UK Water regularly says it is looking for new ideas to solve old problems: the rising costs of treatment, growing populations, ageing assets, and ever-tightening environmental standards. In 2008, Perceptive’s Advanced Process Control (APC) made the leap from petrochemicals into the UK water sector. It has since been used or assessed by 7 of the 12 UK wastewater companies, but the industry seems reluctant to embrace a technology that provides numerous benefits.

What is the technology?

Data-driven model-based monitoring, control and optimisation is widely used in high-value manufacturing sectors such as pharmaceuticals. The as-built plant can be pushed closer to constraints and operated closer to its optimal under all conditions, and with minimal operator intervention. This approach can significantly reduce the cost of operation – less energy, less raw material/chemical, less risk of off-spec product.

A fundamental part of APC is its live assessment of data trustworthiness, ensuring that unreliable data is identified and screened before it has an adverse impact on the operation. Critical signals can be reconstructed in real-time from correlated data; even when a sensor fails, its ‘digital twin’ is immediately available for the controller.

Process capability (headroom) is increased by predicting exactly how much treatment will be required to achieve the desired quality. The system recalculates an optimum control strategy every 90 seconds, based on incoming data, then makes multiple coordinated moves on the plant to compensate for changes.

This two-pronged approach provides more reliable, more efficient operation, even under severe conditions such as storms, first flush events or failure of hardware sensors.

Why APC is a good Fit for water?

Any complex process requires a balance between cost and quality. In wastewater treatment, costs increase and the risk to quality increases as asset condition degrades. Cost and risk both decrease with more responsive, more reliable control. APC works precisely because it addresses cost and quality simultaneously.

When has it succeeded?

• When a clear set of goals and constraints has been identified at the onset of the project, and when the management team wants to see some real change to asset operation.

• When a strong project manager is in place and all stakeholders are informed and engaged.

• When project delivery isn’t delayed or hijacked by unrelated on-site activity

Obstacles to Implementation

The water sector thinks in terms of decades-long asset life, years-long infrastructure projects. The consequences of failure can be huge; the industry is slow-moving and risk averse for good reason. But once an innovation is proven, some companies still remain reluctant to adopt it more widely or exploit its true capabilities. Why?

Energy pigeonhole

ASP energy savings of 35% have been delivered, while 20-30% are typical. But saving energy barely scratches the surface of what APC can deliver. If a project is conceived and delivered solely by the energy team, there may be less buy-in from other stakeholders such as asset managers and quality coordinators. Increased process capability equals extended asset life equals deferred capital expenditure. In the new world of Totex, this should be given a higher priority.

APC does not stand for “A Panacea Control”

APC is extremely fault-tolerant. Because it is based on a digital model of process behaviour, it can continue to optimise process performance even when data goes missing. This makes it an ideal fit for an industry that accepts a degree of asset degradation. But APC cannot address fundamental problems like broken blowers, failed motors and non-existent sensors.

Not Needed / Not Invented Here

APC solutions are installed and supported around the world, built on robust and well-proven industrial standards. Home-grown systems require high levels of manpower for their development, deployment and maintenance.

Not for small sites

Data-driven, intelligent, robust monitoring and control of any site provides hard and soft savings, no matter the asset size. Imagine if the data coming from 20,000 PE works with no 24/7 staffing was truly trustworthy? Imagine if faults could be detected before they impacted performance at such a site – what’s the value of pre-emptive maintenance?

Funding

OpEx? Capital? R&D? Maintenance? Gainshare? Spend-to-save? There appears to be no standard funding mechanism in place for this type of technology, either across the industry or within each company.

We don’t want a “Black Box”

Good, neither do we. Each control system is fully transparent; the behaviour of the controller reflects the actions that a highly trained operator would take, if the data they responded to was trustworthy and if they were able to make coordinated control moves every 2 minutes.

Not an ‘Asset Standard’

No two sites are identical in their design, load, asset condition or operation. Yet some in the industry expect an optimisation scheme to be one-size-fits-all.

Complex

APC is massively more sophisticated than PLC-based systems, far more fault-tolerant and responsive to changing conditions, and provides greater flexibility in its control scope. Yes, it is complicated, in the same way that engine management system and fuel injection replaced inefficient carburettors.

Requires Too Much Time

A comprehensive system, providing tighter levels of ammonia control, peak-tariff and TRIAD management, optimised handling of storm events and remote KPI dashboard reports can be designed, installed and commissioned within 3 months. Such a system will usually provide a hard payback within 12 months on a large site. Once the project is underway, owner input is minimal.

Going forward

If the industry wants to exploit the benefits that APC can bring, a well-proven suite of tools and methodologies exists to realise them. As a first step, a low-cost process audit identifies the scale of opportunity that can be captured, as well as a detailed roadmap for delivery.

There has been investment in sensors and data capture, there is a desire to reduce carbon footprint, and a move towards totex and whole-life asset costs. The industry seems to be ready, but is it willing?

www.perceptiveapc.com/water