Using a digital twin to reduce coagulant costs by 23% at a drinking water plant in Hong Kong
A water treatment plant in Hong Kong implements Plant Optimiser - Envirosuite’s digital twin technology - to reduce coagulant costs at its drinking water treatment and desalination operations.
Future-proofing a treatment plant that serves 7.5 million people a day
Hong Kong is a highly developed territory - ranking fourth on the UN Human Development Index, and the world’s 35th-largest economy.
One of the drinking water treatment plants in Hong Kong provides drinking water to a population of about 7.5 million, across multiple districts of Hong Kong. The operator of the plant has introduced numerous advanced technologies to improve resilience at the plant and in 2022, implemented digital twin technology to better manage coagulant costs at its operations.
In early 2022, the operator selected Envirosuite’s Plant Optimiser for its first-ever digital twin project in conventional water treatment, at the water treatment works. Plant Optimiser was implemented at the coagulation process as the first stage in determining whether digital twins could be applied more broadly at the plant and other similar treatment works in Hong Kong.
Implementing digital twin technology to receive automated recommendations on optimal plant settings
The objective of the digital twin project for the treatment plant is to use Envirosuite's Plant Optimiser technology to create a reliable model that provides actionable advice on the optimum coagulant dosage. The technology creates a digital twin model representing the coagulation, lime dosing, flocculation, and dissolved air flotation systems of the plant.
Plant Optimiser is Envirosuite’s advanced real-time plant monitoring technology using both machine learning and deterministic modelling to predict incidents and identify optimal plant settings with higher accuracy.
Plant Optimiser recommendations over the project period identified 23.3% reduction in alum use compared to business-as-usual operations
The technology creates a digital twin model representing the coagulation, lime dosing, flocculation and dissolved air flotation (DAF) settling systems of the drinking water treatment plant. Using historical and live raw water quality as well as operating setpoint inputs from the operating plant, Plant Optimiser predicts and recommends - every hour – the optimum alum and lime dose for the plant, together with expected pH, turbidity and soluble aluminium in the blended DAF effluent, which are the key performance metrics for that stage of the treatment works. This technology aims to assist operators in process optimisation and potentially reduce the cost of coagulation while maintaining treated water quality objectives.
Example of digital twin technology
Maintaining water quality objectives and improving operational performance
Plant Optimiser recommendations over the project period (June 16 – October 27, 2022) identified a 23.3% reduction in alum use compared to business-as-usual operations. With data provided by Plant Optimiser’s hourly emails, the operation team is less reliant on jar tests while ensuring high-quality drinking water for the local community.
The proof-of-concept digital twin solution was implemented in June 2022. The outputs evaluated against actual plant operations showed that the model can be used as a basis for decision-making to drive down costs of operation related to alum usage, while maintaining plant operations within the required bounds.
EVS Water Plant Optimiser runs plant-wide simulation
Based on hourly advice provided by Plant Optimiser, the operation team is less reliant on jar tests while ensuring high-quality drinking water
The model also identified opportunities for reduction in coagulant dosing while maintaining water quality objectives. It could therefore be applied at other similar plants or considered for expansion into other process operations at the same plant to assist operators in improving performance and lowering costs further.
In conclusion, the digital twin technology has helped the drinking water treatment plant to:
- Identify a 23.3% reduction in alum use compared to business-as-usual operations
- Reduce reliance on jar tests
- Ensure high-quality drinking water for the local community
Find out more here: https://envirosuite.com/platforms/water/plant-optimiser