Jun-2024

Fast response to the urgent need for a wastewater solution

Plant operators are increasingly looking at ways to improve the efficiency and reliability of the treatment of the wastewater produced by their industrial sites.

NSI Mobile Water Solutions

Article Summary

There are many environmental and economic reasons to do so: environmental protection, compliance with local discharge standards, lower water supply costs by reusing treated water, reducing reliance on scarce freshwater supplies, and in general, optimisation of the Water Footprint. Here, Robert Stancombe from NSI Mobile Water Solutions looks at how mobile water treatment suppliers can help industrial sites protect their licence to operate and reduce their environmental impact when a rapid response is needed.

Industrial processes can produce effluents that are challenging in terms of volume, variability, and composition. Difficult-to-treat effluent is often the result of challenging industrial processes that create complex wastewater streams that may contain high levels of suspended solids, oil&grease, heavy metals, and organics (generating high COD and BOD loads), and high bacterial and viral loads that require specific treatment. Additional challenges may come from a huge range of micropollutants that could also be present.

Treating industrial effluent is complex and depends very much on the kind of load and the nature of the process generating the wastewater stream. It can, however, generally be done in several stages. Firstly, pretreatment of potential high loads of suspended solids or oil & grease that would be problematic for the following steps, by filtering, clarification, or air flotation. Then, the treatment of specific pollutants such as heavy metals or organic compounds, by physicochemical or biological processes. Finally, polishing of the treated effluent before discharge or reuse, using if necessary ultrafiltration and/or reverse osmosis depending on specific quality objectives.

It is thus critical to assess the physical and chemical characteristics of the effluent to determine a cost-effective and efficient process for industrial wastewater treatment.

Temporary mobile solutions for wastewater treatment
Plant operators face several challenges. These include worker and expertise shortages, the large footprint of fixed wastewater treatment plants, and tightening budgets. These factors collectively make it more challenging to justify capital investment. The fallout of this has been a reluctance to invest in wastewater projects where the lifetime and return on investment are limited if not non-existent. In light of this, one of the attractions of mobile water services is their flexibility, as the rental payments can be covered by the operational budget, removing the need to raise capital. Mobile water service suppliers – such as Mobile Water Solutions – are often willing to enter into pay-as-you-go, multiyear contracts, which help to improve financial planning thanks to predictable, regular payments.

A typical mobile plant may consist of two or three assets or skid-mounted systems, which can be assembled in a plug-and-play fashion. The containers’ portability enables them to be positioned to make the best use of the available space, eliminating or reducing the need for building infrastructure to house the equipment. Any number of assets can be operated in parallel or series, and their modularity allows additional components or treatment steps to be added for extra functionality or increased throughput, even if it is only needed for a short period. Storage tanks and pumps can also be provided – together with interconnecting fixed pipework or flexible hoses, water meters, and fittings – and mobile generators support a completely standalone set-up.

A lot has changed since Mobile Water Solutions was first introduced into the market. Originally, they were mostly specialised in process & boiler feed water production, with membrane technologies and ion exchange resins mounted inside trailers or containers. However, customer needs have diversified, generating a demand for a broader range of available physical and chemical technologies for not only process water but also industrial wastewater applications. These technologies include disc filters, multi-media, activated carbon filtration, sand-ballasted clarification and air flotation with preliminary coagulation and flocculation, and recycling (UF/RO systems).

Since its integration into Nijhuis Saur Industries (NSI) in December 2022, NSI Mobile Water Solutions now boasts one of the largest and most comprehensive fleets in Europe, offering mobile assets for the treatment of process water and wastewater. The IPF/ICF range offers, for example, a compact containerised solution for the pretreatment of industrial wastewater (with or without flocculation) with flow rates ranging from 2 to 135 m³/h. Each unit includes as a standard a feed pump, a chemical container, dissolved air filtration (DAF), and a sludge pump.

First aid solution in an emergency
A temporary wastewater treatment system is a perfect solution in an emergency. Mobile water solution providers can bridge a gap for operators with a problematic wastewater plant until it can be replaced or repaired or if there are variations in the effluent quality.

A leading Spanish company operating in the food and beverage industry contacted Mobile Water Solutions in an emergency caused by unforeseen issues with their wastewater treatment plant. They needed to urgently reduce the hydraulic flow and the total suspended solids (TSS) load at the intel of their biological treatment plant (anaerobic + aerobic). To tackle the issue, Mobile Water Solutions promptly mobilised a mobile dissolved air flotation (DAF) unit to enable the removal of approximately 80 to 85% of the TSS as the first step for primary treatment. Part of the pre-treated water has then been filtered by multi-media filtration and reverse osmosis process. This second step enabled the partial reuse of this source. After the successful mobilisation on-site for 8 weeks, the customer followed up by extending the contract from an Emergency to a 12-month Planned service.
Many facilities will also need to plan for the maintenance of existing wastewater systems, and mobile water systems can be brought in to cover equipment servicing. In other situations, mobile water solutions can support companies facing changes in local discharge standards to ensure that their licence to operate is protected and avoid costly fines.

A biorefinery located in Sweden needed to improve the treatment of its effluents to comply with new environmental regulations from the local County Administrative Board (CAB), that came into force on January 1, 2022. In addition, the construction of a new anaerobic treatment plant combined with the expansion of the customer’s production resulted in effluent instability.

The customer contracted Mobile Water Solutions to help mitigate the effects of the effluent quality variation. To achieve the desired reduction of metals (lead, cadmium, chromium, and nickel ) in the effluent, Mobile Water Solutions provided a complete end-to-end solution including pumps and pump stations, piping works and material, a mobile clarification asset, and a sludge dewatering system.  After a successful installation, the mobile clarifier achieved high removal efficiency of heavy metals, reassuring the client that their site remained compliant with the new regulations despite ongoing effluent variations.

Optimising wastewater management strategy
There are numerous benefits that mobile solutions can bring to industrial manufacturers facing wastewater challenges. These solutions will support financial planning, ensure business continuity, and contribute to resilient and effective wastewater treatment plants as part of industrial companies’ water cycle optimisation strategies.