aerobic digestion was useful for mixed sludge of west ahwaz sewage treatment plant. results showed that after 12 days 38% of tvs reduced. this meets the environmental standards. after 19 days detention time in the bioreactor, cod, vss, tvs, tss, ts, were 40 ,56, 54.5 ,50.4 ,44.7 percent respectively. kd coefficient was,0.173day-1. aim of this bench scale study is determination of aerobic digest...

This work deals with the effect of combined microwave-ultrasonic pretreatment on the anaerobic biodegradability of primary, excess activated and mixed sludge. The characteristics, biodegradability and anaerobic digester performance for untreated primary, excess activated and mixed sludge were compared to combined microwave-ultrasonic pretreated primary, excess activated and mixed sludge. All sl...

The fate and behaviour of two groups of endocrine disrupting chemicals, steroid estrogens and nonylphenol ethoxylates, have been evaluated during the anaerobic digestion of primary and mixed sewage sludge under mesophilic and thermophilic conditions. Digestion occurred over six retention times, in laboratory scale reactors, treating sludges collected from a sewage treatment works in the United ...

This work explores the effect of additives on the pouring temperature in a waterworks and industrial calcium fluoride sludge co-melting system. Two kinds of sludge were mixed in various ratios to find a mixing ratio at which the operating temperature for subsequent additive tests was relatively low. Various proportions of either sodium carbonate (Na2CO3) or potassium carbonate (K2CO3) reagent w...

In this study, a circulating fluidized bed (CFB) of 125 mm diameter and 1800mm height was used to find the combustion characteristics of sewage sludge (SS) produced in Turkey. Sludge + olive cake, and sludge + lignite coal mixtures were burned separately. Various sludge-to-lignite coal and sludge-to-olive cake ratios (5/95, 10/90, 15/85, 20/80) were tried. On-line concentrations of major compon...

Municipal wastewater sludges are complex fluids displaying non-Newtonian characteristics. Whilst rheological properties of sludges are very important for the design and operation of wastewater treatment facilities, there is a lack of information regarding these properties, particularly for mixtures of primary and secondary sludges. The rheology of wastewater treatment sludge has been widely stu...

reaction constants and heat release during thermophilic aerobic digestion of typical secondary and mixed sludges were determined. maximum reaction constant, determined by measuring the amounts of biodegradable volatile suspended solids (bvss) removed, occurred in the temperature range of 55-60 ºc. measurement of heat releases were carried out, at the same range, by the aid of a temperature prog...

Reaction constants and heat release during thermophilic aerobic digestion of typical secondary and mixed sludges were determined. Maximum reaction constant, determined by measuring the amounts of biodegradable volatile suspended solids (bVSS) removed, occurred in the temperature range of 55-60 ºC. Measurement of heat releases were carried out, at the same range, by the aid of a temperature ...

Basin configuration and equipment design govern whether rectangular secondary clarifiers will experience problems of inadequate sludge transport capacity. The operating factors to be considered, other than peak flows which may be severe, are the potential for sludge bulking and the higher mixed liquor suspended solids concentrations and solids retention times employed for biological nutrient re...

The objective of this work was to optimize the ultrasound (US) pretreatment of sludge. Three types of sewage sludge were examined: mixed, secondary and secondary after partial methanisation ("digested" sludge). Thereby, several main process parameters were varied separately or simultaneously: stirrer speed, total solid content of sludge (TS), thermal operating conditions (adiabatic vs. isotherm...