Since swine wastewater is used by farmers for soil fertilization, evaluation of toxic compounds or micro-contaminants of separate streams is required. This paper uses the toxicity identification evaluation (TIE) procedure for the physicochemical and ecotoxicological characterization of swine wastewater. To distinguish the most important toxic compounds, a physicochemical characterization and phase I-TIE procedure were performed. The acute toxic effect of swine wastewater and treated fractions (phase II-TIE) were evaluated using Daphnia magna determining 48-h LC 50 . Results show a high level of conductivity (23.5 μS cm −1 ), which is explained as due to the concentration of ions, such as ammonium (NH 4 + -N 1.6 gL −1 ), sulfate (SO 4 2− 397.3 mg L −1 ), and chlorine (Cl − 1,230.0 mg L −1 ). The acute toxicity of the swine wastewater was evaluated on D. magna (48-h LC 50 =3.4%). Results of the different water treatments indicate that anionic exchange treatments could reduce 22.5% of swine wastewater's acute toxicity by reducing chlorine (to around 51%) and conductivity (8.5%). On the other hand, cationic exchange treatment increased acute toxicity on D. magna (% RT=−624.4%), by reducing NH 4 + -N (around 100%) and total nitrogen (95.5%). This finding suggests that part of the toxicity comes from anionic compounds, such as chlorine.

Schoenoplectus californicus (C.A. Meyer), Soják is one of the plants most used to treat wastewater in a constructed wetland. Our objective is to study the growth and nutrient uptake of Schoenoplectus californicus Cyperaceae in a constructed wetland fed with swine slurry. The methodology used to evaluate the growth of the Schoenoplectus californicus Cyperaceae was to evaluate the allometric, relative abundance and biomass of the plants in the period 2009 -2010.The results show that Schoenoplectus californicus had allometric growth between 31.2 to 98.4 and relative abundance between 21 to 108 individuals m -2 , during the fall and spring seasons, respectively. These results are influenced by the nitrogen content (between 0.05 to 2.0 kg N ha) present in the constructed wetland. In this same period, the increase in Schoenoplectus californicus biomass (~28%) is related to a decrease in nitrogen loading between 2.0 to 0.05 kg N ha -1 d -1 . Aboveground biomass was greater (500 to 724 g m -2 ) than belowground biomass (4.8 to 22.7 g m -2). Due to nutrient translocation in spring-summer, the N:P ratio aboveground ranged from 9 to 16, while belowground the ratio varied from 7 to 10.

The aim of this study was to establish sustainably feasible areas for the implementation of anaerobic co-digestion plants for agricultural wastes (cattle/swine slurries and cereal crop wastes). The methodology was based on the use of geographic information systems (GIS), the analytic hierarchy process (AHP) and map algebra generated from hedges related to environmental, social and economic constraints. The GIS model obtained was applied to a region of Chile (Bío Bío Region) as a case study showing the energy potential (205 MW-h) of agricultural wastes (swine/cattle manures and cereal crop wastes) and thereby assessing its energy contribution (3.5%) at country level (Chile). From this model, it was possible to spatially identify the influence of each factor (environmental, economic and social) when defining suitable areas for the siting of anaerobic co-digestion plants. In conclusion, GIS-based models establish appropriate areas for the location of anaerobic co-digestion plants in the revaluation of agricultural waste from the production of energy through biogas production.

A Moving Bed Bioreactor (MBBR) was operated during 333 days. Two different effluents were fed in six different phases. Phases I and II were fed with effluent where Pinus radiata was used as raw material, while phases III to VI were fed with effluent where Eucalyptus globulus was used as raw material. The HRT was reduced from 85 to 4 h, and the BOD(5):N:P ratio (100:5:1, 100:3:1 and 100:1:1) was also simultaneously evaluated as an operation strategy. When MBBR was operated with Pinus radiata influent, the performance presents a high BOD(5) removal level (above 95%), although COD removal is below 60%. Most of the recalcitrant COD contained in the effluent has a molecular weight higher than 10,000 Da. When MBBR was operated with Eucalyptus globulus influent, the performance is around 97.9-97.6% and 68.6-65.1% for BOD(5) and COD, respectively (with HRT up to 17 h). In the Pinus radiata and Eucalyptus globus effluents, the color was mainly found in the molecular weight fraction up to 10,000 Daltons.

Differences in biodegradability can affect the treatment of slurry before its use in spraying. The objective of this study was to evaluate the effect of the generation and physical-chemical characterization of swine and dairy cattle slurries on different biological treatment technologies. This research involved monthly sampling (number/composition) for 1 year of 24 swine farms (16%), cattle farms (38%), and mixed swine and cattle farms (46%). The results obtained showed differences in feeding (3 l water kg(-1) food for cattle and 5 l water kg(-1) food for swine) and assimilation (0.6 kg food kg (-1) milk produced and 3 kg kg(-1) weight gain), which may influence the generation of slurry (57 l animal(-1)d(-1) in cattle and 31 l animal(-1) d(-1) in swine) and its composition. In addition, the composition of swine slurry [23 g chemical oxygen demand (COD) l(-1), 3 g total nitrogen (TN) l(-1)] is significantly different (P < 0.01) to cattle slurry (4 g COD l(-1), 0.3 g TN l(-1)). Finally, the composition and the S index applied to swine slurry [COD N(-1) = 8, biological oxygen demand (BOD)5 COD(-1) = 0.3, S index > 0] and cattle slurry (COD N(-1) = 16, BOD5 COD(-1) = 0.6, S index < 0) show a difference on the biodegradability of both slurries. Suitability of anaerobic and aerobic treatment was assessed based on the findings.