Introduction. Introduction. Introduction. Sludge handling in small and mid-size treatment plants. - Introduction

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Sludge handling in small and mid-size treatment plants Dr.-Ing.

(i.e. WWTPs Badendorf, Gudow) - Case Examples: Mid-size Treatment Plants (i.e. WWTPs Ratzeburg, Ratekau) - Summary Biotests

start up Expert s report Optimization Support Associated Partner of Page 1 Page 2 WWTPs > 100,000 PE Schleswig- Holstein

1 Sludge handling in small and mid-size treatment plants Dr.-Ing. Jörn Einfeldt (Privatinstitut für Klärtechnik GmbH, D Bad Schwartau, Germany) - - Case Examples: Small Treatment Plants (i.e. WWTPs Badendorf, Gudow) - Case Examples: Mid-size Treatment Plants (i.e. WWTPs Ratzeburg, Ratekau) - Summary Biotests and chemical investigations Consulting Field investigations and data collection Process design and development Facilities start up Expert s report Optimization Support Associated Partner of Page 1 Page 2 WWTPs > 100,000 PE Schleswig- Holstein GKSS, 2010 Reference: Studie Ermittlung und Bewertung der technischen und logistischen Rahmenbedingungen bei der zukünftigen Klärschlammentsorgung in Schleswig- Holstein, LANU 2005 Page 3 Page 4 1

Biological Treatment, i.e. aeration tank Clarifier 7 Inlet Effluent Return sludge Excess sludge 796 WWTP < 100.

2 Biological Treatment, i.e. aeration tank Clarifier 7 Inlet Effluent Return sludge Excess sludge 796 WWTP < PE Not talking about constructed wetlands Reference: Studie Ermittlung und Bewertung der technischen und logistischen Rahmenbedingungen bei der zukünftigen Klärschlammentsorgung in Schleswig- Holstein, LANU 2005 Percentage of sewage sludge volumes by size class WWTP Carrapateira / Portugal Page 5 Page 6 In Germany: Schleswig-Holstein: 71,5 % (2009) Dumpsite Agricultural use Landscape building, composting Incineration Dumpsite Agricultural use Landscape building, composting Incineration Reference: Umweltbundesamt, Zusammenstellung aus Daten des Statistischen Bundesamtes (Stand 2009) Reference: Umweltbundesamt, Zusammenstellung aus Daten des Statistischen Bundesamtes (Stand 2009) Page 7 Page 8 2

Required degrees of stabilisation assigned to utilisation or disposal

for biological sewage sludge stabilisation process (Reference:

3 Required degrees of stabilisation assigned to utilisation or disposal objectives (ATV-DVWK-M-368E) small mid-size Recommended areas of application for biological sewage sludge stabilisation process (Reference: ATV-DVWK-M-368E) Page 9 Page 10 Disposal costs in / m³ /tos /tds 400 Disposal costs in / tds, incl. transport Agriculture 4%DS 25%DS Reference: DWA-Arbeitsbericht Arbeitsgruppe AK-13.4, KA 2010 (57) No.3 Reference: Page 11 Page 12 3

Drying beds (WWTP As-Salt / Jordan) primary sludge surplus sludge (if necessary aerob

$mechanical sludge dewatering (or sedimentation) fraction drying > 40% ds drying >80%$ waste mono incineration cement industry, gasification, Low-T-Conversion agriculture/

waste mono incineration cement industry, gasification, Low-T-Conversion agriculture/

Page 14 1) Example WWTP Badendorf (1,000 PE) Thickener Clarifier Leachate Aeration

4 Drying beds (WWTP As-Salt / Jordan) primary sludge surplus sludge (if necessary aerob stab.) sludge stabilisation (digestion) mechanical sludge dewatering (raw sludge) mechanical sludge dewatering (or sedimentation) fraction drying > 40% ds drying >80% ds special solutions for pretreatment composting, conditioning coincineration coal/ waste mono incineration cement industry, gasification, Low-T-Conversion agriculture/ landscaping thermal recycling thermal/ material recycling material recycling Page 13 Page 14 1) Example WWTP Badendorf (1,000 PE) Thickener Clarifier Leachate Aeration Tank Humification bed, 3 sections Neversdorf Badendorf ZV Grevesmühlen Gudow Page 15 Page 16 4

$) 1) Example WWTP Badendorf (1,000 PE) Reed bed with drainage system mechanical sludge dewatering (raw sludge) mechanical sludge dewatering (sedimentation / gravity thickening) fraction drying > 40%$ ds drying >80% ds special solutions for pretreatment dewatering / drying / composting Dewatered sludge, 14 days after feeding coincineration coal/ waste mono incineration cement industry,

ds drying >80% ds special solutions for pretreatment dewatering / drying / composting Dewatered sludge, 14 days after feeding coincineration coal/ waste mono incineration cement industry,

5 primary sludge sludge stabilisation (digestion) surplus sludge (if necessary aerob stab.) 1) Example WWTP Badendorf (1,000 PE) Reed bed with drainage system mechanical sludge dewatering (raw sludge) mechanical sludge dewatering (sedimentation / gravity thickening) fraction drying > 40% ds drying >80% ds special solutions for pretreatment dewatering / drying / composting Dewatered sludge, 14 days after feeding coincineration coal/ waste mono incineration cement industry, gasification, Low-T-Conversion > 12 a Agriculture / landscaping thermal recycling thermal/ material recycling material recycling Characteristics: - > 0.6 m²/pe - further degradation of organic material % dry solids Page 17 Page 18 2) Example WWTP Gudow (4,500 PE) 2 Sludge ponds 3) Example WWTP Neversdorf (8,200 PE) old part 2 Clarifier Aeration Tank 2+3 (old) Clarifier 2 Sludge ponds Aeration Tank 1 (new) Aeration Tank Page 19 Page 20 5

primary sludge mechanical sludge dewatering (raw sludge) sludge stabilisation (digestion) surplus sludge (aerob partly stabilized)

$fraction drying > 40% ds coincineration coal/ waste drying >80% ds mono incineration special solutions for pretreatment cement industry,$ thermal recycling thermal/ material recycling material recycling Page 21 Page 22 Examples small WWTP 3) Examples WWTP Neversdorf / Gudow 3)

thermal recycling thermal/ material recycling material recycling Page 21 Page 22 Examples small WWTP 3) Examples WWTP Neversdorf / Gudow 3)

6 primary sludge mechanical sludge dewatering (raw sludge) sludge stabilisation (digestion) surplus sludge (aerob partly stabilized) mechanical sludge dewatering (sedimentation / thickening) 3) Examples WWTP Neversdorf / Gudow Sludge pump Sludge removal and transport fraction drying > 40% ds coincineration coal/ waste drying >80% ds mono incineration special solutions for pretreatment cement industry, gasification, Low-T-Conversion storing, stabilisation 0,5 / 1 a agriculture Leachate sewer (closed) Stirrer Transport Collection Container thermal recycling thermal/ material recycling material recycling Page 21 Page 22 Examples small WWTP 3) Examples WWTP Neversdorf / Gudow 3) Examples WWTP Neversdorf / Gudow Damaged leachate sewer, caused by ice layer in winter Characteristics: % dry solids (for pumping) Page 23 Page 24 6

4) Example Zweckverband Grevesmühlen Zweckverband : Association of several communities, in this case for the purpose of wastewater treatment 4) Example Zweckverband Grevesmühlen Central WWTP

are low Specific annual costs, /MgDS (including operating costs for digestion!

7 4) Example Zweckverband Grevesmühlen Zweckverband : Association of several communities, in this case for the purpose of wastewater treatment 4) Example Zweckverband Grevesmühlen Central WWTP Grevesmühlen: - 40,000 PE - Sludge handling for 80, ,000 PE Centralized sludge handling for 31 WWTPs with a size from 35 to 40,000 PE Reference: Reference: WWTP Grevesmühlen: digester, dewatering Other WWTPs: thickening, 5 %DS, transport Page 25 Page 26 Remarks on sludge thickening for small WWTPs - Static thickening, if costs for sludge transport are low Specific annual costs, /MgDS (including operating costs for digestion!) Static thickening Flotation Mechanical thickening - Centrifuge - Belt thickener - Drum thickener - Screw thickener Remarks on sludge dewatering for small WWTPs - Dewatering (belt filter press, centrifuge, chamber filter press) or Drying (?, different technologies ) for long transport distances mobile or stationary units? - cooperations? - Alternative: Drainbags (< 3,000 PE)? - Step 1: Filling - Step 2: Dripping / Draining (30 35 %DS) - Step 3: Drying, up to 80 %DS (depending on weather conditions) (Reference: DWA-M-381) Output DS [%DS] Reference: KA Betriebs-Info 2011 (41) Nr. 3 oder Page 27 Page 28 7

Ratekau Ratzeburg WWTP Ratekau, 50.000 PE WWTP Ratzeburg, 25.

$dewatering fraction drying > 40% ds drying >80% ds special solutions for pretreatment composting, conditioning Recommended areas of application for$

8 Ratekau Ratzeburg WWTP Ratekau, PE WWTP Ratzeburg, PE Page 29 Page 30 primary sludge surplus sludge sludge stabilisation (digestion) mechanical sludge dewatering (raw sludge) mechanical sludge dewatering fraction drying > 40% ds drying >80% ds special solutions for pretreatment composting, conditioning Recommended areas of application for biological sewage sludge stabilisation process (ATV-DVWK-M-368E) coincineration coal/ waste mono incineration cement industry, gasification, Low-T-conversion agriculture/ landscaping thermal recycling thermal/ material recycling material recycling Page 31 Page 32 8

9 5) Example WWTP Ratzeburg (25,000 PE) 5) Example WWTP Ratzeburg ( PE) Biogastank Digester Digester Storage Combined heat and power unit Sludge dewatering Page 33 Page 34 5) Example WWTP Ratzeburg ( PE) 5) Example WWTP Ratzeburg ( PE) Combined heat and power unit Sludge dewatering (belt filter press) Page 35 Page 36 9

Inflow from WWTP Timmendorf, including excess sludge Page 37 Page 38 primary sludge Chem.-therm.

$(raw sludge) mechanical sludge dewatering 2 digesters fraction drying > 40% ds coincineration coal/ waste drying >80% ds mono$

10 5) Example WWTP Ratzeburg ( PE) 6) Example WWTP Ratekau (50,000 PE) Storage area Inflow from Ratekau, Sereetz, Hemmelsdorf Dosing of lime: nutrient enrichment Inflow from WWTP Timmendorf, including excess sludge Page 37 Page 38 primary sludge Chem.-therm. Desintegration sludge stabilisation (digestion) surplus sludge 6) Example WWTP Ratekau: Flowscheme sludge mechanical sludge dewatering (raw sludge) mechanical sludge dewatering 2 digesters fraction drying > 40% ds coincineration coal/ waste drying >80% ds mono incineration (transport) cement industry, gasification, Low-T-Conversion composting, conditioning agriculture/ landscaping thermal recycling thermal/ material recycling material recycling Excess sludge storage Mechanical thickening Chemicalthermal desintegration Chamber filter press Page 39 Page 40 10

6) Example WWTP Ratekau: CTD Hot water supply Excess sludge Results: - Higher gasproduction (but not scientifically quantified) - Better operating conditions (in activated sludge tank, no more

11 6) Example WWTP Ratekau: CTD Hot water supply Excess sludge Results: - Higher gasproduction (but not scientifically quantified) - Better operating conditions (in activated sludge tank, no more bulking sludge) 6) Example WWTP Ratekau: CTD Filter belt in the background CTD Reactor NaOH Dosing Mixer Sodium hydroxide solution Desintegrated sludge -> digester Copyright PONDUS Verfahrenstechnik GmbH, Teltow Page 41 Page 42 Summary - Many different solutions for sludge handling of small and mid-size WWTPs exist and are well-proven - Different framework conditions require matched process designs - New technologies may produce new operating challenges Thank you for your attention! - Some WWTP operators have to change the process of sludge handling with changing legislative in Germany Page 43 Page 44 11

Sludge Management EENV Overview of Sludge Treatment & Disposal

Sludge Management EENV Overview of Sludge Treatment & Disposal Sludge Management EENV 5000 Overview of Sludge Treatment & Disposal Sludge Management Highly complex and costly Has a cost ranging from 20% to 60% of the total operating costs of the wastewater treatment