Study of Ni(II), Cu(II), Pb(II), and Zn(II) Removal Using Sludge and Minerals Followed by MF/UF

This work examined the removal of heavy metals in a system consisting of ultrafiltration (UF) or microfiltration (MF) membranes combined with sludge and minerals. The metals under examination were Ni(II), Cu(II), Pb(II), and Zn(II), while the system performance was investigated with respect to several operating parameters. Metal removal was achieved through various processes including chemical precipitation, biosorption, adsorption, ion exchange, and finally retention of the metals by the membranes. The pH had a profound effect on metal removal, as the alkaline environment favored the metal removal process. The use of sludge resulted in increased levels of metal uptake which was further enhanced with the addition of minerals. The metal removal mechanisms depended on the pH, the metal, and mineral type. The combined sludge?Cmineral?CUF system could effectively remove metal ions at an alkaline environment (pH?=?8), meeting the US EPA recommended long-term reuse limits of lead and copper and the short-term reuse limits of nickel and zinc for irrigation purposes, provided that specific mineral dosages were added.     

Application of Adsorption and Ultrafiltration Processes for the Pre-treatment of Several Industrial Wastewater Streams

In this work ultrafiltration (UF) was coupled with suitable minerals and dried activated sludge for the pre-treatment of several industrial wastewater streams. The aim was to decrease heavy metal concentrations to low levels so that wastewater can be safely discharged into municipal sewers or biological wastewater treatment can take place without biomass inhibition problems. Industrial wastewater originating from metal plating, chemical and textile industries was employed. The experiments were conducted in a reactor where the UF membrane module was immersed. UF reduced the amount of heavy metals, but the performance was variable with removal efficiencies ranging from 20 to 99.7?%, depending on the metal type and on the wastewater initial characteristics. The prevailing wastewater characteristics were the pH, the presence of certain anions, the suspended solids concentration and the presence of competing cations. The addition of activated sludge and/or minerals could further increase heavy metal removal through the process of sorption. UF assisted by minerals could achieve variable colour and COD removal ranging from 22 to 94?% and 58 to > 99.9?% respectively. Minerals resulted in membrane fouling mitigation, while sludge adversely impacted on fouling.     

An evaluation of apramycin as an in-feed medication for the treatment of post-weaning colibacillosis in pigs

Apramycin, a new aminocyclitol antibiotic produced by a strain ofStreptomyces tenebrarius, has been evaluated as a treatment of colibacillosis in post-weaning pigs. Results are reported from 3 trials in Greece, involving 222 animals. The drug was administered in the feed at 75 ppm or 100 ppm for 21 days. Apramycin at both levels controlled diarrhoea and sickness. Mortality was significantly reduced at 100 ppm. The average daily gain of the treated animals over the three week treatment period was improved by 67% (P<0.001) for the 100 ppm group and by 42% (P<0.01) for the 75 ppm group in comparison with the untreated controls. During the same period the feed conversion ratio was improved by 46% (P<0.001) in the 100 ppm apramycin group and by 26% (P<0.05) in the 75 ppm group as compared to the untreated controls. Average daily feed intake was significantly greater in the treated groups of animals than in the untreated groups.