Agricultural Potential of Biosolids Generated from Dewatering of Faecal Sludge on Unplanted Filter Beds.

The study was conducted to determine the agricultural potential of biosolids produced from the dewatering of faecal sludge on drying beds in Ghana. It was conducted using bench scale filter beds at KNUST in Kumasi, Ghana. Different filter media were used to dewater FS while different loading rates of FS were dewatered on selected filter medium. Different percentages of sawdust mixed with FS were also dewatered and biolsolids produced were dried and analysed for nutrients and heavy metals. The results showed that the average percentage carbon in all the biosolid ranged between 27 and 42.7%, nitrogen was 1.82 – 3.54% and carbon – nitrogen ratio ranged between 8.7 - 23.9%. The level of phosphorus and potassium ranged between 1.73 – 3.69%and 0.81- 3.78% respectively. The average concentration of heavy metals analysed in the dried biosolids were very low where the range of Cu was 0.081- 0.157mg/kg, Fe 1.530- 4.562mg/kg, Pb 0.009- 0.032mg/kg. Cd, Mn, and Zn showed ranges of 0.036 – 0.092, 0.076-0.652 and 0.026-0254 mg/kg respectively. Key words: Biosolid, dewatering, faecal sludge, heavy metals, nutrients

Removal of As, Cd, Cr, Cu, Ni and Zn from polluted water using an iron based sorbent

This research is aimed at investigating the effect of different particle sizes of sand for the dewatering of faecal sludge with respect to the dewatering time, contaminant load in the percolate, rate of clogging and quantity of biosolids produced. Three filter media FM1, FM2 and FM3 were used to dewater the faecal sludge. The experiment was conducted on bench scale consisting of miniature drying beds. Six cycles of dewatering were run where FM1, FM2, and FM3 showed average dewatering times of 10, 10 and 9 days respectively without significant differences (p > 0.05). However the percolate quality showed significant differences between them in the removal of TS, TVS, SS, COD, DCOD and NH3-N with FM1 having the highest removal for each parameter. Accumulation of organic matter in the top 10 cm of the filter bed indicated that FM1 was least likely to clog and it also generated the highest quantity of biosolids

Using integrated GIS and hydrological analysis for sizing culverts of multiple channel crossings at the flooded section of the Daboya-Mankarigu Road (IR10) in Ghana

A culvert is an important structure in Road construction to allow the conveyance of Channels crossing the road. Culverts are sized for a road to accommodate the volume of water crossing the road network to avoid flooding. Ghana Highways has a standard manual for culvert sizing at channel crossing. This manual serves as a guide for the proper sizing of culverts, however, lots of culverts have been found to have failed. Among the reasons for the failure of culverts could be under-sizing, urbanization, climate change, lack of maintenance, etc. The Daboya-Mankarigu Road is situated in the Savanah Region of Ghana in the North Gonja District. The section of the road from Chainage 9 + 075 to 10 + 200 has been experiencing flooding from 2020 to 2021 with a flood depth of 3.315 m in 2020 and 2.00 m in 2021. This study seeks to use integrated GIS and hydrological-based methods to propose new culverts to supplement the existing culverts to control flooding at section (9 + 075 to 10 + 200) of Daboya-Mankarigu Road (IR10). Geographic Information system (GIS) model (SWAT), Hydrological and hydraulic models were used to determine the peak flow at the catchment to Propose new culverts to supplement the existing culverts. Using a design period of 25 years for culverts, the modified rational method was used to determine the Peak flow of the catchment. A 25-year peak flow of 367.155 m3/s was determined and used for hydraulic analysis of the existing culverts. From the study, the existing culvert structures at the section had a hydraulic capacity of 78.732 m3/s which could not accommodate the remaining flow of 288.423 m3/s in the catchment. An observation was made that the changes in the rainfall can cause a change in rainfall intensity. An increase in built-up areas in the catchment can also increase the runoff coefficient which can result in higher peak flow in the catchment. Climate change, change in slope, and Land use in the catchment were also determined to have a huge influence on the adequacy of culverts since the peak flow is dependent on these parameters in the catchment as the years go by. A 4No. 4 m × 4 m box culvert, 3No. 3.5 m × 3.5 m box culvert, and 13 No. 1200 mm pipe culverts with 2 each at different chainages were proposed at suitable locations to supplement the existing culverts using the HDS-5 equations in AutoCAD Civil 3D. A recommendation is made to consider the installation of these new culverts at the flood section to control flooding and avoid overtopping of water on the IR10 road section (Daboya-Mankarigu) in the north Gonja District