Firstly let us understand the process of dewatering
Dewatering is the process of removing ground water or surface water from a construction site, this is done either by pumping or evaporating. This process is done before excavation or laying foundations as it would affect the construction process. This can also be done by removing water from soil by wet classification.
Why is dewatering used in construction sites?
Water accumulating in trenches, excavations and places with inadequate slopes will affect construction process. If water accumulates in a construction site it will lead to soil erosion. This would loosen the soil and weaken the foundation. At most care should be taken when the water is discharged into lakes, wetlands or storm water drains as the grade of soil can reduce in the process of de watering.
In areas containing low permeable soil dewatering is a suitable solution to isolate the permeable layer of soil. Materials such as sheet piles, slurry walls and grout curtains can be used to prevent water from entering the trench or foundation. This process acts as a benchmark to analyse how dewatering affects other areas.
Dewatering must be done perfectly in order to prevent soil erosion on the construction site, most importantly selecting an ideal location to discharge the water is essential. Therefore certain precautions must be followed to ensure safe dewatering process.
Firstly water shouldn’t be directly pumped into slopes, the process must be discontinued in a certain region if the region shows signs of erosion. The channels which are used to transfer the water to other locations must be protected with grass or vegetation which helps the soil remain intact.
Dewatering must not be done under heavy rains as it leads to minimal infiltration and ineffective water discharge. Water contaminated with oil, grease and chemical products must never be discharged directly as it will lead to environmental pollution.
Benefits of Dewatering
Dewatering prevents flooding of the excavated site, it is used to control the water pressure in the side slopes and prevent damage to the slopes due to seepage erosion. It reduces the risk of piping failure as it uplifts the pressure on the floor of excavation. It contributes to effective waste management.
The environmental benefit of getting a new de-watering system will minimise power consumption with the use of modular power packs. These packs are powered by electricity, they comprise of small cylinders containing compressed carbon dioxide. It protects your facility from contamination by removing harmful substances. The water is pumped out using a hydraulic pump which is enclosed in a sealed cabinet. Multiple filters will filter out harmful substances from the expelled water thereby preventing contamination of water bodies such as rivers and lakes. Sludge de-watering is the most effective method, it involves the process of separating sludge into liquid and solid components to minimise waste. This method is more effective than conventional dewatering as it makes the filtration process easier.