Nutrient recovery technologies have been constantly developed and optimised to address challenges in water and wastewater management, sanitation, and agri-food systems, while promoting sustainable management of resources, and circular phosphorus economy. However, these technologies have been rarely explored beyond laboratory-scale in developing countries where it is mostly needed, such as the Philippines. In this study, a nutrient recovery batch reactor system was installed at a local farm to process raw septage from an onsite sanitation system, septic tank, to recover a high-value fertiliser for local crop production. The batch reactor was used for two processes; acid hydrolysis for pre-treatment of septage and chemical precipitation to recover phosphorus fertiliser (RPF). The recovered fertiliser was then applied to produce eggplants and tomatoes, which are the common crops grown in the farm. Results show that an average of 290 g of recovered RPF was produced for every 100 L of raw septage processed. With hydrolysis, 77% of the phosphate concentration were released as phosphates from the solid component of the raw septage. About 98.5% of phosphates were recovered from the hydrolysed septage. The RPF when applied to the farm’s eggplants and tomatoes have yields comparable to that of the commercial fertilisers. This study was able to demonstrate the potential of a resource-oriented sanitation system that promotes nutrient recycling toward sustainable agriculture that further leads to meeting the United Nation’s Sustainable Development Goals, particularly Zero Hunger (goal 2), Clean Water and Sanitation (goal 6), Sustainable Cities and Communities (goal 11), and Responsible Consumption and Production (goal 12).

In light of the hazardous effects of global warming brought on by climate change, bioethanol production is one of the key alternatives in which the world has expressed a great deal of interest. Two factors—indigenous production and price—are crucial for bioethanol to be appealing in Africa and, for that matter, Ghana. The objective of this research is to produce bioethanol from cheap lignocellulosic materials using onsite enzymes produced from cassava peels degrading fungi. Due to Ghana's prominent position as one of the leading cassava producers in the world, the study focused on utilizing cassava peels, which are underutilized in the country. The research was conducted in multiple stages. In the first stage, the peels were prepared by washing, drying, and manually crushing them using mortar and pestle. The second stage involved analyzing the chemical composition of the peels, including starch and insoluble fibre, which were determined as Acid Detergent Fiber (ADF), Neutral Detergent Fiber (NDF), and Acid Detergent Lignin (ADL). The results showed significant levels of cellulose (39.78%) and starch (31.21%), indicating that cassava peels are valuable raw materials for bioethanol production. The content of hemicellulose (21.11%) and lignin (3.84%) were also determined. In the third stage, using a Petri dish, three fungi (ICPF1, ICPF2, and ICPF3) were isolated from two different cassava peels. ICPF1 was only identified from fresh cassava peels (FCP), while all three fungi were identified from decayed cassava peels (DCP). Morphologically, these fungi were identified as Aspergillus niger, Aspergillus flavus, and Rhizopus stolonifer. The fourth stage focused on optimizing the enzyme activity of the three isolates for potential applications, with A. niger demonstrating the highest enzyme activity with a diameter of zone of clearance of 16 mm. Stage five involved optimizing the production of the onsite enzyme in a 50ml flask using A. niger, basal salt medium (BSM), and cassava peels as a substrate. The DNSA method was used to measure the absorbance of maltose and glucose at 540 nm for various substrate concentrations (1%, 3%, 5%, 8%, and 10%) at specific intervals of 2, 4, 6, 8, and 10 days with a spore concentration of 2.1 x 105 cells/ml. The maltose and glucose concentrations were calculated as 7.138mg/ml and 6.398 mg/ml, respectively, and the corresponding enzyme activity was determined as 4.759U/ml and 4.265U/ml. The optimal conditions of Day 4 and a substrate concentration of 10%, along with a fixed temperature of 30°C and a pH of 5.5, were used to prepare the onsite enzymes in a 500 ml flask for the fermentation process. The onsite enzymes were used for saccharification and Saccharomyces cerevisiae for fermentation under simultaneous saccharification and fermentation (SSF) process. A mixture of 20 ml of onsite enzymes and 1.5 g of S. cerevisiae were added to substrate concentrations of 5%, 10%, and 20%, and the ethanol concentration was analyzed daily for 7 days using Gas Chromatography (GC). The highest ethanol concentration (1.316%) was observed on Day 5 with a substrate concentration of 20%, while the lowest concentration (0.123%) was recorded on Day 1 with a substrate concentration of 5%.

The objective of this work was to evaluate the removal of phosphorus and carbon dioxide capture of a conventional septic system upgraded with a sidestream steel slag filter used in recirculation mode. A pilot scale sidestream experiment was conducted with two septic tank and drainfield systems, one with and one without a sidestream slag filter. The experimental system was fed with real domestic wastewater. Recirculation ratios of 25%, 50% and 75% were tested. Limestone soils and silica soils were used as drainfield media. The phosphorus removal efficiency observed in the second compartment of the septic tank was 30% in the slag filter upgraded system, compared to -3% in the control system. The drainfield of silica soils achieved very high phosphorus removal in both control and upgraded systems. In the drainfield of limestone soil, the slag filtration reduced the groundwater phosphorus contamination load by up to 75%. Phosphorus removal in the septic tank with a slag filter was attributed to either sorption on newly precipitated calcium carbonate or precipitation of vivianite, or both. Recirculation ratio design criteria were proposed based on simulations. Simulations showed that the steel slag filter partly inhibited biological production of carbon dioxide in the septic tank. The influent alkalinity strongly influenced the recirculation ratio needed to raise the pH in the septic tank. The control septic tank produced carbon dioxide, whereas the slag filter upgraded septic tank was a carbon dioxide sink.

The efficient recognition and classification of personal protective equipment are essential for en-suring the safety of personnel in complex industrial settings. Using the existing methods, manually performing macro-level classification and identification of personnel in intricate spheres is tedious, time-consuming, and inefficient. The availability of several artificial intelligence models in recent times presents a new paradigm shift in object classification and tracking in complex settings. In this study, several compact and efficient deep learning model architectures are explored, and a new efficient model is constructed by fusing the learning capabilities of the individual, efficient models for better object feature learning and optimal inferencing. The new model construct follows the contributory learning theory whereby each fussed model brings its learned features, which are then combined to obtain a more accurate and rapid model using normalized quantization-aware learning. During the investigation, a separable convolutional driven model was constructed as a base model, and then the various efficient architectures combined for the rapid identification and classification of the various hardhat classes used in complex industrial settings. A remarkable rapid classification and accuracy were recorded with the new resultant model.