Removal of organic Pollutants from wastewater using different treatment technologies

Stability and removal of anti-inflammatory dexamethasone sodium phosphate (DSP), anti-anxiety drug diazepam (valium) and spironolactone (SP) from wastewater produced at Al-Quds University Campus were investigated. Kinetic studies in both pure water (abiotic degradation) and in sludge (biodegradability) at room temperature were investigated. They demonstrated that DSP underwent degradation to its hydrolytic derivative, simply named dexamethasone, in both media. The first order hydrolysis rate of DSP in activated sludge at 25°C (3.80×10-6 s-1) was about 12-fold greater than in pure water (3.25×10-7 s-1). Diazepam showed high chemical stability toward degradation in pure water, and underwent faster biodegradation in sludge providing two main degradation products. The degradation reactions in sludge and pure water showed first order kinetics with rate constant values of 2.6 × 10-7 s-1 and 9.08 × 10-8 s-1, respectively. The potassium-sparing diuretic (water pill) SP underwent degradation to its hydrolytic derivative, canrenone, in both media. The first order hydrolysis rate of SP in activated sludge at 25°C (3.80×10-5 s-1) was about 49-fold greater than in pure water (7.4×10-7 s-1). The overall performance of WWTP was also assessed showing that 90% of spiked DSP and SP were removed together with its newly identified metabolites. WWTP also showed that UF and RO were relatively sufficient in removing spiked diazepam to a safe level. In order to check for different tools to be used instead of ultra-filtration membranes, the effectiveness of adsorption and filtration by micelle-clay preparation for removing DSP was ascertained in comparison with activated charcoal. Batch adsorption in aqueous suspensions of the micelle-clay composite and activated carbon was well described by Langmuir isotherms showing the best results for micelle-clay material. Besides, filtration of DSP, DZ and SP aqueous solutions by columns filled in with a mixture of sand and micelle-clay complex showed complete removal of each drug at concentration higher than sand/activated-charcoal filled filters at flow rates of 2 mL min-1.