Sewage Farming In India
The sewage effluent can also be disposed of by applying it on the land. The percolating water may either Join the Water table or is collected below by a system of underdrains. This method can then be used for irrigating crops. And hence termed as sewage farming, Since it not only disposes the sewage but also helps in increasing crop yields (by 30% or so) as the sewage generally contains a lot of fertilizing minerals and other elements. Fertilizing elements like N, P, K, etc. do help in increasing the yield of cash crops like cotton, sugarcane, plantain, etc. However, crops to be eaten raw or which do not have any skin to be removed before eating should not be grown on sewage farms, although this is seldom practiced by the farmers.
But the sewage effluent must be treated before being used in sewage farming. In order to lay down the limiting standard for sewage effluents and the degree of treatment required, it is necessary to know all the consequences.
Sewage Farming Advantages
- In rural areas, the cost of land is relatively less. At the same time, the rate of water supply is generally less, resulting in concentrated sewage. For such cases, therefore, disposal through the land application may be preferred.
- In disposal bland application, sewage can be applied either raw or after primary treatment while in the disposal by dilution, efficient pretreatment, to meet the effluent quality requirements is must.
- ln hot climates, DO content of natural waters is low and the quantity of water flow is also less, resulting in pollution hazards if a high degree of pre-treatment is not applied to the effluents before discharging them. In such cases, disposal by land application is preferable.
- If the receiving waters are used as a source for water supply at the downstream side, disposal by dilution cannot be adopted unless a high degree of pretreatment is applied to the effluents.
- In disposal by dilution, the recreational use of natural waters will vanish completely.
- Disposal by land application Especially through sewage farming will increase the yield of crops, etc.