Water
- Kshiti Mishra (Deactivated)
- Gert-Jan Swinkels
Rainwater harvesting:
Rainwater is a renewable and sustainable source of water. Use of stored rainwater reduces the environmental impact of the greenhouse by reducing consumption of treated municipal water supplies and pumping of groundwater, which could be subject to scarcity or regulations. It can also help prevent soil erosion by capturing runoff. However, rainwater availability is dependent on weather patterns, making it an intermittent water source. In regions with irregular rainfall, it may not be sufficient to meet greenhouse water needs year-round.
The collected rainwater is generally free from the salts and minerals often found in groundwater, making it suitable for irrigation without the risk of soil salinity buildup. However, Contaminants like debris, pathogens, and pollutants can be present in rainwater. Proper filtration and treatment are necessary to ensure that collected rainwater is of suitable quality for greenhouse use. Techniques such as Reverse Osmosis (RO) can ensure high-quality water free from contaminants, salts, impurities, and microorganisms and pathogens, reducing the risk of diseases in greenhouse crops.
Additionally, the rainwater storage tanks and distribution systems need to remain clean and free from debris, algae, and bacterial growth.
RO filtration is an energy-intensive process, using energy of the order of 2 kWh/m3 water. This not only gives high operational costs, but also environmental concerns if the energy source is not sustainable. The process also generates concentrated brine waste, which must be managed properly to prevent environmental harm.
Seawater Desalination for Greenhouses:
Regions close to the sea, especially arid regions with freshwater scarcity, could employ desalination of seawater to supply irrigation water for the greenhouse. Greenhouses using desalinated seawater reduce the strain on local freshwater sources and ecosystems, helping to preserve natural water resources. However, desalination processes, including reverse osmosis, are energy-intensive, leading to high operational costs and environmental concerns if the energy sources are not sustainable. The disposal of concentrated brine byproduct from desalination can harm marine ecosystems if not properly managed.