Jul-2023

Mobile reverse osmosis

How to get around the shortage of chemical supplies affecting the production of purified water

NSI Mobile Water Solutions

Article Summary

A growing population, an increasing water demand,  and a widespread scarcity of potable water are currently driving the demand for water treatment chemicals worldwide. This is especially so with chemicals needed for the regeneration of IX resins, such as HCI and Caustic. However, the chemical sector has been adversely impacted by the COVID-19 pandemic, and the scarcity of resources, manpower shortages, and other working constraints have significantly hampered the industry’s expansion, which is resulting in a shortage of critical chemicals used for water treatment.

Chemicals can’t be substituted, but implementing alternative solutions is possible. It, however, presents challenges, such as disruption to plant operations and significant expenditure. A further solution is, therefore, the use of mobile Reverse Osmosis (RO) assets upstream of operators’ demineralisation plants, which can help streamline the implementation process and get around the worsening shortage of chemical supplies.

Achieving purified water – traditional vs. mixed technologies methods
Conventionally, to produce high-quality water, it is common practice to rely on ion exchange (IX) technologies using resins, which remove and reduce dissolved ions. Although IX can provide suitable water quality levels, plant operators are increasingly opting for the use of mixed methodologies to improve the performance of the treatment, cost efficiency, and compliance with strict local environmental standards.

One popular option is the implementation of Reverse Osmosis (RO) before Ion Exchange for the production of demineralised water. RO and IX, are often considered complementary technologies. RO uses a semi-permeable membrane to separate up to 95 to 98% of the dissolved solids and particles from a water supply. During the RO phase, the feedwater enters the membrane under pressure, and the water molecules pass through, whilst the contaminants are captured and discharged to the drain.

Compared to alternative methods, a RO unit installed in front of an  IX system has many advantages. It requires limited consumption of regeneration chemicals, which simplifies the operation, keeps costs down, and provides a safer working environment. RO also makes the demineralisation process less taxing on the resins. As a result, fewer regenerations are needed, and less wastewater is produced, leading to considerable savings and lesser environmental impact.

The case for reverse osmosis upstream of a demineralisation plant
In Europe and Germany especially, the increasing water treatment activities, primarily in the northern region, are boosting the demand for water treatment chemicals. Combined with a strong public focus on water quality, growing environmental concerns, and stricter local water discharge regulations, this situation is leading industrial companies to look at ways to improve both water and wastewater treatment methods.

A refinery in Germany has been processing crude oil into fuels, kerosene, light heating oil, and chemical pre-products for over 70 years. In 2021, they experienced issues with the delivery of chemicals needed for the regeneration of their demineralisation streets, due to a shortage of hydrochloride acid (HCl).

The customer initially managed to find an internal solution and received a delivery at the last minute. However, in late 2021, they ran out of options and were urgently looking for a sustainable alternative, that would extend the time between two regenerations and thus save chemicals.

In response, NSI Mobile Water Solutions, part of Nijhuis Saur Industries, first proposed the implementation of two mobile ion exchange systems as a temporary substitute for the on-site demineralisation plant combined with two mobile reverse osmosis. Trailer-mounted ion exchange assets can be deployed rapidly from MWS’ new regeneration and service centre strategically located in the region of Nordrhein Westfalen, Germany, and the largest of its kind in mainland Europe. Once on-site, these high ion exchange capacities and high flow rate plug-and-play units can be commissioned in a matter of hours to get a treated water tank filled quickly, mitigating the related risks to production. MWS also offers off-site resin regeneration, reducing chemical handling on the customer’s site.

However, with the issue being mainly the lack of chemicals and not the customer’s demineralisation plant itself, Mobile Water Solutions also offered the option to install two mobile reverse osmosis assets upstream to feed the plant’s denim streets with up to 200 m³/hr of RO permeate. As such, the time between two regenerations increased tenfold, and the customer saved a corresponding amount of chemicals. After 1.5 months, the customer decided to extend the mobilisation of the assets to the end of 2023.

Conclusion
New treatment processes can be implemented to avoid disruption due to the ongoing chemical supply bottleneck, optimise water usage, and reduce costs. NSI Mobile Water Solutions can help by providing mobile reverse osmosis assets in a way, that does not impede plant activity, either for short-term mobilisation assets (simple trial or temporary need) or long-term use.