**Table 7.**

*Operational characteristics of constructed wetlands within swine sector.*

between 15 and 47 kg P/ha d. The nitrogen and phosphorus removal efficiencies vary from 10 to 24 and 47 to 59%, respectively [110, 111]. There are also experiences hybrid systems (SF/HSS/VSS) operating with plant species emergent and floating, which have achieved nitrogen and phosphorus removal efficiencies higher than 50 and 42%, respectively [112–114]. In general, constructed wetland systems will be operationally work with any previous technology. Thus, activated sludge has been used prior to constructed wetland increasing from 2 to 20 times the nutrients removal than anaerobic lagoons [109, 113]. The metals removal efficiencies have been reported in SF-CW, which have operated at rates from 0.09 to 0.25 kg Cu/ha and 0.58 to 1.58 kg Zn/ha d, obtaining removal efficiencies of up to 83 and 92%, respectively [78, 79, 111].

Currently, there are some innovations related to the constructed wetland treatment [106]. Likewise, the partial recirculation of pre-nitrified slurry has allowed to increase the nitrogen removal via denitrification up to 4 times, decreasing the ammonium volatilization [112, 115]. Other design concepts are based on the use of "*marsh-pond-marsh*" [109]. Constructed wetland technologies, could be improved operationally using intermittent hydraulic rate, which favors the oxygenation improving the nitrification [116].

**Table 7** details the constructed wetlands operational characteristics of constructed wetlands used in the pig sector.

### **5. Future perspective and conclusions**

Currently, the swine production should be looking to set the "new zoo technical order" with improvements in the life quality of the animals. Some reasons are given by environmental and health concerns given by the presence of emerging pollutants in meat and animal excreta. Indeed, swine meat has been reported as one of the sources of staphylococcus microbial resistance in humans [117]. Moreover, studies evidence the consumption of about 63,000 ton/year antibiotics in the livestock production (veterinary/promoters), being the main source of emerging pollutants in swine excreta/slurry [118]. Both water bodies and soil can be affected when these wastes are discharged or revaluated, since current treatment technologies are not designed to remove them. These two factors are further enhanced by the greenhouse gasses emissions responsibility from livestock production. Thus, swine production generates about 24 kg CO2 eq/kg protein, which is mainly attributed to the mismanagement of their excreta/slurries [119]. In this last aspect, it is that the closing of the cycle the generation, treatment and revaluation of swine excreta fulfills a fundamental role. Studies report that reductions of up to 30% in greenhouse emissions could be achieved by a comprehensive management of resources (slurry, excreta, crops remains) between livestock and crop production [120]. Thus, livestock production through appropriate technology and management practices can be a source of nutrients for crops that provide food to animals. Agricultural production would support the energy generation inside farms by anaerobic. In the future, the livestock production could be supported from integral improvement from animal production to treatment and revaluation of wastes.

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**Author details**

Cristina Alejandra Villamar\* and Cristóbal Sardá

\*Address all correspondence to: cristina.villamar@usach.cl

de Santiago de Chile, Santiago, Chile

provided the original work is properly cited.

Departamento de Ingeniería en Obras Civiles, Facultad de Ingeniería, Universidad

© 2019 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

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

*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*
