**5. Regression analysis**

The validation of results from physical and simulation models is further strengthened using linear regression analysis for soil media.

### **5.1 Prediction analysis of pollutant removal using COMSOL multiphysics**

Prediction analysis is carried out using COMSOL Multiphysics in order to determine the pollutant travel distance i.e., (zero concentration at the outlet). For the analysis based on the observation from the physical model used, the radius and time of flow were suitably assumed. By varying the radius of the model and on the basis of *Study on the Impact of Artificial Recharge on Treated Domestic Sewage DOI: http://dx.doi.org/10.5772/intechopen.109868*

the time required from inlet to outlet for the analysis, the parameter BOD is considered with the inlet value of 26.66 and 53.33 mg/l. Following are the boundary conditions used for the prediction analysis.

Infiltration pipe: 0.15 m. Permeability: 1.79 × 10−5 cm/s. Discharge: 2.5 lpm. Porosity: 0.3. Materials used = soil media. Density = 1.46 gm/cm3 (**Table 2**)


#### **Table 2.**

*Simulated model output for pollutant removal (BOD).*

From the prediction analysis, it is observed that the pollutant concentration decreases as the radius increases and reaches zero concentration at a certain distance. Hence, for the known quality of recharge water and site condition, it is possible to establish the pollutant travel distance.

#### **6. Conclusion**

Sewage management is a burning issue and there is a need for this should be addressed because of the disposal issue and nuisance most developing and underdeveloped countries face today. Each one of the counties has set up its own standards for disposal and degree of the treatment that needs to be provided based on the organic load in order to prevent environmental degradation. There is a lag in addressing the treated sewage disposal irrespective of the reuse for different purposes and needs. Since India is one of the countries where there is a large amount of fresh water available and the reuse of treated sewage has never been given importance and focus. But today, each continent is facing a drastic climate change and the global temperature is increasing, there is a need for addressing and promotig sustainable practice and conserving water. This will be one of the sustainability goal that can be reached by the United Nations by 2030.
