Keeping Cumbria flowing Paul Brown UU Andy Harford Atkins

Transcription

1 Keeping Cumbria flowing Paul Brown UU Andy Harford Atkins

2 West Cumbria project WHY are we carrying out the West Cumbria project? WHAT & WHERE is the West Cumbria project? Modelling the West Cumbria project: fixing the demand compliant with standards Copyright United Utilities Water Limited

3 West Cumbria project WHY & WHERE? Environmental concerns mean that from 2022 we will be unable to draw water from a key source. From % of our customers will still have a surplus of water. Ennerdale water however for west Cumbria an alternative source is required. The West Cumbria project is that alternative solution. We are replacing the source and taking the opportunity to pre empt further losses by rationalising the whole supply area. Copyright United Utilities Water Limited

4 Proposed system single source A new source of water for the west Cumbria area: A multi million pound project ( 300million); the largest Thirlmere pipeline project in the UK It consists of: 32 km raw water aqueduct + 65 km of trunk mains An 80 Ml/d WTW 2no service reservoirs (50 Ml and 20 Ml capacity) 2no pumping stations refurbishment and rationalisation of existing assets Copyright United Utilities Water Limited

5 Not just modelling Planning constraints and permissions / Legal Property ownership Stakeholder Management Lake District, Farmers, Industry, Local Authority/Traffic, Customers domestic/industrial, Environment Agency, Government, Friends of groups, Action groups Environment Flora and Fauna, Protected Species, Archaeology, Mining, Political Environment Agency, Local and HM Government, European concerns Engineering disciplines Civil, Geophysical, Tunnelling, Hydraulics, Modelling Management Financial, Project Management, Contractual, Tender process Copyright United Utilities Water Limited

6 All main network model originally 3 models Originally 3 separate models, now combined into one Used as a base for different demand and asset configuration scenarios Copyright United Utilities Water Limited

7 All main network model single model, single source Single model Single source 24,187 pipes 31,531 nodes 31 pumps 39 service reservoirs 151 regulators Copyright United Utilities Water Limited

8 Fix the demand TOP DOWN appraisal using: Water Resource Management Plan United Utilities Supply/Demand team Long range forecasts climate change, leakage levels BOTTOM UP appraisal using: Historical data peaks in demand Freeze / Thaw events Local Authority plans Copyright United Utilities Water Limited

9 Work to a specification Velocity Head loss Head loss per Km Pressure Surge analysis Critical points Water Quality turnover Chlorine residual, Chlorine input SR size turnover vs capacity Copyright United Utilities Water Limited

10 Programme Copyright United Utilities Water Limited

11 Thank you further details at

12 Keeping Cumbria flowing Andy Harford Atkins West Cumbria Chlorine Modelling

13 West Cumbria Chlorine Modelling The Requirement The Objective (Challenges) The Methodology The Programme Project Progress Outcomes Copyright United Utilities Water Limited

14 The Requirement for a Chlorine Model Change of Source water for Allerdale and Copeland DMZs Prediction of Chlorine levels required from new WTW into Existing Network Copyright United Utilities Water Limited

15 The Objectives Confirm the chlorine level required on the outlet of the proposed Williamsgate WTW to give the best optimised solution (baseline chlorine level for each of the three take offs defined as 1mg/l); Whether secondary disinfection is required and if it is; Optimum location for secondary disinfection to ensure that free chlorine residual targets monitored at the customers taps throughout the entire network supplied comply, under all weather conditions, with the following: <0.5 mg/l; 80% or more of measurements >0.1 mg/l and/or programme of mains cleaning and/or replacement; lowest whole life cost options to achieve secondary dosing requirements (chemical dosing vs. onsite generation) Copyright United Utilities Water Limited

16 Challenges to Outcome Increased residence times Low residual chlorine, especially in areas already experience low level residuals Bacterial failures (reported from WQ testing, rather than from customers). Biofilms High chlorine Taste and Odour customer complaints (TCP taste). THM (trihalomethane) a disinfection by product, resulting from chlorine reacting with organics. Costs could I reduce chlorine dosing to lower levels and maintain a residual? Copyright United Utilities Water Limited

17 The Methodology Data Review Assess secondary dosing feasibility Black Bottle Testing Identify secondary dosing Field Testing Asset improvement review Model Calibration Copyright United Utilities Water Limited

18 The Methodology Carry out a review of existing water quality and hydraulic model Black bottle testing of source waters Chlorine monitoring at key locations across the network Model calibration and development of a working model Highlight mains with high wall coefficients for further investigation, mains cleaning and / or rehabilitation Use the model as a tool to identify need / locations for secondary dosing and initial levels required from Williamsgate WTW Assess feasibility and identify lowest totex solutions for secondary chlorination facilities Copyright United Utilities Water Limited

19 The Programme 7 stages of the methodology 10 month duration Copyright United Utilities Water Limited

20 Project Progress Carry out a review of existing water quality and hydraulic model Black bottle testing of source waters Chlorine monitoring at key locations across the network Copyright United Utilities Water Limited

21 Water Quality & Hydraulic Model Data Review Water quality data Identify areas that experience high / low residual chlorine levels to target logging Identify seasonal temperature variation across the system Existing Hydraulic Model (Synergee) Combined or individual zone models Ensure accurately reflects current operation Identify any controls / anomalies that may impact the WQ results Copyright United Utilities Water Limited

22 Black Bottle Testing of Source Waters Chlorine decay is a function of: Initial dose Bulk decay: Raw water characteristics; Treatment; Time; Temperature Wall decay: Length and velocity (i.e. time); Wall condition; Degree of turbulence Copyright United Utilities Water Limited

23 Black Bottle Testing of Source Waters Bulk Water Black Bottle Testing: Collect samples from each of the sources Determine temperature range within the system from historic WQ data Laboratory testing over 20 days at min / max / average system temperatures Measure chlorine at set intervals (i.e. daily) Bulk decay factor (k b ) for different sources may vary different levels of organics, ammonia Testing to be undertaken in two weather seasons (Autumn / Winter) Copyright United Utilities Water Limited

24 Chlorine Monitoring across the Network Logging of chlorine allows: Detailed understanding of where decay is occurring in the system. Avoids errors associated with time of travel, spot readings giving false impression. So then in turn can pin point what remediation is required; especially important for trunk mains / aqueducts. Confirm how well dosing levels are controlled; this could be part of the problem if high / low chlorine symptoms are found. Copyright United Utilities Water Limited

25 Chlorine Monitoring across the Network Importance of planning: Significant costs associated with: Considerable mains rehabilitation in the DMAs Ofwat penalties in the event of further failures Planning includes; Hydraulic analysis Operational engagement Preliminary site visits Copyright United Utilities Water Limited

26 Chlorine Monitoring across the Network Field tests to be split into seven separate sections; Each test over four week period 12 Chloroclams to be installed per test Copyright United Utilities Water Limited

27 Project Outcomes Develop a calibrated model to; Confirm the chlorine level required on the outlet of the proposed Williamsgate WTW Identify benefits of improved dosing control (have produced high level specification of new control system) Determine optimum set dose points (sometimes lower dosing where PCVs d/s can still be achieved) Consider opportunities to reduce water age Identify mains with highest wall decay factor (highest priority for rehab / cleaning) Identify locations where additional dosing can t be avoided Identify key locations where further monitoring is required Copyright United Utilities Water Limited

28 Thank you