A wastewater treatment system including a screen, a vermifilter, macrophytes ponds, and constructed wetlands has been built after a pig housing on slatted-floor. The aims were, all at once, to recycle water for excretion washing and to produce, from the nutrients contained in the effluent, organic matter and plants that can be either sold or reused on the farm to reduce inputs. Analyses, made on the effluent at different steps of the treatment plant, show that the concentrations of the nitrogen, microorganisms and endocrine disruptors are drastically reduced, while the phosphorus and potassium removal go through the byproducts harvesting.

Treatment of liquid manure can result in the production of ammonia, nitrous oxide and methane. Earthworms mix and transform nitrogen and carbon without consuming additional energy. The objective of this paper is to analyse whether earthworms modify the emissions of NH(3), N(2)O, CH(4) and CO(2) during vermifiltration of pig slurry. The experiment used mesocosms of around 50 L, made from a vermifilter treating the diluted manure of a swine house. Three levels of slurry were added to the mesocosms, with or without earthworms, during one month, in triplicate. Earthworm abundance and gas emissions were measured three and five times, respectively. There was a decrease in emissions of ammonia and nitrous oxide and a sink of methane in treatments with earthworms. We suggest that earthworm abundance can be used as a bioindicator of low energy input, and low greenhouse gas and ammonia output in systems using fresh slurry with water recycling.

From preliminary researches on a pilot scale, a complete demonstration plant was built to treat the effluents of a 30 pregnant sow’s piggery. It includes a screen, a vermifilter, a macrophyte lagooning, and a complementary water storage pond; the recycled water is used for flushing, and rainfall is collected to compensate for evapotranspiration. After functioning in 2008 and 2009, it was showed that, during the warm season, the whole plant produced an effluent suitable for flushing, where the concentration decrease was over 70% for the phosphorus and potassium, 95% for the COD and nitrogen, 99.8% for endocrine disruptors (estrogenic activity), and 99.99% for pathogenic micro‐organisms. During the cold season, the dilution by the rain water and the treatment effect of the constructed wetlands lead to similar results. Nevertheless, for this season, suitable floating macrophytes that will cover the lagoons remain to be settled.