In order to harvest energy from sewage, sludge is treated in the Thermal Hydrolysis Plant (THP) before being loaded into airtight tanks called anaerobic digesters. Steam plays a crucial role in the THP, heating and treating the sludge to the required temperature of around 110°C before being cooled and transferred to the anaerobic digesters where the bacteria breaks the sludge down. This process produces the natural gas; methane as well as a fertiliser by-product. The methane is then either exported into the National Grid as bio-gas or piped into large engines producing heat and electricity which can be used on site or exported to the National Grid. The heat produced is used to keep the digesters at the right temperature. Re-using this heat makes this a very efficient process.
As Project Lead for Thermal Hydrolysis Plants (THP) and steam systems implementation, Chris Kind at Severn Trent is responsible for putting in place the right support structure for the frontline team operating and maintaining the plant.
“Prior to my involvement at Minworth I had never worked with steam systems so it’s fair to say it’s been a steep learning curve” says Chris.
Ensuring that they would be putting in place best practice for managing a steam system, Severn Trent engaged with several other utility companies to find out how they managed similar equipment. “The results highlighted that there is no “one way” to manage a steam system when it comes to the people side of things. We needed a structure and management system for steam, and the training of our team members would not be a simple task. Spirax Sarco and their training facility at the Steam Technology Centre in Cheltenham were put forward to us as the organisation we needed to speak to” comments Chris.
The team at Severn Trent are committed to learning and honing what they do so it is no surprise that they have already embraced the best practice approach to steam system operation. What’s more, they have already made some remarkable energy and cost savings across the site.Chris Coleman, Boiler House and Customer Training Support
Requiring specialist support in operating their newly installed steam system safely and efficiently, Severn Trent turned to the team of trainers at the Steam Technology Centre. A comprehensive training programme consisting of several formal courses and informal onsite support sessions, all of which would lead to an industry recognised accreditation, was agreed and put in place.
The programme began with several onsite introductory taster sessions that were delivered by one of the facility’s boiler house specialist trainers. The team had already undertaken basic Steam Awareness training with their boiler house manufacturer before they then enrolled on more in depth training with Spirax Sarco.
Following this basic Steam Awareness training, the team at Severn Trent who would be responsible for the day to day running of the steam boilers onsite needed to grasp the ins and outs of how they work. Once enrolled onto the City & Guilds Accredited Steam Boiler Plant Fundamentals (Shell Boiler), and securing a 100% pass rate, the team demonstrated the acquired knowledge needed to understand the different types of boilers, their fittings and use but also best practice on safe operation through a written examination.
In addition to the Fundamentals course, the Minworth maintenance team members needed to learn the skills required to give them the competence to complete boiler house routine maintenance activities. To do this they were enrolled onto one of Spirax Sarco’s industry recognised accredited courses, the City & Guilds Accredited Steam Plant Maintenance course which involved a written examination. Here, the team had to demonstrate an understanding of steam system maintenance, good installation practices, maintenance of traps, pressure reducing valves, condensate pumps and other ancillary equipment. Achieving a 100% pass rate, the team continued to hone their skills and knowledge in steam system management and enrolled onto the next stage of their formal training.
The final stage of the formal training consisted of the team working towards achieving their Boiler Operation Accreditation Scheme (BOAS) national accreditation. As an approved training provider of BOAS, the specialist boiler house trainers delivered this at the Steam Technology Centre. The team were required to take three written examinations and an interview with an external assessor. On successful completion, the entire team achieved their Certified Industrial Boiler Operators (Cert IBO) status.
In addition to the formal training courses, Severn Trent had access to a dedicated specialist boiler house trainer from Spirax Sarco who would visit the team onsite every month. During the visits, the boiler house trainer ensured the team of engineers understood what they had learnt during each stage of the training programme and could apply the skills and knowledge to their own site safely and correctly. It also meant the engineers had additional access to best practice and could use these sessions to ask any questions related to the steam system or work with the specialist to find solutions when problem-solving.
Due to the success of the completed training programme carried out at the Minworth site, the programme will be rolled out to other Severn Trent sites across the UK.
Chris adds: “The level of training that has been required for the new THP and steam process has been nothing like Severn Trent has undertaken before, our team members have undergone intense levels of training and have stepped up when we have asked a lot of them. The team has visited the Cheltenham site and said that this training felt “different” and far more professional than what they have seen before, this is what I think opened their eyes to what is required of them on a daily basis and the responsibilities they have under the Pressure Systems Safety Regulations (PSSR).”
Chris Coleman, Boiler House and Customer Training Support concludes: “The Severn Trent plant at Minworth is very impressive. Having worked closely with Chris and the team, it is clear why it is such a success. Wherever a customer demonstrates no prior experience of working with steam we always advocate that training in competent steam system management is essential. Fortunately, the team at Severn Trent are committed to learning and honing what they do so it is no surprise that they have already embraced the best practice approach to steam system operation. What’s more, they have already made some remarkable energy and cost savings across the site.”
Spirax Sarco has launched a new steam and thermal energy audit as part of its service portfolio.
For plant managers, two things in life are certain: manufacturing uses a lot of energy; and that energy costs money. In fact, a survey by The Daily Telegraph and YouGov revealed that 28 per cent of manufacturing companies spend more than £250,000 a year on energy . That’s enough to make anyone’s eyes water.
Efficiency is king - a saying that we should all be aware of in the industry. There’s always a way to save more on water use, especially during the wash-down process. Driving down the overheads that make up such a high percentage of our budgets should also be at the top of everyone’s to-do list.