Masango, P. and Skivington, M.
Thames Water
In the past, risk control and management originally was driven by human health and safety needs. Then it quickly encompassed environmental health and safety as it became more and more clear that human health and safety could not be separated from environmental health and safety. This paper outlines a mathematical method of evaluating the process capability of mesophilic anaerobic sewage sludge digestion (MAD) and its inherent risk, based on statistical analysis. Digested sewage sludge has to meet regulatory consent with respect to pathogen level before recycling to land. This statistical analysis can be used to evaluate, numerically, sewage sludge digestion process capability and risk with respect to sewage sludge compliance or non-compliance. The results can then be used for mesophilic anaerobic digestion process optimisation strategies and capital asset (where needed) planning. KEY WORDS Analysis of Variance (ANOVA), Compliance, Enhanced Risk Analysis and Management, Process Capability Evaluation, Sewage Sludge Digestion.
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