Colsen Group 2012

Transcription

1 Colsen Group 2012

2 Colsen Group 2012 Colsen International b.v. Kreekzoom 5, 4561, GX Hulst, NL +31 (0) (0)

3 Table of contents PART I: Colsen 1. About Colsen 2. Services and technologies PART II: The Energy Factory 1. Motive for development 2. Thermophilic sludge digestion 3. Optimizing energy production 4. Nutrient recovery 5. Latest developments Page 3 / 52

4 I.1. About Colsen Colsen LATAM - Argentina Consultancy Technology Colsen Ecopreneur - Chili Bachirat Colsen - Morocco Ahidra Colsen - Spain Engineering Colsen Milieu - Belgium Italia - HydroItalia Colsen Romania - Colsen - van den Hul VOF Colsen Consultancy Technology Engineering Colsen b.v. - The Netherlands Global partners Page 4 / 52

5 I.2. Services & technologies Organic pollutants removal N/P removal & recovery Municipal wastewater treatment plant Technologies Biogas cleaning Industrial wastewater treatment plant Services Post-purification (polishing) / water reuse Agricultural biogas plants Industrial biogas plants Page 5 / 52

6 I.2. Services & technologies Thermophilic digestion Page 6 / 52

7 I.2. Services & technologies Waste water treatment Page 7 / 52

8 I.2. Services & technologies Digestate treatment Page 8 / 52

9 I.2. Services & technologies UASB Page 9 / 52

10 I.2. Services & technologies ANPHOS Page 10 / 52

11 I.2. Services & technologies AMFER Page 11 / 52

12 I.2. Services & technologies NAS -MBR Page 12 / 52

13 I.2. Services & technologies Water re-use Page 13 / 52

14 Table of contents PART I: Colsen 1. About Colsen 2. Services and technologies PART II: The Energy Factory 1. Motive for development 2. Thermophilic sludge digestion 3. Optimizing energy production 4. Nutrient recovery 5. Latest developments Page 14 / 52

15 II.1. Motive for development The Energy Factory: Striving towards Electricity producing waste water treatment, with production of Energy, nutrients and clean water. >100% (Lazarova et al., 2012, Water21) Focus on sludge line: Energy recovery through thermophilic sludge digestion Nutrient recovery Page 15 / 52

16 II.2. Thermophilic sludge digestion The Energy Factory: Striving towards Electricity producing waste water treatment BIDOX Valorization to green gas η 42% electrical Biogas kw(e) + kw(th) Drying Bio-sulphuric acid CHP Ammoniumsulphate WWTP sewage sludge Digestion tank Separator Stripper Anphos Effluent to main stream STP AMFER NAS -SBR Dryer Thermophilic sludge digestion Struvite Page 16 / 52

17 II.2. Thermophilic sludge digestion Conventional sewage treatment: Sludge line: 20 kg DM IE -1 year -1 to sludge; tons sludge per year Sludge treatment and disposal: 40% of STP opex average cost 330 / ton sludge (incl. dewatering and processing costs) Traditional (mesophilic ) sludge digestion: Prim. sludge / sec. sludge = 50 : 50 Hydraulic Retention Time 20 days Average yield: 25 40% odm conversion Page 17 / 52

18 II.2. Thermophilic sludge digestion Sewage treatment of the future: Thermophilic sludge digestion: Tests indicate 60 70% odm conversion Anticipated results More biogas produced Less digested sludge to be processed Lower operational costs More nutrients (N/P) in digestate More H 2 S in biogas Lower sludge disposal quantity Technical need for HRT of days Optimal mixing Strict temperature control Page 18 / 52

19 II.2. Thermophilic sludge digestion More efficiency at higher process temperatures: Thermophilic bacteria Mesophilic bacteria ~90% odm conversion primary sludge ~50% odm conversion secondary sludge Total reduction (prim. sludge / sec. sludge = 50 : 50) 70% odm Up to 50% more biogas; more electrical and thermal energy for use on STP or external More nutrients: NH 4+ -N > 2,500 mg/l; PO 3-4 -P > 600 mg/l More sulphur in biogas: H 2 S > 2,000 ppm Page 19 / 52

20 II.2. Thermophilic sludge digestion Example; three Dutch STP s Tilburg (A) Land van Cuijk (B) Bath (C) STP A B C Capacity (IE) 375, , ,000 Sludge production (kg ODM/IE/year) (Primary + secondary) 16,1 (9,6 + 6,5) 12,4 (0 + 12,4) 10,9 (5,4 + 5,5) Digester volume (m 3 ) 2 x x 5430 Digester loading rate (kg ODM/m 3 /d) 1,86 2,05 1,48 Digester SRT (d) Page 20 / 52

21 II.2. Thermophilic sludge digestion Thermophilic vs. mesophilic sludge digestion: Thermophilic sludge digestion: % improvement Primary sludge (%ODM conv.) Secondary sludge (%ODM conv.) Electrical efficiency (%) Mesophilic (practice) A B C Optimal mesophilic Thermophilic Mesophilic sludge digestion: 40 70% improvement Page 21 / 52

22 II.2. Thermophilic sludge digestion Electricity autarky (self efficiency): = STP Tilburg (A) Land van Cuijk (B) Bath (C) Current mesophilic 60% 18% 38% Optimized mesophilic 82% 32% 66% Thermophilic 120% 42% 97% STPs with primary- and secondary sludge become energy-neutral or energy producing after thermophilic sludge digestion Page 22 / 52

23 II.2. Thermophilic sludge digestion Opex savings sludge treatment: optimized mesophilic and thermophilic digestion vs. current mesophilic digestion Tilburg Land van Cuijk Bath Sludge opex saving: 18 75% (opt. Mesophilic) v.s % Thermophilic Contribution electricity gain: 40 60% (opt. Mesophilic) vs % Thermophilic Page 23 / 52

24 II.2. Thermophilic sludge digestion Thermophilic heat requirement: STP Tilburg (A) Land van Cuijk (B) Bath (C) Heat production (kwth) Heat requirement (kwth) Excess heat (kwth) STPs with primary- and secondary sludge: no additional costs involved; STP with only secondary sludge: negligible cost involved ( 0,02/IE/year) Page 24 / 52

25 II.2. Thermophilic sludge digestion Business case for STP Bath (C) Parameter Current mesophilic digestion Thermophilic digestion Electricity production (kwh) Revenu ( /year) Maintenance costs CHP ( /year) DM production (ton/year) PE use (kg active PE/year) PE costs ( /year) Sludge cake transport off-site (ton/year) Costs sludge transport ( /year) Total costs ( /year) Savings compared to current ( /year) Page 25 / 52

26 II.2. Thermophilic sludge digestion DIGESTMIX system ~90% Optimal odm mixing conversion (promote primary sludge sludge digestion, avoid foam, scum) ~50% No moving odm conversion parts inside secondary the digestion sludge tank Total Accurate reduction temperature (prim. sludge control / sec. sludge = 50 : 50) 70% odm More No extra nutrients: heat necessary, NH 4+ -N > 2,500 because mg/l; thermal PO 3-4 -P energy > 600 production mg/l is More higher sulphur in biogas: H 2 S > 2,000 ppm Page 26 / 52

27 II.2. Thermophilic sludge digestion Alternative for thermophilic sludge digestion: Thermal hydrolysis prior to (mesophilic or thermophilic) digestion. ~90% odm conversion primary sludge ~50% Anticipated Optimal odm mixing conversion results (promote secondary sludge sludge digestion, avoid Disadvantages foam, scum) Total Accurate reduction temperature (prim. sludge control / sec. sludge Operate = 50 : 50) at % bar odm pressure Same More results No extra nutrients: as thermophilic heat NH necessary, 4+ -N > 2,500 because mg/l; thermal PO 3- Operate 4 -P energy > 600 at 140 production mg/l 180 C is digestion More higher sulphur in biogas: H 2 S > 2,000 ppm High capex and opex! Page 27 / 52

28 II.2. Thermophilic sludge digestion Thermophilic sludge digestion vs. thermal hydrolysis Thermophilic digestion Thermal hydrolysis Capex Opex Revenue Overall efficiency ++ - Page 28 / 52

29 II.3. Optimizing energy production Higher BOD removal by AB system BOD removal First stage Conventional % Pre-settlingtank AB system % Adsorption sludge Anticipated results Up to 60 % more primary sludge compared to conventional More biogas Less surplus sludge Disadvantages Need for other denitrification then conventional Page 29 / 52

30 II.3. Optimizing energy production Example: STP Tilburg (A) Primary sludge conversion: 90% Surplus conversion: 50% Primary sludge (kg ODM/day) Conventional (presetteling tank) AB system 6,056 16,150 ODM conv. (kg ODM/day) 5,451 14,535 Surplus sludge (kg ODM/day) 6,464 1,847 ODM conv. (kg ODM/day) 3, Total conv. (kg ODM/day) 8,682 15,459 Page 33 / 52

31 II.3. Optimizing energy production Electricity autarky (STP Tilburg (A)): = STP Conventional (presetteling tank) AB system Current mesophilic 60% 75% Optimized mesophilic 82% 95% Thermophilic 120% 140% More primary sludge results in better efficiency; CHP should be suitable to process additional biogas. This may result in the necessity to increase the capacity ( investment) Page 34 / 52

32 II.3. Optimizing energy production BIDOX Valorization to green gas η 42% electrical Biogas kw(e) + kw(th) Drying Bio-sulphuric acid CHP Ammoniumsulphate WWTP sewage sludge Digestion tank Separator Stripper Anphos Effluent to main stream STP AMFER NAS -SBR Dryer Struvite Desulphurizing and drying of biogas Page 32 / 52

33 II.3. Optimizing energy production Biological biogas desulphurization by oxidation (BIDOX ) BIDOX system High efficiency H 2 S removal less corrosion in CHP No chemical requirements Low running costs No clogging with elemental S; production of bio sulphuric acid Page 33 / 52

34 II.3. Optimizing energy production Biogas drying for better efficiency on CHP Conditioning of desulphurized biogas before use in CHP Higher efficiency on CHP; up to 42% electrical efficiency More uptime of the biogas engine Lower maintenance costs Page 34 / 52

35 II.4. Nutrient recovery Facilitate the main stream of the STP by Partial flow treatment Most Dutch STP s must meet the following effluent requirements: Parameter COD BOD SS N-total P-Total Permit 125 mg/l 20 mg/l 30 mg/l 10 mg/l 2 mg/l Treatment of rejection water removes extra nutrient load to main stream of STP after thermophilic sludge digestion Page 35 / 52

36 II.4. Nutrient recovery Facilitate the main stream of the STP by Partial flow treatment After thermophilic digestion considerably more nutrients (example STP Bath(C)): Mesophilic digestion Thermophilic digestion Flow rejection water (m 3 /day) NH 4 -N concentration (mg/l) NH 4 -N load (kg/day) PO 4 -P concentration (mg/l) PO 4 -P load (kg/day) kg/day extra NH4-N to main stream 199 kg /day extra PO4-P to main stream Necessity for partial flow treatment? Page 36 / 52

37 II.4. Nutrient recovery Facilitate the main stream of the STP by Partial flow treatment BIDOX Valorization to green gas η 42% electrical Biogas kw(e) + kw(th) Drying Bio-sulphuric acid CHP Ammoniumsulphate WWTP sewage sludge Digestion tank Separator Stripper Anphos Effluent to main stream STP AMFER NAS -SBR Dryer Struvite Recovery of Nitrogen Page 37 / 52

38 II.4. Nutrient recovery Recovery of Nitrogen (AMFER ) C2C Nitrogen removal with new air stripping process: Heating to 60 C NH 4+ -N stripping from 2,500 to 500 mg/l (80% N-removal) Fixation of N as ammonium sulphate; 45% (NH 4 ) 2 SO 4 sol. Liquid fertilizer; market value 110/m 3 Page 38 / 52

39 II.4. Nutrient recovery Recovery of Nitrogen (AMFER ) Costs (Example STP Tilburg (A)): Stripping AMFER Partial nitritation/ Anammox Removal (kg N/day) Opex ( /kg N) 1,8 0,7 Total costs ( /IE/year) 0,19 0,36 Page 39 / 52

40 II.4. Nutrient recovery Facilitate the main stream of the STP by Partial flow treatment BIDOX Valorization to green gas η 42% electrical Biogas kw(e) + kw(th) Drying Bio-sulphuric acid CHP Ammoniumsulphate WWTP sewage sludge Digestion tank Separator Stripper Anphos Effluent to main stream STP AMFER NAS -SBR Dryer Struvite Recovery of Phosphorous Page 40 / 52

41 II.4. Nutrient recovery Recovery of Phosphorous (ANPHOS ) C2C Phosphorous removal as struvite: ph increase by air stripping (not necessary after AMFER ) Magnesium salt addition PO P removal from 600 to 10 mg/l (> 90% P-removal) Crystallization and settling; simple dewatering to 40% dm Slow release fertilizer; market value 35/ton Page 41 / 52

42 II.4. Nutrient recovery Facilitate the main stream of the STP by Partial flow treatment BIDOX Valorization to green gas η 42% electrical Biogas kw(e) + kw(th) Drying Bio-sulphuric acid CHP Ammoniumsulphate WWTP sewage sludge Digestion tank Separator Stripper Anphos Effluent to main stream STP AMFER NAS -SBR Dryer Struvite Efficient removal of Nitrogen Page 42 / 52

43 II.4. Nutrient removal NAS (Hybrid activated sludge / anammox) Efficient removal of Nitrogen: Biomass consists of up to 10% anammox Removes > 70% of all N in the anammox stage Overall removal of nitrogen ~95% (liberated as N 2 ) Effluent quality: < 20 mg/l N-total Anammox operate via a shortcut in the nitrogen cycle: Page 43 / 52

44 II.4. Nutrient removal Idea (Anno 2000): use of short-circuit in denitrification reaction Solution: NAS (New Activated Sludge) NAS 1 NAS 2 NAS 3 Settler Implementation of pre-nitritation reactor (NAS 1): Only 50 % NO 2 - formation or too much conversion towards NO 3 - Too much COD removal (40 50 %) for denitrification Effluent NAS 1 perfectly suited for Anammox-bacteria (recently discovered) Can remove N without COD source Need combination NH 4 + and NO 2 - Page 44 / 52

45 II.4. Nutrient removal NAS NAS 1 NAS 2 NAS 3 Settler NAS 1 Proper NH 4 :NO 2 ratio Low SRT Low DO NAS 2 Effluent lower COD:N Saving on O 2 consumption (and energy) N-removal by anammox Saving on O 2 consumption (and energy) No COD requirement (less sludge growth) Conventional denitrification (polishing) NAS 3 Polishing effluent Complete COD removal Complete nitrification Page 45 / 52

46 II.4. Nutrient removal NAS in industrial waste water treatment already in full-scale for years NAS system since 2004 Anaerobic treatment (UASB), followed by ANPHOS N 2 rising bubbles NAS 2 NAS 1 NAS 2 NAS 3 - Clarifier COD:N ratio of NAS is 3:1 COD mg/l NH mg/l Process controlled based on DO and SRT Page 46 / 52

47 II.4. Nutrient removal NAS : second reactor at LWM Bergen-op-Zoom Anaerobic treatment (UASB), followed by ANPHOS Four tanks (NAS 1, NAS 2a, NAS 2b, NAS 3) + settler Process controlled based on DO and SRT COD:N ratio of NAS is 3:1 - COD mg/l - NH mg/l Page 47 / 52

48 II.4. Nutrient removal NAS : second reactor at LWM Bergen-op-Zoom Experiences: When bypass towards NAS 2 was stopped, stable operation! (after 1 year) Effluent quality < 10 mg/l N-total Water reuse project with MBR-RO: Long term measurements by Ugent (LabMET) 3% of total biomass is Anammox, responsible for ~77% N-total removal (article published in Water Research) Optimisation of NOB repressing measures Page 48 / 52

49 II.4. Nutrient removal NAS -MBR: Treating waste water and liquid fraction of digestate Thermophilic digester, separation of digestate, UASB followed by ANPHOS Three tanks (NAS 1, NAS 2, NAS 3) + MBR Process controlled by DO and SRT COD:N of influent NAS is 4 COD 2500 mg/l NH mg/l Page 49 / 52

50 II.4. Nutrient removal NAS -MBR: Treating waste water and liquid fraction of digestate Operational since 1 year Effluent quality < 40 mg/l N total Problems with stable operation of NAS 1 High SS in influent (> 3 g/l) due to digester More N in influent (due to digester) Solution: extra monitoring needed for process control of NAS 1 (at these conditions) NAS -MBR Guarantee of SS-free effluent NAS at higher VSS (=smaller footprint) Ideal pre-treatment for RO (water re-use) Page 50 / 52

51 II.5. Latest developments partial flow treatment NAS ; as partial flow treatment executed as Sequencing Batch Reactor (SBR) SBR-NAS One stage N-removal COD:N ratio < 3 Cases where COD removal is not required Page 51 / 52

52 II.5. Latest developments main stream UNAS N-removal in main stream of sewage treatment B-stage in a two stage sewage treatment as energy factory Page 52 / 52

53 II.5. Latest developments main stream UNAS (mainstream) Low temperature: operational capability for STP mainstream; Granular sludge: no settlingtank but easy separation by hydrocylone; Less aeration because of N-shortcut into denitrification process Page 53 / 52

54 II.5. Latest developments main stream Profits of AB-system with UNAS v.s. AB-system* Aeration Saving kwh/y Pumpenergy Saving kwh/y Thermophile digestion Extra kwhe/y Total savings kwh/y *STP: m3/d, kg CZV/d, kg N-kj/d Page 54 / 52

55 Colsen Group 2012 Colsen International b.v. Kreekzoom 5, 4561, GX Hulst, NL +31 (0) (0)

56 Colsen Group 2012 Colsen International b.v. Kreekzoom 5, 4561, GX Hulst, NL +31 (0) (0)