Wastewater treatment with activated sludge is the most common way of treating wastewater. The process relies on bacteria converting nutrients, BOD and COD into biomass, CO2 and N2. Even though the configuration of activated sludge processes and wastewater treatment plants varies there are common problems which are shared. Filamentous bulking sludge is one problem that is widespread and disturbs...

A lab-scale expanded granular sludge bed (EGSB) reactor was operated at 20°C with low strength wastewater (0.6-0.8 g COD/L) for over 200 days. Reactor was inoculated with mesophilic granular sludge. The up-flow velocity was set to 5 m/h by effluent recirculation. The COD loading was increased up to 12 kg COD/m3/day until the day 76, resulting in hydraulic retention time of 1.5 hours. Physical p...

Sludge management is a major issue for water utilities globally. Poor digestibility and dewaterability are the main factors determining the cost for sludge management, whereas pathogen and toxic metal concentrations limit beneficial reuse. In this study, the effects of low level nitrite addition to acidified sludge to simultaneously enhance digestibility, toxic metal removal, dewaterability and...

Lime treatment of wastewater sludge has been in use for over a century. This paper describes the use of ‘Liquid Lime’ and hydrated lime suspensions as a sludge treatment process for the specific purpose of agricultural recycling. The introduction of ‘Liquid Lime’ treatment has enabled South West Water to achieve full compliance with the Sludge (Use in Agriculture) Regulations at a time when the...

The aim of the present study was the estimation of changes in the phytotoxicity of soils amended with sewage sludge with relation to Lepidium sativum, Sinapis alba and Sorghum saccharatum. The study was realised in the system of a plot experiment for a period of 29 months. Samples for analyses were taken at the beginning of the experiment, and then after 5, 17 and 29 months. Two kinds of sewage...

The adsorption of Cu, Cd, Ni, Zn, and Cr from synthetic solutions on powdered activated carbon (PAC), activated sludge, and dried sludge were investigated under laboratory conditions to assess its ability to remove heavy metals. The adsorption efficiency increased rapidly within the first 30 min and then slowed down as it approached a steady state after 5 h of contact time. The results showed t...

The potential for reuse of iron-rich sludge from waterworks as a replacement for commercial iron salts in wastewater treatment was investigated using acidic and anaerobic dissolution. The acidic dissolution of waterworks sludge both in sulphuric acid and acidic products such as flue gas washing water and commercial iron solution was successful in dissolving the iron from waterworks sludge. The ...

Wastewater treatment plants are one of the main sources of dissemination of antibiotic resistance genes (ARGs) into the environment. The present study was conducted to determine the prevalence and removal of ARGs in different wastewater treatment processes. A total of 36 samples from raw and final effluent of different activated sludge processes were collected and analyzed. Molecular analysis w...

The excessive biological sludge production is one of the disadvantages of aerobic process such as SBR. So the problem of excess sludge production along with its treatment , and disposal in aerobic processes in municipal and industrial waste water can be seen in many parts of the world even in our country . to solve the problem of excess sludge production , reducing in by oxidizing some of t...

Improvement of sludge dewaterability is important for reducing the total costs for the treatment and disposal of sludge in wastewater treatment plants. In this study, we investigate the use of hydrogen peroxide as an oxidizing reagent for the conditioning of waste activated sludge. Significant improvement to sludge dewaterability was attained after the addition of hydrogen peroxide at 30 mg/g T...