Elevation: The elevation of the water source and the treatment plant determines the amount of energy required to transport the water and the type of pumping system needed. The location of the plant should be chosen based on the availability of a reliable water source and the elevation of the source relative to the plant.
Slope: The slope of the land can affect the flow of water and the design of the treatment processes. For example, if the water source is on a steep slope, sedimentation basins may be required to remove large particles before treatment.
Drainage: The drainage patterns of the surrounding land can affect the potential for flooding and the management of stormwater runoff. The design of the plant should take into account the drainage patterns of the surrounding area to ensure that the plant is not vulnerable to flooding or contamination.
Soil type: The type of soil on which the plant is built can affect the stability of the plant and the effectiveness of treatment processes. For example, clay soils may be more prone to settling, which can affect the operation of sedimentation basins.
Land use: The surrounding land use can affect the potential for contamination of the water source. The design of the plant should take into account the potential sources of contamination and incorporate measures to protect the water source.
To determine the capacity of the plant, the following factors are typically considered:
Demand: The demand for water in the surrounding area will determine the size of the plant required. The plant should be designed to meet the peak demand for water, which can be estimated based on population growth projections and historical water usage data.
Water quality: The quality of the water source will affect the treatment processes required and the capacity of the plant. Water with high levels of contaminants or sediment may require additional treatment processes, which can reduce the capacity of the plant.
Treatment processes: The type and number of treatment processes required will affect the capacity of the plant. For example, adding additional treatment processes to remove specific contaminants may require additional space and equipment, which can reduce the capacity of the plant.
Future expansion: The design of the plant should take into account the potential for future expansion to ensure that the plant can meet the future demand for water.
Please clarify what you mean with "topography" in the design of a water treatment plant WTP. Strictly geographically the topography will be determined by the access (location, elevation, ...) to the raw water source(s) as well as by the location of the main water users (city, village, ...).
If, however, you mean the sequence of the water treatment steps and sizing of the process equipment, then this will be determined by the kind and characteristics of the raw water source(s) and by the required water quality at the point of use.
Already mentioned above are nice points. of course the plant need a consideration regarding the topography. While constructing a treatment plant we need to be curious of place where we are laying the scheme. mostly this type of schemes need flat area to protect the plant from wind and excessive erosion toward the treatment plant.
Major factors to be considered are: (1) type of the water source, (2) desired finished water quality, (3) skill of facility operators, and (4) the relative size of available funds.
Uncertainties related to the type of industries and manufacturing processes.
Differences in calculated parameters and actual wastewater parameters.
The total amount of biological oxygen demand (BOD) to degrade organic impurities.
When designing a water treatment plant, topography is an important factor that needs to be considered. Some of the factors that need to be considered are:
Elevation: The plant must be located at a higher elevation than the surrounding area to ensure that the water flows by gravity. The elevation of the raw water source, as well as the elevation of the distribution system, should also be taken into account.
Soil conditions: The plant should be constructed on a stable foundation, and the soil should be able to support the weight of the structures and equipment.
Accessibility: The site should be easily accessible to ensure that materials, equipment, and personnel can reach the plant without difficulty.
Drainage: The site should have proper drainage to prevent flooding and ensure that water is properly discharged from the plant.
Proximity to customers: The plant should be located near the area where the water is to be distributed to reduce transmission losses and improve efficiency.
To determine the capacity of the water treatment plant, the following factors need to be considered:
Water demand: The amount of water needed to meet the demand of the population or industry being served should be determined.
Raw water quality: The quality of the raw water source should be analyzed to determine the type and amount of treatment needed.
Treatment process: The type of treatment process used and its efficiency in removing contaminants should be considered.
Distribution system: The capacity of the distribution system should be considered, as well as the length and diameter of the pipes used.
Future growth: The potential for future growth in the population or industry being served should be considered to ensure that the plant can meet future demands.
Once these factors have been considered, the capacity of the water treatment plant can be calculated based on the water demand and treatment process.
I must remind that Bangladesh and there in India the water solution not been worked on, it's causing suffering to vast majority of people, damaging to worsen the environment.