监控是必不可少的。滴定法所需设备简单、操作简单、测定时间短，是一种成效比非常高的方法；但是目前的滴定法存在建模复杂、滴定点过多、预知条件苛刻等缺点。本论文以电离平衡、电荷平衡与物质平衡为基础，分别建立了测定厌氧消化体系中VFA、铵盐、磷酸盐和碳酸盐浓度的滴定新方法。主要研究内容和研究结果如下： 1、建立了测定厌氧消化体系中VFA浓度的两点pH滴定法，方法具有很高的准确性与精确度。当乙酸、丙酸或丁酸共存时，由于三者电离平衡常数的差异，会对滴定结果产生一定影响，且丙酸的影响大于丁酸。碳酸根对两点pH滴定法的结果影响最为显著；磷酸根对滴定结果的影响属可接受范围；铵根与硫化物对滴定准确度无影响，但滴定过程中生成的少量单质硫颗粒会轻微降低滴定的精密度。另外，通过对实际反应器出水中VFA测定发现，当VFA浓度超过3 mmol／L以上时两点法具有很高的准确度。 2、依据不同的滴定区间分别建立了测定厌氧消化体系中铵根浓度的三种pH滴定法，都具有很高的准确性与精确度。磷酸根对滴定结果有一定的影响，VFA则无影响；碳酸根与硫化物可通过样品预酸化排除其对滴定的影响，但酸化过程中生成的少量单质硫颗粒会轻微降低滴定的精密度；高离子强度会使三种方法的滴定结果偏高，但属可接受范围。另外，三种方法都可以较准确地测定实际废水中的铵根，且第二种方法相较于其它两种方法更准确。 3、依据不同的滴定区间分别建立了五种测定厌氧消化体系中磷酸根浓度的pH滴定法。由于pH 1.65-2.65与11.82-12.82区间氢离子或氢氧根浓度太高，所建立的方法滴定结果误差巨大，不适合滴定低浓度磷酸盐：pH 6.59-7.59区间所建立的三种方法都具有很高的准确性与精确度。铵根是影响这三种滴定方法准确度的最主要因素；VFA仅对第二种滴定方法有轻微影响；碳酸根与硫化物可通过样品预酸化排除其对滴定的影响，但酸化过程中生成的少量单质硫颗粒会轻微降低滴定的精密度；溶液离子强度对三种滴定方法无显著影响。 4、依据不同的滴定区间建立了两种测定厌氧消化体系中碳酸根浓度的pH滴定法，都具有很高的准确性与精确度。VFA的存在对两种方法几无影响，而铵根的影响非常显著，尤其是对第一种滴定方法；硫化物与磷酸根对第二种滴定方法均有一定程度的影响：高的离子强度会使第二种方法的滴定结果偏高。 关键词：厌氧消化；pH滴定；挥发性脂肪酸；铵盐；磷酸盐：碳酸氢盐

 Anaerobic digestion, which could degrade pollutants and generate hydrogen and methane simultaneously, is a favorable technique due to its advantage of high organic loading, less sludge, low cost and energy recycle. However, acidification, ammonia inhibiting and accumulation of phosphate would lead to the instability even failure of the anaerobic digestion. Therefore, methods of simpleness, rapidity and accuracy are crucial to monitor these factors. In this thesis, based on the charge balance, ionization equilibrium and mass balance in the solution, new pH titration methods were established to determine the concentration of VFA, ammonium, phosphate and bicarbonate in anaerobic digestion. Main contents and results of this thesis are as follows: 1.A 2-point pH titration method was developed to determinate the concentration of VFA used hydrochloric acid as the titrant. The method was of high accuracy and precision when determined the concentration of acetic acid as a representative of VFA. The component of propionic acid and butyric acid would influence the titration accuracy owing to their different dissociation constants. When acetic acid coexisted with other buffer systems: The effect of bicarbonate on VFA titration was noticeable due to the loss of carbon dioxide during the titration. The disturbance of phosphate was expected to be weak. Ammonium and sulfide were of little effect on accuracy, however a small amount particles of elemental sulfur generated by oxidation during the titration would cause a decrease of precision slightly. The practical wastewater were test and the results showed that when the concentration of VFA exceed 3 mmol/L, the titration results were accurate enough. 2.Three titration methods were developed according to the different pH ranges to determinate the concentration of ammonium in anaerobic digestion. The results showed that all of three methods were of high accuracy and precision to determine the concentration of ammonium. Phosphate buffer systems had slight influence on these methods, and the effect of VFAs was also insignificant. The impacts of both bicarbonate and sulfide could be exclude through sample acidification as well as dramatically stirring before titration, however the elemental sulfur generated during the acidification would cause a decrease of precision slightly. High ionic strength had a positive effect on the titration. Moreover, the methods also showed accurate results when evaluated with practical effluents. 3.Five titration methods were developed according to the different pH range to determinate phosphate concentration in anaerobic digestion. The methods in the pH range of 1.65-2.65 and 11.82-12.82 were not suitable because of the siginificant errors caused by high concentration of hydrogen ion or hydroxide ion. Three titration methods were established in the pH range of 6.59-7.59 were all of high accuracy and precision for determining phosphate concentration. Ammonium buffer system was the main limiting factor to decrease the accuracy for all three methods, while VFA only had slight effect. The impacts of both bicarbonate and sulfide could be exclude through sample acidification as well as dramatically stirring before titration, however the elemental sulfur generated during the acidification would cause a decrease of precision slightly. In addition, ionic strength had an insignificant effect on the titration. 4.Two titration methods were developed according to the different pH range to determinate carbonate concentration in anaerobic digestion. The results indicated that both methods were of high accuracy and precision. VFA had slight influence on both methods, while the effect of ammonium was significant especially on the first method. Both sulfide and phosphate buffer systems induced a certain error on two methods, and high ionic strength had a positive effect on the second method. Keywords: anaerobic digestion, pH titration, volatile fatty acids (VFAs), ammonium, phosphate, bicarbonate