By Sebastian Schifris – Corporate Water Quality Manager
Israel purifies and reuses almost 75% of its waste water each year for agriculture and vastly outranks even the second most efficient recycled water user – Spain – which only recycles 12% of its waste water for agriculture.
As such, we at Netafim have accepted the role of ‘responsible adult’ in an effort to share our expertise with a world thirsty for knowledge and guidance.
In my position as Chemical Engineer with the Agricultural Division, I currently have water samples from over 100 countries in my laboratory. My team and I test them and then advise and support farmers on water quality for irrigation through drip systems, as well as on treatment levels, filters, dripper types and flow according to the agricultural needs and perspective.
The technology exists for changing every type of water to any kind of quality required. However, costs can be prohibitive and so we as a global leader need to assist the farmer and grower in providing the most cost effective solution.
Maintenance treatment is the key to using irrigation systems effectively and efficiently. However, methods and processes vary in different parts of the world, as does water quality.
2 examples which come readily to mind are the different methods for irrigating banana crops in different parts of the world.
In Central America, where the banana crop is widely exported to the United States, Europe, Russia and the Far East, irrigation water quality drawn from wells is generally good and irrigation pipes can remain in the field for some considerable time. As a result, Netafim recommends maintaining systems by treatment every few years in order to extend their life.
Although water quality is governmentally controlled and regulated, at an acceptable level for this type of use, pipes must be maintained annually. In Israel, where bananas are grown for the domestic market, the crop is generally irrigated using recycled water.
Here is a comparison of the different parameters in Central America and Israel where banana crops were planted in both regions 8 years ago:
The area in Central America is 10 times greater than in Israel. (30- 300 hectares)
- The water source in Central America is well water and the water source in Israel is waste water, after treatment. .
- 1.6lh in-line compensated drippers, which provide constant flow irrespective of changes in working pressure, are used in both areas.
- In Central America, regular maintenance is unnecessary, but flushing is performed every few years. In Israel, annual on-going maintenance is by flushing, disinfection and oxidation.
- Filtration in Central America is by manual screen filter, and in Israel is automatic disc filter
- In Central America, fertilizer is usually solid and needs to be prepared as a solution prior to application. The material is generally cheap and contains impurities. In Israel, liquid fertilizer with few impurities is used. However, this is also a more expensive solution.
Here we see comparisons of water quality:
|Water quality||Central America||Israel|
Clearly, although the needs are similar, water resources could not be more different and the importance of correct, effective treatment, relevant to the geographical area is obvious.
Treatment costs may vary according to geographical area, plot size, labor costs, energy availability and the materials required. These are just a few of the parameters which must be considered when recommending water treatment. Regulation is constantly being updated and is increasingly demanding for both growers and the water treatment plants in order to ensure the highest possible water quality. An example is BOD (Biological Oxidation Demand) where, in the past it was common to use water with a BOD level of 90 mg/L. Today, the required level is 10 mg/L. This is good news for everyone, There is less contamination leading to less maintenance of the irrigation equipment and ultimately to better quality water. The only down side is possible increased costs for the farmer using this type of water.
In both cases, the projects use the most readily available resource. From an economic perspective, the cost of water in Central America is only the cost of the energy required to pump it from the wells. In Israel, the cost is on a tariff basis for treated water and is fixed and adjusted by the Authorities on a regular basis.
Both solutions must provide a sustainable source of income for the grower, and I see my role as providing continuous advice, support and protection in an ever demanding environment.