Market driven approach for faecal sludge treatment products

Inadequate management and treatment of faecal sludge continues to pose risks for public and environmental health. Given the variability of faecal sludge and location-specific nature of solutions, it is difficult to decide on treatment objectives and performance goals for treatment. The Market Driven Approach was developed as a quantitative methodology to determine which faecal sludge treatment products have the highest market potential in a defined location. This methodology provides a way to compare treatment products based on their real value for resource recovery. This paper discusses the results and lessons learned from field-testing in five cities across Africa and South-East Asia

Use of chitosan and Moringa oleifera as conditioners for improved dewatering of faecal sludge

A pilot-scale dewatering research facility was built in Dar es Salaam, Tanzania, and was used to test chitosan and Moringa oleifera as conditioners to improve the dewatering of faecal sludge. Laboratory-scale jar tests were first conducted to determine optimal dosages for the conditioners in faecal sludge samples with varying total solids concentrations. The results for chitosan were 0.5-0.6 mL/gTS, and for Moringa oleifera 5-15mL/gTS. Based on these results, pilot-scale tests were conducted with chitosan, but the use of Moringa was ruled out as it was too resource intensive. Three loading cycles were conducted, and an average of 15.3% reduction in dewatering time was achieved. Based on the laboratory and pilot-scale tests, chitosan is recommended as a conditioner for improved FS dewatering performance. It could be employed at full-scale, but still requires jar tests to determine optimal dosing

Quantities and qualities of fecal sludge : experiences from field implementation with a Volaser in 7 countries during a pandemic

Reasonable estimates for quantities and qualities (Q&Q) of fecal sludge that accumulate in onsite sanitation containments are fundamental for the design of appropriate management and treatment solutions, from community to city-scale. There are increasing attempts to improve Q&Q estimates, but current approaches are still at a conceptual level, and are not yet standardized with confirmed statistical relationships. To reach this level, we will need consistent approaches for planning, measuring, and global collaborations. Hence, the objectives of this study were: (1) to assess and compare Q&Q of fecal sludge from seven cities and communities, and explore statistical relationships that could be used to increase accuracy of Q&Q estimations; (2) to test and launch the Volaser device for measuring in situ volumes of fecal sludge; and (3) to capture lessons learned from field implementation with collaborators in seven countries during a global pandemic when no international travel was possible. The study took place in Ghana, India, Lebanon, Kenya, Sierra Leone, Uganda, and Zambia during the COVID-19 pandemic. Q&Qs were measured in 204 containments with a Volaser, laboratory analysis, and questionnaire. Results indicate that there are differences in Total Solids (TS) and Chemical Oxygen Demand (COD) in fecal sludge based on containment type, toilet type, source, and whether there is a water connection on the premises. Based on the results of this study, together with previously published open-source data, an empirical relationship for Volatile Solids (VS) and TS of 0.49 (R2 = 0.88) was established using 1,206 data points. For COD/TS, no significant relationship was observed. Developing such empirical relationships will be useful for planning and modeling approaches. An external evaluation was conducted to evaluate overall project management, Volaser technology transfer, and effects of collaborating during the COVID-19 pandemic. Success factors for collaborating with new and existing partners without face-to-face meetings included laboratory capacity and experience with analytical methods, study objectives that were relevant for the partner and locality, and a strong quality assurance plan to ensure comparability of results. The lessons learned can be taken forward as ways to reduce carbon footprint, and contribute to resilient, inclusive development research projects

Apparent Lack of BRAFV600E Derived HLA Class I Presented Neoantigens Hampers Neoplastic Cell Targeting by CD8+ T Cells in Langerhans Cell Histiocytosis

Langerhans Cell Histiocytosis (LCH) is a neoplastic disorder of hematopoietic origin characterized by inflammatory lesions containing clonal histiocytes (LCH-cells) intermixed with various immune cells, including T cells. In 50-60% of LCH-patients, the somatic BRAFV600E driver mutation, which is common in many cancers, is detected in these LCH-cells in an otherwise quiet genomic landscape. Non-synonymous mutations like BRAFV600E can be a source of neoantigens capable of eliciting effective antitumor CD8+ T cell responses. This requires neopeptides to be stably presented by Human Leukocyte Antigen (HLA) class I molecules and sufficient numbers of CD8+ T cells at tumor sites. Here, we demonstrate substantial heterogeneity in CD8+ T cell density in n = 101 LCH-lesions, with BRAFV600E mutated lesions displaying significantly lower CD8+ T cell:CD1a+ LCH-cell ratios (p = 0.01) than BRAF wildtype lesions. Because LCH-lesional CD8+ T cell density had no significant impact on event-free survival, we investigated whether the intracellularly expressed BRAFV600E protein is degraded into neopeptides that are naturally processed and presented by cell surface HLA class I molecules. Epitope prediction tools revealed a single HLA class I binding BRAFV600E derived neopeptide (KIGDFGLATEK), which indeed displayed strong to intermediate binding capacity to HLA-A*03:01 and HLA-A*11:01 in an in vitro peptide-HLA binding assay. Mass spectrometry-based targeted peptidomics was used to investigate the presence of this neopeptide in HLA class I presented peptides isolated from several BRAFV600E expressing cell lines with various HLA genotypes. While the HLA-A*02:01 binding BRAF wildtype peptide KIGDFGLATV was traced in peptides isolated from a

Predictive models using “cheap and easy” field measurements: Can they fill a gap in planning, monitoring, and implementing fecal sludge management solutions?

The characteristics of fecal sludge delivered to treatment plants are highly variable. Adapting treatment process operations accordingly is challenging due to a lack of analytical capacity for characterization and monitoring at many treatment plants. Cost-efficient and simple field measurements such as photographs and probe readings could be proxies for process control parameters that normally require laboratory analysis. To investigate this, we evaluated questionnaire data, expert assessments, and simple analytical measurements for fecal sludge collected from 421 onsite containments. This data served as inputs to models of varying complexity. Random forest and linear regression models were able to predict physical-chemical characteristics including total solids (TS) and ammonium (NH4+-N) concentrations, and solid-liquid separation performance including settling efficiency and filtration time (R2 from 0.51-0.66) based on image analysis of photographs (sludge color, supernatant color, and texture) and probe readings (conductivity (EC) and pH). Supernatant color was the best predictor of settling efficiency and filtration time, EC was the best predictor of NH4+-N, and texture was the best predictor of TS. Predictive models have the potential to be applied for real-time monitoring and process control if a database of measurements is developed and models are validated in other cities. Simple decision tree models based on the single classifier of containment type can also be used to make predictions about citywide planning, where a lower degree of accuracy is required.ISSN:0043-1354ISSN:1879-244

Apparent Lack of BRAFV600E Derived HLA Class I Presented Neoantigens Hampers Neoplastic Cell Targeting by CD8+ T Cells in Langerhans Cell Histiocytosis

Langerhans Cell Histiocytosis (LCH) is a neoplastic disorder of hematopoietic origin characterized by inflammatory lesions containing clonal histiocytes (LCH-cells) intermixed with various immune cells, including T cells. In 50-60% of LCH-patients, the somatic BRAFV600E driver mutation, which is common in many cancers, is detected in these LCH-cells in an otherwise quiet genomic landscape. Non-synonymous mutations like BRAFV600E can be a source of neoantigens capable of eliciting effective antitumor CD8+ T cell responses. This requires neopeptides to be stably presented by Human Leukocyte Antigen (HLA) class I molecules and sufficient numbers of CD8+ T cells at tumor sites. Here, we demonstrate substantial heterogeneity in CD8+ T cell density in n = 101 LCH-lesions, with BRAFV600E mutated lesions displaying significantly lower CD8+ T cell:CD1a+ LCH-cell ratios (p = 0.01) than BRAF wildtype lesions. Because LCH-lesional CD8+ T cell density had no significant impact on event-free survival, we investigated whether the intracellularly expressed BRAFV600E protein is degraded into neopeptides that are naturally processed and presented by cell surface HLA class I molecules. Epitope prediction tools revealed a single HLA class I binding BRAFV600E derived neopeptide (KIGDFGLATEK), which indeed displayed strong to intermediate binding capacity to HLA-A*03:01 and HLA-A*11:01 in an in vitro peptide-HLA binding assay. Mass spectrometry-based targeted peptidomics was used to investigate the presence of this neopeptide in HLA class I presented peptides isolated from several BRAFV600E expressing cell lines with various HLA genotypes. While the HLA-A*02:01 binding BRAF wildtype peptide KIGDFGLATV was traced in peptides isolated from all five cell lines expressing this HLA subtype, KIGDFGLATEK was not detected in the HLA class I peptidomes of two distinct BRAFV600E transduced cell lines with confirmed expression of HLA-A*03:01 or HLA-A*11:01. These data indicate that the in silico predicted HLA class I binding and proteasome-generated neopeptides derived from the BRAFV600E protein are not presented by HLA class I molecules. Given that the BRAFV600E mutation is highly prevalent in chemotherapy refractory LCH-patients who may qualify for immunotherapy, this study therefore questions the efficacy of immune checkpoint inhibitor therapy in LCH