Technology combines biological and chemical processes to treat swine manure. Sistrates has been developed for ten years and removes carbon, nitrogen and phosphorus from effluents. The water obtained in the end of the process is so good that it can be reused in the farm. The process also generates fertilizer phosphorus and electricity. Solution reduces environmental impacts of large-scale production. A swine manure treatment system has innovated by combining biological and chemical processes to jointly remove carbon, nitrogen and phosphorus, generating reusable water, electricity and phosphorus fertilizer. Set up at one of Master's poultry farms in Santa Catarina, the Swine Farming Effluent Treatment System (Sistrates) is the result of research initiated in 2010 by Embrapa Swine and Poultry. Another differential is that the process can be applied in a modular and supplementary way, according to treatment needs and conditions in the property. “This project focuses on the treatment of swine manure for large production systems. And it works based on a set of modular systems resulting in an end effluent of excellent quality”, explains the Embrapa researcher Airton Kunz, leader of the project. Effluents from intensive swine farming are a major challenge for rural properties, especially because many do not have arable land to use them as biofertilizers. If they are discarded, the residue poses high environmental pollution potential. Funding The Swine Farming Effluent Treatment System, or Sistrates, is a project funded by the Brazilian National Development Bank (BNDES),, wherein Embrapa is defined as technological institution, Master Agroindustrial as intervening institution, and the Research and the Development Support Foundation (Faped) as support institution. The technology has been perfected by Embrapa research projects such as the biotechnological process in swine farming effluent treatment systems - SISTRATES and the project on the nutritional assessment of phosphate extracted from pig farming effluents. The new technology allows the obtention of a high level of treatability of residual waters, that is, the quality of the water allows it to be reused in the farm itself or, if there is an agricultural area nearby, it can be used in irrigation. “The resulting effluent meets the standards established by resolution 430 of the National Environment Council (Conama), which makes provisions on the conditions and standards for the release of effluents into bodies of water”, informs the Embrapa scientist. The potential market for Sistrates is large intensive poultry production farms, with limitations in arable land for the application of manure or effluents, or with the need to reuse water. Central treatment units in river basins or central biogas plants for the cogeneration of electric or thermal energy are also other potential users. In Santa Catarina state, Master's Farm, where the system is implemented, has the capacity to host 9,500 hens and an annual production of 256,000 pigs. According to the farm director and superintendent Mario Faccin, Sistrates was the answer they needed to solve the problem of production waste and to improve processes, such as the use of water. “The region where the farm is set up has few croplands to use the waste as fertilizer, which became a challenge for production. We also had a very high water consumption and needed alternatives to operate with more sustainability. Today we produce 256,000 pigs a year and are operating with half of the volume of water that we used seven years ago, when production was 241,000 annual animals”, he celebrates. Another point underscored by Faccin is the concern for sustainability “Master always had a great commitment to the sustainability of its operations and this project places us in the vanguard of the environmental front with the establishment of a high efficiency system, whose technology was completely developed in one of our units”, he pointed out. Presentation of Sistrates at Master's Farm (Videira, SC) How it works Sistrates is formed by three distinct modules: Bio, N and P. The first one is formed by biodigesters, N is responsible for nitrogen removal, and P removes phosphorus. The first stage of the process is receiving the waste, in which the manure reaches the reservoirs and goes through a system to separate coarse solids through a sieve with rotating brushes. “The separate solids are moved to a high-rate biodigester and, with gravity, the liquid effluent moves on to the covered lagoon biodigester. These two biodigestors form the first module, Bio”, the researcher details. This module generates biogas to produce electricity. According to the Embrapa analyst Ricardo Steinmetz, the most important thing in this module is obtaining the biogas. “We can recover the biogas, conduct it to generators (engines that generate electricity), condition the gas and produce energy. Thus, in this module there is organic matter removal and energy generation”, he explains. The effluent from the covered lagoon biodigesters has high nitrogen concentration because the process of anaerobic digestion is not capable of removing ammoniac nitrogen. For that purpose, in Sistrates' second module, N, nitrogen is removed through a biological process of nitrification, followed by denitrification, producing nitrogen gas. By the end of the process the effluent will have met the standards for release, presenting an ammoniac nitrogen concentration that is lower than 20 mg/L. The last Sistrates module removes phosphorus through a chemical precipitation process. The phosphorus is converted into solid calcium phosphate. The precipitation reaction requires a 10% calcium hydroxide - a.k.a hydrated lime - suspension. The phosphorus recovered at the end of the process can be used as a fertilizer, according to the Embrapa analyst Fabiane Goldschmidt Antes. Results: electricity, fertilizer, and water for reuse The result of the whole process in Sistrates is the possibility of reusing water, which is allowed due to the good quality of the effluent post-treatment. Farmers also obtain phosphorus, which can be applied to the croplands as fertilizer, and biogas-generated electricity. Kunz also stressed that besides the real-scale in-field validation at Master Farm, the goal is to establish a network of Technological Reference Units (URT) in the main swine producing regions to support technology transfer and the continuous training of technicians, and to allow continuous system improvement. Translation: Mariana Medeiros