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Uithoorn: clean-up chemical sludge

Uithoorn: clean-up chemical sludge

A chemical factory in Uithoorn shut down. The water treatment plant was full of sludge and the factory wanted to clean this up properly. However, everything had to be dewatered before it could be disposed of. Not only the sludge in the water treatment plant, but also the sludge present in several storage tanks, the drainage channel (work that we perform with a dredger and a unmanned dredger) and a detention and settling reservoir. Dewatering: automated and remotely Promeco was contacted for the processing of the sludge. In mid-May of 2014, we started equipping and levelling the site. We installed leak provisions and rolled out our Geotubes, with water tanks as containment provisions. We installed pipes and a mixing system so that the dewatering process could begin: as always, fully automated. The container, that we can control remotely, will remain in Uithoorn until the end of June. Upon completion of our work, the processed sludge will be disposed of by an approved processor. Ton Broeders from Promeco: “Promeco also performs dewatering of sludge from chemical factories. It’s nice that this job was entrusted to us.” Client: the chemical...

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Groningen: clean-up excavation pit

Groningen: clean-up excavation pit

At the foot of the Martini tower, the municipality of Groningen commissioned the construction of the Groninger Forum. Contractor Van der Wiel Infra & Milieu was requested to construct the excavation pit. Before you can pour the underwater concrete, the layer of sludge has to be removed from the excavation pit. Promeco conditioned the sludge that was pumped up for this contractor in such a way that it was quickly dewatered. This enabled it to be transported as quickly as possible through the city centre of Groningen. Client very pleased with sludge processing Ferry Staamer (Van der Wiel Infra & Milieu) looks back on the collaboration with great satisfaction. “It was a great project, all of us collaborated optimally. The product that Promeco rents out, the container and the care for the process, were excellent. Ton Broeders has a lot of experience and I have a great deal of respect for the advanced system that he developed. The container was at our location for twelve weeks. Ton only had to visit us once, during the assembly. He coordinated the process remotely, by telephone and using the telemetry system. This is unique, and quite unlike anything that I had ever seen before. His flocculant monitor is 80% fully automated, you hardly have to do anything. It operates efficiently, requires minimal time and effort, and is thus an excellent investment. I think that I spent one hour per day keeping the container operational. Of course, you have contact more often in the beginning, but this is no longer necessary when you can see that everything is working out fine. Especially, after you have become acquainted with the finer points: assessing the flocculation process. Moreover, he was always available for the supervision, from 06:00 to 23:00, six days a week.” Half a metre of visibility at a depth of 14 metres Staamer is full of praise about the process, and the end result clearly won him over. “We have succeeded in making the water clean enough to attain visibility of 40 cm at up to fourteen metres from the bottom. When you have almost half a metre of visibility at that depth, then you know that you have been successful. Virtually all of the sludge was removed from the...

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Brussels: 8000 m³ foundation piles

Brussels: 8000 m³ foundation piles

Contractor Sodraep started a project in Brussels and used lorries to dispose of the sludge, i.e. the sludge was transported with water. At the time, the contractor did not consider this to be a good idea, and therefore instructed a supplier to look for a suitable flocculant so that the sludge could be effectively dewatered before it was transported. The contractor subsequently purchased Geotubes® and wanted to receive advice about the best approach. Pooling ideas about sludge processing Ton Broeders from Promeco visited the site, assessed the situation and contributed ideas to the design of a flowchart. He compiled a mass flow balance. This enabled Ton to select the correct pumps and the correct sizes for the pipes. The project In Brussels, tens of concrete piles were drilled into the ground down to a maximum depth of thirty metres using an ingenious system. The piles are one metre in diameter. A continuous layer of concrete is located on top of this, but still eight metres below ground level. All of the soil and sludge that had to be removed amounted to approximately 8,000 cubic metres. After it was above ground level, all of the sludge had to be dewatered in order transport it through Brussels; Promeco was deployed for this project. The sludge flow was conditioned by Ton Broeders from Promeco in such a way that it was quickly dewatered in the...

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Middelburg: Boskalis and Promeco

Middelburg: Boskalis and Promeco

Dredging company Boskalis opts for sludge processing by Promeco. At the end of January 2015, by order of the Department of Waterways and Public Works (‘Rijkswaterstaat’), work was commenced on the clean-up of the Canal through Walcheren, at the entrance to the harbour in Middelburg. At this location, Boskalis removed sludge contaminated with copper (originating from the former Vitrite factory). This work got even more complex when, in 2014, unexploded ordnance from the Second World War was found at the site. For this, Boskalis constructed a special unit with which the sludge is excavated under water and also deposited in an underwater container. This container moved under a pontoon and then lifted upwards in an armoured space. The sludge was then sifted and transported to a location outside built-up areas. The sifted material was checked with cameras for the presence of unexploded ordnance. Any ordnance found was handed over to the Explosive Ordnance Disposal Unit. Settling with the help of flocculant The sludge was transported with the addition of a great deal of water. Ton Broeders from Promeco: “This water must then be removed. This takes partly place as a result of natural settling in large barges and partly due to settling using flocculant in the polishing stage before discharge into the surface water. Boskalis selected Promeco for the sludge processing.” New installation developed by Promeco For the polishing, Promeco used optimised flocculant dosing including the use of in-line dry solids measurements, based on ultrasonic sound. The measuring instrument for this project was imported from Canada because the microwave technique that is usually used is less suitable for salt water. The installation and software from Promeco can detect a rapid change in dosage requirement. Unique in the world! Naturally, the discharged water meets the requirements of the competent authorities. Remote measuring As always, we can control the installation remotely with the help of telemetry. The operators can monitor all of the relevant parameters on their smart phones, at any time of the day. The water quality will eventually be improved, and the eco-system in the entire Canal will benefit from...

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Leiden: settling of sludge in ship

Leiden: settling of sludge in ship

Contractor De Heer Land en Water removed sludge from ponds and ditches in a park in Leiden. They used long pressure pipes to pump the sludge into a ship; this ship could then be used to transport the sludge to its final destination. However, the sludge first had to be dewatered… Ton Broeders from Promeco was deployed and is pleased with the outcome. “This was a nice project with a short preparation time. We were able to quickly help the client.” Allowing the sludge to optimally settle Since a great deal of water is required for the pipe transport, there was a risk of the ship filling up full with thin slurry within a few hours. Solution: using the correct method of dewatering, so that only stabilised sludge remains before it is transported. Promeco was engaged to optimally dose flocculant into the dredging pipe so that the sludge quickly settled in the ship. What is the cleverest way of going about this? By not only measuring the flow rate, but also the dry solids passing through the pipe. Ton Broeders: “Most of the transport water could be returned as clear water to the receiving water. Here, we dewatered as much as 450 cubic metres per hour: a considerable flow rate.” Discharge box By dosing flocculant into the pipe, sludge flocks are produced. However, you have to be careful: a flock may not be allowed to transform into several particles since this will cause the sludge to settle more slowly. The objective is to absorb the turbulence so that you slow down the sludge flow. We developed a discharge box especially for this project, which we used to absorb the fall energy of the...

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IJmuiden: removing layer of lime

IJmuiden: removing layer of lime

Tata Steel in IJmuiden used water to cool steel slag. Lime was dissolved in this water. Due to CO2 in the air, this precipitates into the cooling-water reservoir. Result: a substantial layer of lime at the bottom of the cooling-water reservoir. This is not desirable when using cooling water. Promeco was contacted in order to remove the layer of lime in a sustainable manner and to return clear water to the reservoir. Pumping up the layer of lime Engineering and consultancy firm Antea Group has conceived restrictive measures in order to minimise this problem in the future. For the time being, the layer of lime still has to be properly removed. For this purpose, the consultancy firm contacted Promeco. We were allowed to pump up the layer of lime (without damaging the underlying gravel layer and watertight construction) and collect it in Geotubes by means of flocculation. Unmanned dredger Result: we have collected solidified lime in Geotubes and returned clear water in the settling reservoir. The soil sealing of the reservoir has been left intact. We deployed the dredging company Pruim Baggertechnieken for the accurate dredging of this layer of lime, i.e. without damaging the soil sealing. This company is specialised in small-scale precision dredging projects. Special note: the work was performed using an unmanned dredger. Remote- controlled: Geert Pruim had everything firmly under...

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Leiden: flocculating drilling fluid

Leiden: flocculating drilling fluid

Bauer Funderingstechniek BV provided foundations for a round multi-storey car park on the Lammermarkt in Leiden. These foundations consisted of twenty-metre long, piles manufactured on-site under the fourteen-metre deep base of the excavation pit. When manufacturing these foundation piles, drilling fluid was released that was collected by Bauer and pumped into settling containers. This allowed the solids from the drilling fluid to settle. Promeco was contacted in order to speed up the settling process. We conducted research and with the help of flocculant we were able to successfully do the job. Small quantity of flocculant Note: it usually concerns larger quantities of flocculant for optimal dosing; in this case, it concerned extremely small quantities. The objective was to have as little flocculant as possible in the excavation pit. Research proved we could perform the work optimally using a small quantity. And this was indeed the case! We provided clear recycled water in the excavation...

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Oss: excavation pit dock

Oss: excavation pit dock

The shipyard Heesen Yachts in Oss has started constructing a large new dock, so that it will soon be able to build yachts with a maximum length of 80 metres. The large excavating company Martens en Van Oord was requested to excavate the soil for the excavation pit. A part of this soil was removed by using a dredging pump on a hydraulic excavator. A great deal of water is required for transporting the predominantly sandy material. This transport water had to be recycled and returned to the excavation pit. The sand immediately settles in the settling containers. By agitating, the fine material would be released so that it is returned to the excavation pit. However, this is undesirable because this would produce a layer of sludge that would make it impossible to pour concrete. Optimal dosing of flocculant Promeco was requested to add flocculant by means of optimal measuring and dosing, ensuring that the sludge in the containers could also be collected. Unique: we have measured the dry solids content of the fine material that was released during the transition from one container to the other. With this data, together with the flow rate, the flocculant dosing was optimised, allowing clear water to flow back into the excavation pit. Watch the film below! We monitored the work with our remotely controllable Polymer Preparation and Dosing Installation. Video clear water in Oss: Click on the illustration below for a video: clear water routed back to the excavation pit. It is downloaded as .mov-file and is 1.4 MB. Foto’s van ons werk in...

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Veere: advice – implementation

Veere: advice – implementation

During the Second World War, a dyke in Veere was intentionally bombed by the allies: part the land had to be flooded. Many years of high- and low tides have created tidal channels: now known as the ‘Veerse Kreek’, with its tributaries. The area has several wells that are up to 14 metres deep. Wells that contain salt-water and dead water at the bottom, and fresh water and the environment at the top. Thinking, arranging, doing Ton Broeders: “The tributaries contained a large amount of dredge spoil. The whole area had to be improved for recreational purposes. We had to dispose of most of the sludge in the deep wells. This had to take place very carefully, because if too much of the salt-water came up the well, this would affect the aquatic environment in the fresh water layer. After conducting practical test, we went to work. Dosing sludge, optimising, taking measurements from a boat. Closely monitoring the processes and acting as an adviser for the management. Of course, we performed the flocculant dosing and ultimately filled the wells. We were very pleased when we received compliments afterwards. For us, this was ‘think-arrange-do’ at its best.”...

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Storage area embankments

Storage area embankments

The ‘Kruisven’ in Nederweert is located in a peat bog area. There were two types of sludge that had to be processed separately: because one was more polluted than the other. An open storage area, enclosed by Geotubes® Ton Broeders: “The type with the best quality was dewatered in Geotubes®. All of these Geotubes® were used to create embankments, in a rectangular shape. The other type of sludge was sprayed into the area between the embankments, whilst adding flocculant. An open storage area, enclosed by Geotubes®, was thus created. A discharge gate was constructed in one of the corners so that the clear return water could be routed back to the original pond. Result: the pond was clean again and the sludge was separated into two parts, stored and dewatered. Promeco performed the water bed survey, drew up the plans, the specifications and drawings and provided the project management, daily supervision and environmental support. In addition, we have used our automated Polymer Production and Dosage System (PPDS) (‘Polymeer Aanmaak en Doseer Installatie (PADI)’) to provide the optimal dosage of flocculant.” Client: ‘Bosgroep’, a management company for nature reserves  ...

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