The study explored the production of biogas from Lemon grass, Cow dung and Poultry droppings. The three substrates were pre-fermented according to standard methods. Six (6) kg of each pre-fermented substrate was mixed with water in ratio 1:1 v/v to form slurry and digested for 30days. A total of 0.125m(3), 0.191m(3) and 0.211m(3) of biogas were respectively produced from the Lemon grass, Cow dung and Poultry droppings with deviations of 0.00234m(3), 0.00289 m(3) and 0.00484 m(3) respectively. The cooking test carried out revealed that the scrubbed gas had higher cooking rates for water (0.12L/min, 0.085L/min and 0.079L/min for Lemon grass, Cow dung and Poultry droppings respectively) while the cooking rates for unscrubbed gas were 0.079L/min, 0.064L/min and 0.06L/min respectively. The pH of the medium fluctuated optimally between 6.5 and 7.8. The research demonstrated that Lemon grass produced less volume but better quality biogas compared to Cow dung and Poultry droppings.

a b s t r a c tAnaerobic digestate have been identified as a rich source of essential plant nutrients. Nevertheless, its safety measured by the concentration of pathogen present is of great concern to end users. This research explored the efficiency of the mesophilic biodigestion process in the stabilization and sanitization of cow dung and chicken droppings. Six (6) kg each of cow dung and chicken droppings were collected fresh and free from impurities, pre-fermented, mixed with water in the ratio 1:1 w/v to form slurry, fed into the respective reactors and digested for 30 days at an average ambient temperature of 30 AE 2 C. The pH of the medium fluctuated between 6.5 and 8.0. The analysis of the feedstock and effluent of the digesters showed that a total solids reduction of 75.3% and 60.1% were recorded for cow dung and chicken droppings while the reduction in total coliforms was 95% and 70% respectively for the dung and droppings. Microbial analysis of the biofertilizer produced reveals both aerobic and anaerobic organisms which include species of Pseudomonas, Klebsiella, Clostridium, Bacillus, Bacteroides, Salmonella, Penicillum and Aspergillus. Escherichia coli and Shigella spp. were removed while species of Salmonella and Klebsiella were still present in the digestate. Notwithstanding these results, the digestate still requires further treatment for it to be suitable for application on unrestricted crops either as fertilizer; otherwise a health problem would be created as attempt is made to improve soil fertility.

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This research was aimed at assessing the fertilizer quality and public health implications of using digestate biofertilizer from the anaerobic digestion of food wastes and human excreta. Twelve (12) kg of food wastes and 3kg of human excreta were mixed with water in a 1:1 w/v to make 30-l slurry that was fed into the anaerobic digester to ferment for 60days at mesophilic temperature (22-31°C). Though BOD, COD, organic carbon and ash content in the feedstock were reduced after anaerobic digestion by 50.0%, 10.6%, 74.3% and 1.5% respectively, nitrogen, pH and total solids however increased by 12.1%, 42.5% and 12.4% respectively. The C/N ratios of the feedstock and compost are 135:1 and 15.8:1. The residual total coliforms of 2.10×10(8)CFU/100ml in the digestate was above tolerable limits for direct application on farmlands. Microbial analysis of the digestate biofertilizer revealed the presence of Pseudomonas, Klebsiella, Clostridium, Bacillus, Bacteroides, Penicillum, Salmollena, and Aspergillus. Klebsiella, Bacillus, Pseudomonas, Penicillum and Aspergillus can boost the efficiency of the biofertilizer through nitrogen fixation and nutrient solubility in soils but Klebsiella again and Salmollena are potential health risks to end users. Further treatment of the digestate for more efficient destruction of pathogens is advised.

This study was aimed at establishing a water quality database in the study area where none existed previously. Groundwater samples from bore-holes, hand-pump, and hand-dug wells of four densely populated towns in SouthWestern Nigeria were analyzed in respect to physicochemical factors, biological factors, and the metals Nickel (Ni), Lead (Pb), Cadmium (Cd), Zinc (Zn), Copper (Cu), and Iron (Fe) for six consecutive months from September 2012 to February 2013 to give mean values for each town and water source. Total aerobic plate, total coliform bacteria, and Escherichia coli (E. coli) were detected in most of the water samples from the different towns and sources considered. Except for total suspended solids and total solids, the physicochemical parameters of all the samples were within permissible limits. The concentrations Pb, Ni, Cr, and Cd were above the minimum permissible limits. The presence of coliforms and E. coli in the groundwater samples indicates fecal contamination. The microorganisms isolated in this study include Enterobacteriaceae, Staphylococcus aureus, E. coli, Citrobacter, Klebsiella, Pseudomonas, Bacillus, that bore-hole water samples were safer for drinking that water samples from hand-pump, and hand dug wells across the communities.