StorageDryer - Sewage Sludge Drying Small Plants Brochure

SLUDGESOLAR DRYING OFThe world’s Number 1 in solar dryingBackgroundThe end-product of all sewage purification, in addition to the purified water, is sewage sludge. All the harmful substances, such as heavy metals, pharmaceutical residue, household and other chemicals, and pathogenic substances are accumulated in it.Sludge disposal is therefore becoming more and more laborious and costly, Europe-wide. Even today, sludge treatment and disposal are already the main cost factors in sewage purification in many countries. Further restrictions and increase in costs in sludge disposal are to be expected in future, because:- New EU regulations will exclude earth-filling with sewage sludge in the middle term.- The utilisation of sludge as an agricultural fertiliser is subject to increasingly strict limitations, and its acceptance by agriculture, the food industry and the public has decreased dramatically in recent years.- In the opinion of many experts, the use of sludge for re-cultivation is a dieing practice, because large quantities of harmful substances are spread on the surfaces, along with the beneficial substances.- Incineration of mechanically dewatered sludge is possible only with ancillary fuelling with other energy sources.- The transport routes are tending to become longer, and the transportation costs are rising.- Rising energy costs are making conventional drying increasingly unaffordable.Solar Drying – a possible solution: Pre-dewatered sludge Liquid sludge (25% DS) (3% DS)DriedDried Against the background of rising disposal and transportation costs, it makes sense from both an energy and an economical point of view to reduce the mass of the sludge to be disposed of to an absolute minimum locally. This can be done by extracting the water that makes up the greatest part of the sludge: around 95% in the case of liquid sludge, and around 75% after mechanical de-watering. In addition, dried sludge has the calorific value of lignite, and can be burnt CO2 - neu-trally. This considerably increases the reliability of disposal. If you are looking for an absolutely environmentally friendly, industrial-scale, proven and at the same time unbeatably cost-effective drying process – Thermo-System has just that:- Using environmentally friendly solar energy, the water is removed from the sludge in an ingeniously simple manner, thus considerably reducing the quantity of sludge.- The solar-dried sludge is neutral in odour, biologically stable and easy to store. In prin-ciple, all options are open for storage, transport and disposal – and new pathways are opened up- Compared with conventional drying processes, the operating and investment costs are minimal. All 100% of the thermal energy comes from the sun, or is covered by waste heat.- The sole requirement is the availability of a suitable area. If external heating is used (CHP-Combined Heat and Power unit, biogas plant, etc.) the required area can be reduced substantially.Reduction of mass through solar drying when loaded with:Reduction of mass: 50 - 70 % Reduction of mass: 90 - 97 %We have implemented drying plants sized between 1,000 und 600,000 PE worldwide. With over 100 drying plants in operation, we have the most comprehensive fund of experience in the planning and construction of solar sewage-sludge drying plants.From the point of view of physics, 5 factors are decisive for effective drying:1. The temperature of the drying air2. The humidity of the drying air3. The velocity of the flow of air over the sludge4. The surface structure of the material to be dried5. The temperature of the sludgeOur plants’ fully automatic process controls keep these factors continuously at an optimum, taking into account the current weather conditions and the characteristics of the sludge. Years of experience and intensive research in this area guarantee our position as market and technology leader, and the excellent performance of your plant.Building shell 1A completely enclosed, highly transparent shell that isproof against hail, wind and snow load preventsuncontrolled exchange of air and unnecessary heat losses.Air-circulation fans 2Regulated, position-controlled indoor ventilators ensure optimal air-flow conditions over the sludge at all times – independent of the ambient conditions.Ventilation flaps 3By means of the regulated ventilation flaps, the exchange of air with the surroundings is adjusted precisely to the requirements.Exchange of air with fans 4Speed-controlled fans allow large quantities of air to be introduced, thus making it possible to utilise the natural drying potential of the ambient air – irrespective of the prevailing wind conditions.Plant Description: Technical ExecutionDrainage floor (optional) 5Our liquid-sludge plants do not need mechanical dewatering units of any kind. Low-maintenance, non-clogging drainage floors permit reliable, operator-friendly dewatering in the drying plant itself.Air conditioning 6A central regulator and control device processes the measured data, and regulates and monitors all compon-ents, optimising the drying process in accordance with the weather conditions and the state of the sludge.Turning equipment 7An “ELECTRIC MOLE®” or a “SLUDGE MANAGER®” – both of them fully automatic, stainless steel robots – mix, turn and move the material for drying, depending on the application. Our multiple award-winning soluti-ons are as robust as they are reliable and efficient. For more details and technical data, refer to our detailed brochures.2751Processor SensorsSensors4 36The ProcessAdvantages of the Thermo-System processTo achieve optimal drying, and to rigorously avoid the possible for-mation or odours, Thermo-System sludge-drying plants work a batch process. This way, the drying process can be optimally adjusted to the decreasing moistness of the sludge. As an alternative, we offer continuous solutions based on our SLUDGE MANAGER®.Loading the drying chambersThe drying chambers are loaded by means of a wheel loader, lorry, sludge pump or conveyor belt. With very little equipment, and thus extraordinarily low investment and operating costs, or fully automa-ted – whichever you prefer The DS content of the sludge can be anything between 2% and 40% – our equipment can deal with any degree of dewatering.The drying processAs a rule, the drying process is fully automatic. No intervention whatever is required on the part of the operator until the desired DS content is reached. Our process control regulate all the components.Removal of the dried sludgeThe removal of the dried sludge, and its loading into lorries, skips or silos, are carried out either with wheel loaders, or fully automatically. Because of the great reduction in volume during drying, this takes only a minimal amount of time, even when a wheel loader is used. Loading by lorryLoading by geyser Automatic loading- Optimum drying through fully automatic process control and air conditioning- Avoidance of odours- Low work and maintenance effort- Intelligent, extraordinarily robust, maintenance-friendly turning machines in stainless steel- Temporary storage of sludge is possible- Aerobic subsequent stabilisation of the sludge - Used even in large plants with up to 600,000 PE and up to 5 MW waste heat- Substantial reduction of pathogenic substances- Very economicalOptionsCovering materialDouble-layer polyethylene (inflatable foil)Polyethylene blister foilPolycarbonate ribbed double sheetsSingle-pane safety glassSnow and wind loadsDepending on the construction and covering material of the drying chamber, snow loads between 25 and 250 kg per m² can be implemen-ted. The structural requirements contribute heavily to the building costs, so the necessary data on snow and wind loads must be clarified before a price quotation is made.GatesSwing, sliding and tambour gates with a headroom of 2.5 - 5 m in any width.Arrangement of the drying chambersFlexible arrangement and subdivision of the chamber space are possible.Access is from the front, centre, or wherever there is room. Access from one side is sufficient.Automatic loadingSemi- and fully automatic loading with belts, screw conveyors or sludge pumps.Process control systemProfiBus or Internet connection, process control system, monitoring functions, teleservice.Utilisation of waste heatA sophisticated air-conditioning system permits optimum utilisation of waste heat from other processes (from a district heating power station, biogas plant, auxiliary heating, etc.).This way, the required area can be substantially reduced.Exhaust air treatmentThe odour emission of Thermo-System drying plants is below the level encountered at the respective sewage plants, so as a rule, treatment of the exhaust air is not necessary. But just in case, retrofitting is possible at any time.Scientific supervisionThe further development and practical use of our drying plants are supervised by scientists at the University of Hohenheim, which is regarded as the leading institute in the area of low- temperature solar drying. This ensures that the Thermo-System process maintains its technological lead. Numerous publications and scientific papers bear witness to the excellent performance and functionality of our technology.Steinbrück, Germany (15,000 EP) Discovery Bay, USA (20,000 EP)Stockach, Germany (50,000 EP)Oregon, USA (1,400 EP)Louannec, France (4,900 EP)Oldenburg, Germany (350,000 EP)Bredstedt, Germany (8,000 EP)Bad Vöslau, Austria (300,000 EP)Nogent, France (15,000 EP)Palma, Spain (600,000 EP)Krems, Austria (180,000 EP) DS content before drying- Liquid sludge (with drainage floor): 1 - 10% DS- Pre-dewatered sludge (without drainage floor): 10 - 40% DS DS content after drying- Depending on requirements, yearly average: 50 - 90% DS Area required Depending on local conditions, climate, final DS content and sludge characteristics, in purely solar operation (without utilisation of waste heat) the following approximate quantities of sludge can be dried per m² of plant area per year:- Liquid sludge (2 - 6% DS): 2 - 6 t of sludge- Pre-dewatered sludge (25 - 30% DS): 0.5 - 3 t of sludge When waste heat from other processes is utilised (e.g. from a CHP-Combined Heat and Power unit) the throughput can be greatly increased and the area requirement reduced. Filling height on loading- Drying plants for liquid sludge: 20 - 50 cm- Drying plants for pre-dewatered sludge: 10 - 30 cm Filling height at end of drying- Drying plants for liquid sludge: 1 - 3 cm- Drying plants for pre-dewatered sludge: 5 - 15 cm Electric power requirements- Drying plants for liquid sludge: 10 - 20 kWh per tonne of evaporated water- Drying plants for pre-dewatered sludge: 20 - 30 kWh per tonne of evaporated water Working time- Loading one drying chamber, per batch: 1 - 2 person-hours- Emptying one drying chamber, per batch: 0.5 - 1 person-hours- During drying: No intervention required Reduction of mass- Drying plants for liquid sludge: 90 - 97%- Drying plants for pre-dewatered sludge: 50 - 70% Subsequent aerobic stabilisation Depending on operating objectives, type of sludge and season, 5 - 30% of the dry organic substance can be degraded. Cost effectiveness With its combination of intelligent, low-operating-cost technology and quality materials, the Thermo-System process is exemplary in its cost-effectiveness. Not for nothing is Thermo-System the market leaderTechnical DataFor their assistance and support in the investigation of specific subjects, we would like to thank, in particular:Institute for Agricultural Technology, University of HohenheimInstitute for Residential Water Management, University of StuttgartInstitute for Environmental and Animal Hygiene, University of HohenheimMinistry for the Environment and Transport, Baden-WürttembergGerman Federal Foundation for the EnvironmentBavarian State Office for Environmental ConservationIf you are interested in our Thermo-System sludge-drying plant, we will be happy to make a cost estimate for your location. Please send us the filled-in questionnaire, which you can request from us directly or down-load from our homepage at www.thermo-system.com.Further information08.ks.10.11.en.00Thermo-System Industrie- und Trocknungstechnik GmbH Echterdinger Straße 57 D - 70794 Filderstadt, Germany Telephone: + 49 (0) 711 489459-0Fax: + 49 (0) 711 489459-90E-mail: info@thermo-system.comInternet: www.thermo-system.com 081110_KS_pdf_en_s1.pdf 081110_KS_pdf_en_s2.pdf 081110_KS_pdf_en_s3_4.pdf 081110_KS_pdf_engl_s5.pdf 081110_KS_pdf_en_s6.pdf 081110_KS_pdf_en_s7.pdf 081110_KS_pdf_en_s8.pdf 081110_KS_pdf_en_s9.pdf 081110_KS_pdf_en_s10.pdf