A model is outlined for the major biochemical respiratory mechanisms of a conceptualised heterotrophic facultative organism (representing the heterotrophic facultative mass of activated sludge) subjected to four different sets of conditions: steady-state aerobic, steady-state anoxic, steady-state aerobic changed to anoxic, and steady-state anoxic/anaerobic changed to aerobic. Proposals and impl...

The combination of PCR amplification of 16S rRNA genes with denaturing gradient gel electrophoresis (DGGE) analysis was used to reveal the compositions and dynamics of bacterial communities in a sewage treatment plant with two systems, i.e., an anoxic-anaerobic-aerobic system (inverted A20) and an anaerobic-anoxic-aerobic one (conventional A20) over a period from February to July 2009, during w...

The European Union (EU) Project Routes aimed to discover new routes in sludge stabilization treatments leading to high-quality digested sludge, suitable for land application. In order to investigate the impact of different enhanced sludge stabilization processes such as (a) thermophilic digestion integrated with thermal hydrolysis pretreatment (TT), (b) sonication before mesophilic/thermophilic...

The operation of an activated sludge process at a paper mill (AIPM) in Hedera, Israel, was often characterized by disturbances. As part of a research and development project, a study on new biological treatment was initiated. The study included the operation of three pilot units: a. anaerobic treatment by upflow anaerobic sludge blanket (UASB); b. aerobic treatment by two pilot units including ...

The sewage sludge production in Egypt is rapidly increasing resulting from the continuous increase of population, urban planning and industrial developments. This sludge needs to be adequately treated and environmentally managed to reduce the negative impacts of its application or disposal. Therefore, the main currently pressing needs are to find/develop more efficient, economical and sustainab...

Presents the findings of a study conducted to examine the efficiency of the combined anaerobic-aerobic reactors for the treatment of three different tannery industrial wastewaters, focusing on the fate of chromium and other associated metals. Examines elimination rates of such metals with respect to each successive treatment process. Discusses the correlation between the chemical characteristic...

Textile effluents are characterised by high content of recalcitrant compounds and are often discharged (together with municipal wastewater to increase their treatability) into centralized wastewater treatment plants with a complex treatment scheme. This paper reports the results achieved adopting a granular sludge system (sequencing batch biofilter granular reactor - SBBGR) to treat mixed munic...

Biochemical degradation test of food coal-tar dyes using sludge was studied in order to evaluate their safety. It was found that some dyes were little decomposed under aerobic condition but four azo dyes were readily decomposed under anaerobic condition. These were Food Yellow No. 4, No. 5, and Food Red No. 2, No. 102. Decomposed products of these four azo dyes by sludge under anaerobic conditi...

A biological nutrient removal (BNR) activated sludge (AS) scheme incorporating external nitrification in a fixed media system is evaluated. A laboratory scale investigation of the scheme indicates that it holds considerable potential for BNRAS system intensification through major reduction in sludge age and oxygen demand and significant improvement in sludge settleability. Because the BNRAS sys...

Aerobic, anoxic, and anaerobic selectors have become popular for controlling filamentous bulking in activated sludge systems; however, selectors are not always successful. Regression analyses of data collected from 48 full-scale wastewater treatment plants, with operating selectors, provided a method for ranking the importance of selector operating and design parameters (with respect to their i...