Some treatment plants in operation have not been designed to fulfill the required standards of phosphorus removal. A possibility to upgrade the efficiency of phosphorus removal could be elimination of the phosphorus returned with sludge processing liquors by releasing and recovering from sewage sludge. The phosphorus recovery can occur from sewage sludge by chemical methods or from supernatant ...

Sewage sludge at the rate of 0, 40, 80, 120 and 240 t/ha showed that the number of filled grains per panicle, dry weight of grains and weight of 1000 grains of rice (Oryza sativa L.) were the significantly highest where 240 tons of sewage sludge per hectare was added. The contents of N, P, K, Ca, Mg, Fe, Cu, Zn and Pb in rice grains increased significantly with increasing rate of sewage sludge ...

Anaerobically treated sewage sludge was found to contain extraordinarily high concentrations of 4-nonylphenol, a metabolite derived from nonionic surfactants of the nonylphenol polyethoxylate type. Concentrations in activated sewage sludge, in mixed primary and secondary sludge, and in aerobically stabilized sludge were substantially lower, suggesting that the formation of 4-nonylphenol is favo...

The main objective of this study was to investigate the rheology of mixed primary and secondary sludge and its dependency on solid content and temperature. Results of this study showed that the temperature and solid concentration are critical parameters affecting the mixed sludge rheology. It was found that the yield stress increases with an increase in the sludge solid content and decreases wi...

Sewage sludge was used as fertilizer in agriculture in Switzerland since the begin ning of modern waste water treatment. During the last 40 years several difficulties arose with the agricultural use. The problems with pathogenic germs could be solved with a prepasteurisation. The contamination with heavy metals was reduced during the years but remained a cause for concern. The fear of mad cow d...

Short chain chlorinated paraffins (SCCPs) are listed as persistent organic pollutant candidates in the Stockholm Convention and are receiving more and more attentions worldwide. In general, concentrations of contaminants in sewage sludge can give an important indication on their pollution levels at a local/regional basis. In this study, SCCPs were investigated in sewage sludge samples collected...

Morera, M. T., Echeverría, J. C. and Garrido, J. J. 2001. Mobility of heavy metals in soils amended with sewage sludge. Can. J. Soil Sci. 81: 405–414. Sewage sludges added to arable land can improve soil fertility and physical properties. However, the concentrations of heavy metals commonly found in sludges limits their application to soil. The purpose of this paper is to evaluate the mobility ...

Sewage sludge is an unavoidable secondary pollution produced in the process of sewage treatment. At present traditional methods of treating sludge (e.g. landfill, incineration or land application) have some disadvantages and shortages. Direct thermochemical liquefaction of sludge is a new treatment method, which has the advantage of both treatment and energy recovery. Research progress and appl...

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...

Environmental pollution has become a world wide concern. One of the main sources of such pollution is sewage wastewater and sludge. Their utilization without proper treatment can pollute the ecosystem (plant, soil, surface and ground water). Sewage wastewater and sludge contains several pollutants such as: pathogens, toxic organic compounds, heavy metals, high level of BOD & COD, seed weed. The...