MANURE TREATMENT Klaas Castelyn Elke Declerck Sam Gielen Mathieu Goudeseune Kris Van de Vyvere

MANURE TREATMENT

Klaas CastelynElke DeclerckSam GielenMathieu Goudeseune Kris Van de Vyvere

25,5 million chickens 5,8 million pigs 1,3 million beefs 186.000 other animals ------------------------------- Total: 33 million animals

16 million Kg N 60 million Kg N 80 million Kg N 3 million Kg N ------------------------ 160 million Kg N/year

MANURE Sam Gielen - Presentatie Milieutechnische Constructies



Organic Fertilizer Invention of artificial fertilizer leads to

manure surplus and eutrofication

manure processing


European Community A regulation is a legislative act of the European Union which

becomes immediately enforceable as law in all member states simultaneously.

A directive is a legislative act of the European Union which requires member states to achieve a particular result without dictating the means of achieving that result.

Nitrate Directive (1991) – Nitrate level of 50 mg /L Water Framework Directive, NEC Directive


Regional Level Flanders Mestdecreet

• Oprichting Mestbank• Emmisienormen (170 Kg/ha)• Nitraatresidu• Uitscheidingsnormen• Emissierechten• Mestverwerking


Livestock Reduction




Pre- treatment can help to improve fermentation and reduce the volume.

Microwave pre-treatment Ultrasonic pre-treatment Heat pre-treatment Acid pre-treatment Caustic pre-treatment …

Breakdown of organic material by microbial population working together in

an oxygen free environment.

BiogasMethane: 55 – 65 %

Carbon dioxide: 35 – 45 %

Primary goals: Energy production (electricity, hot water,

steam) Reduce the mass of solids

Secundairy goals: Pathogen destruction Pretreatment for nutrient recovery Reduction of odors Reduced greenhouse gas emissions Conversion to more available N (N to NH3). Improved flow properties Improved fertilizer efficiency

Wet or dry digestion? Wet: up to 15% DS Dry: 20 – 40 % DS

Pig manure: 6 – 10 % DS Chicken manure: higher, but little structure

dry digestion not possible

Single or multi step digestion? Multi step: methanogenesis seperated

from hydrolyse, fermentation and acetogenesis

expensive

The type of waste being digested Its concentration Its temperature The presence of toxic materials The pH and alkalinity The hydraulic retention time The solids retention time The ratio of food to microorganisms The rate of digester loading The rate at which toxic end products of

digestion are removed

Waste Characteristics Lignin and other some other hydrocarbons High nitrogen and sulfur concentrations Watersoluble

Dairy Manure Composition (Stafford, Hawkes et al. 1980)

Dilution of Waste Reduce the concentration of inhibitory

constituents Stratification Intense mixing

Foreign Materials Animal bedding, sand and silt

Toxic Materials fungicides and antibacterial agents small quantities of toxic materials

Nutrients C/N < 43 C/P < 187 Excreted manure: C/N ratio of 10

Temperature Psychrophilic AD: T < 20 °C

Mesophilic AD: T: 30-35 °C retention time: 15-30 days

Thermophilic AD: T > 55 °C retention time: 12-14 days able to destroy a larger number of pathogens more costly and complicated

Hydraulic Retention Time (HRT) The number of days the materials stays in the

tank. HRT = V/Q

It establishes the quantity of time available for bacterial growth and subsequent conversion of the organic material to gas.

Solids Retention Time (SRT) digester stability It is the quantity of solids maintained in the

digester divided by the quantity of solids wasted each day.

Food to Microorganism Ratio the key factor the bacterial consortia can only consume

a limited amount of food each day F/M ratio: the ratio of the pounds of waste

supplied to the pounds of bacteria available to consume the waste is the food to microorganism ratio

A lower F/M ratio: greater percentage of waste converted to gas

End Product Removal adversely affect the digestion process organic acids, ammonia nitrogen, and hydrogen

sulfide. lowering the influent waste concentration or

elutriation

pH between 6.8 and 8.5

Digester Loading (kg / m3 / d) diluted or concentrated? size and performance?

Low rate processes: covered anaerobic lagoons plug flow digesters mesophilic completely mixed digesters

High rate processes: thermophilic completely mixed digesters anaerobic contact digesters hybrid contact/fixed film reactors

Anaerobic Lagoons (Very Low Rate) covered ponds at psychrophilic or ground temperatures low gas production rates long retention time high dilution factor seasonal variations lowcost

Completely Mixed Digesters (Low Rate) heated and mixed mesophilic range thermophilic range intense mixing reasonable conversion of solids to gas. high cost of installation energy cost

Plug Flow Digesters (Low Rate)• the least expensive• horizontal or vertical reactor• simple, economical system • heated • stratification • removing of solids

Contact Digesters (High Rate) separating and concentrating the solids in a separate

reactor and returning the solids to the influent. degradable waste can be converted to gas since completely mixed or plug flow thermophilic or mesophilic range dilute and concentrated waste

Sequencing Batch Reactors (High Rate) digestion and separation in the same tank separation gravity a more dilute, screened waste is treated

Contact Stabilization Reactors (High Rate) more efficient efficiently converting slowly degradable

materials in a highly concentratedreactor

not appropriate for digesting manure: ‘High rate’ digesters which retain bacteria Not effective in converting particulate solids to

gas Clogging

Summary of Process Attributes

Benefits of Co-digestion: improved nutrient balance and digestion equalization of particulate, floating,

settling, acidifying additional biogas collection possible gate fees for waste treatment additional fertilizer (soil conditioner)

reclamation renewable biomass (“Energy Crops”)

disposable for digestion in agriculture.

Drawbacks of Co-digestion: increased digester effluent chemical

oxygen demand (COD) additional pretreatment requirements increased mixing requirements high utilization degree required hygienisation requirements restrictions of land use for digestate crop costs and yield

Primary Waste Streams that can be digested with Manure?

Energy crops Remains of agriculture and horticulture

products Remains of food industry Secundairy materials Animal waste category II Animal waste category III

Some examples: Food Industry:

Breweries Potato Processing Sugar Beet Processing Dairy Processing Meat Processing and Rendering Facilities Catering, Institutional, Domestic, and Restaurant Wastes

Grain Industry: Ethanol Plants with Wet and Dry Distillers Grains Damaged Grains Biodiesel Plants Soybean Processing Grain Milling Wastes

Crop Residues: Corn Stover Alfalfa or other Legumes Switch Grass and Small Grains

In agricultural area: maximum 60 000 ton/yof which minimum 60 % homegrown manure en crops

In industrial area: no limitations

function of the conversion of volatile solids to gas. 1kg volatile solids destroyes = 2.81 m³ methane 1 m³ methane = 1060 kJ at conversion efficiency 35 %

1 kg of volatile solides = 0,29 kWh of energy

Manure from m3 biogas/kg OM net. energie prod. (MJ/kg DS)

milch cow 0,2 1pig 0,3 - 0,5 4laying-hen 0,7 9

Loading rates: Conventional Digesters: 2 – 10 kg/m³/d Lagoon: 0.04 kg/m3/d

Expected Percentage VS Conversion to Gas

Digester euro/cow

Conventional 365Thermophilic 550Lagoon 620

Goal Methods

Gravity settling Mechanical separation

Screen separators Screw presses Belt-filter presses Centrifuge

Comparison Flocculents and polymers

Summary

liquid fraction Raw manure

solid fraction

Load reduction for subsequent processes

Making handle fractions (recovering of C, N, P, K, Mg, (water)

Odor reduction

Gravity settling

The use of settling tanks or basin with sloped access area where solids settle by gravity

Advantages:

Treatment of thin sowmanure (< 6% d.s.)

Stockage & sales costs ↓

Easy to operate/install

Disadvantages:

Large size requirement

High construction costs

Requires loader to remove solids

Mechanical separation

“technical efficiency”: part of P2O5 & N in solid fraction (preferable as high as possible)

Screen separators

cheap and simple perforated plate d.s. in solid fraction 6-10%

(vibrating screens 12-21%)

Screw presses

Rotatable screw supplies for increasing pressure

Closed design

Belt-filter presses

Two belts (support-sieving& pressure belt) Adaptable pressure (kind of manure dependant) Continu washing Efficiency ↑ with polymers

Centrifuge

Density solid and liquid material! Centrifugal force Very efficient, ↑ with polymer

(wetter cake) Expensive

Comparison

P mostly in solid fraction whereas K and N stay in liquid fraction

Solid separation may not be cost effective for smalloperations!

Centrifuge Screw press

Belt press

Cost price (EUR)

150.000-215.000

17.250-24.000 75.000-175.000

Flow rate (m³/h)

7-31 4-10 5-20

Elec.cons.(kWh/m³)

2-2,5 1,5-2 /

Flocculents (lime, alum) and polymers (derivatives of PAM)

Increase removal of solids

Increase removal of nutrients (N & P)

COD ↓ so chemical costs ↑ for biological denitrification

Cost

Materials pumping/addition equipment Mixing devices (if needed)

Not always recommended (V↑)

Summary:

Solid/liquid separators may accomplish the following:

Reduce the V of manure storage needed

Improve anaerobic digestion

Reduce pipe clogging systems

Possible further produce value-added by-products

Allow the use of irrigation or direct soil injection equipment

Reduce pumping horsepower needed and increase pumping distances

Goal Methods

Drying by stableswarmth Drying Composting Thermical transformations

Burning Pyrolysis Gasification

Consistency with legislation

Prevent leach out to air and water

Reduction N & P-emission

Making manure suitable for export to other countries requiring organic fertilizers (+hygienisation)

Drying by stableswarmth

“The use of warm stable air for drying manure in favour of transport over long distances or other treatment processes + reduction of NH3 concentration in stables (eutrophication +acidification ↓)”

Air heating originates from body heat pigs

Relative atmospheric humidity ↓ Water uptake capacity ↑

Drying until saturation of air condesation (cooling) Perforated plate + ventilator + air treating system (H2SO4)

2 NH3 + H2SO4 (NH4)2SO4 (fertiliser)

Pig manure more labor intensive than poultry manure (d.s.)

Foregoing separation (L/S) not necessary No liquid fraction ideal method for groundless farms Not that suitable for treatment sowmanure (d.s. < 5%) VLAREM II: when use as endproduct min 80% d.s.

Final product: - organic fertiliser- energy source for burning- carrying material for composting

Known used systems: INNOVA concept (initiative of Dorset & Wolters Agro Milieutechniek and Hendrix UTD), Farmers Freedom, S.AIR, Euromatic

Costs: drying installation + airscrubber 20.2 €/m³ (not yet hygienised)

Capacity: average of 1000 m³ ( ± 1000 ton) pig manure per year, fast implementation

Drying

“The removal of water by means of thermal heat to obtain a volume and mass reduction. The appropriate seedkilling and augmentation of storage life leads to a marketable product.”

Direct dryers Indirect dryers:

Less complex & less moving parts Off-gases very voluminous requirement for large air treatment Heat recovery possible Direct dryers susceptible for fire/explosion danger

Only suitable for large manure treatment plants with

maximal energy-efficiency!

Variable mixing ratio (0.25 – 0.75)

Costs: sludge (Aquafin) ≈ solid fraction pig manure 65 €/ton (30% d.s.)

Known used systems: Trevi condensation dryer

Condensation drier with drying unit in front and heat-exchanging unit on top

Trevi condensation dryer

Extremely adaptable construction Drying and hygienisation in a single unit No need to treat off-gases

Warm air (70-80°C) blown through solid fraction Humidified air is cooled NH3 –rich condensate

(biological unit!)

Equipped with 3 belts (predrying – drying – hygienisation)

Continuous recycling of air in closed system (NH3 & odor emission prevention)

Little space required

Composting/biothermical drying

“Composting is the aerobic decomposition of biodegradable organic matter, producing compost.”

Natural breakdown of organic matter Controlled decomposition

Speeds the process Improves the quality of the product

Composting technologies

Windrow composting Static piles = most used! Enclosed (in-vessel) composting Vermicomposting (worms)

Favourable moisture content manure between 35-65%

Use of pig manure or (solid fraction 20-35% d.s.) in addition with filling material (strow, horsemanure, grass, …)

Advantages

Reduces weight (0.5 – 0.66 %) and volume (60 %) Easier handling characteristics Reduce/eliminate pathogens and weed seeds Reduce odors Stabilize nitrogen May create a saleable product

Disadvantages

High initial cost Labor (monitoring and maintenance)

Scale dependant on process control and emission restrictions

Costs: 30-38 €/ton pig manure (30 % d.s.) (transport included)

Thermical transformations

Combustion

“Oxidation of the organic material present in manure, producing energy and a renewable mineral endproduct. Mass and bacteriological risk of the manure are reduced.”

Poultry manure or solid fraction pig manure (30 % d.s.)

Fulfilment of the three conditions (the 3 "T"s) to reach a perfect combustion:

optimum temperature of 850°C long residence time (> 2 s) maximum turbulence

Fluidised bed reactor (e.g. Seghers Bettertechnology)

Costs: 75 €/ton pig manure (30 % d.s.)

Pyrolysis

“Thermal conversion (destruction) of organic materials in the absence of oxygen.”

Temperature (450 – 750 °C) Split up in gaseous, liquid & solid fraction by

combination of thermal cracking and condensation reactions

Gaseous: H2, CH4, CO, CO2, others Liquid: acetic acid, acetone, methanol & complexe

oxigenated connections mostly used as a fuel Solid: C-rest & originally present inert material

Gasification

“Thermal conversion of organic materials at elevated temperature (750- 1400°C) and reducing (substoichiometric) conditions to produce primarily permanent gases (CO, H2, CH4, etc.).”

Further treatment of gases required, surely in case of manure gasification (removal of moisture, NH3, COS, H2S) syngas ( LHV: 4-8 MJ/Nm³)

Use of pure oxygen, syngas with LHV (stookwaarde) 10-15 MJ/Nm³

Barriers:

High investment costs (only large scale feasible, typical capacity 100 000 – 400 000 ton/year)

Manure delivery not always sure Large air treatment required in conformity with Vlarem II

… aeration…Remove[s] organic material or oxygen demand… [and] a portion of the N and P

by biological uptake… .

CentrifugeStorage thin

fraction100 m³manure

Lagune

70 m³effluen

t

Storage biological

sludge

12 m³sludge

Biologicalreactor

Settlebarrel

Organic nitrogen (protein, urea)

Ammonia nitrogen (NH4

+-N)

Degradation through bacteria

nitrite nitrogen (NO2

--N)

nitrate nitrogen (NO3

--N)

Nitrogen gas (NO3

--N)

Nitrosomas

Oxygen

Nitrobacter sp.

Oxygen

Bacteria

No oxygen

liquidmanure

nitrification

denitrification

Thin fraction

Buffer

Biology 1 Biology 2

Setling tank 1Setling tank 2

Lagune1

Lagune 2 Effluent

Vergister

Example Hooglede-Gits

Photo’s taken up 21/09/2008

The manure originates from meat pigs

Effluent (spreading on the field) Rich in potassium 5,00 kg/1000L Poor in phosphate 0,08 kg/1000L Poor in nitrogen 0,33 kg/1000L

8500 m³ manure/year the manure originates from meat pigs 17 min aeration and 43 min without

areation in the biology tank

Effluent (spreading on the field) Rich in potassium 4,31 kg/1000L Poor in phosphate 0,37 kg/1000L Poor in nitrogen 0,31 kg/1000L

How much spreading on the field?Not too much to salt up from the fieldMaximum 70 ton/ha/year

How and when spreading on the field

If N<1kg NH4+-N/1000L it is not

obligatory for emission poor spreading on the field.

If nitrogen is < 0,6 kg N/ton spreading on the field in winter is possible

Example Egem

Photo’s taken on 21/09/2008

Constructors of a biological manure treatment plant in Belgium.

Bio Armor Belgium Colsen bv Polymetal nv Trevi nv Waterleau

Pumping up sludge and spreading on the foam

Addition of plant lipids (corn oil, line seed oil,…)

Adding Lime

Procesdiscription Manure + CaO or CaMgO

==> pH rise till 10 -11 temp rise till 40°C

Mineral N evaporates as NH4

Hygeinisation (germs are killed) Water chemically bonded or evaporates

==> Dry weight rises 10 – 15%

Adding Lime

Scrubber is needed for the absorption of NH4 (H2SO4)

(H2SO4)

Because of high pH no other organic odours are formed

Endproduct = organic mineral fertilizer with nutritional en neutralasing value

==> attractive in agriculture

Adding Lime

Energy-use Low because there’s only mixing and

airscrubbing

Costs Less known Laviedor €5 ton-1

Industrial WWT: €62 – €87 ton-1 sludge

Adding Lime

1 company in Flanders: Laviedor

Treat poultry manure

End product = HUMOCAL

Practical problems because of complaining

neighbours==> extra investments

O. M.

N P2O5 K2O S CaO MgO

35 4 3 10 0.7 6 2.5

Percentual composition of Humocal

Remove sulphur smell, precipitated with a catalyst.

Ammonium nitrogen removal throughout stripping and catalyst oxidation N2

There is only one constructor in flanders. (Smelox)

Elektrolysis

Elektrolysis

Oxidation effect in electrolysis very reactive 02 is formed Wich oxidises dissolved matter

many organic structures fall apart Al en Fe used as anode and kathode

Flotation effect In electrolysis H2 en O2 gasbubbles are formed

suspended particles adsorb and rise to the surface

Elektrolysis

Flocculation effect At the Fe- and Al-anodes Al en Fe ions are formed

Excellent floc-forming auxiliaries pH influence!

N03 reduction Catalytic reduction

*Cu/Pd catalysator *excess Fe2+/Cu catalysatorH2 H+ Fe2+ Fe3

unwanted products : NH4 high pH needed

UF microporeus membrane unwanted products: NH4 NO2 NH2O

interesting for small scale research stadiumresearch stadium

Elektrolysis

One of the main benefits of manure evaporation is the reduction of up to 87% of the manure which allows the transport of the N,P,K from areas with a great concentration of livestock to areas with plant cultivation to become much cheaper.

In this way it is possible to reduce area requirements by 50%.

It is also possible to irrigate a much greater amount of the distillate to the land without overfertilizing.

Efficiently using the heat from steam to evaporate water.

In a multiple-effect evaporator, water is boiled in a sequence of vessels, each held at a lower pressure than the last.

Because the boiling point of water decreases as pressure decreases, the vapor boiled off in one vessel can be used to heat the next, and only the first vessel (at the highest pressure) requires an external source of heat.

diagram of a double-effect falling film evaporator. Condensing vapors from flash tank B1 heat evaporator A2. 1=feed, 2=product, 3=steam, 4=vapors

Multiple-effect evaporator (65 à 75 kcal/litre water)

VOMM thin film evaporator (650 à 750 kcal/litre water)

4 fermentation reactors of 2000m³ There are 3 generators of 1mega Watt

(8000 to 8200 working hours)

Anaerobic digestion9% DW

20% DW

80% DWGoes to agriculture

Thickener (photo)

Spiessens technology

1/3 of the digestate is recuperated as heat (0,8 megawatt)

2/3 of the heat originates from a wood stove. The wood stove burns waste wood. (1,6 mega Watt)

Thickener in Deinze

Constructed Wetlands

Natural Wetlands = areas with a lot of water Swamps Lakes Flood area of rivers Undeep parts of rivers

Constructed Wetlands = wetlands built to treat contaminated water (manure)


Differences

They remain constant in size

They are not directly connected with groundwater

They accommodate greater volumes of sediment

They more quickly develop the desired diversity of plants and associated organisms



Conventional systems Biological

processes Fossil energy A lot of energy /

area High costs

Plant based systems Biological processes Renewable energy Less energy / area Low costs Integrated in

landscape Habitat for a lot of

species


• Plants– Pleustophytes: float on the surface

don’t need a substrate

– Hydrophytes: live under water don’t reach the surface

– Helophytes: bottom-substrate reach the surface


Common Duckweed


• Plants– Pleustophytes: float on the surface

don’t need a substrate

– Hydrophytes: don’t reach the surface

– Helophytes bottom-substrate reach the surface


Common Reed Cattail


Carex sp.

Scirpus sp.


• Pleustophytfilters– Only active at the surface– Sedimentation under the roots

• Helophytfilters3 types:– surface flow wetland– Subsurface flow wetland– Percolation field


– Surface flow wetland• A lot of plantation on a substrate• Water is less than 0.4 m (ideal 40 - 50 cm)

• Water flows through plants


– Subsurface flow wetland• Water level under substrate level• Water flows through roots


– Percolation field• Water flows vertical• Flows through roots and bottom

wetland


• Removal processes– BOD– Suspended solids– N removal– P removal– Heavy metals– Pathogens


• BOD– Suspended solids are removed by

sedimentation or filtration– After sedimentation (an)aerobic processes

occur– O2 from diffusion

fotosynthetic algae translocation through aerenchym

– T° influence– Wetland: min. 70% removal– Max BOD 280 kg/ha/d – 5 days residence time


• Suspended solids


• N removal


• P removal


• Heavy metals


• Pathogens

Contructed WetlandsPolluent Removal process

Organic material (BOD) Biological degradation, sedimentation, microbial uptake

Organic contaminants (pesticides)

Adsorption, volatilisation, fotolyse and (a)biotic degradation

Suspended solids Sedimentation, filtration

Nitrogen Sedimentation, (de)nitrification, microbial uptake, plant uptake, volatilisation

Phosphorus Sedimentation, filtration adsorption, plant uptake, microbial uptake

Pathogens Natural death, sedimentation, filtration, predation, UV degradation, adsorption

Heavy metals Sedimentation, adsorption, plantuptake

Contructed Wetlands

Role of the plant

Contructed Wetlands

Thin Fraction

Biology Adding lime Fysicochemistry Electrolysis Evaporation Filtration Constructed wetlands

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Biology Adding lime Fysicochemistry Elektrolysis Evaporation Filtration Constructed wetlands

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Documents

MANURE TREATMENT Klaas Castelyn Elke Declerck Sam Gielen Mathieu Goudeseune Kris Van de Vyvere