Wastewater Treatment Energy Recovery Potential. An Integrated Assessment. Patrick A. Breach : Slobodan P. Simonovic :

Transcription

1 Wastewater Treatment Energy Recovery Potential An Integrated Assessment Patrick A. Breach : pbreach@uwo.ca Slobodan P. Simonovic : simonovic@uwo.ca

2 Introduction Anthropogenic nutrient impact on SW quality Rapidly increasing population and urbanization Harmful algae blooms and fish kills SDGs propose 50% reduction in untreated wastewaters 2

3 Introduction Economic barriers for plant construction and upgrade Chemical energy recovery from wastewater treatment processes can be utilized to offset Biogas utilization Biosolids incineration 3

4 Introduction Questions: How will treated wastewater fractions have to change to avoid surface water degradation? Can energy recovery help to offset the cost of treatment so that more plants can be constructed? Objective: Create a hypothetical dynamic scenario to evaluate feedbacks between wastewater treatment, energy recovery, and water quality 4

5 Methodology System Structure Nutrient Input Investment Untreated WW Agricultural runoff Water Quality Cost reduction Economic Constraints Gap Energy Recovery Energy Recovery Potential Treatment Plants 5

6 Methodology System Structure Agricultural Runoff Agricultural Runoff Nutrient Concentration Population Nutrient Input Untreated WW Agricultural runoff Water Quality Net Natural Flux SW Nutrient Anthropogenic Flux Nutrient Load per Capita <Time> <GDP per Capita> Peaking Factor Water Quality Gap Nutrient Standards 6

7 Methodology System Structure Plant Aging and Decommisioning Constraint Offset WW Treatment Plants Economic Constraint Factor Plant Construction Contraint Shape Queue Fraction Surface Water Construction and Planning Time Water Quality Based Construction Water Quality Gap Perception Time Wastewater Nutrient Concentration Removal Efficiency Treatment Plants Average Plant Design Life Plant Allocation Growth Based Construction <Plant Capcity> <WW Increase> Treated WW Fraction <WW Treatment Plants> <WW Generated> 7

8 Methodology System Structure <Unit Treatment Cost> Investment Annual Investment Total Investment <FINAL TIME> Target Assessment <Time> Planned Investment Contraint Shape <WW Treatment Plants> Economic Constraint Factor Constraint Offset 8

9 Methodology System Structure O&M Costs Biogas Energy Factor Unit Treatment Cost Biogas Utilization Capital Costs Energy Recovery Electricity Price Dry Solids Content Plant Allocation Biosolids Incineration <Time> Time of Rapid Adoption Biosolids Heating Value Steam Electric Heat Rate Energy Recovery Biogas Energy Recovery BEF * Q Q* C s * HV Biosolids Energy Recovery HR <WW Treatment Plants> Plant Capcity 9

10 Methodology Assumptions Future Plant Allocation Economic Constraints Plant Allocation i t T i 0.5* 1 exp Pi* R i 1 Total Investment Annual Investment * t f t Target Assessment Planned Investment 10

11 Methodology Parameterization Monte Carlo Analysis Parameter Unit Min. Peak Max. Constraint Shape Time of Rapid Adoption years Queue Fraction Perception Time years Construction + Planning Time years Plant Capacity m 3 /day Planned Investment billion $ Peaking Factor

12 Results Baseline Parameter Set Simulated nutrient over-enrichment of (a) Phosphorus, (b) Nitrogen and (c-d) wastewater treatment variables for the period of using the baseline parameter set 12

13 Results Baseline Parameter Set Simulated (a) energy recovery and investment variables (b-c) for the period of using the baseline parameter set 13

14 Results Monte Carlo Analysis 14

15 Conclusions Loadings of P and N projected to increase faster than increased treatment can accommodate Substantial amount of wastewater energy generation is possible if the technologies become more widely adopted Cost offset did not result in a significant reduction in nutrient over-enrichment Bottom-up non-point source nutrient management strategies should be implemented 15