Carbon footprint of urban source separation for nutrient recovery

Source separation systems for the management of domestic wastewater and food waste has been suggested as more sustainable sanitation systems for urban areas. The present study used an attributional life cycle assessment to investigate the carbon footprint and potential for nutrient recovery of two sanitation systems for a hypothetical urban area in Southern Sweden. The systems represented a typical Swedish conventional system and a possible source separation system with increased nutrient recovery. The assessment included the management chain from household collection, transport, treatment and final return of nutrients to agriculture or disposal of the residuals. The results for carbon footprint and nutrient recovery (phosphorus and nitrogen) concluded that the source separation system could increase nutrient recovery (0.30–0.38 kg P capita−1 year−1 and 3.10–3.28 kg N capita−1 year−1), while decreasing the carbon footprint (−24 to −58 kg CO2-eq. capita−1 year−1), compared to the conventional system. The nutrient recovery was increased by the use of struvite precipitation and ammonium stripping at the wastewater treatment plant. The carbon footprint decreased, mainly due to the increased biogas production, increased replacement of mineral fertilizer in agriculture and less emissions of nitrous oxide from wastewater treatment. In conclusion, the study showed that source separation systems could potentially be used to increase nutrient recovery from urban areas, while decreasing the climate impact

Incorporation of main line impact into life cycle assessment of nutrient recovery from reject water using novel membrane contactor technology

Wastewater treatment plant (WWTP) nutrient recovery has recently gained traction in the search for new pathways for fertilizer production. In particular, concentrated waste streams such as reject water from sludge digestion are suitable. The environmental impact of a novel nutrient recovery technology using a membrane contactor (NPHarvest) was examined with an environmental life cycle assessment (LCA). Impact hotspots were benchmarked against a comparable technology (struvite precipitation and ammonia stripping), and the impacts of the two technologies were found to be similar for most studied environmental impact categories. To allow for the inclusion of effects on other parts of the WWTP while limiting the general system boundaries to the reject water treatment, a novel approach to capture the main line impact was developed. The effects on the main line contributed substantially to the overall results. The overall results indicated clear nutrient recovery benefits related to substituted materials in mineral fertilizer production. Additionally, reject water nutrient recovery provided even greater benefits due to reduced N2O emissions and the reduced use of precipitation chemicals in the WWTP main line. Nonetheless, both nutrient removal and recovery were necessary for the two technologies to reach a net zero climate impact in their current pilot scales. Further development of the NPHarvest technology—such as mitigating NH3 emissions, exploring alternative input chemicals and optimizing energy consumption (especially for crystallizing the ammonium salt solution that is produced)—is recommended before full-scale implementation

The Impact of Borderline Quantiferon-TB Gold Plus Results for Latent Tuberculosis Screening under Routine Conditions in a Low-Endemicity Setting

Quantiferon-TB Gold Plus (QFT-Plus) is an interferon gamma release assay used to diagnose latent tuberculosis (LTB). A borderline range (0.20 to 0.99 IU/ml) around the cutoff (0.35 IU/ml) has been suggested for the earlier QFT version. Our aims were to evaluate the borderline range for QFT-Plus and the contribution of the new TB2 antigen tube. QFT-Plus results were collected from clinical laboratories in Sweden and linked to incident active TB within 3 to 24 months using the national TB registry. Among QFT-Plus results from 58,539 patients, 83% were negative (<0.20 IU/ml), 2.4% were borderline negative (0.20 to 0.34 IU/ml), 3.4% were borderline positive (0.35 to 0.99 IU/ml), 9.6% were positive (≥1.0 IU/ml), and 1.6% were indeterminate. Follow-up tests after initial borderline results were negative (<0.20 IU/ml) in 38.3%, without any cases of incident active TB within 2 years. Applying the 0.35-IU/ml cutoff, 1.5% of TB1 and TB2 results were discrepant, of which 52% were within the borderline range. A TB2 result of ≥0.35 IU/ml with a TB1 result of <0.20 IU/ml was found in 0.4% (231/58,539) of all included baseline QFT-Plus test results, including 1.8% (1/55) of incident TB cases. A borderline range for QFT-Plus is clinically useful as more than one-third of those with borderline results are convincingly negative upon retesting, without developing incident active TB. The TB2 tube contribution to LTB diagnosis appears limited

Specificity and Dynamics of Effector and Memory CD8 T Cell Responses in Human Tick-Borne Encephalitis Virus Infection

<div><p>Tick-borne encephalitis virus (TBEV) is transferred to humans by ticks. The virus causes tick-borne encephalitis (TBE) with symptoms such as meningitis and meningoencephalitis. About one third of the patients suffer from long-lasting sequelae after clearance of the infection. Studies of the immune response during TBEV-infection are essential to the understanding of host responses to TBEV-infection and for the development of therapeutics. Here, we studied in detail the primary CD8 T cell response to TBEV in patients with acute TBE. Peripheral blood CD8 T cells mounted a considerable response to TBEV-infection as assessed by Ki67 and CD38 co-expression. These activated cells showed a CD45RA-CCR7-CD127- phenotype at day 7 after hospitalization, phenotypically defining them as effector cells. An immunodominant HLA-A2-restricted TBEV epitope was identified and utilized to study the characteristics and temporal dynamics of the antigen-specific response. The functional profile of TBEV-specific CD8 T cells was dominated by variants of mono-functional cells as the effector response matured. Antigen-specific CD8 T cells predominantly displayed a distinct Eomes+Ki67+T-bet+ effector phenotype at the peak of the response, which transitioned to an Eomes-Ki67-T-bet+ phenotype as the infection resolved and memory was established. These transcription factors thus characterize and discriminate stages of the antigen-specific T cell response during acute TBEV-infection. Altogether, CD8 T cells responded strongly to acute TBEV infection and passed through an effector phase, prior to gradual differentiation into memory cells with distinct transcription factor expression-patterns throughout the different phases.</p></div

Transcription factor profile of TBEV-specific cells.

<p>(A) Plots are gated on total CD8 T cells (black background) or TBEV-specific (NS3 ILL) CD8 T cells (green dots). (B) Bar plots show the median and 10–90th percentiles of each marker in ILL⁺ specific cells from five donors. (C) Bar plots show the median and 10–90th percentiles of each marker in total CD8 T cells from five donors (D) Bar chart represents subset distribution of T-bet, Eomes and Ki67 in TBEV-ILL-specific cells. (E) Bar chart represents subset distribution of T-bet, Eomes and Ki67 in total CD8 T cells. (F) Median and 10–90th percentiles of Eomes⁺Ki67⁺T-bet⁺ total CD8 T cell subset at day 7, 21 or 90 after hospitalization in infected subjects (n = 10) together with healthy controls (n = 16). (G) Median and 10–90th percentiles of granzyme B and perforin in Eomes⁺ and Eomes⁻ total CD8 T cell subsets at day 7 after hospitalization. Statistical analysis was performed by using non-parametric repeated measures ANOVA test or Mann-Whitney test. *, p < 0.05; **, p < 0.01; ***, p < 0.001.</p

Activation of T cells in the acute phase of TBE infection.

<p>(A) CD38 and Ki67 co-expressing cells in the total CD8 T cell population over time in one representative patient. (B) Median and 10–90th percentiles of CD38 and Ki67 co-expression in CD8 T cell subsets at day 0, 7, 21 and 90 after hospitalization in infected subjects (n = 20) and in healthy controls (n = 20). (C) Ki67 expression vs CMV-pp65 HLA MHC class I tetramer staining over time in one donor. Percent Ki67⁺ CMV pp65⁺ cells are indicated in the plot. (D) Kinetics of Ki67 expression in CMV⁺ (red line) and CMV⁻ (black line) CD8 T cells in four donors over time. (E) Stainings of perforin, CD45RA, PD-1, Bcl-2, CD127, granzyme B, CD27 and HLA-DR at day 7 after hospitalization. Gated on total CD8 T cells. (F) Bar plots show the 10–90th percentiles of HLA-DR, Bcl-2, PD-1, granzyme B, perforin and CD127 expression together with CD27 in terms of mean fluorescence intensity in CD38 and Ki67 co-expressing CD8 T cell subset at day 7 after hospitalization, non-activated Ki67⁻CD38⁻ (N-A) cells at day 7 after hospitalization or in non-activated healthy controls (N-A HC). (G) Bar chart represents the subset distribution of CCR7, CD45RA and CD127 (IL7Rα) in CD38 and Ki67 co-expressing cells at day 7 after hospitalization. (H) CD38 and Ki67-coexpressing cells in CD4 cell population over time in one infected patient. (I) Median and 10–90^th percentiles of CD38 and Ki67 co-expression in CD4 T cell subset at the day of hospitalization (day 0) and at day 7, 21 and 90 after hospitalization in infected subjects (n = 20) together with healthy controls (n = 20). Statistical analysis was performed using non-parametric repeated measures ANOVA test or the Mann-Whitney test. *, p < 0.05; **, p < 0.01; ***, p < 0.001.</p

Functional profile of TBEV-specific effector and memory CD8 T cell responses.

<p>(A) PBMCs from infected subjects (n = 5) and healthy controls (n = 5) were stimulated for 6 hours with a pre-selected TBEV peptide pool in the presence of brefeldin A and monensin. Intracellular expression of MIP-1β, IFN-γ, and TNF, as well as the cell surface expression of CD107a, were assessed by flow cytometry and are shown as respresentative flow plots at day 21 after hospitalization. (B) Bar plots show the 10–90th percentiles of CD107a, MIP-1β, TNF and IFN-γ production in response to a pre-selected peptide pool at day 0, 7, 21 and 90 after hospitalization (n = 5). (C) Pie charts indicate the mean composition of the total response in CD8 T cells with regards to their capacity to express one, two, three or four functions at days 7, 21 and 90 after hospitalization. (D) Dominant polyfunctional profiles at day 7, 21 and 90 after hospitalization. The percentage of parent populations is indicated for each dominant population. (E) Bar chart represents the subset distribution of CD27, CD45RA and CD57 in cells responding with CD107a, MIP-1β, IFN-γ, or TNF after stimulus with a pre-selected peptide pool day 7, 21 and 90 after hospitalization. (F) Heat map represents subset distribution of Eomes and T-bet in cells responding with CD107a, MIP-1β, IFN-γ, or TNF after stimulus with the pre-selected peptide pool at day 0, 7, 21 and 90 after hospitalization. Statistical analysis was performed by using the non-parametric repeated measures ANOVA test. *, p < 0.05; **, p < 0.01; ***, p < 0.001.</p