background about land application of wastewater and Wastewater Irrigation around the World • typology and Categories of wastewater reuse • current international case study of wastewater reuse strategies in agriculture from developed and developing countries successful and failure and lessons to learn
In the contemporary 21st century, there is still water shortage and quality crisis around the world due to rapid increment in global population, climate change, industrialization, changes in land use, poor wastewater management and poor water utilization practices (UN Water 2). Furthermore, most of the irrigated areas worldwide are experiencing water crisis due to groundwater and surface pollution and other factors which contribute to poor water quality and the large volumes of water that goes to waste. UN Water defines the term agricultural wastewater as the extra water after heavy rainfall or excess water used in homes or industries, but find its way down the flooded areas, basins, border strips, and furrows and later utilized in surface irrigation (3). The other term used to describe wastewater is irrigation tailwater due to its uses in irrigation. The achievement of irrigation efficiency modicum is determined by the level of tail water runoff needed for effective water penetration along the waste water furrows.
The need to conserve large volume of water globally has attracted the concept of wastewater re-use and management. Wastewater reuse for agricultural purposes has gained popularity in most of the agricultural producing nations in the world. Wastewater management stands for an agronomic alternative under investigation and acute adoption in areas with increasing demand for water to cater for increasing urban population and to be used in irrigated lands (Winpenny, Heinz and Koo-Oshima 212). The shortage of water is associated with political, social and economic repercussions, especially in developing countries. It is, thus, important for such nations to consider wastewater management as a portion of the cohesive, ecosystem-based wastewater management scheme where the sustainable development dimensions, political, environmental, economic and social dimensions. It is for that reason that in 2012, the World Water Forum reverberated wastewater management problems in the world and the henceforth consideration of wastewater as the forepart of the global water politics. The proliferation of irrigated land depends on the proper treatment of wastewater considering UNESCO’s 2012 report that quoted World Water Development statement that only 20% of global wastewater passed through proper treatment (UNESCO 8). Treated wastewater has the other key benefits other than serving as an alternative source of irrigation water as they act as good sources of plant nutrients. Wastewater supplies the agricultural soil with organic matter and nutrients such as potassium, phosphorous, and nitrogen.
Typologies and Categories of Wastewater
Typologies and categorization of wastewater vary depending on the properties of raw wastewater such as percentage VM, BOD or suspended solids and concentration. The three elements vary with dietary culture, climate, and wastewater origin and sewerage system type. For example, Latin America has an average BOD of 1 or less and a BOD value of 2 in India and 1.2 in France. In most cases, wastewater re-use typology is categorized under three main categories, namely Gray Water re-uses, effluent water reuse, and industrial wastewater re-use typology (GESAP). The three typologies of wastewater are classified based on the pollution categorization which places the typologies depending on the physical state and biodegradability of wastewater. Physical states of wastewater entail the identification of fractions of soluble and insoluble…