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iPURXL: Scale-Up of Liquid Nano-reactor for the Destruction of Contaminants in Turbid Fluids

Periodic Reporting for period 2 - iPURXL (iPURXL: Scale-Up of Liquid Nano-reactor for the Destruction of Contaminants in Turbid Fluids)

Reporting period: 2016-07-01 to 2017-06-30

Manufacturers and even local authorities discharged process/waste waters/sewage direct to the natural environment. The negative impacts were seen on whole ecosystems as contaminants progressed downstream to ground and potable water sources. Fluids which are untreatable on site must be discharged to third party “trade” sewers. As treatment costs increase in line with contaminant load, there are cost advantages to using/discharging as little water as possible. iPURXL can deliver against both cost and environmental standards for growers, manufacturers and local authorities struggling to manage compliance affordably. Compliance and cost were the initial drivers for this system but other benefits have since emerged.

End user trials of an adapted single cassette 1 tonne MWF unit were carried out on, amongst others:-

1. Meat rendering fluid sample from which only large solids had been removed.
2. Salad leaf washing systems to recover water once sent to waste.
3. Water tainted with oils to reduce rinse water use and make disposal to drain an option.
4. Pasteurising anaerobic digestion waste liquid to be re-used for hydroponic crop production.
5. Commercial and local authority swimming pools to remove Cryptosporidium. The technical advantage being the self cleaning aspect of the patent which requires no moving parts.
6. Dense oil pollution of water.

The system, in its scalable design, degrades organic material, including bacteria, in a liquid environment. It does this by passing the liquid over a fixed catalyst continually irradiated by UV with little drop in transmission due to its self cleaning attributes. The market for this system can be anything from large industrial processing to improve water quality, to a solar driven small unit to supply potable water. It's benefits are the robustness of the technology, its simplicity and it's low cost compared to other systems currently employed to do the same job. We have no time in this project to cover all the possible uses.

The overall objectives are to provide industry with a more economic and simpler method of tackling waste water cost and cutting the environmental impact of waste. We also aim to increase the shelf life of orange juice and similar cloudy beverages by cols pasteurisation using the catalyst and UV. To achieve this we intend to engineer the system to provide sufficient catalyst surface area in contact with the liquids to make the system economic and reduce the corruption of the catalyst by improving filtration.
The anchoring of the catalyst to give long working life has been accomplished. The design enables rapid servicing in twelve month periods. Refurbished catalyst supports are used rather than disposable items although the UV emitters are a replacement item. The Horizon 2020 grant has enabled this detailed examination of our process and to show that the obstacles to scaling up can be overcome.
The project was set up to confirm one of a series of scale up options. This was to be achieved using the resources of PERA TECHNOLOGY. It became evident that this organisation were under some funding pressures as our work was held back when staff were made redundant. Although we suffered delays, the project eventually caught up as more of the testing fell to others who were more efficient. We have now tested and confirmed materials and manufacturing methods for a large proportion of our prospective end users. Large scale and laboratory scale systems have been built and tested. As a result we have many sales opportunities to fulfil.

Having chosen the most practical design, based on commercial availability of constituent parts, we have a workable, large scale system. A self-cleaning quartz and UV system which efficiently controls bacteria and reduces COD levels. The system has been site tested for various flow rates. The target market is geared towards very turbid liquids being processed. There is a commercial decision in dealing high COD fluids as the addition of low levels of a chemical, Hydrogen Peroxide, reduces the number of catalytic units required. If one takes a long term view of investment then more equipment will pay off as H2O2 is not required.
Wherever we are in the world, water has become a scarce resource. Depending on the size of iPURXL used we can re-use water for wash down purposes. A larger iPURXL unit can bring water back to the front of the process as in crop washing to remove soil and bacteria. The iPURXL system is modular so it may be expanded at intervals. Where bacteria control is the aim we are able to treat liquids such as orange juice so that shelf life is extended without using heat, (pasteurisation) saving energy and maintaining the taste of the juice.

We are designing a large unit to re-circulate hydroponic liquid, (nutrient rich water) at a rate of 15 tonnes per hour at a new test facility for vertical farming. (Crops grown under LED lighting alone in a sterile room) The remit is to control bacteria in very cloudy liquids (~10% transmittance), to have low maintenance and include electronic monitoring of fluids, UV and flows. This system, when it moves to commercial size will need 150 tonnes of water processing per hour.

We have reached the stage where we are confident that the technology works. It is reliable and requires very little cleaning and maintenance. We do however need to take the design, which uses standard parts, and fine tune it for ease of production and maximise the lamp power by purchasing bespoke items. We can improve on UV transfer so that the rate of fluid treated can increase. i.e. The work of two units may be done by one if reflectance and lamp power/position can be altered. In this endeavour we would need some expert advice from perhaps a partner company. The loss of PERA one third through the project has impacted on this aspect of design. The small redesign to meet food standards has been carried out by Campden BRI.
Established waste improvement methods have high capital costs and require technical staff to monitor it daily. They use bacteria based systems plus high energy consuming filtration. Manufacturers, especially in the food industries, cannot expand because water companies have set a ceiling on water consumption.
The pressure to re-use water is therefore high but companies face an expensive capital outlay and the recruitment of qualified staff to run current plant options. This is the market that we believe would benefit from the catalytic rather than bacterial decay of organic material. The catalyst route is more reliable, requires less supervision and has a lower requirement for heavy civil construction. The iPURXL design is based on modules and we have developed a pre-filter which removes solids which may be recovered as a sludge.
The scalability means we can operate in individual parts of the manufacturing process so that process water, (especially rinse water), use is greatly reduced. Often it is better to deal with six individual sources rather than the cumulative flow! The benefits are also seen in cleaner working environments for the workforce giving less chance of bacterial infections.