EVALUATION OF BIOGAS POTENTIALS OF Cymbopogon citratus AS ALTERNATIVE ENERGY IN NIGERIA

This research explored the potentials of Cymbopogon citratus (Lemon Grass) for biogas production as a cost effective alternative energy source in Nigeria. The Cymbopogon citratus was crushed to small sizes between 20 to 50mm and pre-fermented for 40 days in a PVC drum. Six (6) kg of the pre-fermented Cymbopogon citratus was mixed with water in ratio 1:1 w/v to form slurry and digested for 30 days. The floating drum gas collection system was used to collect the gas after it was passed through water and lime respectively for scrubbing. A total of 0.125m3 (6.95x10-4 m3/kg/day) and 0.0897m3 (4.98x10-4 m3/kg/day) of biogas was produced from the Cymbopogon citratus before and after scrubbing respectively. The gas produced was used for cooking test. The scrubbed gas had higher cooking rates for both water and rice respectively (0.12L/min and 0.0052L/min) while the cooking rates for unscrubbed gas were 0.079L/min and 0.0036L/min respectively. During this period, daily ambient temperatures of the research environment varied from 310C to 420C while the digester temperature fluctuated between 28oC and 36.70C. The pH of the medium fluctuated optimally between 6.5 and 7.8. The research demonstrated that Biogas could be produced from Cymbopogon citratus in quantity and quality comparative with those in literatures

Water resources potentials of Hadejia River Sub-catchment of Komadugu Yobe River Basin in Nigeria

A. Sobowale1, J. K. Adewumi1, J. A. Otun2, D. B. Adie2(1. Department of Agricultural Engineering, University of Agriculture, Abeokuta. Nigeria;2. Department of Water Resources Engineering, Ahmadu Bello University, Zaria. Nigeria) Abstract: A water audit of the Hadejia river sub-catchment of Komadugu Yobe River basin of Nigeria (KYB) has been carried out.  The available water in this sub-catchment was compared with existing and potential water demands; results show that about 2,619 million cubic meters (MCM) of surface water is available annually upstream of Wudil (HS 1), 658 MCM is available between Wudil and Hadejia (HS 2), while 905 MCM is available between Hadejia and Gashua (HS 3).  Analysis of direct ground water recharge revealed that 86 mm, 94 mm and 8 mm of water is recharged to groundwater annually in the three hydrological sections HS 1, HS 2 and HS 3 respectively.  It is obvious that the least ground water recharge takes place in the Hadejia - Nguru Wetlands.  Presently, no water stress was observed in the sub catchment, the potential water balance of the area shows that about 75% of the available water between Wudil and Hadejia section (HS 2) would be used up by 2010 going by the current development rate.  Projections show that the water use rate will reach 100% by 2018.  At this time, water scarcity will be experienced in this sub-catchment if urgent steps are not taken to address the situation.  Integrated water resources management (IWRM) strategies were advanced for the sub-catchment in order to avert the crisis.Keywords: water resources potentials, water budget, river catchment system, soil moisture deficit, runoff, recharge, Nigeria Citation: Sobowale A, J K Adewumi, J A Otun, and D B Adie.  Water resources potentials of Hadejia River Sub - catchment of Komadugu Yobe River Basin in Nigeria.  Agric Eng Int: CIGR Journal, 2010, 12(2): 1-6.  &nbsp

Turbidity removal from surface water using Tamarindus indica crude pulp extract

Plant-based coagulants are potential alternatives to chemical coagulants used in drinking water treatment. This paper examined the turbidity removal efficiency of Tamarindus indica fruit crude pulp extract (CPE) towards evaluating a low-cost option for drinking-water treatment. Laboratory analysis was carried out on high turbidity raw water samples (i.e. 478 NTU) using T. indica CPE of concentrations ranging from 500 to 3000 mg/L as natural coagulant, using jar tests. Results obtained showed turbidity removal efficiency of the coagulant ranging from 64 to 99%. An optimum dose of 3000 mg/L resulted in highest turbidity removal efficiency of 99%. However, the treated water samples were observed to be of high acidity with pH values lower than 3.0, suggesting the need for pH adjustment. Nevertheless, this study demonstrated the potentials of T. indica CPE in coagulating high turbidity surface water.Keywords: Coagulation; crude pulp extract, pH, turbidity removal, T. indic

Determination of Levels of Regulated and Emerging Trihalomethanes (THMs) Disinfection By-Products (DBPs) in a Community Drinking Water Supply

Ahmadu Bello University (ABU) drinking water treatment plant (ABUDWTP) uses calcium hypochlorite to supply chlorine in disinfecting drinking water supply to the university community. Between 2008 and 2010, 252 water samples were taken in duplicates along the treatment and distribution systems of ABUDWTP with ammonium chloride as de-chlorinating agent in accordance with United States Environmental Protection Agency (USEPA) Method 551.1. This was aimed at determining the concentrations of trihalomethanes (THMs) disinfection by-products (THM-DBPs) and the degree of wholesomeness of the drinking water supplied. The THM concentrations in the samples were analysed using Agilent Gas Chromatograph after preliminary extraction with methyl tert-butyl ether (MTBE). Samples’ analyses identified six THMs - two additional to the regulated four. These are Dichlorobromomethane and 1,2-Dibromomethane here classified as emerging THM disinfection by-products (EmerTHM-DBPs). Measured total mean concentration of the regulated THMs (TRegTHM-DBPs) at house level was 1.0601E-02±1.6625E-05 mg/L as against 9.9704E-02±6.4706E-05 mg/L for total mean emerging THM-DBPs (TEmergTHM-DBPs). This TRegTHMs concentration indicates house level water is within acceptable limits of international standards despite being above the national permissible limit of 0.001 mg/L. Though not considered under exiting drinking water quality index TEmergTHM-DBPs were found to account for over 90% of gross THM-DBPs (GTTHM-DBPs) at each sampling stage. These TEmergTHM-DBPs could create health complications on consumers as they are either suspected carcinogens or recognised to increase the risk of carcinogenicity and mutagenicity in humans. Both are irritants of several body tissues and are implicated in several health abnormalities including reproductive and fertility disorders as well as liver and kidney damage. In view of these likely supplementary health burdens, this paper advocates additional stricter monitoring and control of these emerging THM-DBPs as they will most probably compound and increase the frontline of health challenges from chlorine disinfected ABU drinking water supply to its consumer

Assessment of regulated halo-acetic acids disinfection by-products and their concomitant risks in Ahmadu Bello University Zaria drinking water supply

Abstract The conventionally treated drinking water supplied to the Ahmadu Bello University community was assessed for its levels of regulated halo-acetic acids. This is because the Ahmadu Bello University water treatment plant uses calcium hypochlorite in the chlorinated disinfection of its treated water during the treatment process. Longitudinal sampling was undertaken along the treatment and distribution stages of drinking water supply in the community. Between 2008 and 2010, 252 samples were collected and analysed for the regulated halo-acetic acids in accordance with USEPA Method 551.1 (1995) using Methyl Tert-Butyl Ether (MTBE) as extractant and a calibrated Agilent Gas Chromatograph measured their concentrations. All the regulated halo acids recorded their highest concentrations in the chlorinated water sample and these decreased towards house-level water sample except for dichloroacetic acid which increased from the booster station sample with 3.2500E-03±5.8452E-03 mg/L to the house level sample with 3.2511E-03±9.1256E-05 mg/L. The total regulated halo-acetic acid (THAAs) concentrations also decreased from the chlorinated sample concentration of 1.8324E+00±8.1252E-02 mg/L. to the house level concentration of 4.8826E-01±2.8735E-02 mg/L, a situation likely attributable to the turbulent flow during distribution resulting in the increased volatility of the acids in the distribution system. Although not specifically regulated by the Nigerian National Standards, the concentrations of these acids at house level (4.8826E-01±2.8735E-02 mg/L) drinking water is more than the maximum permissible limits of these regulated acids under the USEPA drinking water standard’s maximum contaminant level (MCL) of 0.060 mg/L. In view of their implication in increased risk of cancer and other effects including problems of the reproductive system, these acids’ concentration in household drinking water need to be rigorously monitored and regulated to minimize their risk to health.turbulent flow during distribution resulting in the increased volatility of the acids in the distribution system. Although not specifically regulated by the Nigerian National Standards, the concentrations of these acids at house level (4.8826E-01±2.8735E-02 mg/L) drinking water is more than the maximum permissible limits of these regulated acids under the USEPA drinking water standard’s maximum contaminant level (MCL) of 0.060 mg/L. In view of their implication in increased risk of cancer and other effects including problems of the reproductive system, these acids’ concentration in household drinking water need to be rigorously monitored and regulated to minimize their risk to health

Modeling and Optimization for Production of Rice Husk Activated Carbon and Adsorption of Phenol

Modeling of adsorption process establishes mathematical relationship between the interacting process variables and process optimization is important in determining the values of factors for which the response is at maximum. In this paper, response surface methodology was employed for the modeling and optimization of adsorption of phenol onto rice husk activated carbon. Among the action variables considered are activated carbon pretreatment temperature, adsorbent dosage, and initial concentration of phenol, while the response variables are removal efficiency and adsorption capacity. Regression analysis was used to analyze the models developed. The outcome of this research showed that 99.79% and 99.81% of the variations in removal efficiency and adsorption capacity, respectively, are attributed to the three process variables considered, that is, pretreatment temperature, adsorbent dosage, and initial phenol concentration. Therefore, the models can be used to predict the interaction of the process variables. Optimization tests showed that the optimum operating conditions for the adsorption process occurred at initial solute concentration of 40.61 mg/L, pretreatment temperature of 441.46°C, adsorbent dosage 4 g, adsorption capacity of 0.9595 mg/g, and removal efficiency of 97.16%. These optimum operating conditions were experimentally validated

Occurrence and Levels of Acetonitriles as Emerging Disinfection By-products in a Community Drinking Water Supply

Drinking water from Ahmadu Bello University (ABU) Zaria water treatment plant was sampled and analysed for haloacetontriles (HANs) disinfection by products (DBPs) between 2008 and 2010. This was to determine the degree of wholesomeness of the drinking water supplied to the university community. On analyses, samples were found to positively contain dichloroacetonitriles, dibromoacetonitrile, and bromochloroacetonitrile among the commonly known haloacetronitriles in drinking water. They were detected at chlorination stage and sometimes in the house level water samples. Bromochloroacetonitrile mean concentration of 1.3927E-02±6.1033E-06 mg/L was detected in the chlorinated samples and was lost in samples from the distribution system most probably due to its hydrolysis in water. On the other hand, mean levels of dibromoacetonitrile and dichloroacetonitrile were observed to increase from 1.0605E-02±3.3349E-05 mg/L of and 1.36431E-03±1.4647E-06 mg/L, respectively, in the chlorinated sample to 2.4731E-02±5.2273E-04 mg/L and 2.2190E-03±1.8910E-06 mg/L in the house level water samples, respectively. This trend in mean concentration could be traceable to influence of increased acidity (decreased pH) and total organic carbon. These showed that the treated drinking water supplied to the university community was within the WHO, 2004 provisional guideline recommendations that individual haloacetonitrile could have concentration exceeding 0.01 mg/L. However, the distributed water contained higher levels than the generally assumed concentration of 0.002 mg/L (WHO, 2004). This has implication for increased glutathione (GSH) lipid peroxidation and covalent bond associated with haloacetonitrile related radioactivity to gut tissues resulting from scavenging reactive oxygen (ROS). Although not among the regulated DBPs, HANs presence in distributed drinking water could open up a new frontier of DBPs health risks. Hence, their levels need be monitored, their effects determined and adequately documented for regulation. Thus, would wholesome and potable drinking water (a human right) be guaranteed to the students, staff and their dependant family members of the ABU community