Integrated physicochemical and biological treatment process for fluoride and phosphorus removal from fertilizer plant wastewater.

The phosphate fertilizer industry produces highly hazardous and acidic wastewaters. This study was undertaken to develop an integrated approach for the treatment of wastewaters from the phosphate industry. Effluent samples were collected from a local phosphate fertilizer producer and were characterized by their high fluoride and phosphate content.

Bioassay and use in irrigation of untreated and treated wastewaters from phosphate fertilizer industry.

Wastewater from phosphate fertilizer industry that contains essentially a significant amount of both fluoride and phosphate was treated by separative precipitation of fluoride ions with hydrated lime. Thus, a phosphate-rich effluent with low content of fluoride was obtained. The microtoxicity of the treated wastewater was then monitored by LUMIStox and its phytotoxicity was investigated on tomato (Lycopersicon esculentum), wheat (Triticum aestivum), maize (Zea mays), ryegrass (Lolium perenne), and alfalfa (Medicago sativa) seed germination and plant growth.

Adsorption of a textile dye "Indanthrene Blue RS (C.I. Vat Blue 4)" from aqueous solutions onto smectite-rich clayey rock.

The adsorption of a textile dye, namely, Indanthrene Blue RS (C.I. Vat Blue 4) onto smectite-rich clayey rock (AYD) and its sulphuric acid-activated products (AYDS) in aqueous solution was studied in a batch system with respect to contact time, pH, and temperature.

Separative recovery with lime of phosphate and fluoride from an acidic effluent containing H3PO4, HF and/or H2SiF6.

Fluoride content and flow-rate of fertilizer plant wastewater from phosphoric acid and/or triple superphosphate (TSP) production lead to the discharge of several thousand tons of fluoride (F(-)) per year and even more for phosphate (PO4(3-)). Since sustainability is an important environmental concern, the removal methods should allow phosphorus and fluoride to be recycled as a sustainable products for use as raw materials either in agricultural or industrial applications. In the present work, separative recovery with lime of these two target species was investigated.

Electrochemical oxidation post-treatment of landfill leachates treated with membrane bioreactor.

Integration of membrane bioreactor (MBR) with electrochemical process was investigated as treatment of stabilized landfill leachates, collected from Djebel Chekir (Tunisia). Results showed that at optimum conditions for the membrane and with organic loading rates of 1.9 and 2.

Lead removal from aqueous solutions by a Tunisian smectitic clay.

The adsorption of Pb(2+) ions onto Tunisian smectite-rich clay in aqueous solution was studied in a batch system. Four samples of clay (AYD, AYDh, AYDs, AYDc) were used. The raw AYD clay was sampled in the Coniacian-Early Campanian of Jebel Aïdoudi in El Hamma area (South of Tunisia).