Dr. Martin T. Auer MTU Department of Civil & Environmental Engineering Mass Balance, Kinetics & Reactors

Environmental Response …the question is not will a system will respond, but rather when and to what extent. (Cooke et al. 1999) and, as engineers, we might add ‘ at what cost ’ ?

Lake and River Management …the environmental engineering equivalent of building a bridge to nowhere. (Thomann and Mueller 1987, p. ix)

Drinking Water Treatment …the environmental engineering equivalent of building a bridge that falls down. (Thomann and Mueller 1987, p. ix)

Plug Flow Reactor Completely-Mixed Flow Reactor Reactor Analogs

CMF Reactor

Control Volume

Zero Order Kinetics Oxygen in Dollar Bay Zero Order k = 0.13 mg∙L -1 ∙d -1 C t = -k∙t + C 0

First Order Kinetics Radioisotope Decay k = yr -1 t 0.5 = yr lnC t = -k∙t + lnC 0

Temperature and Kinetics Theta Function

Temperature and Kinetics WWTP Nitrification Effluent Ammonia Load (MT∙d -1 ) J F M A M J J A S O N D

CMF Reactor with first order decay time-variable or steady state application

For many years, Allied Chemical and its ancestors produced soda ash … a chemical used to soften water and in the manufacture of glass, soap, and paper. The raw materials were two locally abundant minerals: CaCONaClNaCOCaCl 3232  and the products were soda ash (Na2CO3) and calcium chloride (CaCl2) waste. The wastes were deposited in 2000 acres of lagoons along the banks of 9 Mile Creek. The waste continually leaks from the lagoons into the creek, making the water highly ‘salty’. Chloride in 9 Mile Creek

Response Time assume no input, divide by V, collect terms and integrate, assume SS when 95% completed, i.e.

Response Time Wastewater Treatment Grit removal, 0.5 hr 1°, 2° settling, 1-2 hr Activated sludge, 4-8 hr Anaerobic digestion, d Drinking Water Treatment Rapid mix, <1 min Flocculator, 30 min Disinfection, 15 min Natural Systems Onondaga Lake (0.25 yr) Lake Ontario (8 yr) Lake Michigan (136 yr) Lake Superior (179 yr) Typical ‘fast’ k, 30 yr -1 Typical ‘slow’ k, 0.03 yr -1

CCe tss kt    F H G I K J  1 1  CCeCe t kt kt  F H G I K J   F H G I K J   F H G I K J    CCe t kt  F H G I K J  F H G I K J   Time-Variable Response

SS CMF Application to Lakes where W = Q∙Cin, i.e. the loading

SS CMF Application to Lakes

Batch Reactor in Pipe

Train of Batch Reactors

PF-CMF Comparison: Reactor Efficiency

PF-CMF Comparison: Sensitivity to Spikes

PF Reactor – Application to Rivers

Example 4.14 PCBs in Lake Superior Dr. Perlinger’s research group sampling on Lake Superior aboard the U.S. EPA research vessel Lake Guardian.