Trickling filter

About: Trickling filter is a research topic. Over the lifetime, 1098 publications have been published within this topic receiving 20219 citations.

Biological Cr(VI) reduction in a trickling filter under continuous operation with recirculation

Abstract: BACKGROUND: Hexavalent chromium (Cr(VI)) is toxic to humans, animals and plants. Conventional treatment technologies reduce Cr(VI) to the less toxic and mobile Cr(III), but these methods are usually expensive and generate secondary waste. Microbial Cr(VI) reduction has recently gained attention as a detoxification process, since it enables Cr(VI) reduction through relatively cheap and simple methods. The aim of this work was to investigate the mechanism and the performance of biological Cr(VI) reduction using mixed cultures originated from industrial sludge under continuous operation with recirculation in a pilot-scale trickling filter. RESULTS: Biological Cr(VI) reduction was studied using a pilot-scale trickling filter filled with plastic media under continuous operation with recirculation and the use of indigenous bacterial population. The effect of the organic carbon (electron donor) concentration was examined for constant Cr(VI) influent concentration at about 5.5 mg L−1 and volumetric flow rates ranging from 60 to 900 mL min−1. The highest reduction rate achieved was 1117 g Cr(VI) m−2 d−1 for a volumetric flow rate of 900 mL min−1. The system's reduction capacity was significantly affected by chromate loadings, resulting in frequent backwashing of the filter. The determination of the reduction mechanism was also studied using batch cultures of free suspended cells and culture supernatant. CONCLUSION: The high reduction rates combined with the low operating cost indicate that the above technology can be a viable solution for the treatment of industrial chromate effluents. Copyright © 2008 Society of Chemical Industry

A quantitative theory of the action of microbes attached to a packed column: Relevant to trickling filter effluent purification and to microbial action in soil

Abstract: A packed column with microorganisms attached is regarded as a series of “theoretical compartments” each separated by a “theoretical film” of biomass. Liquid medium is supposed to pass down the column so that it remains for an equal time in each compartment. The theoretical film of biomass is assumed to have an active layer in contact with the liquid medium, the thickness of the active layer of biomass is estimated from the kinetics of diffusion of the limiting substrate. The efficiency of the column is represented by the number of theoretical compartments per unit length of column. In aerobic processes it is supposed that oxygen will be the rate-limiting nutrient. Expressions are derived for the amounts of substrate that will be consumed in aerated and non-aerated columns. The theory is applied to calculate some of the parameters of a trickling filter for effluent purification. The theory may be readily tested since it involves only measurable and meaningful parameters of a microbial culture.