Sludge handling in Bottrop

Transcription

1 Sludge handling in Bottrop Dr.-Ing. K.-Georg Schmelz Emschergenossenschaft / Lippeverband Essen, Germany

2 Sludge handling in Bottrop Structure 1 Introduction 2 Sludge network system 3 Production of fuels on a sewage sludge basis - coal-polymer conditioning - trials using different high calorific fractions - shredder fluffing agglomerate-polymer conditioning 4 Sludge incineration in fluidised bed furnances 5 Summary and conclusions

3 Where we are working

4 Where to find our wastewater treatment plants

5 EMSCHERGENOSSENSCHAFT and LIPPEVERBAND two water associations with wide experience The EMSCHER Association founded in 1899 The LIPPE Association founded in 1926 EG and LV are two of the largest water associations in Germany Total area: Wastewater: square kilometres approx. 6 million PE

6 Sludge pressure pipelines 8 km 20 km Folie 6

7 2 Sludge network system Three WWTPs are connected: - Alte Emscher Duisburg: 500,000 PE - Emscher Mouth TP: 2,400,000 PE - Bottrop WWTP: 1,340,000 PE The sludge of the three WWTPs is treated at the Central Sludge Treatment Plant in Bottrop 60,000 tons dry matter per year Conditioning, dewatering, incineration

8 Digestion Incineration Waste Water Treatment River Emscher Conditioning 1 adding coal Conditioning 2 adding polymers + Dewatering

9 3 Production of fuels on a sewage sludge basis The production of fuels from sewage sludge is caused by history The wastewater in the Emscher area was characterised by coal loadings from the mining companies So the sewage sludge had a high fine coal portion (up to 30 % of the dry matter) The dewaterability on filter presses was very good (up to 50 % dry solids in the filter cake) The dewatered sludge could be used as a fuel in a power station in the neighborhood

10 3 Production of fuels on a sewage sludge basis Since the late seventies of the last century the coal mining in the Emscher area decreased rapidly The content of fine coal in the wastewater also decreased In the early eighties coal admixture facility Continue producing a fuel from sewage sludge Incineration in 2 new fluised bed furnances

11 3 Production of fuels on a sewage sludge basis - previous system (coal-polymer conditioning) For an autonomous incineration in the fluised bed incinerators the dewatered sludge must have: - calorific value: 4,400 kj/kg (wet material) - water content: % by weight - Ashes content: 45 % by weight So it was necessary to add % fine coal mixture of hard coal and lignite Particle size: 0 2 mm

12 3 Production of fuels on a sewage sludge basis - previous system (coal-polymer conditioning) Conditioning 1 Conditioning 2 DS = 20 %

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14 3 Production of fuels on a sewage sludge basis - trials with various high calorific value fractions Aim: replace the primary energy carrier coal trials using other high calorific value materials - recycling materials (e. g. plastics) - renewable raw material (e. g. sawmill waste) a lot of materials were suitable for conditioning and dewatering best results we got with shredder fluffing agglomerate (made from old cars) see the next slides

15 Recycling of old cars: the situation today Liquids out/ Demontage Shredder Waste Let out all liquids Take away battery, tyres Take out spare parts Pressing the body Spare parts Recycling Scrap steel main grinding iron separation non-iron separation Iron scrap Non iron metals SHF (Shredderheavy fraktion) 50% 50% 50% 50% SLF (Shredderlight fraktion) About 20% of the weight of the car are going to landfill From 2015 in the EU only 5% are allowed to be discharged

16 The Volkswagen-SiCon-Process for Shredderfluffing Treatment Shredder-Material Shredder-Material Main process of treatment Fe NE Raw granular Raw fluffing Raw sand Special treatment for different costumers granular fluffing sand rest disposal Recycling (e.g. PVC) NE-metal production,... Sewage sludge dewatering,... Blast furnance,...

17 3 Production of fuels on a sewage sludge basis We have the following requirements to the material: a good dewatering result (>40 % DS) a calorific value of more than 4,400 kj/kg wet sludge no additional load in the filtrate water no additional emissions from the incineration no worsening of the ashes as possible no changes of the existing system low costs availability over a long period in future the existing disposal ways must be possible

18 Delivery and mixing of the conditioning products Mixing basin situated in by-pass Mixing basin at time in future

19 3 Production of fuels on a sewage sludge basis - new system (SA-polymer conditioning) Shredder agglomerate X

20 Filter cake with Shredder Fibres

21 3 Production of fuels on a sewage sludge basis - new system: results from the large scale trial Dewatering result could be improved (+2 to +5 %-points!) The fluffing material can be mixed into the sludge nearly as easy as the coal (dust) The stripping behaviour of the filter cake from the filter presses was very good combustion performance: no changes, normal filtrate water: no higher concentrations flue gas: no increased emissions

22 4 Sludge incineration fluidized-bed furnance steamer 400 C, 40 bar 2 x 7.0 t/h waste gas washing chimney sludge 2 incinerators each 7.0 t/h turbine 2.7 MW filter for ashes washing-zone for heavy metals

23 Schlammanfall

24 4 Sludge incineration and disposal of ashes in the past: ashes are used to produce mining mortar for filling underground hollow spaces from mining today: building material for road construction in future: store the phospherous-rich ashes in monodump-sites to recover the phospherous later (when the recycling methods are further developed and economic)

25 5 Summary and conclusions Emschergenossenschaft and Lippeverband are two of the largest water associations in Germany the production of fuels from sewage sludge is caused by history (coal mining) the content of fine coal in the wastewater (and the sludge) makes it possible to produce a fuel for power stations coal mining decreased rapidly since the seventies from the eighties fine coal must be added to the sludge to go on in fuel production from sludge the aim today is to replace the coal through recycling or renewable raw materials

26 5 Summary and conclusions the use of shredder fluffing agglomerate for conditioning seems to make it possible to replace the coal by a recycling product Advantages for both sides: - the car-industry - Emschergenossenschaft

27 Thank you for your attention!