Ricardo Luís Radis Steinmetz

Advanced swine manure treatment and utilization in Brazil.

Animal production has changed from subsistence to an industrial model, lowering production costs but giving rise to higher potential environmental impact. When the effluents are not correctly managed, serious pollution events can occur. In Brazil liquid manure is commonly stored in reception pits or covered lagoons (biodigestors), followed by land application as a biofertilizer. In some regions there is an excess of manure due to low soil support capacities, and in these cases new technologies have to be adopted to export or treat the excess effluent. Manure storage time in pits/covered lagoons and new polymers to separate the solid fraction have been studied in Brazil. Treatment technologies, like swine manure treatment systems (SMTS), have been developed from a technical and economical point of view to optimize the processes and give a technological alternative to pork producers increasing production while reducing environmental impact.

Performance of two swine manure treatment systems on chemical composition and on the reduction of pathogens

Swine effluents must be correctly handled to avoid negative environmental impacts. In this study, the profiles of two swine manure treatment systems were evaluated: a solid-liquid separation step, followed by an anaerobic reactor, and an aerobic step (System 1); and a biodigester followed by serial lagoons (System 2). Both systems were described by the assessment of chemical, bacterial and viral parameters. The results showed that in System 1, there was reduction of chemicals (COD, phosphorus, total Kjeldhal nitrogen - TKN - and NH(3)), total coliforms and Escherichia coli; however, the same reduction was not observed for Salmonella sp. Viral particles were significantly reduced but not totally eliminated from the effluent. In System 2, there was a reduction of chemicals, bacteria and viruses with no detection of Salmonella sp., circovirus, parvovirus, and torque teno virus in the effluent. The chemical results indicate that the treated effluent can be reused for cleaning swine facilities. However, the microbiological results show a need of additional treatment to achieve a complete inactivation for cases when direct contact with animals is required.

Chemical phosphorus removal: a clean strategy for piggery wastewater management in Brazil

The intensive production of animal protein is known to be an environmental polluting activity, especially if the wastewater produced is not managed properly. Swine production in Brazil is growing, and technologies to manage all pollutants present in the wastewater effluent are needed. This work presents a case of study of phosphorus (P) removal from piggery wastewater using Ca(OH)2, and demonstrates the feasibility of this strategy for P management. The effluent of a swine manure treatment plant was treated with Ca(OH)2. According to the addition of Ca(OH)2 the pH of the effluent ranged from 8.0 to 10.0. Different conditions of sludge dewatering were evaluated, and the chemical composition of sludge was investigated. Ion chromatography analysis of effluent samples showed that 92% of total P (TP) was present as soluble P (SP) whereas 75% of SP species were present as phosphate. The efficiency of P removal was typically 90% at pH 8.5 and higher than 98% at pH 10.5. The sludge was separated by sedimentation, centrifugation or filtration and dried. The TP content of dried sludge was 9.3% (w/w). X-ray diffraction analysis of the dry sludge showed the presence of amorphous compounds of Ca and P, which is an indication that the sludge obtained from the swine manure treatment has a potential for application as biofertilizer.

Effect of storage time on swine manure solid separation efficiency by screening

Confined animal feeding operations (CAFOs) have suffered considerable transformations since the last decade in Brazil, because of increasing of their production scale. Swine production is following this same trend, and the volume of manure produced and the form that is managed has a direct impact on houses air quality and efficiency of treatment systems. The objective of this work was to study the manure solid-liquid separation efficiency by screening, subject to different screen opening sizes and pit disposal time under tropical climate conditions. An ammoniacal nitrogen producing rate of 24 mg/L per storage day was observed and a decrease in screen separation efficiency in the first eight days of storage, obtained by solid group analysis. The storage time influenced directly the degradation of organic fraction indicated by the chemical oxygen demand increase overtime. The results suggest that the efficiency of solid-liquid separation is increased when carried out with the shortest storage time.

Detection of circoviruses and porcine adenoviruses in water samples collected from swine manure treatment systems.

Samples collected from two swine manure treatment systems including: swine manure treatment system and demonstrative unit (SMTS and DU), were analyzed by qPCR to quantify the amount of porcine adenovirus (PAdV) and porcine circovirus (PCV2) present. Positive samples were tested for virus integrity using DNase assay. Fifty-six water samples were collected monthly from March 2009 to May 2010. PAdV genome was found 66% of the samples in the SMTS and in 78% of the samples in the DU system. PCV2 was detected in 96% of samples collected from the SMTS system and in 86% of samples from DU. DNase assay revealed that there were undamaged virus particles of both PAdV and PCV2 in all sampling sites in the SMTS. However, undamaged particles of both viruses were detected in samples from the DU system in the affluent and middle sites, though undamaged PCV2 was absent in the effluent samples.

Enrichment and acclimation of an anaerobic mesophilic microorganism's inoculum for standardization of BMP assays.

Appropriate enrichment of anaerobic microorganisms consortium is crucial for accurate biochemical methane potential (BMP) assays. An alternative method to produce and maintain a mesophilic methanogenic inoculum was demonstrated. Three sources of inoculum were mixed and acclimated for 857days in order to reach steady conditions (pH=7.90±0.46; VS/TS>50%; VFA/alkalinity=0.16±0.04gAcetic Acid/ [Formula: see text] ). Biogas yield >80% was obtained after 70days of inoculum acclimation in comparison to standard cellulose (>600mLN/gVS). Methanogen community analysis based on 16S rDNA of the inoculum revealed Archaea concentration of 3×10(12) gene copies/g (Methanobacteriales 8×10(10); Methanomicrobiales 8×10(10); and Methanosarcinales 4×10(11) gene copies/g). The proposed method for development and maintenance of microorganism enrichment inoculum demonstrates consistent BMP data which is a requirement for dependable prediction of biogas production at field scale operations.

Assessment of a tannin-based organic polymer to harvest Chlorella vulgaris biomass from swine wastewater digestate phycoremediation

This study investigated the efficiency of an organic tannin polymer alone or amended with polyacrylamide to harvest Chlorella vulgaris biomass grown in a laboratory-scale photobioreactor treating swine wastewater digestate. The effect of biomass concentration, tannin (TAN) dosages and changes in pH were evaluated in jar test experiments. Among the TAN concentrations tested (11, 22, 44, 89, 178 mg L(-1)), 11 mg L(-1) showed the highest biomass recovery (97%). The highest coagulation/ flocculation efficiencies were obtained at pH 5 to 7. Flocculation efficiency improved from 50 to 97% concomitant with the increasing biomass concentrations from 45 to 165 mg L(-1), respectively. Recovery efficiencies above 95% were achieved with the same TAN dosage (11 mg L(-1)) irrespective of the concentration of organic carbon present (75 to 300 mg TOC L(-1)). Overall, the results suggest that TAN could become an interesting alternative choice of non-toxic organic polymer for harvesting Chlorella sp. from organic-rich wastewater.

Nitrogen removal from swine wastewater by combining treated effluent with raw manure

Effluents from swine raising can be harmful to the environment if not correctly managed. Nitrogen (N) is usually the main element present at high concentrations in the effluent. Since the use as biofertilizer is not always a feasible alternative, the treatment of swine wastewater is necessary. Variations in N species and water solubility make the treatment difficult and expensive. Additional N removal at low cost via denitrification may be possible by recirculating nitrified effluent in the barns. In this study, raw manure (RM) was homogenized with treated effluent (TE) at RM/(RM + TE) ratios of 1.0, 0.9, 0.8, 0.7, 0.6, 0.5 and 0 in order to simulate the effect of reused water on swine wastewater nitrogen removal. Samples were collected daily during four days and analyzed for pH, oxidation-reduction potential, NH4-N, NO2-N, NO3-N and chemical oxidation demand. The oxidized nitrogen (NOx-N) half-life degradation was estimated using linear regression. NOx-N species half-life less than one day was obtained when treated effluent was combined and thoroughly homogenized with raw manure. It is suggested that combining raw manure with treated effluent (e.g. water reuse) can be a simple and cost-effective strategy to remove nitrogen from swine wastewaters.

Culturing and molecular methods to assess the infectivity of porcine circovirus from treated effluent of swine manure.

Samples were collected at the effluent of two swine manure treatment systems and were analyzed by qPCR to determine the presence and amounts of porcine circovirus (PCV2) genetic material. ST cells were inoculated with the positive samples to evaluate virus viability and for viral genotyping. Twenty-five water samples were collected monthly from treated effluent (March 2009 to December 2010). The PCV2 genome was identified by qPCR in 60% of the samples, and all of the positive samples were able to infect ST cells in vitro. Positive samples were genotyped and 60% of them were positive for both PCV2a and PCV2b, 20% were positive for genotype 2a, and 20% were positive for genotype 2b. Our results suggest that these viruses were able to resist the regular wastewater treatment, and this finding demonstrates the necessity of adding a virus inactivation step to the treatment system to guarantee the safety of water reuse.

Influence of solid-liquid separation strategy on biogas yield from a stratified swine production system.

As the fourth largest swine producer and exporter, Brazil has increased its participation in the global swine production market. Generally, these units concentrate a large number of animals and generate effluents that must be correctly managed to prevent environmental impacts, being anaerobic digestion is an interesting alternative for treating these effluents. The low-volatile solid concentration in the manure suggests the need for solid-liquid separation as a tool to improve the biogas generation capacity. This study aimed to determine the influence of simplified and inexpensive solid-liquid separation strategies (screening and settling) and the different manures produced during each swine production phase (gestating and farrowing sow houses, nursery houses and finishing houses) on biogas and methane yield. We collected samples in two gestating sow houses (GSH-a and GSH-b), two farrowing sow houses (FSH-a and FSH-b), a nursery house (NH) and a finishing house (FH). Biochemical methane potential (BMP) tests were performed according to international standard procedures. The settled sludge fraction comprised 20-30% of the raw manure volume, which comprises 40-60% of the total methane yield. The methane potential of the settled sludge fraction was approximately two times higher than the methane potential of the supernatant fraction. The biogas yield differed among the raw manures from different swine production phases (GSH-a 326.4 and GSH-b 577.1; FSH-a 860.1 and FSH-b 479.2; NH -970.2; FH 474.5 NmLbiogas.gVS(-1)). The differences were relative to the production phase (feed type and feeding techniques) and the management of the effluent inside the facilities (water management). Brazilian swine production has increased his participation in the global market, been the fourth producer and the fourth exporter. The segregation of swine production in multiple sites has increased its importance, due to the possibilities to have more specialized units. Generally, these units concentrate a large number of animals and generate effluents that must be correctly managed to avoid environmental impact. Due to the biodegradability of manure, anaerobic digestion is an interesting alternative to treat these effluents. The low volatile solid concentration in the swine manure suggests the need for solid-liquid separation as a tool to improve biogas generation capacity. The present study aimed to determine the influence of simplified and cheap solid-liquid separation strategies (based on screening and settling) and different manure of each swine production phases (gestating and farrowing sows houses, nursery houses and finishing houses) on biogas and methane yield. We collected samples in two gestating sows house (GSH-a and GSH-b), two farrowing sows house (FSH-a and FSH-b), a nursery house (NH) and a finishing house (FH). The Biochemical Methane Production (BMP) tests were performed according to international standard procedure (VDI 4630). The settled sludge fraction responds for 20-30% of raw manure volume, producing 40-60% of the total methane yield. The methane potential of settled sludge fraction was about 2 times higher than the supernatant fraction. There are differences on biogas yield between the raw manure of different swine production phases (GSH-a 326.4 and GSH-b 577.1; FSH-a 860.1 and FSH-b 479.2; NH 970.2; FH 474.5 NmLbiogas.gVS(-1)). The differences are relative to production phase (feed type, feeding techniques, etc.), but also the management of the effluent inside the facilities (water management).