Sterilising the waste before it leaves the building

The customer is a spin-out company established from a plant-science research institute, formed as a joint venture involving the institute, an affiliated research council and other research partners. The company produces proteins, metabolites and complex natural products — including pharmaceuticals, vaccines and antigens — using a patented plant-based expression technology developed at the affiliated institute. Rather than relying on yeast, bacterial or animal-cell cultures, the proteins are grown in plant tissue and then extracted from the leaves.

In 2016 the company built a new two-storey, roughly 1,000 m² bioscience R&D facility next to the affiliated institute. Construction ran from June 2016 with the building handed over around the turn of the year and the facility due to be fully operational by the end of March 2017. The build was delivered by the main contractor, with the customer's project manager coordinating the specialist process equipment on behalf of the affiliated institute.

The driver was regulatory. The facility operates as a contained-use site working with Level 1 genetically modified microorganisms (GMMs), alongside bacteriology and microbiology research. The plants themselves are not genetically modified — they are used as bioreactors — but the process solutions and laboratory sink waste the work generates can contain residual viable microbiological material. Under the UK's GMO (Contained Use) regime, that liquid effluent has to be inactivated before it can leave containment via the drain.

In practical terms, all process solutions and laboratory sink waste had to pass through an on-site effluent treatment facility that holds each batch at a minimum of 121°C and 2 barA for 20 minutes, so that nothing can be discharged to the foul sewer unless those time and temperature parameters have been met. The system therefore had to:

• Sterilise batches of effluent reliably and prove, every cycle, that the required conditions had been met before allowing discharge — stopping and alarming if they were not;
• Hold roughly two days' worth of waste water so that production was never gated by the treatment cycle;
• Integrate with the new building's services and the customer's own holding-tank pump; and
• Install outdoors — the treatment plant sits outside the main building — which meant designing for weather and frost protection from the outset.

It also had to be procured the hard way: specified into a live main-contractor building tender rather than sold across a desk. Astell quoted both routes in parallel — directly to the customer and to the main contractor's estimating team — to make sure the system was carried correctly into the build.

Astell designed and built a bespoke EFF350H batch effluent decontamination system — a gravity-fed, single-tank plant that fills, heats the liquid to sterilising temperature, holds it for the set period, then cools it below 60°C before discharge. A 350-litre jacketed sterilisation vessel is paired with a 600-litre holding tank so incoming waste water can be buffered while a batch is processed. The controller is multi-program, so the plant can run whichever temperature-and-time combination the validated process calls for — for example 121°C held for 20 minutes, or a higher temperature such as 135°C held for a correspondingly shorter time. For this facility the in-service cycle was set at a minimum of 121°C for 20 minutes.

To eliminate possible leaks the system is designed with all of the connections above the liquid level in the sterilisation tank, and the pressure vessel's design and working pressure, coupled with a series of risk assessments, means standard pressure relief valves are not necessary — an approach that meets the requirements of pressure system regulations. The system design will not allow release of the tank's contents unless a successful sterilisation cycle has been completed and recorded. If the required parameters are not met the system raises an alarm and stops, with the batch being reprocessed before any discharge.

• 350 L 316L jacketed sterilisation tank (approximately 300 L usable)
• 600 L stainless-steel holding tank — around two days' waste water
• Programmable cycle (for example, 121°C / 20 min, or higher)
• Batch cooled below 60°C before discharge
• Integral 48 kW steam generator
• Gravity-fed, single-tank, direct-steam design
• LOGI touch-screen PLC controller
• Cycle data archive, Ethernet and RS232, printer
• Designed to PED 2014/68 EU, CE 0353
• Sterilisation tank agitation
• 0.2 micron sterilisable vent filter
• Stainless-steel frame and 316L orbitally-welded pipework
• Discharge interlock — no release without a completed cycle
• Failsafe alarms

As the specification was refined in close consultation with the customer, the package grew from a stand-alone tank into a fully integrated, delivered-and-installed plant: a 48 kW steam generator, air compressor, stainless-steel frame and delivery were all folded into a single turnkey package, and an electrical tank-to-tank connection was added so the customer's own holding-tank pump could feed the Astell plant. The final installed footprint, including steam generator and compressor, was approximately 3.2 m × 1.65 m × 2.4 m.

This was a genuinely collaborative project rather than an off-the-shelf supply. Astell's area sales manager and technical director worked through the site's requirements with the customer's project contact, including responding to formal requests for information raised through the main contractor. Because the plant was to sit outdoors, the design specified that the contractor build a ventilated, frost-protected enclosure with removable panels for servicing — a requirement written into the proposal well before delivery.

Astell delivered and positioned the equipment on site, and the contractor built a protective enclosure over the effluent plant. The unit was then piped and wired in, ready for Astell's service team.

Astell's service team returned to complete commissioning of the effluent plant and to train the customer's staff on its operation. Astell supplied user manuals and a Certificate of Conformity with the system, along with supporting ISO 9001 and PED certification for the customer's project file. Astell also provided the plant's full alarm schedule and, at the customer's request, added a green/red status-light indication driven from the plant's existing fault output.

This put the effluent decontamination system into service as the new facility itself came online, marking the transition from project delivery to day-to-day use.

This project was one of many effluent decontamination systems Astell has built, and it demonstrated the company's ability to engineer such a system to a customer's exact containment and site requirements. That capability is one Astell would go on to formalise under AstellBio, its dedicated brand for effluent treatment systems. This project stands as an early, formative example of the bespoke effluent decontamination work that brand was built to deliver — and Astell's designs and processes have continued to develop since.