Effects of ten years treated wastewater drip irrigation on soil microbiological properties under Mediterranean conditions

Water shortage in most countries of the southern Mediterranean basin has led to the reuse of municipal wastewater for irrigation. Despite numerous advantages for soil fertility and crop productivity, recycling wastewater in the soil also has several ecotoxicological and sanitary problems. To evaluate the chronic soil contamination and the cumulative impact of wastewater, we compared two plots, all under orangegrove that had been drip irrigated for 10 years. The first plot was irrigated with treated wastewater; the second one was irrigated with groundwater. No negative effects of treated wastewater drip irrigation treatment were observed on the measured soil parameters (pH, organic matter and cation exchange capacity). A slight increase in the concentration of soil enteric bacteria and soil fungal densities was recorded in the wastewater plot reaching a maximum value in the first soil layer (0 to 20 cm). This result was recorded essentially around the emitters. Groundwater plots and wastewater plots exhibited similar repartitions of soils DNA quantity with depth, with the highest values in the upper layer and a progressive decrease with soil depth. For both soils, DNA quantity was positively affected by soil organic matter content. This work confirms that, under suitable conditions, treated wastewater use in irrigation can have positive effects, not only in the aspects of soil quality, but also in social terms, as it allows the maintenance of irrigated agriculture in areas where groundwater has been polluted by seawater intrusion.Keywords: Treated wastewater, groundwater, drip irrigation, enteric bacteria, soil DNA.African Journal of Biotechnology Vol. 12(39), pp. 5761-577

Effect of PCP Pesticide Contamination on Soil Quality

In recent years, soil contamination with pesticides has become a crucial news issue with serious short- and long-term effects on human health and its environment. Pesticides play a significant role in the success of modern farming and food production. These compounds have potential for toxicity and adverse effects on human health and ecological soil systems. Pentachlorophenol (PCP) is one of the most recalcitrant chemicals polluting the environment for its stable aromatic ring system and chloride content. Nowadays, many sites are contaminated with this substance. In these areas, concentrations may stay high for a long time because of slow degradation in the soil due to the negative effects that PCP has on soil microbial populations. Bioremediation of PCP contaminated sites can be realized introducing directly, into a contaminated system, microorganisms able to consume selectively the target compound (bioaugmentation) or increasing the microbial indigenous population by addiction of nutrients in form of organic and/or inorganic fertilizers and biosolids (biostimulation). In the present chapter, we present an overview of the effect of PCP pesticide contamination on soil microbial populations (density and diversity), enzymatic activity and physicochemical parameters. Additionally, the bioremediation process will be detailed

Détection des bactéries multirésistantes au laboratoire de bactériologie du CHU de Limoges

LIMOGES-BU Médecine pharmacie (870852108) / SudocLYON1-BU Santé (693882101) / SudocSudocFranceF

Co-Composting of Various Residual Organic Waste and Olive Mill Wastewater for Organic Soil Amendments

The valorization of different organic residues like municipal solid wastes, sewage sludge and olive mill wastewater is becoming more and more worrying in the different modern communities and is becoming relevant and crucial in terms of environmental preservation. The choice of the treatment technique should not be only from the point of view of economic profitability but, above all, must consider the efficiency of the treatment method. Thus, an attempt to remove polyphenols from olive mill wastewater would have a double interest: on the one hand, to solve a major environmental problem and to recover and valorize the olive mill wastewater for advanced applications in food processing and soil amendments. It is also interesting to think of associating two harmful wastes by co-composting such as sewage sludge-vegetable gardens, sewage sludge-municipal solid waste, and green wastes-olive mill wastewater…, to get a mixed compost of good physical–chemical and biological qualities useful for agricultural soil fertilization. Finally, in order to be more practical, we will describe specifically in this chapter a new variant of composting and co-composting technology intended for waste treatment that is very simple, inexpensive and easy to implement

Treated waste water reuse impact on soil microbial community structure as assessed by Automated Ribosomal Intergenic Spacer Analysis (ARISA) fingerprint technique

International audienc

Impact assessment of irrigation by treated wastewater on soil bacterial genetic structure diversity of Nabeul-Tunisia irrigated areas

International audienc

Soil DNA evidence for altered microbial diversity after long-term application of municipal wastewater

Water resources constitute a social, agricultural and economic problem in most countries of the southern Mediterranean Basin. Alternative strategies have been developed such as the reuse of municipal wastewater for irrigation in agriculture. Despite numerous advantages for soil fertility and crop productivity, recycling wastewater in soils also has several ecotoxicological and sanitary problems. Few investigations have assessed the risk by evaluating the impact of wastewater irrigation on soil microbes. Here, we report for the first time the short- and long-term effects of treated municipal wastewater irrigation on the density and genetic structure of bacterial and fungal soil communities. Soils from agricultural sites in Tunisia that had been irrigated with wastewater for 4, 8, 16 and 26 years were characterised. Soil physicochemical and microbial characteristics were assessed by sampling at 0–20 and 20−40 cm depth at each site. Quantitative changes in bacterial and fungal communities were measured by indirect counts on synthetic culture media and qualitative modifications were evaluated by using molecular ecology methods: B- and F-ARISA for Bacterial and Fungal Automated Ribosomal Intergenic Spacer Analysis, respectively. These methods allowed genotyping the structure of bacterial and fungal communities from soil DNA extracts. Our results revealed a significant increase in microbial densities related to the duration of irrigation with wastewater. In addition, wastewater irrigation led to changes in the genetic structure of bacterial and fungal communities, the magnitude and specificity of these changes being significantly correlated with the duration of such irrigation. These results show that wastewater management schemes have a major effect on indigenous microbial abundance and composition in soils that could be related to the recurrent inputs of organic compounds and mineral/metallic elements. In an agro-ecological context, irrigation with municipal wastewater represents an impacting practice that now needs to be evaluated more fully in terms of ecosystem services for sustainable agriculture

Combined bioaugmentation and biostimulation techniques in bioremediation of pentachlorophenol contaminated forest soil

Pentachlorophenol (PCP) is quite persistent in the environment and severely affects different ecosystems including forest soil. The main objective of this work was to study different bioremediation processes of artificially PCP (100 mg kg-1) contaminated forest soil (Sc). In fact, we used bioaugmentation by adding two different bacterial consortia B1 and B2, biostimulation procedures by amendments based on forest compost (FC), municipal solid waste compost (MC), sewage sludge (SS), and phosphate, and their combined treatments. Soil physical and chemical properties, residual PCP, soil microbial biomass carbon, soil respiration and some enzymatic activities at zero time and after 30 d of incubation, were evaluated. A net reduction of PCP, 71% of the initial concentration, after 30 d-incubation occurred in the sample Sc+B1+FC, as the best performance among all treatments, due to natural attenuation, immobilization of PCP molecules in the forest soil through organic amendments, and the action of the exogenous microbial consortium B1. The single application of FC or B1 led to a depletion of PCP concentration of 52% and 41%, respectively. Soil microbial biomass carbon decreased in PCP contaminated soil but it increased when organic amendment also in combination with microbial consortia was carried out as bioremediation action. Soil respiration underwent no changes in contaminated soil and increased under FC based bioremediation treatment. These results demonstrate that the combined treatments of biostimulation and bioaugmentation might be a promising process for remediation of PCP contaminated soil

Effects of Date Palm Waste Compost Application on Root Proteome Changes of Barley (Hordeum vulgare L.)

Proteomic analysis was performed to investigate the differentially abundant proteins (DAPs) in barley roots during the tillering stage. Bioinformatic tools were used to interpret the biological function, the pathway analysis and the visualisation of the network amongst the identified proteins. A total of 72 DAPs (33 upregulated and 39 downregulated) among a total of 2580 proteins were identified in response to compost treatment, suggesting multiple pathways of primary and secondary metabolism, such as carbohydrates and energy metabolism, phenylpropanoid pathway, glycolysis pathway, protein synthesis and degradation, redox homeostasis, RNA processing, stress response, cytoskeleton organisation, and phytohormone metabolic pathways. The expression of DAPs was further validated by qRT-PCR. The effects on barley plant development, such as the promotion of root growth and biomass increase, were associated with a change in energy metabolism and protein synthesis. The activation of enzymes involved in redox homeostasis and the regulation of stress response proteins suggest a protective effect of compost, consequently improving barley growth and stress acclimation through the reduction of the environmental impact of productive agriculture. Overall, these results may facilitate a better understanding of the molecular mechanism of compost-promoted plant growth and provide valuable information for the identification of critical genes/proteins in barley as potential targets of compost

Impact of the use of wastewater for irrigation of cultivated plots on the soil microbiological quality in semi-arid zone (Tunisia): approaches at the plot and catchment area scales

International audienc