Sludge Management - Revision history

Wiki Gardener at 09:14, 18 June 2014

2014-06-18T09:14:13Z

Ranisha: /* Viscosity */

2014-03-18T13:14:11Z

Viscosity

Fungai Cecilia Sandamu at 20:22, 4 April 2013

2013-04-04T20:22:34Z

Fungai Cecilia Sandamu at 20:20, 4 April 2013

2013-04-04T20:20:24Z

Show changes

Michel andre at 15:22, 21 February 2011

2011-02-21T15:22:47Z

Michel andre at 11:00, 16 February 2010

2010-02-16T11:00:45Z

JanS at 13:59, 26 April 2009

2009-04-26T13:59:12Z

JanS at 13:57, 26 April 2009

2009-04-26T13:57:03Z

JanS at 13:55, 26 April 2009

2009-04-26T13:55:34Z

JanS at 13:52, 26 April 2009

2009-04-26T13:52:02Z

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-= Sludge Storage =
+= Overview =
 To retain the maximum fertilizing quality of digested slurry, i.e. it's nitrogen content, it should be stored only briefly in liquid form in a closed pit or tank and then applied on the fields. Preferably, it should be dug into the soil to prevent losses on the field.
 Sludge storage is normally effected according to one or the other of the following three techniques:
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 The practice of spreading liquid slurry also presents problems in that not only storage tanks are needed, but transport vessels as well. The amount of work involved depends also on the distance over which the slurry has to be transported. For example, loading and transporting one ton of slurry over a distance of 500 m in an oxcart (200 kg per trip) takes about five hours. Distributing one ton of slurry on the fields requires another three hours.
-{| cellpadding="10" border="0" align="center" class="IMGright" style="width: 286px;"
+{| border="0" align="center" cellpadding="10" style="width: 286px" class="IMGright"
 |-
+|
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 <br/>
-= Composition of sludge =
+= Composition of Sludge =
 == Process of Biomethanation ==
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 For an average daily substrate feed rate of 50 kg per livestock unit (LSU = 500 kg live weight) and a daily gas yield of 1 m<sup>3</sup> biogas/LSU, the mass of the influent substrate will be reduced by some 2% through the process of bio-methanation (volumetric weight of biogas: 1.2 kg/m<sup>3</sup>).
 == Viscosity ==
-The viscosity of the slurry decreases significantly, because the amount of volatile solids is reduced by about 50% in the course of a stable process of fermentation. In addition, the long carbon chains (cellulose, alcohol and organic acids) are converted into short carbon chains (see also under [[Biogas_Basics#Methanogenesis|Microbiological_Methanation]]).
+The viscosity of the slurry decreases significantly, because the amount of volatile solids is reduced by about 50% in the course of a stable process of fermentation. In addition, the long carbon chains (cellulose, alcohol and organic acids) are converted into short carbon chains (see also under [[Biogas_Basics#Methanogenesis|Microbiological Methanation]]).
 <br/>
 == Odor ==
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 The effluent sludge is much less odorous than the influent substrate (dung, urine). Given sufficient retention time, nearly all odorous substances are completely digested.
-{| cellpadding="10" border="0" align="center" class="IMGright" style="width: 208px;"
+{| border="0" align="center" cellpadding="10" style="width: 208px" class="IMGright"
 |-
+|
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 |}
 <br/>
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 == Nutrients ==
-The fertilizing properties of digested slurry are determined by how much mineral substances and trace elements it contains. In tropical soil, the nitrogen content is not necessarily of prime importance - lateritic soils, for example, are more likely to suffer from a lack of phosphorus. All plant nutrients such as nitrogen, phosphorous, potassium and magnesium, as well as the trace elements essential to plant growth, are preserved in the substrate. The [[Nitrogen-content and C/N-ratio of organic substrates|C/N ratio is]] reduced by the simultaneous loss of carbon, thus generally improving the fertilizing effect of the digested sludge, since a lower C/N ratio (ca. 1:15) has a favorable phytophysiological effect. [[Annual Manure Yield and Nutrient Content of Animal Excrements|Table B4]] lists the approximate nutrient contents of various substrates, whereby it should be remembered that the actual values may vary considerably, depending on fodder eaten by the animals.
+The fertilizing properties of digested slurry are determined by how much mineral substances and trace elements it contains. In tropical soil, the nitrogen content is not necessarily of prime importance - lateritic soils, for example, are more likely to suffer from a lack of phosphorus. All plant nutrients such as nitrogen, phosphorous, potassium and magnesium, as well as the trace elements essential to plant growth, are preserved in the substrate. The [[Nitrogen-content_and_C/N-ratio_of_Organic_Substrates|C/N ratio]] is reduced by the simultaneous loss of carbon, thus generally improving the fertilizing effect of the digested sludge, since a lower C/N ratio (ca. 1:15) has a favorable phytophysiological effect. [[Annual_Manure_Yield_and_Nutrient_Content_of_Animal_Excrements|Table B4]] lists the approximate nutrient contents of various substrates, whereby it should be remembered that the actual values may vary considerably, depending on fodder eaten by the animals.
 The phosphate content ("P<sub>2</sub>O<sub>5</sub>" is the form of phosphorous available for plants) is not affected by fermentation. Some 50% of the total phosphorous content is available for plants in the form of phosphate. Similarly, anaerobic fermentation does not alter the rate of plant-available potassium (75 to 100% of the total potassium).
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 Assuming that the soil should receive enough fertilizer to replace the nutrients that were extracted at harvesting time, each hectare will require an average dose of about 33 kg N, 11 kg P<sub>2</sub>O<sub>5</sub> and 48 kg K<sub>2</sub>O to compensate for an annual yield of 1-1.2 tons of, for example, sorghum or peanuts. Depending on the nutritive content of the digested slurry, 3-6 t of solid substance per hectare will be required to cover the deficit. For supply with a moisture content of 90%, the required quantity comes to 30-60 t per hectare and year. That roughly corresponds to the annual capacity of a 6-8 m<sup>3</sup> biogas plant.
-{| cellspacing="0" cellpadding="0" border="0" class="IMGcenter"
+{| border="0" cellspacing="0" cellpadding="0" class="IMGcenter"
 |-
-| style="width: 45%;" | <br/>
+| style="width: 45%" | <br/>
 | [[File:Sludgeexp.jpg|thumb|330px|Field experiments with sludge in Thailand (Photo: Kossmann (gtz/GATE)]]
-| style="width: 45%;" | <br/>
+| style="width: 45%" | <br/>
 |}
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 = Further Information =
 <br/>
 = References =
 [[Category:Biogas]]

@@ Line 42: / Line 42: @@
 For an average daily substrate feed rate of 50 kg per livestock unit (LSU = 500 kg live weight) and a daily gas yield of 1 m<sup>3</sup> biogas/LSU, the mass of the influent substrate will be reduced by some 2% through the process of bio-methanation (volumetric weight of biogas: 1.2 kg/m<sup>3</sup>).
 == Viscosity ==
-The viscosity of the slurry decreases significantly, because the amount of volatile solids is reduced by about 50% in the course of a stable process of fermentation. In addition, the long carbon chains (cellulose, alcohol and organic acids) are converted into short carbon chains (see also under [[Microbiological Methanation|Microbiological_Methanation]]).
+The viscosity of the slurry decreases significantly, because the amount of volatile solids is reduced by about 50% in the course of a stable process of fermentation. In addition, the long carbon chains (cellulose, alcohol and organic acids) are converted into short carbon chains (see also under [[Biogas_Basics#Methanogenesis|Microbiological_Methanation]]).
 <br/>
 == Odor ==

← Older revision		Revision as of 20:22, 4 April 2013
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	Serious ecological damage can be done by applying fertilizing sludge in excessive amounts or at the wrong time, namely when the assimilative capacity of the plants is low. Nitrogen "washout" can cause over-fertilization (eutrophication) of ground and surface water.		Serious ecological damage can be done by applying fertilizing sludge in excessive amounts or at the wrong time, namely when the assimilative capacity of the plants is low. Nitrogen "washout" can cause over-fertilization (eutrophication) of ground and surface water.
		+
		+	<br/>
		+
		+	= Further Information =
		+
		+	<br/>
		+
		+	= References =

	[[Category:Biogas]]		[[Category:Biogas]]

@@ Line 84: / Line 84: @@
 === Eutrophication  ===
 Serious ecological damage can be done by applying fertilizing sludge in excessive amounts or at the wrong time, namely when the assimilative capacity of the plants is low. Nitrogen "washout" can cause over-fertilization (eutrophication) of ground and surface water.
 [[Category:Biogas]]

@@ Line 13: / Line 13: @@
 The practice of spreading liquid slurry also presents problems in that not only storage tanks are needed, but transport vessels as well. The amount of work involved depends also on the distance over which the slurry has to be transported. For example, loading and transporting one ton of slurry over a distance of 500 m in an oxcart (200 kg per trip) takes about five hours. Distributing one ton of slurry on the fields requires another three hours.
-{| cellpadding="10" border="0" align="right" width="286" class="IMGright"
+{| width="286" cellpadding="10" border="0" align="right" class="IMGright"
 |-
+|
@@ Line 40: / Line 40: @@
 === Viscosity  ===
-The viscosity of the slurry decreases significantly, because the amount of volatile solids is reduced by about 50% in the course of a stable process of fermentation. In addition, the long carbon chains (cellulose, alcohol and organic acids) are converted into short carbon chains (see also under [[Microbiological_Methanation|Microbiological_Methanation]]).
+The viscosity of the slurry decreases significantly, because the amount of volatile solids is reduced by about 50% in the course of a stable process of fermentation. In addition, the long carbon chains (cellulose, alcohol and organic acids) are converted into short carbon chains (see also under [[Microbiological Methanation|Microbiological_Methanation]]).
 === Odor  ===
@@ Line 46: / Line 46: @@
 The effluent sludge is much less odorous than the influent substrate (dung, urine). Given sufficient retention time, nearly all odorous substances are completely digested.
-{| cellpadding="10" border="0" align="right" width="208" class="IMGright"
+{| width="208" cellpadding="10" border="0" align="right" class="IMGright"
 |-
+|
@@ Line 57: / Line 57: @@
 === Nutrients  ===
-The fertilizing properties of digested slurry are determined by how much mineral substances and trace elements it contains. In tropical soil, the nitrogen content is not necessarily of prime importance - lateritic soils, for example, are more likely to suffer from a lack of phosphorus. All plant nutrients such as nitrogen, phosphorous, potassium and magnesium, as well as the trace elements essential to plant growth, are preserved in the substrate. The [[Nitrogen-content_and_C/N-ratio_of_organic_substrates|C/N ratio ]]is reduced by the simultaneous loss of carbon, thus generally improving the fertilizing effect of the digested sludge, since a lower C/N ratio (ca. 1:15) has a favorable phytophysiological effect. [[Annual Manure Yield and Nutrient Content of Animal Excrements|Table B4]] lists the approximate nutrient contents of various substrates, whereby it should be remembered that the actual values may vary considerably, depending on fodder eaten by the animals.
+The fertilizing properties of digested slurry are determined by how much mineral substances and trace elements it contains. In tropical soil, the nitrogen content is not necessarily of prime importance - lateritic soils, for example, are more likely to suffer from a lack of phosphorus. All plant nutrients such as nitrogen, phosphorous, potassium and magnesium, as well as the trace elements essential to plant growth, are preserved in the substrate. The [[Nitrogen-content and C/N-ratio of organic substrates|C/N ratio is]] reduced by the simultaneous loss of carbon, thus generally improving the fertilizing effect of the digested sludge, since a lower C/N ratio (ca. 1:15) has a favorable phytophysiological effect. [[Annual Manure Yield and Nutrient Content of Animal Excrements|Table B4]] lists the approximate nutrient contents of various substrates, whereby it should be remembered that the actual values may vary considerably, depending on fodder eaten by the animals.
 The phosphate content ("P<sub>2</sub>O<sub>5</sub>" is the form of phosphorous available for plants) is not affected by fermentation. Some 50% of the total phosphorous content is available for plants in the form of phosphate. Similarly, anaerobic fermentation does not alter the rate of plant-available potassium (75 to 100% of the total potassium).
 === Nitrogen compounds  ===
@@ Line 86: / Line 86: @@
 Serious ecological damage can be done by applying fertilizing sludge in excessive amounts or at the wrong time, namely when the assimilative capacity of the plants is low. Nitrogen "washout" can cause over-fertilization (eutrophication) of ground and surface water.
-[[Category: Biogas]]
+[[Category:Biogas]]

@@ Line 49: / Line 49: @@
 |-
+|
-[[Image:Dispsludge.jpg]]&lt;small class="IMGLEGEND"&lt;/small&gt;
+[[Image:Dispsludge.jpg]]
 <small class="IMGLEGEND">'''Sludge disposal in Thailand (oder zu soileffekt)'''<br> </small><small class="IMGSOURCE">''Photo: Kossmann (gtz/GATE)''</small>

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 <br>
 == Sludge storage  ==
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 |-
+|
 [[Image:Drysludge1.jpg]]
 <small class="IMGLEGEND">'''Drying of digested sludge and sludge disposal in Thailand'''<br> </small><small class="IMGSOURCE">''Photo: Kossmann (gtz/GATE)''</small>
 |}
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 === Composting  ===
 Nitrogen losses can be reduced by mixing the digested sludge with organic material. As an additive to crop residues for composting, biogas sludge provides a good source of nitrogen for speeding up the process. At the same time it enriches the compost in nitrogen, phosphorus and other plant nutrients. Furthermore, the aerobic composting process, by it's temperature, effectively destroys pathogens and parasites that have survived the anaerobic digestion treatment. The ready-made compost is moist, compact and can be spread out by simple tools. With most available transport facilities in developing countries, it is easier to transport than liquid manure.
 == Composition of sludge  ==
@@ Line 49: / Line 49: @@
 |-
+|
-[[Image:Dispsludge.jpg]]<small class="IMGLEGEND"</small>
+[[Image:Dispsludge.jpg]]&lt;small class="IMGLEGEND"&lt;/small&gt;
 <small class="IMGLEGEND">'''Sludge disposal in Thailand (oder zu soileffekt)'''<br> </small><small class="IMGSOURCE">''Photo: Kossmann (gtz/GATE)''</small>
 |}
@@ Line 85: / Line 85: @@
 Serious ecological damage can be done by applying fertilizing sludge in excessive amounts or at the wrong time, namely when the assimilative capacity of the plants is low. Nitrogen "washout" can cause over-fertilization (eutrophication) of ground and surface water.