Excellent engineering: from manure to drinking water
Piet van Riemsdijk (58) has been running in the fields of engineering and construction for many years. Trained as a mechanical engineer, he went to work as a piping engineer at an engineering firm in Rotterdam after graduation. Soon he was sent into the field and met many masters there. He has now been working as a self-employed person for thirty years and recently completed a wonderful green project as construction manager: a manure processing plant at Twence in Zenderen.
Pete still enjoys his work, which feels more like a hobby. Even during his first job, he often traded his desk for the field. Colleagues from other disciplines sometimes asked him to do some work in the areas of E&I, civil, concrete work or reinforcement. “Such a discipline engineer then said: I’ll show you how to inspect this, so you can do it yourself in the future. It was actually like that with all the work I did. Then suddenly I was checking rebar to be able to release it for concrete pouring. I am very grateful to the many people who passed on their knowledge to me. That’s how I developed into an overall construction manager.”
Reducing manure surplus
Pete did assignments at Tata Steel through BuildingCareers (formerly SAB Detachment) for many years, making various modifications to a hundred-year-old plant. He has also done a number of greenfield projects, including building a trio of waste treatment plants, a biomass plant and a trio of oil terminals. So with that experience, he was the right person to build a manure processing plant for Twence. With the goal: to reduce the manure surplus in the Netherlands by 250,000 tons of manure per year and to sustainably convert it into green energy and reusable biological raw materials.
Out of nowhere, after almost two years, stands a complete factory that contributes to a better environment, then you feel quite a bit of pride
How do you ferment 250,000 tons of manure?
Manure contains, in addition to energy, the minerals: nitrogen, phosphate and potassium. Local farmers deliver the agreed amount of manure by trucks. That is pumped into the digester, where bacteria convert the organic matter into gaseous methane and CO2. This biogas is upgraded to natural gas quality with an engineering plant. This green gas is delivered to the public natural gas grid, providing energy to 3,000 households per year. The distilled constituents (or fraction) remaining in the digester is further processed into a thin and thick fraction. The thin fraction is further processed in this plant. This can be used to make various fertilizer substitutes for agriculture and raw materials for industry. The thick fraction is used as a phosphate fertilizer in areas where phosphate is in short supply. The process is 100% circular farming. “These kinds of greenfield projects are what I like best to work on as a construction manager. Coming from nowhere, after almost two years, there is a complete plant that contributes to a better environment, then you feel quite a bit of pride.”
Plan of action
A project of this size requires good organization and always consists of three phases: design, construction and commissioning. In addition, you deal with many different disciplines. For example, there is an overall project manager, a contractor project manager, a civil project manager, a mechanical engineer, safety expert, assembly coordinators, etc.. Really a project organization, both with the contractor and the client. “On the first day of a project, I meet everyone, study the general contractor’s plan of action and look at the schedule. From that, I can quickly tell if the contractor understands. If I foresee problems based on this, I write a management of change. In it I describe the possible problems, make a proposal for a new approach and after joint approval we proceed in the new way. I have weekly meetings about the progress, safety and planning with those responsible. This allows us to make immediate adjustments at all levels should unforeseen circumstances arise. Good communication and planning are really essential to keep the team running like a well-oiled machine. On this project, everything went very smoothly.”
Career tips for young engineers
“If I want to give something to young engineers it’s: work on your people skills, that’s going to help you in everything. In addition, deliver quality, but also be honest when you make a mistake. The latter is of course, not nice but something like that always comes out anyway. Then it’s better to say it right away and limit any damage. People appreciate that.”