Degradation kinetics of dense nonaqueous phase liquids in the environment under impacts of mixed white and colored noises

This study presents three stochastic dense nonaqueous phase liquid degradation kinetic models, forced by Gaussian white noise, Ornstein–Uhlenbeck colored noise and their mixture, respectively. Compared to the previous efforts, the proposed mixed-noise forced model is a more generalized representation of conventional stochastic models. This feature exists because any of the stochastic terms (no matter they come from the inside or out of the system) can be accounted for by a deterministic term and a type of colored, white, or mixed noise. The implicit in the model solutions include: the colored noise may lead to a misunderstanding results and much attention should be received to recognize the impact of colored noises; the decrease of noise intensity and/or increase of correlation time change the probability distribution functions from bimodal to approximate unimodal shapes, implying increased ease of capturing the statistical properties of model solutions; the introduction of a new colored noise may counteract the function of a white noise, thus providing us an alternative for mitigating the impact of a known noise on model solutions. The ongoing work is undertaken to develop an integrated numerical-simulation and statistical-inference method for the characterization of white and colored noises based on observation data.