Modification of the sewage sludge ash P-mineralogy by thermo-chemical treatment with LF slags
© Lehrstuhl fĂĽr Abfallverwertungstechnik und Abfallwirtschaft der Montanuniversität Leoben (11/2022)
As an essential nutrient Phosphorus (P) is an important constituent in fertilisers used in agriculture. However, almost the entire amount of P used in Europe must be imported from sources worldwide. High amounts of P are concentrated in sewage sludge from mostly municipal sewage. From 2029 P-recycling from sewage sludge is mandatory for wastewater treatment plants in Germany. In this study, a process which uses a thermo-chemical treatment of sewage sludge ash (SSA) with Ca-carriers, is developed. The method succeeds in producing materials which match the demands for plant available P and as proven by chemical extraction and pot trials as required by national and European regulations for fertilisers. This was achieved by treating the molten SSA with burnt lime and slags from Ca-rich ladle furnace (LF-slag) which results in the formation of better soluble P-minerals in comparison to the phases whitlockite and apatite mostly abundant in SSA.

Improving the dry magnetic separation of BOF-slag by applying an innovative pre-treatment process
© Lehrstuhl fĂĽr Abfallverwertungstechnik und Abfallwirtschaft der Montanuniversität Leoben (11/2022)
To approach circular economy by enhancing the internal recycling potential of BOFslag, an innovative pre-treatment process for the dry magnetic separation is investigated. It consists of slow-cooling to enlarge the slag crystals, followed by microwave irradiation to generate intergranular cracks to enhance the mineral liberation during comminution. It can be shown that the pre-treatment leads to an increase in the separation degree by at least four percent. This can be further enhanced by a factor of five by using solid-state oxidation.

Application of paper sludge for co-fermentation in MBT
© Wasteconsult International (5/2015)
During the production of paper and packaging materials, various paper sludges are producedas waste material. This research project, funded by the DBU, investigates cofermentation in the digesters of mechanical biological treatment plants (MBT) as an ecological and economical solution for the use of these residuals. Three types of paper sludge from different ways of paper production were analyzed. The slurries were checked for possible inhibition effects upon the biogas process in MBT and their Biogas yield. First results have shown that the co-fermentation of paper sludges in digesters of MBT plants could be useful. The results found so far do not show definite inhibition effects.

Lodgment of Polluted Sludge in Geosynthetical Tubes
© Lehrstuhl fĂĽr Abfallverwertungstechnik und Abfallwirtschaft der Montanuniversität Leoben (11/2014)
Sludge often arise as unintentional spin-off product in industrial processes. With regards to Transport (e.g. thixotropy, high water content) and further recycling (especially when contaminated) sludge is very inconvenient. However, with improved technical features sludge material might become usable as construction material for example in dams and embankments.

Effect of sewage sludge compost application on the potential toxic elements of soil and plant in 2009-2012
© European Compost Network ECN e.V. (6/2014)
In the spring of 2003 we established a small plot experiment with sewage sludge compost that contains 40% sewage sludge, 25% straw, 30% rhyolite and 5% bentonite. In 2006, 2009 and 2012 the experiment was re-treated. We ploughed into the soil 0, 9, 18 and 27 t ha-1 sewage sludge compost in five repetitions. We used spring crops and autumn cereals as corn, pea and triticale in crop rotation. Now we present some potential toxic elements (Co, Cu, Ni and Pb) content of soil samples collected from the 0-30 cm soil layer after harvesting, in 2009-2012.

RecoPhos and Other Thermo-Chemical Processes for the Recovery of Phosphorus from Sewage Sludge
© Lehrstuhl fĂĽr Abfallverwertungstechnik und Abfallwirtschaft der Montanuniversität Leoben (11/2012)
In modern sewage treatment plants (STP), about 90 % of the influent’s phosphorus can be re-moved via chemical and/or biological processes. This entire amount is found in the sludge and, after thermal treatment, also in the ashes. If sewage sludge is mono-incinerated, the resulting ashes represent the sludge matter with the highest possible P-concentration and the smallest mass to be treated respectively.

Fluidized Bed Incinerator in Tongliao (Inner Mongolia, China) – Industrial Sewage Sludge and Liquid Waste Incineration under Difficult Circumstances –
© TK Verlag - Fachverlag fĂĽr Kreislaufwirtschaft (10/2012)
Lonza Engineering Ltd. Basel, Switzerland (member of Lonza Group AG) and its wholly owned subsidiary Lonza Guangzhou Engineering & Consulting Co., Ltd., China provides customer oriented services with a professional and experienced engineering team. The company has more than 15 years of project management experience in China.

Sewage Sludge Treatment – Experiences in International Contracts from Different Views –
© TK Verlag - Fachverlag fĂĽr Kreislaufwirtschaft (10/2012)
The recent years WTE Wassertechnik GmbH has realised interesting projects with its engineers, it has realised big projects, has been looking for technical challenges, has mastered these and year by year new superlatives followed. So, for example, the infrastructure project in Zagreb, the biggest at that time in Europe, different sewage plants with more than 2 million PE (Warsaw, Istanbul), the second largest sewage plant with membrane technology, the biggest primary settlement tank with selfrotary covers, the biggest pump performances, the biggest mud throughput, the biggest sludge treatment with thermal pressure hydrolysis and a lot of other projects were realised.

Sewage Sludge as a Resource for Phosphorus
© TK Verlag - Fachverlag fĂĽr Kreislaufwirtschaft (10/2012)
Sewage sludge is a suitable resource for phosphorus. Because of the presence of harmful substances, particularly heavy metals, the application to agricultural land is seen more and more critically and is already partially banned. The aim is therefore to treat sewage sludge in a way that harmful substances are eliminated and nutrients, particularly phosphorus, can be recovered. The recovered phosphorus has to be suitable as a potential fertiliser. It has to have a low concentration of heavy metals and a good accessibility for plants, which means, that phosphorus has to be present in its soluble form. At the moment there is no efficient recovery procedure on a large scale available, which offers a high recovery potential, an elimination of harmful substances and a product with a good uptake by plants.

Pelleting of Sewage Sludge
© TK Verlag - Fachverlag fĂĽr Kreislaufwirtschaft (10/2012)
The untreated primary sludge produced in the sewage treatment plant with a dry matter content of about 4 – 5 % by mass is stabilized by means of different technical methods, dried to a DM content of 80 – 85 % and serves as raw material for further processing. Predominantly, municipal sewage sludge is pelleted, the composition of which is relatively homogeneous on account of its origin. Basically, industrial sewage sludge can also be pelleted, yet its structure and composition may vary a lot.

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