Advanced Water Management Centre, The University of Queensland, St Lucia, QLD 4072, Australia.
Water Sci Technol. 2011;64(4):880-6. doi: 10.2166/wst.2011.662.
The biodegradability and bioavailability of hydrolysis-limited substrates under anaerobic (and aerobic) conditions can be represented by two key parameters--degradability (f(d)), or the percentage that can be effectively be destroyed during digestion, and first order hydrolysis coefficient (k(hyd)), or the speed at which material breaks down. Biochemical methane potential (BMP) testing uses a batch test (in triplicate), and by fitting against a first order model, can fit both parameters in the same test. BMP testing is now being widely used for anaerobic process feasibility and design purposes, and standardisation efforts are ongoing. In this paper, we address a number of key issues relating to the test method and its analysis. This includes proposal of a new fitting and parameter estimation method, evaluation of the impact of inoculum to substrate ratio on fitted parameters, and comparison to performance in continuous systems. The new parameter estimation technique provides an estimate of parameter uncertainty and correlation, and is clearly more suitable than model transformation and linear regression. An inoculum volume ratio of at least 50% (2:1 on VS basis) was required on a cellulose substrate to use methane production as primary indicator, as found by comparing methane production and solubilisation of cellulose. Finally, on a typical material, waste activated sludge, the batch test was slightly conservative in terms of degradability and rate, indicating a bias in the BMP test. The test is a cost-effective and capable method to evaluate potential substrates, but it should be noted that it is generally conservative, especially if sub-optimal inoculum is used.
在厌氧（和好氧）条件下，水解受限底物的生物降解性和生物可利用性可以用两个关键参数来表示——降解性（f(d)），即在消化过程中可以有效破坏的百分比，以及一级水解系数（k(hyd)），即物质分解的速度。生物化学甲烷潜能（BMP）测试使用分批测试（一式三份），并通过与一级模型拟合，可以在同一测试中拟合这两个参数。BMP 测试现在广泛用于厌氧工艺可行性和设计目的，并且正在进行标准化工作。在本文中，我们解决了与测试方法及其分析相关的一些关键问题。这包括提出一种新的拟合和参数估计方法，评估接种物与底物比对接配参数的影响，并与连续系统的性能进行比较。新的参数估计技术提供了参数不确定性和相关性的估计，显然比模型转换和线性回归更适合。在纤维素底物上，至少需要 50%（按 VS 基础计算为 2:1）的接种物体积比，才能将甲烷产量用作主要指标，这是通过比较甲烷产量和纤维素的溶解来发现的。最后，在典型的材料——活性污泥上，分批测试在降解性和速率方面略有保守，表明 BMP 测试存在偏差。该测试是一种经济有效的评估潜在底物的方法，但应注意的是，它通常是保守的，特别是如果使用次优接种物。
