Sulfhydryl groups as potential biomarkers of water pollution

Thiols represent a source of environmental pollution especially wastewater. The present work aims to evaluate the degradation of sulfur in two biological treatment plants in Tunisia: conventional plant of Rades Malienne, and vertical and horizontal flow from the Grombalia plant. We analyzed (1) wastewater properties, (2) the hydrosulfur (thiol) group, (3) membrane processes ultrafiltration technique and (4) characterization of the quality of wastewater from different plants. We used ultrafiltration membrane assisted ZnO and TiO2 NPs application on real effluents from different biological treatment plants. STEP1 is found to be more loaded with sulphur. Application of AC-ZnO membrane gives 99.07% and 99.55% of sulfur removal from wastewater of STEP1 and STEP3. STEP3 is 50 times less charged on sulfur than STEP1. We suggested that when the sulphur content is high, this leads to an increase in mineral elements. This could be explained by the interactions between thiols and the major elements that cause mineral pollution.

Research on marine pollution problems and solutions in China from the perspective of marine tourism

Based on the perspective of marine tourism, this paper integrates various types of marine pollution, and puts forward high-quality development solutions and future extension direction of marine tourism. Through the research, it is found that the main culprits of marine pollution mainly include the following seven points: human activities produce garbage; white pollution; ship pollution; exploration of marine oil and gas resources and mineral pollution; land reclamation; pollution in mariculture industry and new estrogen pollution. The causes of marine pollution and countermeasures are discussed.

Physicochemical characterization of leachates produced in the Rabat-Salé-Kénitra Region landfill technical center and monitoring of their treatment by aeration and reverse osmosis

The aim of this work is to study the physicochemical characterization and monitoring of the treatment of leachate generated by the landfilling of household and similar waste in the landfill of Rabat-Salé-Kénitra Region. The analysis of the results showed a high concentration of easily biodegradable organic matter. The pollutant load is of the order of 3,850 mg/L of the chemical oxygen demand (COD), 1.260 mg/L of the biochemical oxygen demand (BOD5), and shows an average content of nitrates (NO3-=56.6 mg/L). This mineral pollution is caused by a high electrical conductivity, which reaches an average value of 15.9 mS/cm, and a low concentration of heavy metals in the raw leachate such as lead (Pb = 1.591 mg/L), copper (Cu = 1.017 mg/L), and cadmium (Cd = 0.109 mg/L). The biological treatment allows for the successive biodegradation of 40% of the BOD5, and 33% of the COD. Moreover, the reverse osmosis filtration in organic membranes achieves a reduction of 98% for BOD5, 97% for COD, 85% for lead, and 67% for copper. In this study, biological and reverse osmosis treatments represented an effective treatment for the organic and metallic leachate pollutants of this landfill.

Detoxification Assays of Tunisian Tannery Wastewater under Nonsterile Conditions Using the Filamentous Fungus Aspergillus niger

The ability of Aspergillus niger strain to reduce organic and mineral pollution as well as the toxicity of two tannery wastewaters, the unhairing effluent (UE) and the final effluent (FE), taken from a local Tunisian tannery and under nonsterile conditions, was studied. Raw effluents show alkaline pH ≥11; thus experiments were carried out at initial pH values and at pH adjusted to 6. Characterization of effluents also revealed high salt levels (EC > 17 mS/cm) and high organic matter content (25 g/L for the UE and 7.2 g/L for the FE) but a low biodegradability since BOD5 did not exceed 2.5 and 1.25 g/L for the UE and the FE, respectively. The results of the biological treatment showed that A. niger was able not only to grow at high pH and salinity values, but also to reduce organic and mineral pollutant load. After treatment, the COD reduction for the UE reached 90% and 70% at pH=6 and at initial pH (12.13), respectively. For the FE, the decrease of COD values reached 75% at pH=6 and 64% at initial pH (11.64). Monitoring of mineral pollution levels showed a reduction in chromium (Cr) concentrations reaching 70% for the FE. This was reflected by an increase of the biomass of A. niger from 9.25 g/L (control) to 9.84 g/L for the FE. To confirm the efficiency of the biological treatment using A. niger, phytotoxicity (tomato seeds) and microtoxicity (Escherichia coli and Bacillus subtilis) tests were carried out. Results of this monitoring showed an important decrease in the toxicity levels for both effluents.

Using Lime Treated Acid Mine Water for Irrigation

The disposal of acid sulphate mine water poses a universal problem. Although water quality is much improved when neutralised by lime treatment high salt loads nevertheless make release to better quality surface streams undesirable. The feasibility of using such water for irrigation was evaluated using a steady state chemical equilibrium model to predict the composition of water draining from successive soil segments under a range of leaching fractions. Large amounts of gypsum are expected to precipitate in the soil profile resulting in a greater reduction in salinity than would occur if the water contained chloride instead of sulphate. A comparatively smaller reduction in crop yields can thus be expected and a greater variety of the marginally salt sensitive crops can be grown. The precipitation of gypsum however results in an increased sodium hazard to soil physical properties. This does not appear serious when evaluated against published data on soil hydraulic conductivity as affected by sodium and electrolyte concentration. A drastic reduction in the salt load in drainage from irrigated land compared to that in the applied water is predicted. Irrigation with lime treated acid mine water does not only seem feasible but also advantageous for the protection of water resources from mineral pollution.

The Economic Impact on an Urban and Industrial Complex of Mineral Pollution in the Water Supply – A Case Study

The only water source available to the most dense urban industrial and mining territory in the Republic of South Africa is subjected to increasing mineral pollution. Investigations of the causes and effects are referred to as well as to the mathematical modelling of the water system that could lead to improved water quality. The economic effects and costs to the Community as a whole are described and quantified.