Browsing by Author "Nartey, Eric Gbenatey"

Now showing 1 - 3 of 3
  • Thumbnail Image
    ItemOpen Access
    Assessing consistency in the aerobic co-composting of faecal sludge and food waste in a municipality in Ghana
    (Springer, 2023-10-30) Nartey, Eric Gbenatey; Sakrabani, Ruben; Tyrrel, Sean; Cofie, Olufunke
    Background: A faecal sludge (FS) co-composting study assessed the extent of consistency in compost characteristics between and within batches. The study focused on the consistency of the co-composting process by measuring the variability of key parameters. Method: The set up consisted of 12 FS and food waste (FW) co-composting piles in three successive batches (1, 2 and 3). Consistency was assessed in the three successive batches of co-composted FS and food waste (FW). Within batches, consistency was assessed in each of them by dividing it into four separate replicate piles. Characteristics of interest were E. coli, as well as selected physico-chemical parameters (pH, EC, Mg, Ca, N, NH4-N, NO3-N, P, avail. P, and K) and heavy metals (Se, Fe, Cd, Cu, Hg, Ni, Pb and Cr). Data were subjected to analysis of variance (ANOVA) using SPSS. Result: Results show that, E. coli levels were not consistent between the successive batches during the entire co-composting process. While variations between batches were only observed for EC and nutrient parameters, variations were evident for several measured characteristics within batches. The measured coefficient of variations (CVs) within batches ranged between 0–125% and 3–111% for heavy metals and nutrients, respectively. Conclusion: In conclusion, there was less consistency in nutrients between successive batches and CV within batches was wide. Consistency levels for E. coli may not be an issue if pathogen inactivation is complete. Recommendation: It is recommended that a threshold value be created for determining what is an acceptable level of variation in FS co-composting.
  • Thumbnail Image
    ItemOpen Access
    Storage duration and temperature affect pathogen load, heavy metals, and nutrient levels in faecal derived fertiliser
    (Taylor & Francis, 2024) Nartey, Eric Gbenatey; Sakrabani, Ruben; Tyrrel, Sean; Cofie, Olufunke
    There are debates regarding the safety of faecal derived fertiliser (FDF) due to notions that harmful substances may persist at undetectable levels. A major concern is the recolonisation of indigenous pathogens and nutrient changes while undergoing storage. Abiotic factors such as duration and temperature on indigenous pathogen re-growth and nutrient during FDF storage have received little research attention. In this study, we assess the effect of varying storage temperature conditions and duration on indigenous E. coli re-growth and NPK changes of different FDF (enriched co-compost, NECo and co-compost, Co) during storage. A 2 × 3 × 6 factorial design was used with factors: fertiliser, temperature, and duration. The factorial had 36 experimental conditions in a completely randomised design with three replications. FDF samples were collected monthly for 6 months and analysed for pH, EC, organic carbon, N, NH4-N, NO3-N, P, K, E. coli, and total coliform. Findings show storage temperature and duration did not affect indigenous E. coli re-growth and total N in stored NECo and Co. However, NH4-N concentrations of NECo decreased between 27% and 55% with increasing duration of storage at lower temperatures (5°C and 25°C). The significance of this study for the FDF industry is that it is safe after storage and longer storage do not necessarily influence nutrient losses in stored FDF. Future studies are recommended to investigate the effect of moisture on stored FDF.
  • No Thumbnail Available
    ItemEmbargo
    Transformation of solid and liquid wastes into fertiliser to minimize urban catchment pollution
    (Cranfield University, 2024-12) Nartey, Eric Gbenatey; Sakrabani, Ruben; Tyrrel, Sean F.
    Decentralised treatment systems play a critical role in managing faecal sludge (FS) in sub-Saharan Africa (SSA) where safely managed sanitation is lagging with 79% of the population without it. The systems that treat FS and food waste (FW) into faecal derived fertilisers (FDFs) play a more critical role in linking safely managed sanitation to improved food security. To recover nutrients and organic matter to their fullest potential is urgent in the context of SSA. The International Water Management Institute (IWMI) and partners have led research to convert urban FS and FW through co-composting into various FDF for use in agriculture. Though some strides have been made in developing and commercialising FDF, there are still some research and knowledge gaps including limited information on nutrient and pathogen flow in the decentralised FS and FW treatment system; limited information on the shelf life of stored FDF and on residual effect of FDF application on crops and soil. Hence, this study aimed to generate new knowledge and understanding on the recovery of nutrients and E. coli inactivation during treatment and use of fertiliser produced from FS and solid waste. The methodology involved different experimental set-ups to collect primary data. This followed an end-to-end monitoring of FS and FW treatment to produce FDF, storage of FDF and the use of the FDF in successive lettuce cultivation. Findings from this study, show that between 50-70% of total N from FS is lost at the dewatering stage of treatment. More than 50% of total N is lost during co-composting. While E. coli inactivation efficiency of the dewatering process is minimal (0-14%) in the percolate, dewatered FS on the other hand observed higher E. coli inactivation efficiency of 88-98% (1-2 log reductions). Inactivation efficiency of co-composting stage for E. coli was 100%. No detectable presence of indigenous E. coli was observed in FDF at the end of storage. Storage temperature and duration did not affect re-growth of indigenous E. coli in co-composted FDF. Longer storage of enriched FDF co- compost (NECo) under lower temperatures resulted in decreasing NH4-N concentrations. The field experiment show, residual effect of FDF co-compost (Co) gave lettuce yield of 344% more compared to the control by the second cycle. E. coli was absent on lettuce after successive cultivations. Co plots had higher gross margins/profit per cycle of cultivation. The ROI for Co was 385.7 for first cycle and 309.2 for second cycle.