The preparation and applications of Tilapia (Oreochromis niloticus) fish scale biochars (FSB) as an adsorbent in the removal of indigo carmine dye (ICD) from aqueous solutions is described. The biochars were prepared through pyrolysis over a temperature range of 200 °C–800 °C and characterized for surface charge, functional groups, thermal stability, particle size and morphology, elemental composition, crystallinity, and surface area by using pHpzc, Fourier transform infrared (FTIR) spectroscopy, thermo-gravimetric analysis (TGA), transmission electron microscopy/scanning electron microscopy (TEM/SEM), energy dispersive X-ray (EDX) spectroscopy, powder X-ray diffraction (PXRD) and Brunauer-Emmett-Teller (BET) techniques, respectively. Batch experiments were carried out to determine the variation of adsorption process with initial dye concentration, contact time, initial solution pH, adsorbent load, temperature and adsorbent pyrolysis temperature on the removal of the dye. The percentage removal increased with increase in initial dye concentration and adsorbent dosage. A pH of 2 was the most appropriate for the adsorption experiments. The equilibrium data fitted pseudo-first-order kinetics and Freundlich models, while the thermodynamic parameters confirmed that the adsorption process was endothermic.

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Nitrogen fertilizers applied either in single or split application is the main agronomic inputs to sugarcane production. The objective of this study was to determine the effects of nitrogen fertilizer rates and split application on yield of first ratoon crop of late (CO 421) and early maturing (D 8484) sugarcane varieties. Analysis of variance at p≤0.05 indicated that the mean yields were 117.6 and 124.3 ton cane per hectare for CO* 421 and D* 8484 respectively at harvesting. This study showed that there was no significant difference in the effects of nitrogen fertilizer rate and split application on yield.

This chapter describes an up-to-date critique of the use of adsorption as a wastewater treatment technique for the removal of dyes. The topics range from the classification of dyes, their occurrence in water and toxicity, various treatment methods, and dye adsorption dynamics onto agricultural wastes and inorganic adsorbents such as clay and metal oxides and adsorption onto microbial biomass under varying operational conditions. It is demonstrated that the discussed materials form alternative adsorbents for dye adsorption from aqueous solutions with comparable or better removal efficiencies relative to the non-renewable coal-based granular activated carbons; they are cheap and abundant. The relative performance of the adsorbents under different environmental parameters for dye removal has also presented. The deductions made and alluded to from various kinetic and adsorption isotherm models are also discussed. The chapter presents the past, present, and suggestions for future considerations in search of non-conventional adsorbents for dye sequestration from aqueous solution.

The objective of this work was to investigate the occurrence and fate of five heavy metals in water, sludge, and sediments from a conventional municipal wastewater treatment facility in Kisumu City, Kenya. The effluent quality was compared with the effluent quality parameters stipulated by the National Environmental Management Authority (NEMA) to assess the efficiency of the plant and potential effect of the discharged effluent on the recipient river. The levels of the heavy metals recorded in the sludge samples were significantly higher than those in the corresponding water samples. The order of the metal percentage removal efficiency (%R) from the treatment plant was Mg>Cu>Mn>Fe>Zn. It is concluded that the plant is a point source for Zn loading into the recipient waters which poses potential risk to end users downstream. The heavy metal-laden sludge was within permissible limits for utilization in agricultural lands.