Anaerobic digestion is now commonly used for sludge treatment. Most industrial digesters operate under mesophilic (37°C) or thermophilic (55°C) conditions. These two regimes are considered as optimal for methane production. In this work, continuous sludge digestion has been operated at labscale at 5 different temperatures comprised between 28° and 55°C. The reactors were first inoculated with a...

The unbalanced nutrients of algal sludge (low C/N ratio) were regarded as an important limitation factor to anaerobic digestion process. Adding high carbon content of waste paper in algal sludge feedstock to have a balanced C/N ratio was undertaken in this study. The results showed adding 50% (based on volatile solid) of waste paper in algal sludge feedstock increased the methane production rat...

Electrical heating has been proposed as a potential method for pathogen inactivation in human waste sludge, especially in decentralized wastewater treatment systems. In this study, we investigated the heat production and E. coli inactivation in wastewater sludge using electrical thermal treatment. Various concentrations of NaCl and NH4Cl were tested as electrolyte to enhance conductivity in slu...

Wastewater sludge is a complex raw material that can support growth and protease production by Bacillus licheniformis. In this study, sludge was treated by different thermo-alkaline pre-treatment methods and subjected to Bacillus licheniformis fermentation in bench scale fermentors under controlled conditions. Thermo-alkaline treatment was found to be an effective pre-treatment process in order...

Digested sludge (DS) is a waste product of anaerobic digestion that produced during the biodegradation excess sludge. It cannot be used as substrate for further biogas production owing to its recalcitrant nature. In present study, we heat treatment technique convert DABYS microflora (DABYS = digested sludge-assimilating and biogas-yielding soil microflora), which degraded DS methane gas, could ...

Microbial processes have been extensively used in engineered systems, esp. wastewater treatment, in situ bioremediation and most recently for biofuel production. While excess biomass may be desirable in some processes, it is detrimental to other systems including Activated Sludge Process (ASP), biofilters and subsurface bioremediation schemes, where uncontrolled microbial growth leads to increa...

The aim of this paper is to synthesize and analyze information on how the process of granulation is affected by environmental and operational conditions in the reactor. Various factors affecting granulation process as gleaned from the literature are organic loading rate (OLR), upflow velocity (Vup), sludge volume index (SVI), specific methenogenic activity (SMA), VSS/SS ratio, liquid in flow ra...

Recovering nutrients, especially phosphate resource, from wastewater have attracted increasing interest recently. Herein, an intermittently aerated membrane bioreactor (MBR) with a mesh filter was developed for simultaneous chemical oxygen demand (COD), total nitrogen (TN) and phosphorous removal, followed by phosphorus recovery from the phosphorus-rich sludge. This integrated system showed enh...

The following sludge reduction alternatives were tested in wastewater biological reactors: oxic-settling-anaerobic (OSA-process); ultrasonic disintegration (UD); chlorination (CH); 3,3',4',5tetrachlorosalicylanilide (TCS); and folic acid (FA). Compared to the control system, UD reduced 55% of the sludge production, and greater substrate and nutrient removal efficiency was achieved. CH worsened ...