Wastewater from Olive Oil Mills in Israel and Palestine: Interactions with Soil and Agrochemicals, and Mechanisms of Incorporation into Soil -Finalization of field and process study

点击翻译按钮获取中文摘要

Due to the often practised disposal into the environment, olive mill wastewater (OMW) is a serious environmental problem in Palestine and Israel. It could act as fertilizer for soil if soil hydrophobization and phytotoxicity can be overcome by suitable application strategies. Our objectives are (i) to understand OMW-soil interaction processes and their effects on soil wettability, phytotoxicity and interaction with agrochemicals; (ii) to monitor short-term and long-term effects of OMW application in lab and field studies; (iii) to identify components responsible for changes in soil properties and (iv) to analyse interaction mechanisms of OMW OM with soil in interplay with climatic conditions. In the first two years, we completed the screening study. In field (Gilat and Bait Reema) and lab studies, we have investigated the influence of seasonal conditions of OMW application on soil quality. The field sites are typically representative for modern olive cultivation in South Israel and for traditional Palestinian olive agriculture in the West Bank, respectively. They strongly differ from each other with respect to soil type and texture, cultivation intensity, climate and irrigation.In this proposal, we ask for extension by a third year, in order to be able to finish the field experiments and the lab studies as planned. This will complete the datasets of field and lab experiments in order to draw final conclusions on the processes and mechanisms and to become publishable.The interesting relations between climatic conditions, processes and OMW effects foreshadow the intensive interplay between deversible egradation, reversible sorption and physical immobilization of OMW compounds, and they show how locational differences are reflected in the degree and persistence of the OMW effects. Verification of the findings will be possible with the data from the finalizing sampling events and the completion of lab incubation studies. This requires a final sampling in late summer 2014 and completion of soil analyses of the samples taken in late 2013. Lab experiments require final data and phytotoxicity analysis and, for Gilat, finalization of the set of conditions. Samples from field experiments and laboratory experiments will be investigated for their water repellency (contact angle, water drop penetration time), their phytotoxicity (cress germination tests), their carbon isotopic ratio (delta13C), their linear sorption coefficient towards simazine and diuron and their thermal characteristics including amount of thermolabile and thermostable OM and their calorific value. The resulting process understanding will open a perspective for OMW wastewater reuse in small-scale and family-scale olive oil production businesses in the Mediterranean area and will further help to comprehend the until now not fully unravelled effects of wastewater irrigation on soil water repellency.