WATER I NNOVATE Pascal Harper Product Manager

2 What is ?

3 What does do? Describes H 2 S behaviour in liquid phase Based on Hvitved-Jacobsen sewer model –Biofilms and suspended biomass –Considers anaerobic - aerobic conditions –Useful for H 2 S formation Modified by: –Adding mechanism for H 2 S to SO 4 2- oxidation Describes movement of H 2 S & O 2 into and out of liquid phase Based on mass transfer models for VOCs & O 2 in the literature –quiescent surfaces, weirs/drop structures, channels, dissolved air aeration, surface aeration, trickling filters Liquid Phase Formation Model Mass Transfer Emission Model

4 Emission variation over 48 hrs

5 98 percentile contour plots Static emission rates ODOURsim® variable emission rates

6 Asset Management Issues: Odour budgets limited. Need high-level screening tool to prioritise capital expenditure. Need re-useable tool to examine growth impacts for PRO5 bids. ODOURsim ® benefits: Can be used as screening tool using “typical” wastewater charaterisitics. Fully calibrated model can be held in “library” for future scenarios. Can combine both population load and spatial impacts. Provides evidence for Local Authority Planning decisions – “encroachment”.

7 for High-Level Scoping - Example Case: We want to assess impact of future growth in catchment area for local WwTW. Method: Take existing calibrated / validated ODOURsim ® model for existing population. Pro-rata new population load (2015/2020 pe. estimates) into input file. Re-run model with new input file to generate emissions. Re-run dispersion model to plot new contour boundaries. Alternative screening method: Assume input wastewater stoichiometric ratios. (Using historic data). Examine diurnal flow profile from telemetry flow logging. (DWF period) Generate flow and load data from ratios and flow profile. Run ODOURsim and Dispersion models.

8 Capital Delivery in the Water Industry Capital Programme Project Options Operational Handover Asset Manager Project Manager Process Engineer Operations

9 Process Engineering Issues: Need simple, fast techniques for designing odour control measures. Need to identify correct sources of odour. Need reliable, accurate model. Need flexibility to simulate options prior to build. Need to keep time/costs to minimum. ODOURsim ® benefits: Validated model – based on peer reviewed research. Uses familiar wastewater characteristics. Predictive model – process sizings, flow and loading rate effects calculated. Provides more detailed insight and understanding – “granularity”. Allows peak to mean calculation for OCU design.

10 for Process Design - Example Case: What effect does the PST weir height have on emissions? Method: Build, calibrate / validate ODOURsim ® model for existing scenario. Modify weir height in node properties window. Re-run model with to generate emissions for comparison. Benefits: Model demonstrates impact of process changes on odour emissions. Gives designer confidence in proposed solution. Standardises techniques for odour evaluation.

11 Capital Delivery in the Water Industry Capital Programme Project Options Operational Handover Asset Manager Project Manager Process Engineer Operations

12 Operations Issues: Needs a compliant works at least cost. No complaints, abatement notices, or prosecutions. Evidence to support compliance argument. Simple solution, least manpower/chemical requirement. Reuseable tool to verify impact of operation changes on odour footprint. ODOURsim ® benefits: Satisfies FIDOL requirement of CoP. Non-seasonal – does not require assessment only in summer months. Can predict impact of operational changes – flow splits, liquor returns.

13 for Operations - Example Case: We want to assess odour impact of modifying the liquor return flows and loads on a WwTW. Method: Take existing calibrated / validated ODOURsim ® model for current flow regime. Add new liquor flow and load into input file. Re-run model with new input file to generate emissions. Re-run dispersion model to plot new contour boundaries. Benefits: Model allows optimisation to be trialled in risk-free environment.

14 Benefits to the Capital Delivery Process. Asset Manager Project Manager Process Engineer Operations Future scenarios can be simulated Evidence to support WSRA bids Cost effective vs Olfactometry Non-seasonal – less lead time Validated model – Peer reviewed Greater accuracy of results FIDOL requirement met Operational changes modelled