Effluent safety limits

Simultaneous Nitrification Denitrification to Meet Low Effluent Nitrogen Limits

Simultaneous nitrification denitrification (SND) has been referred to as a biological process for nitrogen removal where nitrification and denitrification occur concurrently in the same aerobic reactor. SND facilities, investigated in this study, have been shown to remove 80 to 96 percent nitrogen without additional carbon and alkalinity. Carbon availability and bulk dissolved oxygen (DO) conce...

Chapter 173-205 WAC WHOLE EFFLUENT TOXICITY TESTING AND LIMITS

WAC 173-205-010 Purpose. 173-205-020 Definitions. 173-205-030 Applicability. 173-205-040 Determining the need for effluent characterization. 173-205-050 Effluent testing for toxicity. 173-205-060 Additional effluent characterizations. 173-205-070 Monitoring for compliance with whole effluent toxicity limits. 173-205-080 Samples for whole effluent toxicity testing. 173-205-090 Response to noncom...

Assessing Safety Benefits of Variable Speed Limits

Safety Control Synthesis with Input Limits: a Hybrid Approach

We introduce a hybrid (discrete–continuous) safety controller which enforces strict state and input constraints on a system—but only acts when necessary, preserving transparent operation of the original system within some safe region of the state space. We define this space using a MinQuadratic Barrier function, which we construct along the equilibrium manifold using the Lyapunov functions whic...

Exploring the limits of safety analysis in complex technological systems

From biotechnology to cyber-risks, most extreme technological risks cannot be reliably estimated from historical statistics. Engineers resort to probability safety analysis (PSA), which consists in developing models to simulate accidents, potential scenarios, their severity and frequency. However, even the best safety analysis struggles to account for evolving risks resulting from inter-connect...