जल विज्ञान: वर्तमान अनुसंधान

Steroid hormones, naturally synthesized by human and animals, as well as synthetic/plant-derived ones usually in contraception, may be eventually released into the environment, especially in excreta. Levels of these hormones have been detected in significant concentration in sewage effluent around the world. These compounds have the ability, at very low concentrations, to alter normal functioning of the endocrine system, which is responsible for growth and development in vertebrate systems. Their eventual discharge into water bodies can affect reproduction and development in wildlife. Recycling of waste water for human domestic consumption necessitates the need to monitor the water quality of the effluent, as well as a check for these estrogens. Treated sewage effluent from the Darvill Waste Water Works (DWWW) is discharged into the Umsunduzi River; re-use options are being investigated. Samples were collected and assayed for estrone and 17-ß-estradiol (estradiol) by enzyme-linked immunosorbent assay (ELISA). The steroid hormone concentrations detected were similar to those reported for sewage effluent in Britain, Italy, Germany, Canada and The Netherlands. Preliminary removal efficiencies were noted to be comparable to those reported.

The research seeks to investigate the effect of catalyst (1-wt % Platinum on activated carbon) on the wet oxidation process of treating paper mill effluent. The study also assesses the effect of temperature, oxygen partial pressure and initial Chemical Oxygen Demand (COD) concentration of debarking wastewater on the contaminants during the catalytic wet oxidation process. Catalytic wet oxidation process was studied at 120-180°C temperature, 0-10 bar oxygen partial pressure, 0-1 g/L catalyst concentration and 1000-3000 mg/L initial COD concentrations. Responses such as COD, Total Organic Carbon (TOC), Color, Lignin/Tannin, Biochemical Oxygen Demand (BOD) and pH were measured and analyzed. In the study, it was realized that changes in temperature, oxygen partial pressure, catalyst concentration and initial COD influenced the oxidation process with the best combination occurring at a temperature of 180°C, 10 bar oxygen partial pressure, 1 g/L catalyst concentration and 3000 mg/L initial COD concentration. At these conditions; 74% of COD, 97% of lignin/tannin, 54% of TOC and 90% of color were removed from the wastewater.

For the last decade, we have seen an upsurge in the scientific documentation of emerging contaminants which comprises several chemical and microbial constituents that have not traditionally been considered as contaminants and are present in the environment on a global scale. Emerging contaminants can originate from a variety of animal- and human-waste sources, including municipal, agricultural, and industrial wastewater pathways. The emerging contaminants comprise, nanoparticles, endocrine disrupter compounds, pharmaceuticals and personal care products, prions, cyanobacteria, plasticizers, organometallic compounds, among others. The trail to the environment can be from rapid and direct discharges of effluent into a water body or the slow leaching of stored waste through soils. These emerging contaminants represent a shift in traditional thinking, as many are produced industrially yet are dispersed to the environment from domestic, commercial, and industrial uses. The emerging contaminants present the biggest challenge of analysis as some of them are present in nanograms or pictograms and in fact, these environmentally relevant concentrations lend toxicity.