**4. Swine slurries treatment technologies**

### **4.1 Organic matter removal**

Anaerobic treatment technologies are widely used in this field, because they allow to remove organic matter, pathogens, odors, generating by-products (biogas,

**89**

(0.02–0.5 m3

H2S/m2

biogas/m2

from anaerobic lagoons have been made covering them.

greater than anaerobic lagoons; but have clogging problems [93].

The most advance technology has been developed to improve operational problems of conventional technologies. On the one hand, AFBR systems (Anaerobic

Fluidized Bed Reactor) are technologies studied mainly at laboratory scale. They use support material (clay, wood and PVC), which is suspended due to the

*Nutrients Cycle within Swine Production: Generation, Characteristics, Treatment…*

bio-fertilizer) [93]. There several anaerobic technologies, such as: biodigesters, anaerobic lagoon, complete mixing anaerobic reactors, anaerobic filters, UASB or Upflow Anaerobic Sludge Blanket, among other [94]. Worldwide, anaerobic technology based on conventional anaerobic mesophilic reactors (4935 plants) and thermophilic reactors (321 plants) treat around 49 million ton/year slurries, which have been built in Europe, mainly in Germany (more than 70%) [87]. State subsides, innovation technologic and centralization of biogas plants using agricultural wastes (livestock, crop) have favored their implementation [90, 91]. Meanwhile, more than 7000 technologies based on anaerobic lagoon have been built, but with only 60% operationally actives in the United States [63]. The conventional anaerobic reactors (complete mixture, piston flow) have been limited by its costs, remaining in disuse or only in building project around 77% [94]. However, currently these technologies are being replaced by more efficient technologies in terms of removal of nutrients, odors and pathogens [68, 71]. Technologies such as tubular biodigesters are the most used in countries where the livestock production in non-intensive. The *anaerobic lagoons* are extensive and conventional typology, where organic matter is biodegraded without hydraulic or thermal control (environmental conditions) [95]. In the livestock sector, these systems offer some advantages related to their storage capacity and operation easy [96]. However, they can also cause odors, requiring spaces far spaces from neighboring population [94, 96]. Anaerobic lagoons obtain organic matter removal efficiencies between 26 and 79%, working under environmental conditions (5–32°C) and with residence times from 90 to 232 days [97, 98]. The lagoon design must consider thermal vertical stratification, suggesting depths between 0.8 and 4.0 m to maintain facultative conditions upper and anaerobic zone bottom [69, 99]. Its longer residence time also favors the macro (organic matter, nutrients) and micro (metals) nutrients precipitation. Thus, has been observed that anaerobic lagoon accumulates more than 50% COD, TN, P and Cu in the bottom, decreasing pH from 6.5–7.2 throughout its depth (>1.5 m) [99]. Another advantage is related with their disinfection capacity, due to its prolonged time exposure to solar radiation, causing cell lysis of pathogenic microorganisms [100]. However, this time exposure generates greenhouse gas emission

d) [69] and odors (168–262 OC/m3

are controlled systems, where the hydraulic retention time (residence time) is equal to the cell retention time [102]. The complete mixture is achieved through the recirculation from 25 to 40% of biogas generated [103]. It can operate under psychrophilic, mesophilic, and thermophilic conditions, which are carried out in two stages (acidogenic and methanogenic reactors) [93, 103]. This technology has been widely used mainly in Europe, obtaining organic matter removal efficiencies from 25 to 74%, but with organic loading between 5 and 40 times greater than anaerobic lagoon [87, 93]. CSRT reactor have been improved with the recirculation [93]. Other conventional technologies as anaerobic filters or AF generate biofilm around of the material support surface, while the flow goes up throughout the filter [102]. Inert (nylon meshes, polyurethane foams, polypropylene rings) and organic (blocks, wood chips) support material have been used [93]. The main advantage of this technology is that can operate at organic loading between 69 and 142 times

s) [101]. Operational improvements mainly related to the emission of gases

The conventional full mix reactors or CSRT (Continuous Stirred Reactor Tank)

, 101 μg NH3/m2

s, 5.7 μg

*DOI: http://dx.doi.org/10.5772/intechopen.89733*

#### *Nutrients Cycle within Swine Production: Generation, Characteristics, Treatment… DOI: http://dx.doi.org/10.5772/intechopen.89733*

bio-fertilizer) [93]. There several anaerobic technologies, such as: biodigesters, anaerobic lagoon, complete mixing anaerobic reactors, anaerobic filters, UASB or Upflow Anaerobic Sludge Blanket, among other [94]. Worldwide, anaerobic technology based on conventional anaerobic mesophilic reactors (4935 plants) and thermophilic reactors (321 plants) treat around 49 million ton/year slurries, which have been built in Europe, mainly in Germany (more than 70%) [87]. State subsides, innovation technologic and centralization of biogas plants using agricultural wastes (livestock, crop) have favored their implementation [90, 91]. Meanwhile, more than 7000 technologies based on anaerobic lagoon have been built, but with only 60% operationally actives in the United States [63]. The conventional anaerobic reactors (complete mixture, piston flow) have been limited by its costs, remaining in disuse or only in building project around 77% [94]. However, currently these technologies are being replaced by more efficient technologies in terms of removal of nutrients, odors and pathogens [68, 71]. Technologies such as tubular biodigesters are the most used in countries where the livestock production in non-intensive.

The *anaerobic lagoons* are extensive and conventional typology, where organic matter is biodegraded without hydraulic or thermal control (environmental conditions) [95]. In the livestock sector, these systems offer some advantages related to their storage capacity and operation easy [96]. However, they can also cause odors, requiring spaces far spaces from neighboring population [94, 96]. Anaerobic lagoons obtain organic matter removal efficiencies between 26 and 79%, working under environmental conditions (5–32°C) and with residence times from 90 to 232 days [97, 98]. The lagoon design must consider thermal vertical stratification, suggesting depths between 0.8 and 4.0 m to maintain facultative conditions upper and anaerobic zone bottom [69, 99]. Its longer residence time also favors the macro (organic matter, nutrients) and micro (metals) nutrients precipitation. Thus, has been observed that anaerobic lagoon accumulates more than 50% COD, TN, P and Cu in the bottom, decreasing pH from 6.5–7.2 throughout its depth (>1.5 m) [99]. Another advantage is related with their disinfection capacity, due to its prolonged time exposure to solar radiation, causing cell lysis of pathogenic microorganisms [100]. However, this time exposure generates greenhouse gas emission (0.02–0.5 m3 biogas/m2 d) [69] and odors (168–262 OC/m3 , 101 μg NH3/m2 s, 5.7 μg H2S/m2 s) [101]. Operational improvements mainly related to the emission of gases from anaerobic lagoons have been made covering them.

The conventional full mix reactors or CSRT (Continuous Stirred Reactor Tank) are controlled systems, where the hydraulic retention time (residence time) is equal to the cell retention time [102]. The complete mixture is achieved through the recirculation from 25 to 40% of biogas generated [103]. It can operate under psychrophilic, mesophilic, and thermophilic conditions, which are carried out in two stages (acidogenic and methanogenic reactors) [93, 103]. This technology has been widely used mainly in Europe, obtaining organic matter removal efficiencies from 25 to 74%, but with organic loading between 5 and 40 times greater than anaerobic lagoon [87, 93]. CSRT reactor have been improved with the recirculation [93].

Other conventional technologies as anaerobic filters or AF generate biofilm around of the material support surface, while the flow goes up throughout the filter [102]. Inert (nylon meshes, polyurethane foams, polypropylene rings) and organic (blocks, wood chips) support material have been used [93]. The main advantage of this technology is that can operate at organic loading between 69 and 142 times greater than anaerobic lagoons; but have clogging problems [93].

The most advance technology has been developed to improve operational problems of conventional technologies. On the one hand, AFBR systems (Anaerobic Fluidized Bed Reactor) are technologies studied mainly at laboratory scale. They use support material (clay, wood and PVC), which is suspended due to the

*Livestock Health and Farming*

adequate agriculture sites [86].

crop type, according to the international revaluation legislation [83, 84]. These tools would allow the cadasters establishment, which could facilitate the communication between nutritional requirements sites (agricultural soils) and nutrients-generating sites (animal farms) [85]. Preliminary Chilean studies have reported opportunities of livestock slurries revaluation in agriculture relating nutrients recovery sites with

*Diagram of decision-making process within of the cycle of generation, treatment, and revaluation of swine slurry.*

The biogas production from anaerobic digestion of swine slurries is another revaluation alternative. In Europe, technologies based on biogas generation have been favored by state subsidies (10–30% investment cost) at farms level. These initiatives have allowed the building the more than 5000 anaerobic digestion projects [65, 87]. Swine slurries have potential capacity of methane generation between 0.25 and

tons/year of waste and with a production between 0.7 and 5.7 million m3

**4. Swine slurries treatment technologies**

**4.1 Organic matter removal**

[90, 91]. Preliminary Chilean studies have allowed to establish the potential generation of bioenergy (biogas) from anaerobic co-digestion (livestock/crop wastes) at regional level [92]. **Figure 1** describes excretes management in the swine production.

Anaerobic treatment technologies are widely used in this field, because they allow to remove organic matter, pathogens, odors, generating by-products (biogas,

CH4/kg VS [88]. Meanwhile, co-digestion with lignocellulosic materials (e.g. crop waste) could increase more than 16% produced methane [89]. Thus, centralized plants of anaerobic co-digestion are the current trend within European agricultural sector. Successful experiences have been reported in Germany and Denmark, where more than 32 plants have been built with a capacity between 16,000 and 200,000

biogas/year

**88**

0.30 m3

**Figure 1.**

recirculation of the flow [102]. These characteristics partially avoid clogging [103]. On the other hand, UASB technology has been applied at the laboratory and pilot level. These treatment units generate biomass granulated, which sediments (4 m/h) improving the cellular retention time [102]. The flow goes up, favoring the washing of biomass non-granulated the granules are dense, harboring multi-species and diverse microbial communities. However, the granulation processes require longer periods of formation (2–8 months). Other innovative technologies from UASB systems are the EGSB (*Expanded Granular Sludge Bed*). This last technology is hydraulically improved respect to UASB, because it operates at greater flow velocity (>4 m/h) than UASB [104]. In general, UASB reactors are a viable alternative, since they are considered high load systems, operating at organic loadings between 2 and 162 times higher than conventional systems (anaerobic lagoons, CSRT). The organic matter removal efficiencies reach ranges between 19 and 86% [93, 94, 103, 105]. In addition, they offer other operational advantages related to their volume (0.006–0.5 times less volume than lagoons and CSRT) and sludge production (granular from UASB vs. suspended from lagoons/CSRT) [104]. Moreover, UASB generates higher biogas production (0.28–4.05 m3 /m3 d) than conventional systems (0.02–1.69 m3 /m3 d), thanks to the fact that they operate at higher organic loading (1–8.1 kg COD/m3 d) [69, 93].

**Table 6** and **Figure 2** describe the operational characteristics of anaerobic technologies applied on swine slurries.

#### **4.2 Nutrients and metals removal**

Constructed wetlands are used as a cost-effective alternative for the nutrients removal within the livestock sector [70]. In Europe, there are around 60 livestock farms, which treat 17,000 tons/year using constructed wetlands [87]. In the United States, about 33% (~ 70 farms) of constructed wetlands are used within livestock sector, being mainly (~ 83%) surface flow constructed wetlands (SF-CW) [70].

Operationally, there is experience in the use of different types of constructed wetlands within swine sector. However, SF-CW are the most used technology, mainly to avoid clogging [106]. Generally, SF-CW are used after the anaerobic lagoon, operating at nutrient loading between 5 and 36 kg N/ha and between 1 and 6 kg P/ha. The nitrogen and phosphorous removal efficiencies obtained reach values from 50 and 90 to and 25–66%, respectively [106–109]. Moreover, horizontal subsurface flow constructed wetlands HSS-CW have been studied at laboratory and pilot scales, operating at nutrient loading between 69 and 252 kg N/ha d and


*CSRT, continuous stirred reactor tank, AF, anaerobic filter, AFBR, anaerobic fluidized bed reactor, UASB, upflow anaerobic sludge blanket. \* =BOD5 units, ^ = COD units,° = VS units.*

**91**

*^ = NH4+*

**Table 7.**

**Figure 2.**

*(c) AF, (d) AFBR, (e) UASB.*

*Tl*, *Sa* 6 (HSS-

*Pc, Pa, Tl* Hybrid

*Ci, So, Pa* Híbrido (3

*Sa, Sc, Sv, Je, Spa, Ta, Tl*

*Pa, Tl, Cp, Ca, Sl, Sm, Fu, Is, Ma, Ac, Se, Apa, Ls, Rl, S, P, Lm, Sta, Msp, Eca*

*Gm, Ga, Gs, Mm,* 

*Poa*

**Species Type Prior** 

lagoon-HS)

*Ec* 1HSS Activated

(2VS + 1HSS)

Hybrid 8(HS+ HSS + VS)

VS + 1 HSS)

*Nutrients Cycle within Swine Production: Generation, Characteristics, Treatment…*

*Schemes of different types of anaerobic reactors used in the swine slurry treatment. (a) Lagoon, (b) CSRT,* 

**HRT (days)**

**kg N/ ha d**

18 7–40 3.0–

214 —

11–13 4.8–27.2 44–51

27.5 69.0– 262.0

— 11.2– 36.0

*Cdp, Ap, Tl* 2HSS Filtration Tank 4.8 93.3 22.1 — — [111]

Acorus calamus: Ac; Alisma plantago-aquatica: Apa; Althernanthera philoxeroides: Ap; Canna indica: Ci; Carex pseudocyperus: Cp; Carex acutiformis: Ca; Cynodon dactylon Pers: Cdp; Elodea canadensis: Eca; Eichhornia crassipes: Ec; Filipendula ulmaria: Fu; Glyceria aquatica: Ga; Glyceria maxima: Gm; Iris pseudacorus: Ip; Juncus effusus: Je; Lemna minor: Lm; Lythrum salicaria: Ls; Mentha aquatica: Ma; Myriophyllum spicatum: Msp; Molinia maxima: Mm; Phragmites australis: Pa; Phragmites communis: Pc; Poa aquatic: Poa; Populus spp.: P; Ranunculus lingua: Rl; Salix spp.: S; Scirpus lacustris: Sl; Scirpus maritimus: Sm; Scirpus validus: Sv; Scirpus cyperinus: Sc; Schoenoplectus americanus: Sa; Sparganium erectum: Se; Sparganium americanum: Spa;

— — **kg P/ ha d**

22.0

0.9– 6.0 7–9

15.0- 47.0

> 30 —

**Loading rate Efficiency (%) Reference**

50–84^ 78–88^

> 10.0- 24.0^

50^ 54–67^

— 1.2–10 0.4–1 99.3^ 99.6^ [113]

4–5 76.3 2.6 64^ 61^ [114]

**N P**

37–51^ 13–31^ [109]

25–38^ <10^

> 47.0- 59.0^

42^ 47–49^

1.1–1.8 78–90\* 56–66^ [106]

[107, 108, 106]

[110]

[112]

**Treatment**

Anaerobic Lagoon

Lagoon Nitrifying unit

Sludge

Anaerobic lagoon + Sand filter Recirculated treated purine (25–100%)

> Activated sludge

digester

Aeration lagoon

Stratiotes aloides: Sta; Symphytum officinale: So; Typha angustifolia: Ta; Typha latifolia: Tl.

16HSS Anaerobic

*Operational characteristics of constructed wetlands within swine sector.*

4HSS Anaerobic

*DOI: http://dx.doi.org/10.5772/intechopen.89733*

**Table 6.**

*Operational characteristics of anaerobic reactors within swine sector.*

*Nutrients Cycle within Swine Production: Generation, Characteristics, Treatment… DOI: http://dx.doi.org/10.5772/intechopen.89733*

#### **Figure 2.**

*Livestock Health and Farming*

(0.28–4.05 m3

/m3

technologies applied on swine slurries.

**4.2 Nutrients and metals removal**

**Technology Loading kg (BOD5 \* , COD^, VS°) /m3 d**

*anaerobic sludge blanket.*

*\* =BOD5 units, ^ = COD units,° = VS units.*

*Operational characteristics of anaerobic reactors within swine sector.*

recirculation of the flow [102]. These characteristics partially avoid clogging [103]. On the other hand, UASB technology has been applied at the laboratory and pilot level. These treatment units generate biomass granulated, which sediments (4 m/h) improving the cellular retention time [102]. The flow goes up, favoring the washing of biomass non-granulated the granules are dense, harboring multi-species and diverse microbial communities. However, the granulation processes require longer periods of formation (2–8 months). Other innovative technologies from UASB systems are the EGSB (*Expanded Granular Sludge Bed*). This last technology is hydraulically improved respect to UASB, because it operates at greater flow velocity (>4 m/h) than UASB [104]. In general, UASB reactors are a viable alternative, since they are considered high load systems, operating at organic loadings between 2 and 162 times higher than conventional systems (anaerobic lagoons, CSRT). The organic matter removal efficiencies reach ranges between 19 and 86% [93, 94, 103, 105]. In addition, they offer other operational advantages related to their volume (0.006–0.5 times less volume than lagoons and CSRT) and sludge production (granular from UASB vs. suspended from lagoons/CSRT) [104]. Moreover, UASB generates higher biogas production

d) than conventional systems (0.02–1.69 m3

**Table 6** and **Figure 2** describe the operational characteristics of anaerobic

Constructed wetlands are used as a cost-effective alternative for the nutrients removal within the livestock sector [70]. In Europe, there are around 60 livestock farms, which treat 17,000 tons/year using constructed wetlands [87]. In the United States, about 33% (~ 70 farms) of constructed wetlands are used within livestock sector, being mainly (~ 83%) surface flow constructed wetlands (SF-CW) [70]. Operationally, there is experience in the use of different types of constructed wetlands within swine sector. However, SF-CW are the most used technology, mainly to avoid clogging [106]. Generally, SF-CW are used after the anaerobic lagoon, operating at nutrient loading between 5 and 36 kg N/ha and between 1 and 6 kg P/ha. The nitrogen and phosphorous removal efficiencies obtained reach values from 50 and 90 to and 25–66%, respectively [106–109]. Moreover, horizontal subsurface flow constructed wetlands HSS-CW have been studied at laboratory and pilot scales, operating at nutrient loading between 69 and 252 kg N/ha d and

> **Efficiency % (BOD5 \* , COD^, VS°)**

Lagoon 0.05–0.08° 24–32 26–79\* 0.43–0.80° 86–95 [69, 93, 97,

CSRT 0.41–2.04° 20–60 25–74\* 0.19–0.83° 60–79 [93, 94, 103] AF 3.44–11.34° 31–55 35–61^ 0.03–0.29° 61–87 [93] AFBR 1.1–6.6^ — 66–91^ 0.17–0.53^ 75–84 [103] UASB 1.0–8.1^ 20.7–35 19–86\* 0.28–0.50^ 54–87 [93, 94, 103,

*CSRT, continuous stirred reactor tank, AF, anaerobic filter, AFBR, anaerobic fluidized bed reactor, UASB, upflow* 

**Biogas m3**

**kg (BOD5 \* , COD^, VS°)**

 **biogas/**

**% Methane** **Reference**

98]

105]

fact that they operate at higher organic loading (1–8.1 kg COD/m3

**Temperature °C**

/m3

d), thanks to the

d) [69, 93].

**90**

**Table 6.**

*Schemes of different types of anaerobic reactors used in the swine slurry treatment. (a) Lagoon, (b) CSRT, (c) AF, (d) AFBR, (e) UASB.*


Acorus calamus: Ac; Alisma plantago-aquatica: Apa; Althernanthera philoxeroides: Ap; Canna indica: Ci; Carex pseudocyperus: Cp; Carex acutiformis: Ca; Cynodon dactylon Pers: Cdp; Elodea canadensis: Eca; Eichhornia crassipes: Ec; Filipendula ulmaria: Fu; Glyceria aquatica: Ga; Glyceria maxima: Gm; Iris pseudacorus: Ip; Juncus effusus: Je; Lemna minor: Lm; Lythrum salicaria: Ls; Mentha aquatica: Ma; Myriophyllum spicatum: Msp; Molinia maxima: Mm; Phragmites australis: Pa; Phragmites communis: Pc; Poa aquatic: Poa; Populus spp.: P; Ranunculus lingua: Rl; Salix spp.: S; Scirpus lacustris: Sl; Scirpus maritimus: Sm; Scirpus validus: Sv; Scirpus cyperinus: Sc; Schoenoplectus americanus: Sa; Sparganium erectum: Se; Sparganium americanum: Spa; Stratiotes aloides: Sta; Symphytum officinale: So; Typha angustifolia: Ta; Typha latifolia: Tl. *^ = NH4+*
