Wastewater and Sludge Reuse Management in Agriculture

Huge quantities of treated wastewater (TMWW) and biosolids (sludge) are produced every day all over the world, which exert a strong pressure on the environment. An important question that is raised is “what to do with them?”.An effort is put by the scientific community to eliminate the concept of “waste” and to replace it with the concept of “recycling of resources”, by means of effective management, which does  not concern only the users, but all the other groups involved in the problem, such as facility administrators, operations, politicians, scientific community and the general  population. Sludge concentration data showed that there exist 516 chemicals in biosolids which create a serious health risk.   It is pointed out that this risk will be greatly exacerbated by chemical toxins present in the sludge which can predispose skin to infection by pathogens. Consequently, the need for science-based policies are necessary to effectively protect public health. The risk assessment due to sludge, is difficult to evaluate of due to the large number of unknown interactions involved. People living near the sludge application sites may suffer from such abnormalities as:  eye, nose, and throat irritation, gastrointestinal abnormalities, as nausea, vomiting, diarrhea, including cough, difficulty in breathing, sinus congestion, skin infection and sores. Many problems seem to be related to biosolid and wastewater application in agriculture, which should be solved. A universal one, acknowledged as an “international health crisis” is the resistance of pathogens to antibiotics and to the evolution of multidrug resistance of bacteria”. Certain anthropogenically created environments have been identified as major sources of multidrug resistance bacteria such as in water treatment plants, concentrated animal feeding operations etc. All these, and many other health problems, render the safety of sludge and biosolid and wastewater agricultural reuse, for the time being questionable even though the application is done according to official guidelines. It is therefore necessary that more research work be conducted on the short and long term application effects of sludge on human health, and on the environment so as to successfully address these problems Also,the existing guidelines must be reconsidered on the basis of the research findings to be attained. It is only then that the application of these inputs to land could be as safe as possible

An Investigation into the Possibility of Reusing Wastewater and Sludge on Soil Enriched with Humic Acid of Young Growing Seedlings of Cupressus Arizonica Greene

The influence of Humic acids (HA) in combination to Treated Municipal Waste Water (TMWW) and biological sludge (S) reuse was studied, for the characteristics of growth and metal accumulation in the forestal species Cupressus Arizonica Greene and soil characteristics. The experiment was held at the forestal seedbed of Agrinio at an experimental spacing of random groups containing 12 combinations of TMWW, S and HA plus control, in 4 replicates, meaning 12x4. The findings were: The interventions affected statistically significant the micronutrients capacity of Cu, Fe, Zn, and Mn of soil, leaves and roots. Humic acids raised significantly the availability of Cu and Zn micronutrients in the soil, but did not affect their concentrations in leaves and roots. The higher concentration of Cu and Zn in the leaves was found in the absence of humics with the intervention of E1 (control), while in the presence of humics with the intervention of E11 (Control+TMWW+200mg/kg HA). In the roots the higher concentration of Cu and Zn was achieved in the absence of humics with the intervention of E1 (control), while in the presence of humics with the intervention of E2 (Control+200mg/kg HA). Closing, in the soil, the highest concentration of Cu and Zn was observed in the absence of humics with the intervention of E10 (control+S), while in the presence of humics with the intervention of E8 (TMWW+S+200mg/kg HA)

pH and organicmatter impact on the indices of soil metal load assessment under wastewater and biosolid reuse

Backgound: Experimental data were used to study the impact of pH and organic matter on soil pollution indices, with the view to express them as a function of the above two variables. Results: Data were from an experiment performed in a greenhouse using 12 wastewater and sludge treatment combinations in four replications, using Lactuca sative var Longifolia as a test plant. The experimental data were analyzed by means of linear multiple regression analysis, and the equations found were considered as revised forms for the calculation of pollution indices, which could be used as a tool for the assessment of the level of soil pollution by heavy metals. Conclusion: Tentative critical levels of the pollution indices were established on the basis of the reference revised Index PLIn. However, additional work is necessary, such as calibration of the revised indices on the basis of percentage crop yield loss, towards a more accurate assessment of the heavy metal soil pollution levels

Microplastics in Agricultural Soils: A Case Study in Cultivation of Watermelons and Canning Tomatoes

Thirty soil samples were collected from fields that have been used for cultivating watermelons and canning tomatoes for over 10 years. The microplastics (MPs) within these samples were separated with a density floatation method and the use of sieves and filters. The microplastics found were black and originated from the black agricultural mulch film (BMF) used in these cultivations. ATR-FTIR spectroscopy revealed that these microplastics are of the same material as the virgin BMF and as a virgin polyethylene film used as blank. SEM images showed that used BMF and MPs found in soil were oxidized by their exposure to sunlight and create fibrous edges that lead to the creation of smaller size MPs. The number of MPs found in fields with watermelon (301 ± 140 items kg−1) were more than four times higher than in fields with canning tomatoes (69 ± 38 items kg−1) due to the double planting each year and to the second planting last year being closer to the sampling episode. All the sample sites were collected from agricultural fields away from the industrial area; therefore, these results prove that agricultural activities might have caused contamination of soils with MPs. This is corroborated even more by the fact that no MPs were found in five extra samples that were taken from uncultivated areas as blanks

Assessment of toxic heavy metals concentrations in soils and wild and cultivated plant species in Limni abandoned copper mining site, Cyprus

Mine tailings represent a serious source of soil pollution with public health implications. The objectives of this study were(1) to assess the level of toxic and heavy metal mobilization from the tailing spoil-heap of Limni abandoned mine at Cyprus and the extent of soil contamination to the surrounding area by using pollution indicators; (2) to investigate the uptake and accumulation of heavy metals by cultivated crops; and (3) to estimate the potential of native wild plant species grown in the studied area to be used in phytomanagement approaches. The tailing spoil heap exhibited significantly higher S, Zn, Cu and Pb concentrations compared to the ones found in control reference samples (RS). The lateral mobilization of Mg, S, Zn, Cu and Pb resulted to the contamination of the tailing surrounding areas with these metals. Moreover, Mn and Cu concentrations in the tailing and the surrounding areas exceeded the MPLs for agricultural soils. The severe to very severe pollution of the tailing surrounding sides with S, Zn and Cu was also evident by the calculated values of enrichment factor and geoaccumulation index. The values of combined pollution index also uncovered the extremely high pollution of the tailing and the moderate pollution of the surrounding sites with all analyzed elements. The concentration of Cd in fig, peanut and lemon fruits, as well as in the grains and straw of barley exceeded MPLs, highlighting the potential Cd-mediated hazardous effects from the consumption of these produces. The examination of heavy metal content in wild native plant species showed that Inula viscosa L. has the potential to be used for the phytostabilization of Cd and Pb, and Allium ampeloprasum L. for the phytostabilization of Pb. Overall, results suggest that the Limni mine tailing and its surrounding sites are highly polluted; thus agricultural activity in the studied area should be prohibited and phytomanagement should be urgently carried out

Use of treated municipal wastewater in irrigated agriculture--Review of some practices in Spain and Greece

Approximately, seventy (70) percent of world water use including all the water diverted from rivers and pumped from underground is used for agricultural irrigation, so that the reuse of treated municipal wastewater for purposes such as agricultural and landscape irrigation reduces the amount of water that needs to be extracted from natural water sources as well as reducing discharge of wastewater to the environment. Thus, treated municipal wastewater is a valuable water source for recycling and reuse in the Mediterranean countries and other arid and semi-arid regions which are confronting increasing water shortages. Treated wastewater reuse in agriculture is a common practice in the Mediterranean countries and there is a considerable interest in the long-term effects of treated wastewater on crops intended for human consumption. This paper reviews the fundamentals of agricultural irrigation using treated municipal wastewater and the status of municipal wastewater reuse in Greece and Spain with studies related to the effects on soils and plants.Crops Irrigation Reclaimed wastewater Soils Urban wastewater Water quality Water reuse