The treatment and disposal of excess sludge has been a rising challenge for wastewater treatment plants worldwide. In this study, simultaneous sludge reduction and nutrient removal was evaluated in laboratory scale sequencing batch reactors (SBRs). Two SBRs were operated alongside for a duration of 370d. One SBR was operated to achieve nutrient removal (control-SBR) at 10d solids retention time...

Sequencing batch reactor (SBR) systems were used for the development of a system and operating procedures for the high production and storage of polyhydroxyalkanoates (PHAs) by wastewater treatment (activated sludge) bacterial cultures. The systems were maintained at a nominal hydraulic retention time (HRT) of 10 hours, and a temperature of 20°C. The solids retention time (SRT) was maintained a...

Accumulation of substrate onto the biomass was quantified under steady-state and shock conditions in a fixed bed reactor fed with an oleic acid-based synthetic effluent. The accumulation of substrate onto the sludge was more dependent on oleic acid concentration than on oleic acid loading rate and decreased the acetogenic, acetoclastic and hydrogenophilic activity. However, even when the methan...

The performance of an upflow anaerobic sludge blanket (UASB) reactor and a hybrid UASB-filter reactor was investigated and compared for the treatment of domestic wastewater at different operational temperatures (28, 20, 14 and 10°C) and loading rates. For each temperature studied a constant CODt removal was observed as long as the upflow velocity was lower than 0.35 m/h. At these upflow velocit...

The study was focused on two goals: (i) the confirmation of the existence of a general relation between the content of polycyclic aromatic hydrocarbons (PAHs) in sewage sludge and in plants growing in it, regardless of the type and content of sewage sludge, and (ii) if so, the answer to the question whether the uptake of PAHs by plants depends on their type. To realize the set aims, the content...

The paper will report about the experiences at an Austrian large wastewater treatment plant of 720,000 population equivalents, where anaerobically digested sewage sludge is further stabilised under aerobic conditions. Enhanced stabilisation of the anaerobically digested sludge was required at the plant in order to get a permit for landfill disposal of the dewatered stabilized sludge. By impleme...

The objective of this presentation is to relate the abundance and mobility of Cd in components of terrestrial ecosystems with implications for land utilization of sewage sludge. The uptake of Cd by crop plants is a function of the quantity of the element in the soil plus other soil factors affecting the Cd ion activity or electrochemical potential at the plant root surface. The natural abundanc...

Recovery of biodegradable plastics from activated sludge is a promising sustainable technology. In this study, polyhydroxybutyrate (PHB) – a biodegradable plastics material was produced by activated sludge performing enhanced biological phosphorus removal (EBPR) in batch experiments under anaerobic, aerobic and anaerobic/aerobic conditions. Under anaerobic conditions, the PHB content of 28.8% o...