Wastewater from Biodiesel Production as a Carbon Source for Denitrification of Sludge Liquor in SBR

Sludge liquor from an anaerobic sludge digester with an average N–NH4 concentration of γ = 1185 mg L–1 was treated in a pilot-scale SBR (sequencing batch reactor) system. The returned activated sludge of a WWTP was used as inoculum. The average efficiency of N–NH4 removal was over η = 90 %. Concentrations of N–NH4 in the effluent were typically below 10 mg L–1. The maximal achieved nitrification rate was rN = 9.1 mg g–1 h–1 (relative to MLVSS). Wastewater of methyl ester wash arising during biodiesel production was used as an external carbon source for denitrification. A dosage of 3.5 – 4.5 g of COD per 1 g of nitrogen available for denitrification was found optimal. Typical effluent N–NO3 concentration was about γ = 25 mg L–1 and maximal achieved denitrification rate was rD = 14.5 mg g–1 h–1. Operation of the SBR was stable at a HRT of τ = 4 – 5 days

APPUCATION OF A SHORT-TIME HYDROPONICS FOR SELECTION OF APPROPRIATE DECIDUOUS WOODY PLANTS SPECIES FOR REMEDIATION PURPOSES

A rapid trial of accumulation capacities for heavy metals Pb, Cd, and Cr of selected fast-growing deciduous woody plant species is presented. The Sorbus aucuparia, Populus tremula x P. tremuloides, Salix x blanda, S. viminalis, S. miyabeana, and S. elbursensiswere clonally micropropagated by induction of organogenesis. Samples of roots and aboveground parts from plantlets grown in aseptic conditions in agar semisolid substrate and hydroponics media supplemented by the heavy metal salts were taken at 2, 4, and 8 days of cultivation.The concentrations and distributions of the accumulated metals were determined using the ICP-OES method and verified by autoradiography. Practically, amounts of accumulated heavy metals increased linearly up to the end of the experiment and were higher in the roots than in aboveground parts in both, the agar cultures and hydroponics. It could be concluded that all tested species displayed a high efficacy of metal uptake and could represent prospective trees for phytoremediation of polluted soils