Optimising chemical dosing in a challenging operating climate

Adeel Hassan, product manager WMFTS
Adeel Hassan, WMFTS product manager

Rising operating costs and tightening regulations are challenges for wastewater treatment plant operators, but better optimisation of chemical dosing can drive efficiencies, said Adeel Hassan, product manager at Watson-Marlow Fluid Technology Solutions (WMFTS).

Wastewater treatment providers are facing a challenging operating climate in 2023 as authorities around the world tighten environmental regulations which govern chemical use and wastewater disposal. They are also coming under pressure from the rapid rise in operating prices and customer expectations on sustainability.

According to Hassan, there are six factors to consider in chemical dosing to achieve the best performance in onsite wastewater treatment (WWT).

First, chemical and operational savings are critical to staying competitive in a global market and maintaining cost control. When factoring in the pressure to modernise and increase capacity, it can be a complex task to understand where to make the most effective efficiencies.

Energy consumption is in the spotlight as utilities strive to meet sustainability goals and net zero carbon targets, along with managing rising costs. A changing climate and growing pressure from the public for utilities to reduce waste while minimising environmental impact is also driving change and increasing expectations.

Peristaltic pumps, such as WMFTS range of Qdos chemical metering pumps, provide highly accurate dosing by enabling precise, incremental adjustments from 0.1ml up to 2,000ml per min. By only using what is needed, chemical quantities and costs are reduced.

The second factor is to keep abreast of regulations. As WWT facilities in the municipal and industrial sectors look to upgrade equipment to meet tightening regulatory demands, regulations themselves are also changing. For example, the EU Council Directive 91/271/EEC on urban wastewater treatment states that by 2040, all water released into the environment, from treatment plants serving 100,000 people or more, must be free of pharmaceuticals, pesticides, antibiotics, manufacturing chemicals and other harmful substances, resulting in the need for increased treatment.

In the US, the Environmental Protection Agency’s Safe Drinking Water Act sets legal limits on over 90 contaminants in drinking water, which changes and is added to periodically. The legal limit for a contaminant reflects the level that protects human health and that water systems can achieve using the best available technology. Its rules also set water-testing schedules and methods that plants must follow.

As the need for greater transparency around sustainability goals and metrics increases, suppliers like WMFTS have to support clients in optimising chemical use and eliminating the risk of spills of pollutants into the environment. Treated effluent must meet high-quality standards before being released into the environment. Inaccurate dosing and regulatory breaches can result in large fines and damage to a company’s reputation.

Third is to put safety first. The health and safety profile of pumps is a consideration for plant managers and the Qdos pumps feature leak detectors which stop automatically and alert operators in the event of a pumphead failure.

The units are self-contained and, once valves are shut off, the pumphead can be quickly and easily replaced without tools or spillages for safe maintenance. This minimises the possibility of operators coming into contact with chemicals and prevents chemical spills into the environment.

By comparison, other pump types require disassembly for repair and maintenance, risking chemical spillage and exposing staff to potential contact with chemicals.

The fourth factor is to optimise equipment effectiveness. WMFTS Qdos pumps help operators save on capital expenditure. Long established in the market, a peristaltic pump has a long product life and does not require pulsation dampeners, degassing valves or back pressure valves.

Qdos pumps offer quick maintenance at longer intervals — reducing the impact of process downtime, rapid process recovery, and lowering cost of ownership.

The high accuracy of Qdos pumps enables the use of more concentrated chemicals and smaller, more efficient, dosing systems, which in turn reduces both energy and transport costs. Furthermore, accurate, linear and repeatable chemical dosing allows the use of fewer chemicals, even with varying process conditions.

Another factor is to boost sustainability. Municipal and industrial organisations are seeking to reduce vulnerability through conservation and reuse of water — with some undertaking onsite assessments of WWT plant operations at every stage of the process. The benefits will be a reduction in water footprint and cost of supply.

These factors are important considerations especially where on-site management of water impacts directly on local communities and consumers are increasingly proactive around environmental concerns.

Qdos peristaltic pumps are engineered with sustainability in mind provide solutions that deliver longevity, reliability, and ease of maintenance. WMFTS has partnered with EcoVadis to achieve gold standard certification for business sustainability.

Hessisch-Lichtenau WWTP, Germany

Finally, make tangible efficient gains. The installation of a Qdos dosing pump at WWTP serving the town of Hessisch-Lichtenau, Germany, has demonstrated that the deployment of chemical dosing technologies which deliver a reduction in carbon dioxide emissions and environmental risks.

As a result of installing a Qdos Conveying Wave Technology (CWT) pump, the plant has met environmental discharge limits through ferric chloride sulphate dosing to treat wastewater. This has achieved a 97.5% reduction in phosphorus load over the first year since installation.

While the challenge of meeting regulatory standards, reducing capital expenditure, and striving for sustainability is complex, accurate chemical dosing can help WWT plants to continually drive efficiencies. The potential overall savings available by choosing the right dosing pump, and investing now to save later, will help utilities run operations with greater precision, efficiency, and cost control.