Enrichment of water bodies with nutrients from wastewater is one of the causes of eutrophication to aquatic ecosystems. This study investigated the use of biochar derived from rice husk, coconut husk, and coffee husk in adsorbing nitrates (NO3-N) and nitrites (NO2-N) from slaughterhouse wastewater. It also explored the desorption efficiencies of the adsorbed nutrients to ascertain the applicability of the enriched biochars as slow-release fertilizers. To characterize the physicochemical properties of the biochars, scanning electron microscopy (SEM) was used. Fourier transforms infrared spectroscopy (FTIR), elemental analysis (CHNO) Langmuir and Freundlich, and the isotherm models were employed to fit the experimental equilibrium adsorption data. It was observed that the Langmuir isotherm model has the best fit of NO3-N and NO2-N on all the biochars. And this was based on the coefficient of correlation values. Also, the coconut husk biochar has the highest adsorption capacities of NO3-N and NO2-N at 12.97 mg/g, and 0.244 mg/g, respectively, attributing to its high porosity as revealed by the SEM images. The adsorption capacities for the rice husk char were 12.315 and 0.233 mg/g, while that for coffee husk char were12.08 mg/g and 0.218 mg/g for NO3-N and NO2-N, respectively. The relatively higher amount of NO3-N adsorbed to that of NO2-N could be attributed to its higher initial concentration in the solution than nitrite concentration. The desorption efficiencies of nitrates were 22.4, 24.39, and 16.79 %, for rice husk char, coconut husk char and coffee husk char, respectively. For the rice husk char, coconut husk char and coffee husk char, the nitrites desorption efficiencies were 80.73, 91.39, and 83.62 %, respectively. These values are good indicators that the studied biochar can be enriched with NO3-N and NO2-N and used as slow-release fertilizers.

Extracts of the rhizomes of Kniphofia foliosa exhibited antiplasmodial activities against the chloroquine-sensitive (D6) and chloroquine-resistant (W2) strains of Plasmodium falciparum with IC 50 values of 3-5 g/mL. A phenyloxanthrone, named 10-acetonylknipholone cyclooxanthrone (1) and an anthraquinoneanthrone dimer, chryslandicin 10-methyl ether (2), were isolated from the rhizomes, along with known quinones, including the rare phenylanthraquinone dimers, joziknipholones A and B. The structures of these compounds were determined based on spectroscopic data. This is the second report on the occurrence of the dimeric phenylanthraquinones in nature. In an in vitro antiplasmodial assay of the isolated compounds, activity was observed for phenylanthraquinones, anthraquinone-anthrone dimers and dimeric phenylanthraquinones, with joziknipholone A being the most active. The new compound, 10-acetonylknipholone cyclooxanthrone, also showed anti-plasmodial activity. In an in vivo assay, knipholone anthrone displayed marginal antimalarial activity.

Phosphate solubilizing and nitrogen-fixing bacteria have a vital role in improving soil fertility and reverting adversely affected soil properties. These bacteria could contribute towards sustainable agriculture with a focus on reducing excessive use of commercial fertilizers. This study aimed at investigating autochthonous populations of phosphate solubilizing and nitrogen-fixing bacteria from Lake Ol’Bolossat sediments. The total microbial counts ranged between 4.8 x 103 to 8.5 x 105 cfu/ml. A total of 50 bacteria were isolated, 34 were obtained from Pikovskaya’s agar medium while 16 were obtained from Norris Glucose Nitrogen free medium. Based on morphological and 16S rRNA gene analyses, the isolates were clustered under the genera Bacillus, Arthrobacter, Pseudomonas, Paenibacillus, Fictibacillus and Acinetobacter. Among potentially novel strains, four strains NFDA2, PKGBC1 (MT799539), PKGB5 and SCEC2 (MT799543) belonged to genus Bacillus, three strains NFGA1 (MT799529), NFGA4 and SCDB3 belonged to the genus Pseudomonas, two strains NFEB6 (MT799528) and NFDC5 belonged to the genus Paenibacillus, one strain PKHC3 (MT7995441) belonged to the genus Arthrobacter while one strain NFDC4, belonged to the genus Acinetobacter. Generally, the phosphate solubilizing bacteria were the most diverse and genera Bacillus, Fictibacillus and Pseudomonas were the most dominant, however, nitrogen-fixing bacteria were dominated by genera Arthrobacter and Pseudomonas.

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Sustainable treatment of fecal matter is a long-standing challenge in sanitation, particularly in developing countries. Although recent developments have seen the evolution of innovative onsite sanitation technologies, the treatment of fecal waste collected still remains a daunting task. This study evaluated the effect of formulated feedstock: fecal matter from urine-diverting dry toilets and kitchen waste (1:0, 1:1, 2:1, 4:1, and 0:1) on waste weight reduction, Hermetia illucens’s larval weight gain, and crude protein content during co-digestion. Samples were collected after every 2 days for larval weight determination and protein content analysis using the Kjeldahl method of nitrogen determination. The waste reduction index (WRI) was determined after 50% pupation. The larvae grew on all substrates yielding 32.97–38.6% dry matter (DM) protein content and larval weight ranging from 1.12 to 1.70 g per five larvae. Results indicate that a 1:1 co-digestion ratio resulted in a high WRI (3.61), DM crude protein content (38.6%), and larval weight (1.70 g per five larvae). This study used the circular economy-based approach which provides a win–win situation to sanitation provision and environmental management while realizing products with potential for livelihood improvement.