- Email: [email protected]
Anaerobic co-digestion of urban and rural wastes
PERGAMON
Renewable Energy 16 (1999) 106&1069
Anaerobic Co-digestion of Urban and Rural Wastes Mogens Hedegaard and Volker Jaensch
Department 660-Bioenergy, KRUGER A/S, International Division, Khunsagervej 2-4, DK-8230 Aabyhoej.
ABSTRACT So far the technology of anaerobic digestion has not been able to meet the predicted expectation to its potential. Many factors have been influencing this but a generally trend has been that the biogas plants constructed have had problems of both technical and financial art even they as a rule have been subsidised with close to 50%. Recently KRUGER has succeeded in construction of a new generation of standard&l biogas plants for co-fermentation of both rural and urban wastes. The intention has been to put the technology back to its original enthusiasm by demonstrating viable solutions in both technical and financial terms. Furthermore, in 1997 a concept of energy neutral wastewater treatment has been demonstrated by means of co-digestion of sewage sludge and MSW which project was supported by the THERMIE programme of the EU. This concept has had an important impact to the chosen technical solutions at wastewater treatment plants and has contributed to a renewed interest in anaerobic digestion related to sewage plants. 0 1998 Published by Elsevier Science Ltd. All rights reserved.
KEYWORDS
Biogas, co-digestion, urban and rural wastes, standard&l
engineering, heat exchanging.
CONTENT 1. Presentation of actual constructed biogas plants - Schweden and Denmark. 2. New concept, mechanical cell-wall disintegration related to a German biogas plant. 3. Process description of the Genthin biogas plant supplied with mechanical cell disintegration. 0960-1481/99/%-see front matter PII: SO960-1481(98)00372-3
Q 1998 Published
by Elsevier Science Ltd. All rights reserved.
WREC 1998
1.a. Kristianstads bioeas slant - Schweden.
[email protected] plant is Sweden’s largest plant for treatment of household, industrial and agricultural waste. The recovered biogas set-&s as energy source for heat production in the “AMverket”. The energy content in the gas corresponds to the heat requirements for 600-800 households. It is the intention in future, if possible, also to use the gas in the vehicles transporting the biological waste. Furthermore source separated household waste, organic waste and manure are transformed into an environmentar friendly fertiliser. The pasteufisatton step ensures 100% sanitation which means that the fertiliser can be spread on farmland without risk.
capecity:
73,000 ton.9 /year
Digester vdume: Gas quantity: Energy productIon: Client:
2QOhsMay 135 ton&Jay of manure 35 tcddey of wganic hlduew we!3te 30 tondday WQenic twwhold waste 4,500 ma S-Q,000 ms btoQae/day l.Q-2.oMw Krtetianstad~ Renhllttnlngs AS
Form of a&red: scopeof ellpgy:
(Km) TUrllkeyWpptyKrOQerAfS Supply and inetellation of the
PIUCMS:
1065
1066
1 .b.
WREC
1998
Grin&ted bioeas dant - Denmark.
THERMIE project BM 77/94 “Grindsted Municipality Waste Water Treatment Plant” CPH generation based upon co-digestion of#WSWand sewage sludge. Kri@erA/S THERMIE Coordinator att. Mogens Hedegaard Aboulwarden 52 DK- 8700 Horwns Tk otherporticiponts in the THERM/E project ore: CRINDSTEO Munidpality att Tage Christensen DK- 7200 Grindsted S.E.E. SA att. Ceorges Petmawodsky 8- 1050 8~s.sels
1067
WREC 1998
1.c. Laholm bioas dant - Schweden. FLOW
DIAGRAM
- LAHOLM
BlOGAS PLANT
6
Process: BigadmP
I.
Primary and mixing tank incorporated in the recep-
4. Digester: retention time 19 to 22 days at 3R’C.
tion building.
5. Combined heat and power
6. Storage tank for digested manure.
requirement is reduced to max. 10% of the gas yield. 3. Pasreurisation unit; heot treatmentat 70Tfor
unit; conversion of biogas
to combinedheat and power.
2. Counter-current heat exchangers; the process heat min. 1
hour.
TECHNICAL
I
DATA
Capacity:
100 tons of livestock manure/d 20 tons of organic industtial waste/d
STANDARD
SOLUTIONS
The Laholm plant is a Bigadaa standard plant for which the mechanical, SCADA and electrical equipment is delivered pre-assembled IO the site in 2 or 3 prefabricated container
Reactor volume: 2250 m’ 3-4BOO m’ of biogas/d
modules.
Combined heat
As extra equipmenl. a complete combined heat and power mm
and power:
350 kW electricity
can be supplied. also built into a container module.
500 kW heat
The standard solution offers the following advantages:
Gas yield:
Client:
Laholms Biogas AB
Short construct!on period and less dependency on weather
- formed
conditrons
by three interested partres
SHK Energi
Rapid and unproblematic running-in
Lahohn Municipality
Flexible plant design facilitating removal/extension
Vallberga Lantmitnn
Lower installation and construction costs
Form of supply: Turnkey, I. Kruger Engineering AS Bigadan”
Kriiger
1068
WREC
1998
3. New concert. mechanical cell-wall disintegration related to a German bioaas olant. Genthin WasteAiVastewater Tresbnent Plant
WREC 1998 .
j3.
.
n
1069
I1disitt~n.
the
she supp~ementatyorganic waste is received batch-wise in a 80 cbm tank where it is @sed
by ) is means of steam prod& by the CHP unit. Emission gas from the steam treatment used as primary combustion air by the CHP unit meaning that any kind of air poRution is avoided. Aftet steam pasteurization the supplementary organic waste is loaded to the mixing tank (300 cbm ) and mixed in with the cell disintegrated biological sludge prior to regular loads from here to the 3,m cbm digester. The digester itself is also connected to the mechanical cell disintegration facility enabling further cell disintegration of the total substrate. The innovative principle is to maximii the biodegradability by intensive mechanical cell disintegration of all substrate under a minimised specific
energy consumption. The heat recovery system comprises substrateMMate heat-exchangers recovering heat Ram the digested substrate to preheat raw subs&ate, which aheady is preheated as a function of the steam pasteurisntion of the supplementary organic wastes. Final digestion temperature is reached by substrate/water heat-exchanging. An in&grated innovative step by the heat exchanging system is that biological sludge for recycling, within tbe wastewater treatment plant and not bemg sttbjact to cell disintegration, also is passing through the heat-exchangas and preheated. Bspecially in periods of cold weather this is expected to means a higher capacity and mare.offtcient operation of the SBR wastewater treatment plant. The digester can be operated both in mesophilic and thermophilic temperatme level. Leaving digester and heat ax&anging the digested material is loaded to a covered and gas-tight afterdigestion tank of capacity 300 cbm substrate and 200 cbm bii. I~C~US~UI of ana&-@&ion tank also presents an innovative step where certain amounts ofbiogas is e to be caught compared to the usual system of immediate processing or uncovered gas-tight storage of digested material. The after-digested sludge is fhtally dewatered in an existing belt-press and the sludge cake is rscycled to farmland by means of an existing container system. The liquid phase is returnhtg to a 3,000 cbm pmstorage tank to the SBR wasmwatm beatmutt plant for recycling to water purification. Much transpottation energy can be saved by being related to a wastewater tmatmsnt plant enabling dewatering prior to final disposal upon farmland. The produced biogas originating from’both the main digester and f&n the after-digestion tank is loaded to a CHP unit with steam pmduction for fmteurisation out of the gas-engine con&u&n flus gas wf&h slso pmaents an innovative step. Heat from the gas-engine cooling water is exdmqed into a centralised heat transmission system and sold to the detergent factory Henkel for industrial purposes. The excessive electricity produced is delivered to the public grid. Key figures are
:
j!g&t Biological sludge from industrial wastewater . . . . . . . . . . . . . . . . . . Biological sludge from municipal wastewater . .. . . . . . . . . . . . ... Septic sludge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. Industrial waste, f& . . . . . , . . . . . . . . . . . . . . . . . . . . . . . . ._. . . . . . . . . . . . . .. Household waste, kitchen waste . . . . . . . . . . . . . . . . . . . . . . . . . . . ., . .__
28 tons/day with 5.5 % dry matef 28 ton411ywith 9.5 % dry matter
Biogas production . . . . .. . ... .. .. .. .. . .. . . . . .. . .. . .. . .._... ._._... ...
5,300 cubicmeter/day (65 YOmethane)
Total electricity production . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ___. . . . . Ndelectri4Q’pfodu&ondeliveredtopublicgrid ... .. . ... . .. TotaJheatprodurtieo . . . . 4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . N~~tpmductiontransmitted(sotd) . . . . . . ..a.................
I2.090 9,500 I7.500 13,090
Digester
: 3.000 cbm
CHP unit : 500 kwu
18tons/daywith8%drymatter 18tonsAlaywith8%drymatter 14tosm’daywith8%drymatter
kWh#ay kWWday kwwday (44 gAMuute) kWWay (33 ul/mmute)
Renewable Energy 16 (1999) 106&1069
Anaerobic Co-digestion of Urban and Rural Wastes Mogens Hedegaard and Volker Jaensch
Department 660-Bioenergy, KRUGER A/S, International Division, Khunsagervej 2-4, DK-8230 Aabyhoej.
ABSTRACT So far the technology of anaerobic digestion has not been able to meet the predicted expectation to its potential. Many factors have been influencing this but a generally trend has been that the biogas plants constructed have had problems of both technical and financial art even they as a rule have been subsidised with close to 50%. Recently KRUGER has succeeded in construction of a new generation of standard&l biogas plants for co-fermentation of both rural and urban wastes. The intention has been to put the technology back to its original enthusiasm by demonstrating viable solutions in both technical and financial terms. Furthermore, in 1997 a concept of energy neutral wastewater treatment has been demonstrated by means of co-digestion of sewage sludge and MSW which project was supported by the THERMIE programme of the EU. This concept has had an important impact to the chosen technical solutions at wastewater treatment plants and has contributed to a renewed interest in anaerobic digestion related to sewage plants. 0 1998 Published by Elsevier Science Ltd. All rights reserved.
KEYWORDS
Biogas, co-digestion, urban and rural wastes, standard&l
engineering, heat exchanging.
CONTENT 1. Presentation of actual constructed biogas plants - Schweden and Denmark. 2. New concept, mechanical cell-wall disintegration related to a German biogas plant. 3. Process description of the Genthin biogas plant supplied with mechanical cell disintegration. 0960-1481/99/%-see front matter PII: SO960-1481(98)00372-3
Q 1998 Published
by Elsevier Science Ltd. All rights reserved.
WREC 1998
1.a. Kristianstads bioeas slant - Schweden.
[email protected] plant is Sweden’s largest plant for treatment of household, industrial and agricultural waste. The recovered biogas set-&s as energy source for heat production in the “AMverket”. The energy content in the gas corresponds to the heat requirements for 600-800 households. It is the intention in future, if possible, also to use the gas in the vehicles transporting the biological waste. Furthermore source separated household waste, organic waste and manure are transformed into an environmentar friendly fertiliser. The pasteufisatton step ensures 100% sanitation which means that the fertiliser can be spread on farmland without risk.
capecity:
73,000 ton.9 /year
Digester vdume: Gas quantity: Energy productIon: Client:
2QOhsMay 135 ton&Jay of manure 35 tcddey of wganic hlduew we!3te 30 tondday WQenic twwhold waste 4,500 ma S-Q,000 ms btoQae/day l.Q-2.oMw Krtetianstad~ Renhllttnlngs AS
Form of a&red: scopeof ellpgy:
(Km) TUrllkeyWpptyKrOQerAfS Supply and inetellation of the
PIUCMS:
1065
1066
1 .b.
WREC
1998
Grin&ted bioeas dant - Denmark.
THERMIE project BM 77/94 “Grindsted Municipality Waste Water Treatment Plant” CPH generation based upon co-digestion of#WSWand sewage sludge. Kri@erA/S THERMIE Coordinator att. Mogens Hedegaard Aboulwarden 52 DK- 8700 Horwns Tk otherporticiponts in the THERM/E project ore: CRINDSTEO Munidpality att Tage Christensen DK- 7200 Grindsted S.E.E. SA att. Ceorges Petmawodsky 8- 1050 8~s.sels
1067
WREC 1998
1.c. Laholm bioas dant - Schweden. FLOW
DIAGRAM
- LAHOLM
BlOGAS PLANT
6
Process: BigadmP
I.
Primary and mixing tank incorporated in the recep-
4. Digester: retention time 19 to 22 days at 3R’C.
tion building.
5. Combined heat and power
6. Storage tank for digested manure.
requirement is reduced to max. 10% of the gas yield. 3. Pasreurisation unit; heot treatmentat 70Tfor
unit; conversion of biogas
to combinedheat and power.
2. Counter-current heat exchangers; the process heat min. 1
hour.
TECHNICAL
I
DATA
Capacity:
100 tons of livestock manure/d 20 tons of organic industtial waste/d
STANDARD
SOLUTIONS
The Laholm plant is a Bigadaa standard plant for which the mechanical, SCADA and electrical equipment is delivered pre-assembled IO the site in 2 or 3 prefabricated container
Reactor volume: 2250 m’ 3-4BOO m’ of biogas/d
modules.
Combined heat
As extra equipmenl. a complete combined heat and power mm
and power:
350 kW electricity
can be supplied. also built into a container module.
500 kW heat
The standard solution offers the following advantages:
Gas yield:
Client:
Laholms Biogas AB
Short construct!on period and less dependency on weather
- formed
conditrons
by three interested partres
SHK Energi
Rapid and unproblematic running-in
Lahohn Municipality
Flexible plant design facilitating removal/extension
Vallberga Lantmitnn
Lower installation and construction costs
Form of supply: Turnkey, I. Kruger Engineering AS Bigadan”
Kriiger
1068
WREC
1998
3. New concert. mechanical cell-wall disintegration related to a German bioaas olant. Genthin WasteAiVastewater Tresbnent Plant
WREC 1998 .
j3.
.
n
1069
I1disitt~n.
the
she supp~ementatyorganic waste is received batch-wise in a 80 cbm tank where it is @sed
by ) is means of steam prod& by the CHP unit. Emission gas from the steam treatment used as primary combustion air by the CHP unit meaning that any kind of air poRution is avoided. Aftet steam pasteurization the supplementary organic waste is loaded to the mixing tank (300 cbm ) and mixed in with the cell disintegrated biological sludge prior to regular loads from here to the 3,m cbm digester. The digester itself is also connected to the mechanical cell disintegration facility enabling further cell disintegration of the total substrate. The innovative principle is to maximii the biodegradability by intensive mechanical cell disintegration of all substrate under a minimised specific
energy consumption. The heat recovery system comprises substrateMMate heat-exchangers recovering heat Ram the digested substrate to preheat raw subs&ate, which aheady is preheated as a function of the steam pasteurisntion of the supplementary organic wastes. Final digestion temperature is reached by substrate/water heat-exchanging. An in&grated innovative step by the heat exchanging system is that biological sludge for recycling, within tbe wastewater treatment plant and not bemg sttbjact to cell disintegration, also is passing through the heat-exchangas and preheated. Bspecially in periods of cold weather this is expected to means a higher capacity and mare.offtcient operation of the SBR wastewater treatment plant. The digester can be operated both in mesophilic and thermophilic temperatme level. Leaving digester and heat ax&anging the digested material is loaded to a covered and gas-tight afterdigestion tank of capacity 300 cbm substrate and 200 cbm bii. I~C~US~UI of ana&-@&ion tank also presents an innovative step where certain amounts ofbiogas is e to be caught compared to the usual system of immediate processing or uncovered gas-tight storage of digested material. The after-digested sludge is fhtally dewatered in an existing belt-press and the sludge cake is rscycled to farmland by means of an existing container system. The liquid phase is returnhtg to a 3,000 cbm pmstorage tank to the SBR wasmwatm beatmutt plant for recycling to water purification. Much transpottation energy can be saved by being related to a wastewater tmatmsnt plant enabling dewatering prior to final disposal upon farmland. The produced biogas originating from’both the main digester and f&n the after-digestion tank is loaded to a CHP unit with steam pmduction for fmteurisation out of the gas-engine con&u&n flus gas wf&h slso pmaents an innovative step. Heat from the gas-engine cooling water is exdmqed into a centralised heat transmission system and sold to the detergent factory Henkel for industrial purposes. The excessive electricity produced is delivered to the public grid. Key figures are
:
j!g&t Biological sludge from industrial wastewater . . . . . . . . . . . . . . . . . . Biological sludge from municipal wastewater . .. . . . . . . . . . . . ... Septic sludge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. Industrial waste, f& . . . . . , . . . . . . . . . . . . . . . . . . . . . . . . ._. . . . . . . . . . . . . .. Household waste, kitchen waste . . . . . . . . . . . . . . . . . . . . . . . . . . . ., . .__
28 tons/day with 5.5 % dry matef 28 ton411ywith 9.5 % dry matter
Biogas production . . . . .. . ... .. .. .. .. . .. . . . . .. . .. . .. . .._... ._._... ...
5,300 cubicmeter/day (65 YOmethane)
Total electricity production . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ___. . . . . Ndelectri4Q’pfodu&ondeliveredtopublicgrid ... .. . ... . .. TotaJheatprodurtieo . . . . 4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . N~~tpmductiontransmitted(sotd) . . . . . . ..a.................
I2.090 9,500 I7.500 13,090
Digester
: 3.000 cbm
CHP unit : 500 kwu
18tons/daywith8%drymatter 18tonsAlaywith8%drymatter 14tosm’daywith8%drymatter
kWh#ay kWWday kwwday (44 gAMuute) kWWay (33 ul/mmute)