Prodromos H. Koukoulakis

Current status in wastewater treatment, reuse and research in some mediterranean countries

AbstractThe status of treated wastewater reuse as experienced in some Mediterranean Basin countries such as Greece, Israel, Italy and Cyprus is examined. General background information is given for each of these Mediterranean countries, including natural water resources, climatic conditions (temperature, rainfall), generated wastewater, crops cultivated and irrigated with effluent, and related aspects of reuse. The examined parameters include treatment strategies, wastewater reuse standards applied in each country, effluent reuse research in progress in the above target countries related to the treatment technologies, water quality, regulations, economics, public acceptance, risk assessment, benefits, keys for potential success and main constraints. Emphasis has been given to the benefits of treated wastewater reuse in integrated water resources management systems and its role for water cycle management, solving water scarcity issues mainly in arid and semi-arid regions of the Mediterranean basin. The exp...

Soil pollution under the effect of treated municipal wastewater

Soil heavy metal pollution due to wastewater reuse was assessed by means of the concentration factor (CF) and/or pollution load index (PLI).In this respect, a greenhouse pot experiment was conducted, using a completely randomized block design, including five treatments of treated municipal wastewater (0%, 25%, 50%, 75%, and 100%), in four replications. Brassica oleracea var. Capitata was used as a test crop. The optimum CFs were expressed as a function of maximum dry matter of cabbage plant parts yield, and the values obtained per plant part were as follows: stems—Zn-CF 2.96, Co-CF 0.85, Ni-CF 0.92; whole plant—Cu-CF 3.90, Ni-CF 0.87, and Pb-CF 11.52; and leaves—Pb-CF 11.78. The PLI was calculated as the geometric mean of the CF of each metal, and was related to the maximum dry mater yield of cabbage stems and heads. The optimum values found were: stems PLI 1.99–2.55 and heads 2.25.

Distribution of elemental interactions in Brussels sprouts plants, under the Treated Municipal Wastewater

Abstract The distribution of the macro, micronutrients and heavy metal interactions in the various plant parts (roots, leaf, and sprout) of Brassica oleracea var. gemmifera (Brussels sprouts), was investigated in a greenhouse experiment of randomized block design, in Agrinion, Greece. The statistical design included two variables: (i) Treated Municipal Wastewater (TMWW), and (ii) fresh irrigation well water (control). The analytical data of plant and soil samples collected were processed statistically by means of regression analysis, ANOVA and t-test, using an SPSS package. The ultimate goal of the experiment was to establish a scientific basis for the safe re-use of TMWW in the irrigation of Brussels sprouts, and possibly of all vegetables, with least accumulation of heavy metals in the sprouts.

Heavy metal accumulation in Brussels sprouts after irrigation with treated municipal waste water

Abstract This study aims at investigating the effects of the treated municipal wastewater (TMWW) on the essential and heavy metal interactions, and on the accumulation of these metals in the sprouts (edible plant part) of Brassica oleracea var gemmifera (Brussels sprouts). The statistical design included two variables: (a) TMWW, and (b) fresh irrigation water (control), in six replications, with a total of 12 experimental plots of 2.5×1.8 m = 4.5 m2 size. The following were found: a large number of interactions were identified in the sprouts (182), but only 74 of them were statistically significant. Also among them, the following interactions, i.e., Mn×N, Mn×Fe, Fe×Mn, Fe×N, N×Zn occurred not only in the sprouts, but according to our previous work, in the heads of Brassica olevacea var. Italica (Brocolli) as well, suggesting a consistency of occurrence of these interactions. However, the comparative effect of TMWW, on the interactions studied, in very few cases was found to be statistically significant, in comparison to that of the control. The elements N, P, Zn, Co, Ni and Cd accumulated mainly in the sprouts, while K, Ca, Mn, and B were concentrated in the leaves, the differences in the accumulation between the respective effects of TMWW and control, being statistically non-significant.

Contribution of elemental interactions in total essential nutrient and heavy metal content in cabbage under treated wastewater irrigation

Abstract A greenhouse experiment was conducted in Agrinion, Greece, using a randomized block design, testing five levels of treated municipal wastewater (TMWW), i.e., 0%, 25%, 50%, 75%, and 100% of irrigation water, in four replications. The vegetable Brassica oleracea var. capitata (cabbage) was used as a test plant. The purpose of the experiment was to investigate the effect of different TMWW levels on the contribution of elemental interactions in total macroelement, microelement, and heavy metal content of different cabbage plant parts (roots, leaves, stems, and heads), with emphasis on the edible parts (heads). From the 362 statistically significant interactions, 70.72% were synergistic, 16.85% antagonistic, 8.01% synergistic–antagonistic, and 4.42% antagonistic–synergistic. The highest mean contribution of elemental interactions regarding total macroelements in cabbage heads was observed for potassium (K), calcium (Ca), and magnesium (Mg) with 1256.2, 1022.6, and 155.98 mg/100 g head dry matter (dm), respectively, whereas the lowest was found for heavy metals i.e., lead (Pb), nickel (Ni), chromium (Cr), and cobalt (Co) with 0.642, 0.143, 0.0112, and 0.0046 mg/100 g head dm, respectively. The toxic cadmium (Cd) did not contribute to heads in statistically significant levels.

Proposed Indices for Assessing Soil Pollution Under the Application of Sludge

The assessment of soil pollution with heavy metals has been studied, based on experimental soil and plant analytical heavy metal data obtained by a pot experiment conducted during 2010–2011 in a green house. A completely randomized block design was used, including the following sludge treatments (in tons per hectare): 0, 6, 12, 18, 24, 30, and (30+treated wastewater) in four replications. Lettuce (Lactuca sativa L.) var. longifolia was used as a test plant. Three indices were proposed, i.e., (1) elemental pollution index, (2) heavy metal load, and (3) total concentration factor. They were found to be linearly and statistically significantly related to the pollution load index, which was used as a reference index, and curvilinearly related to lettuce dry matter yield. It was concluded that the above indices could be used for the assessment of soil pollution level.

Elemental antagonism in vegetables under treated municipal wastewater

Abstract We investigated the occurrence of the antagonistic interactions between essential elements and heavy metals, in various plant parts (roots, leaves, sprouts and heads), under treated municipal wastewater reuse (TMWW) in Brussels sprouts, and broccoli, and their effect on the elemental composition of plants. The statistical design included two treatments, i.e. (a) TMWW and (b) ordinary natural irrigation water (control), in six replications. Most of the concomitant antagonistic interactions under both TMWW and control occurred in the roots and leaves of Brussels sprouts (23), while in broccoli leaves only 15 such interactions took place under TMWW and control, none of them having occurred in the roots. On the other hand, in the heads of broccoli, only eight interactions were found under the TMWW, in comparison to only three in controls. Also, in Brussels sprouts three concomitant interactions occurred under TMWW in the sprouts, and none in controls.

Interrelationships of pollution load index, transfer factor, and concentration factor under the effect of sludge.

A greenhouse experiment was conducted during 2010–2011. A complete randomized blocks design was used including seven treatment levels of sludge(tons per hectare), i.e., 0, 6, 12, 18, 24, 30, and “30+ treated wastewater”, in four replications. Lettuce (Lactuca sativa L var longifolia) was chosen as a test plant. The purpose of the experiment was to study the relationships between soil Pollution Load Index, heavy metal transfer factor, and concentration factor and to determine optimum concentration factor values. The following were found: several mathematical relationships were established between the above parameters that could be used for the study of heavy metal accumulation in soils and plants under the effect of the applied sludge. They can be also used for the calculation of one of the above parameters as a function of the others. Based on the experimental data, the optimum concentration factor for several heavy metals were determined by multiple linear regression analysis, expressing the concentration factor as a function of the maximum dry lettuce matter yield, and of optimum/minimum heavy metal content of plant dry matter. The mean value of the calculated concentration factor obtained for each separate metal was: Zn, 2.93; Cd, 0.39; Co, 1.47; and Ni, 0.52.

Interactions between leaf macronutrients, micronutrients and soil properties in pistachio (Pistacia vera L.) orchards

Abstract - The interactions between: (i) leaf dry matter macronutrietns, micronutrients and soil chemical properties, (ii) leaf macro- and micronutrients, (iii) soil macro- and micronutrients and (iv) soil chemical properties, and soil micro- and macronutrients in 50 pistachio orchards were investigated in leaves and soils by means of regression analysis. Most of the soils were deficient in plant-available P, Zn, Mn, Fe, and B, while they were excessively supplied with Cu. Leaf analysis showed that most of the trees were sufficient in K, Mg, Mn and B, but deficient in N, P and Fe, and excessive in Zn and Cu. It was found that almost all the significant elemental interactions occurring in pistachio leaves or soils were synergistic, contributing considerable quantities of available nutrients and, therefore, improving the nutrient status of pistachio trees, and the level of soil fertility. On the other hand, the interactions between K and Mg in leaves, and between soil pH and leaf N or soil Fe, Mn and B, were antagonistic. It is suggested that these results must be taken into account during fertilization of pistachio trees, in order to avoid nutritional disorders and to promote plant growth, productivity and nut quality.

Critical ranges of pollution indices: a tool for predicting soil metal pollution under long-term wastewater reuse

ABSTRACT A greenhouse experiment was conducted in pots, for two years (2015–2016), in Amaliada, Greece, using a randomized block design, including six treatments with mixtures composed of Zn, Mn, Cd, Co, Cu, Cr, Ni, and Pb, each metal taking part in the mixture at concentrations of 0, 10, 20, 30 40, and 50 mg/kg soil in four replicates each. Beta vulgaris (beet) was used as a test plant. The aim of the experiment was to calibrate the following pollution indices: “pollution load index,” “elemental pollution index,” “heavy metal load,” and “total concentration factor,” in order to determine the level of soil pollution under variable levels (low to very high) of metal mixtures. The irrigation of the plants was conducted with treated municipal wastewater based on field capacity and percent wilting point. The above pollution indices were classified into four soil pollution classes, i.e., “optimum,” “low,” “high” and “very high” on the basis of percent dry matter plant losses.