Sludge management in waste stabilization ponds (WSPs) is essential for safeguarding the system performance. Sludge accumulation patterns in WSPs are strongly influenced by the pond hydrodynamics. CFD modeling was applied to study the relation between velocity profiles and sludge deposition during 10 years of operation of the Ucubamba WSP in Cuenca (Ecuador). One tracer experiment was performed ...

Aerobic granular sludge was cultivated adopting internal-circulate sequencing batch airlift reactor. The contradistinctive experiment about short-term membrane fouling between aerobic granular sludge system and activated sludge system were investigated. The membrane foulants was also characterized by Fourier transform infrared (FTIR) spectroscopy technique. The results showed that the aerobic g...

Dewatering of sewage sludge is an important part of proper sludge management practice. It is becoming a more challenging issue for water industries as new regulations on sludge disposal are being imposed. In this paper, the application of mechanical thermal expression (MTE) to dewater sewage sludge and the conditioning of sludge by mixing with brown coal are investigated. Raw sludge, sludge flo...

This is a literature review for the year 2015 and contains information specifically associated with suspended growth processes including activated sludge, upflow anaerobic sludge blanket, and sequencing batch reactors. The review encompasses modeling and kinetics, nutrient removal, system design and operation. Compared to past reviews, many topics show increase in activity in 2015. These includ...

The recent United Kingdom ban on the disposal of sewage sludge at sea has led to the prediction that land application of sludge will become more widespread. The positive aspect of recycling nutrients may, however, be offset by the risk of contamination by heavy metals that are frequently present in sludge. The environmental impact of applying metal-rich sewage sludge to agricultural land was, t...

Sludge production from wastewater treatment process is high, and the disposal of excess sludge will be forbidden in a near future, thus increased attention has been turned to look into potential technology for sludge reduction. The study attempts to review alternative sludge disposal methods, including anaerobic digestion, aerobic digestion and landfills. In these sludge processes, excess sludg...

(Hydro)thermal treatments of sewage sludge is a promising option that can simultaneously target safe waste disposal, energy recovery, and nutrient recovery/recycling. The speciation of phosphorus (P) in sludge is of great relevance to P reclamation/recycling and soil application of sludge-derived products, thus it is critical to understand the effects of different treatment techniques and condi...

A model describing a given system should be as simple as possible - but not simpler. The appropriate level of complexity depends both on the type of system and on the intended use of the model. This paper addresses the critical question of which purposes justify increased complexity of biofilm (reactor) models. Additional model features compared to conventional models considered are: (1) the in...

The mechanical properties of dewatered, anaerobically digested sewage sludge were determined from soil laboratory tests. The sludge material is largely composed of organic clay sized-particles, a sizable fraction of which is in an active state of biological digestion which can continue over many years under field conditions. Moderately digested sludge material was found to have a typical specif...

Seeding of nitrifying bacteria into the activated sludge process may decrease the necesary volume needs for a stable nitrification process. Both theoretical and experimental studies were carried out in order to evaluate the effects of seeding. A model was developed for prediction of the effects of seeding of nitrifying bacteria from a separate stage into the activated sludge process. Seeding te...