What is the wastewater and its uses?
Unconventional water is water from sources that have not traditionally been used in agricultural production, especially low-quality water. The two main sources are:
Wastewater after being used for household, municipal and industrial purposes.
Salt water from groundwater, drainage channels, and surface springs.
Among these sources is the spectrum of quality and quantity. The extremum of the water quality spectrum of wastewater is undiluted raw wastewater at the bottom and quaternary treatment at the top. In salt water, the low-quality ends can be seawater and groundwater, which is very brackish with a conductivity of over 25 ds/m, and the top can be water with a conductivity of4 ds/m) and desalination (if available for agricultural production of high-quality plants or if water is scarce and financial means are sufficient).
Wastewater is already a common source of water, as safer (cleaner) water sources are not available in some areas. In other countries, NCW (Non-conventional water) is becoming the main source of water for agriculture as traditional quality water sources are diminished or diverted for other purposes. NCW can be used as is or mixed with other waters to achieve the desired quality and quantity. For untreated but usually diluted wastewater, safety measures should be taken in accordance with WHO,FAO,UNEP guidelines. The goal of increasing the use of NCW is primarily to benefit urban areas and countries where traditional renewable water resources are limited, or demand has already reached or exceeded supply.
Cities and municipalities, for example, produce streams of water that are already used for home use. This stream is waste and must be safely disposed of or reused as a downstream resource. In addition to its value as water, it can also contain nutrients that are useful for agricultural production. However, there can be a discrepancy between production (which can be relatively constant) and demand from agriculture, which depends on the irrigated area and the time of year. Agricultural production near the city is the cheapest application.
The use of this water requires the following considerations:
>Reuse security / policy.
>Current reuse status.
>Governance / Policy / Law / Monitoring and Compliance.
>Long-distance transportation network and pump requirements.
The production of salt-tolerant plants can generate economic value from salt water if the environmental conditions are good. Excess water should be used to prevent salt build-up in the vents, and for sustainability reasons, this excess water should not cause environmental or resource degradation.
Whatever the source of the NCW, it must be an element of a broader water management approach that includes strategies for demand management and supply and conservation. The economics of using NCW compared to other sources and developing implementation strategies, including capacity building, are important because proper management is essential for safe use in agriculture.