Farmers in Bengaluru’s periphery and neighbouring districts, for the past few decades, have been growing non-edible flowering plants using wastewater. The farms, located in the city’s western parts on the way to neighbouring Ramnagara, come from apartments located nearby. The farmers use wastewater to grow marigolds, which are then sold in markets in Bengaluru.
Bengaluru-based water conservation scientist Sreekanth Vishwanath said that the farmers have been engaging in wastewater farming for three decades now. Elaborating on the process, he said, “The water is not treated; it is directly irrigated in the lands. We are working with farmers to grow non-edible crops as a pre-emptive measure, so that the wastewater does not percolate into the groundwater and thereby polluting it. These non-edible crops, in this case marigolds, are used to make garlands and for decorative purposes.”
Vishwanath told TNM that this method saves money for the farmers, as they use readily available water. He added that this use also helps in partially preserving the quality of groundwater (often the only source of drinking water in rural areas), as the pollutants in the wastewater do not directly permeate the groundwater.
According to experts, the wastewater cannot be used if it contains industrial pollutants. The farmers, however, have devised their own method to examine whether the water is usable or not, said Vishwanath. “They detect the usability of the water through a visual guide like a change of colour owing to industrial pollutants. Upon noting any difference, the farmers neither store it nor pump the water into the fields,” he said.
The farmers have been using this method to grow other crops like mulberries as well, which are fed to silkworms.
Ram Prasad, co-founder of the citizens’ group Friends of Lakes, who works in this field said that wastewater is collected in a 2-feet-deep artificial pond, and stored there for 24-48 hours before it is used in the farms.
“The water is stored in these ponds before usage to kill any pathogens. The water is penetrated using natural resources like sunlight to eradicate any pathogens which is why the bunds are not deeper than two feet. It then becomes useful to irrigate into the farms and use for agricultural purposes,” he said.
Ram Prasad said that it is pivotal for the farmers to ascertain where the wastewater is coming from, and also mentioned that they must be careful so as to not come into direct contact with it, as it could pose a health hazard.