River and Lake Bank Filtration System For Water Sustainability

The use of river and lake bank filtration is one of the oldest techniques of achieving water treatment. Water that naturally collects in pools, rivers, lakes, and other reservoirs often attracts all sorts of impurities. The question of how to handle wastewater before released into water bodies has not been solved. Without proper treatment, the consumption of water from such sources can lead to various infections. Human beings discovered centuries ago that by digging either wells or galleries at considerable distances from the water sources, they could draw out clean water.

Water from the lake, river, or reservoir percolates through the soil layers into the reservoir. As the water moves through the soil, it is subjected to multiple treatment processes. These processes have a combined effect of improving the quality of the water. For the water to have desirable qualities, the newly percolated water has to stay in the aquifer for a considerable time. This will not only provide the chance to lose undesirable qualities through natural processes but will also ensure that it gets diluted by water that has already been in storage for a long time. 

The upper layers of the aquifer are responsible for the removal of large particles and suspended matter. However, compounds such as heavy metals are consequently eliminated through adsorption. The soil layers often contain adsorbents that are useful for this purpose. Similarly, organic material undergoes decomposition both in the presence of air and within the soil layers with limited oxygen. The key water cleansing operations in bank filtration include adsorption treatment, ion exchange, and bio-remediation activity.  

As the water is being drawn from the well to facilitate the bank filtration process, the water existing within the aquifer tends to decrease. As a result, this leads to the reduction of the water table that surrounds the source of recharge. This in effect prompts the water within the lake or river to flow into the aquifer, thus, facilitating the occurrence of another cycle of the filtration process. 

To ensure that the water extracted from the system is of the highest quality possible, the extraction should be done at a good distance from the point of recharge. Digging a well too close to the recharge zone means that great quantities of water can be pumped out. However, the main drawback with this method is that the newly percolated water might not have experienced satisfactory treatment. 

The other option is to place wells far from the recharge zones. While this method will provide water of the highest quality, it will have very low recharge rates that might not be sustainable. Hence, the best strategy is to balance the distance between the well and the recharge zones. 

Experts recommend that the distance is chosen such that the incoming water takes between a month or two to reach the well. This is a factor that is dependent on the type of subsurface materials that exist in a given region. 

The use of bank filtration is not only limited to ancient and remote use. In modern times, nations have utilized this technology either on its own or in combination with other conventional treatment strategies. For instance, the Rhine river is one of the well-known sites for this type of water treatment. Various municipalities such as Dusseldorf have benefited from this technology. Furthermore, the United States and many other nations have also employed the use of this method to great levels of success. 

Bank filtration is not only applicable in the treatment of raw water to produce freshwater. One of its key potentials is the remediation of wastewater before being returned to natural water bodies. 

While wastewater from different sources such as sewerage and homes might have undergone preliminary treatment, it may not be safely incorporated into water bodies. This is because they may still contain harmful substances that might affect the water ecosystem. Furthermore, this water often contains several nutrients that might lead to eutrophication, a process in which nutrients in water lead to massive vegetative growths, hence, depriving other sea organisms of the much-needed oxygen. 

In wastewater treatment using bank filtration, alluvium is often used as the choice aquifer material. This is because of its ability to absorb great quantities of organic. Such soils also contain valuable microorganisms that feed onto the unwanted constituents of the water, rendering it safe. 

To achieve wastewater remediation using the method, the effluent wastewater from the treatment facilities is directed to percolation pools. The pools are positioned in areas that are located next to rivers so that the water percolates into either the rivers or lakes.

The effectiveness of the method often improves with time especially as the clogged particles limit the flow rate. However, excessive deposition might limit the flow. 

• Bank filtration is a slow process that needs some amount of time. Thus, setting up a project that might handle large volumes of water is costly. 
• With time, organic material stents clog the inter-spaces between the alluvial soils. While this might initially increase filtration, it can block the flow eventually. However, this can be easily mitigated by natural flooding or manual removal. 
• The major drawback is the lack of sufficient scientific knowledge to enable the exact prediction potential of a bank in its effectiveness in water treatment. 

• The procedure is effective in the treatment of freshwater and in reducing the toxicity of wastewater before its return to water bodies. 
• Bank filtration is useful in its ability to dampen pollution. The procedure is suitable for the elimination of shock loads. For instance, these may include chemical or petroleum spills.
• When used in combination with conventional treatment methods, the procedure greatly reduces the capital costs both in the short and long term.
• The water enjoys great stability. This makes it difficult for reinfection by disease causing microbes.
• A clogged aquifer can be easily mitigated through the action of floods. Furthermore, the microbial components that find their way into the media also help eliminate this action. The action of water such as erosion also improves the action of the system by removing toxic compounds. 

The use of bank filtration is not just applicable on large scale but can also be used by individuals. Community organizations desiring to tap into this potential treatment can facilitate the establishment of wells from which the community can benefit from the withdrawal of clean water. The system’s popularity through the ages is based on its ability to eliminate organic material as well as change taste, color, and smell. The method also succeeds in lessening the number of biological materials. 

Both River and Lake Bank filtration systems are self-sufficient operations that provide holistic ways of handling wastewater and raw water from lakes. Bank filtration ought to be increasingly incorporated into the treatment of municipal water treatment technology to minimize capital, operational expenses, and chemical usage.