ion exchange resins mounted inside trailers, which could be transported on industrial sites to provide a temporary supply of high purity water. 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, multimedia and acti - vated carbon filtration, sand-ballasted clarification, and air flotation with preliminary coagulation and flocculation, and recycling (UF/RO systems). MWS’s mobile dissolved air flotation series, for exam - ple, can be used as pretreatment upstream of a biological plant to remove biodegradable fats, TSS and fibres. These assets can also act as a clarification plant downstream of a biological plant to remove light sludge particles not captured by secondary decanters or perform tertiary treatment. A typical mobile plant (see Figure 1 ) may consist of two or three assets or skid-mounted systems, which can be assembled in a plug-and-play fashion. The contain- ers’ 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 treat- ment 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 metres and fittings – and mobile generators support a standalone setup. These units are characterised by their high standardi- sation level, which can significantly reduce development, assembly, and commissioning costs. However, each unit must be tested prior to site mobilisation for calibration and, in some cases, must be adjusted for good integration into the operator’s wastewater treatment process system. Case 1: First aid solution in an emergency situation A temporary wastewater treatment system is a preferred solution in a crisis, such as a potential wastewater spill or an unsatisfactory operation resulting in the treated water not meeting the specified limits. At one of the UK’s leading waste and resource manage- ment companies that can receive wastewater from hydro- carbon processing operations, rainfall run-off from the company’s landfill site is collected in a lagoon and tested for contamination before being safely discharged into the local watercourse. Leachate, which all landfill sites produce, is collected by road tanker and taken to the local sewage treatment works for disposal. The wettest recorded winter resulted in the run-off lagoon becoming full. The high rainfall also generated more leachate than usual, contaminating the lagoon. Faced with 40,000m 3 of contaminated water that could not be dis- charged onto the watercourse, the customer contacted MWS. Its reverse osmosis technology included pretreat- ment filters to treat the contaminated water to a quality suitable for direct discharge to the watercourse.
The concentrated reject stream from the reverse osmosis plant was tankered to the sewage treatment works, but the volume was reduced by two-thirds, reducing tanker movement, minimising environmental impact, and saving money on tankering costs. “We could only manage four tankers a day at this rural site, and that would take nearly a year to empty the lagoon if we had no more rain. We had to reduce the volume; therefore, mobile reverse osmosis technology was the most suitable option,” said the leach- ate treatment manager. Emergency hire equipment offers immediate enhance- ment to effluent treatment, helping companies achieve compliance and offering them the breathing space to plan a permanent fix. Mobile water service providers can indeed bridge a gap for operators with a problematic wastewater plant until it can be replaced or repaired or even bridge a time period if there are variations in the effluent quality. Case 2: Keeping refinery online during DAF repairs At a refinery processing over four million tonnes of crude oil per annum, nearly 70% of the crude oil is used for fuels production, including jet fuel that supplies almost every flight departing from Hamburg airport and heating oil for 250,000 homes in Northern Germany. The refinery is also a chemicals company, manufacturing some 450,000 tonnes of petrochemical products per annum. The refinery was experiencing issues with its existing DAF (dissolved air flotation) unit, exposing the client to a potential plant failure. The customer contracted MWS to provide a temporary solution while repairing its wastewa- ter treatment plant. MWS first conducted a jar test. A conclusive report and a rapid response from the team led the facility to call on MWS to facilitate the set up of a mobile DAF unit, a dos- ing station, two tanks, and two pumps. The solution pro- vided pre-treatment and biological treatment of 200 m 3 /h of wastewater. The temporary mobile assets were on-site for two weeks, giving plant engineers peace of mind while their existing system was being repaired. Case 3: Temporary mobile water systems 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. Another refinery producing and supplying 10.3 met - ric tonnes per annum of oil products contacted MWS in Bavaria and northern Austria to provide mobile water service during the planned maintenance of the on-site DAF (dissolved air flotation) used to treat a wastewater stream. The technical specification needed to meet a flow rate of 80 m 3 /hr, combined with reducing TSS, COD, and hydrocarbons. MWS provided a mobile floatation unit on a stainless- steel frame, complying with the required water quality, TSS <30 ppm, COD <250 ppm and HC <5 ppm, whilst removing the need to purchase equipment and associated lead times. The original project was planned for a one-to-two-month time period. However, this flexible service was extended to ten months due to unforeseen events.
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PTQ Q4 2022
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