Influence of vegetation and gravel mesh on the tertiary treatment of wastewater from a cosmetics industry.

To estimate the influence of gravel mesh (fine and coarse) and vegetation (Phragmites and Arundo) on the efficiency of a reed bed, a pilot plant was included after the wastewater treatment plant of a cosmetic industry treatment system according to a 22 factorial experimental design. The maximum biochemical oxygen demand (BOD5), chemical oxygen demand (COD) and total phosphorous (TP) reduction was observed in the reactor, where Phragmites and fine gravel were used. In the reactor with Phragmites and coarse gravel, the maximum total Kjeldahl nitrogen (TKN) and total suspended solids (TSS) reduction was observed.

Inhibition kinetics of phenolic compounds in aerobic degradation of organic wastewaters.

This study proposed a kinetic model for the aerobic degradation of high strength organic wastewaters with high concentrations of phenolic compounds. The model was based on the conventional Monod kinetic equation incorporating phenols' inhibition. Furthermore, a methodology for determining biokinetic constants was proposed.

Granulation mechanism of a UASB reactor supplemented with iron.

The aim of this paper was to propose a granulation mechanism in order to interpret all the experimental observations that arose during experiments on two UASB reactors, where one was supplemented with ferrous iron at a dose of 0.01 g Fe(2+) per g COD feed. This supplementation with ferrous iron allowed COD removal of more than 98% at a loading rate of 9 g COD/L per day, which was 24% higher than for the reactor not receiving the ferrous iron.

Determination of granule size distribution in a UASB reactor.

Granular sludge is the key factor for an efficient operation of an upflow anaerobic sludge blanket (UASB) reactor. In order to monitor the granularity of anaerobic sludge, the determination of the granule size distribution is of vital importance. For this reason, several techniques have been proposed; however, they are either tedious, imprecise or expensive and hardly applicable in full-scale treatment plants.

Effect of ferrous ion on the biological activity in a UASB reactor: mathematical modeling and verification.

The effect of ferrous ion on the biological activity in a upflow anaerobic sludge blanket (UASB) reactor was studied. A mathematical model was developed and validated in order to simulate the dynamic behavior of a UASB reactor. This model took into consideration of all the biological and physicochemical reactions.

Electrochemical detoxification of four phosphorothioate obsolete pesticides stocks.

The phosphorothioate pesticides are widely used for crop production and fruit tree treatment, but their disposal causes serious environmental problems. Four commercial phosphorothioate pesticides (Demeton-S-methyl, Metamidophos, Fenthion and Diazinon) were treated by an electrolysis system using Ti/Pt as anode and stainless steel 304 as cathode. A number of experiments were run in a laboratory scale pilot plant and the results are presented.

Degradation of methylparathion in aqueous solution by electrochemical oxidation.

The electrochemical degradation of methylparathion has been investigated by using Ti/Pt as anode, Stainless Steel 304 as cathode, and sodium chloride as electrolyte. The pesticide is rapidly degraded, but full mineralization is not observed. Degradation products have been monitored through gas chromatography and mass spectrometry, and the overall degradation process has been monitored through dissolved and particulate organic carbon, sulfur, and phosphorus measurements.