Biosorption of heavy metals in industrial wastewater using micro-organisms (Pseudomonas aeruginosa)

Heavy metal ions are often present in industrial wastewater, and sometimes there is the need to reduce their concentrations to some certain minimum. Biosorption is one of the methods by which this reduction can be achieved. The purpose of this study is to explore the biosorption technique as an alternative to conventional methods such as reverse osmosis, electro dialysis, ultra filtration, ion-exchange and chemical precipitation in the removal of heavy metal ions from industrial wastewater. Biosorption of the heavy metals namely cadmium, zinc and silicate were conducted using Pseudomonas Aeruginosa. Samples of wastewater from an industrial source were collected in a 2L container and poured into six containers. Measured quantities of the biomass were then introduced into the samples. The concentrations of heavy metals in the samples were determined with an atomic absorption spectrometer. The results yielded a significant reduction in the heavy metal ion concentrations in the samples, with even the highest initial concentration greatly reduced. Biosorption technique can be a very good alternative to conventional methods in terms of availability of materials, cost-effectiveness and absence of precipitates and slurry

Synthesis of Heterocyclic Azo Dyes from Quinolin-8-ol

Six derivatives of heterocyclic azo dyes were synthesized by coupling diazotized aniline and 4-nitroaniline with quinolin-8-ol, 5-nitrosoquinolin-8-ol and 5-nitroquinolin-8-ol respectively. Benzene diazonium salt and 4-nitrobenzene diazonium salt were prepared by treating aniline and 4-nitroaniline respectively with HNO2 generated in situ from NaNO2/HCl at 0-5oC. 5-nitrosoquinolin-8-ol was prepared by treating a solution of quinoline-8-ol in conc. HCl/H2O with solution of sodium nitrite at 0-4o in an ice-salt bath. Oxidation of 5-nitrosoquinolin-8-ol with conc. HNO3 at 17o gave 5-nitroquinolin-8-ol. The dyes were of intense colouration. They were characterized by FT-IR, NMR and elemental analysis. Keywords: Aniline; 4-nitroaniline; quinolin-8-ol; diazotization; nitrosation; oxidation; coupling reaction

Potentials of Momordica angustisepala fiber in enhancing strengths of normal portland cement concrete

Presence of cracks in concrete affect the integrity. It reduces the life expectancy of concrete structures and is often responsible for collapse of structures, especially in the developing nations. At the root of these cracks is the very low tensile strength of concrete. Various techniques have been suggested for the enhancing the tensile strength, among which is the use of discontinuous micro fibers of various nature. This research investigated the use of Momordica angustisepala (Ma) fiber to enhance concrete strength. Concrete containing coconut fiber was adopted as a control. Slump test, air entrainment test, compression test and split tensile test were carried out on specimens. Results of the research indicate that an optimum Momordica angustisepala fiber contents of 0.25 and 0.5% enhanced respectively the compressive strength by 4.37% and the tensile strength by 10%. The results clearly show that this renewable material has the potential to enhance the compressive and tensile strengths of concrete

Effect of municipal solid waste contamination on some geotechnical properties of soil.

This study examined some geotechnical engineering properties of municipal solid waste contaminated soils in selected locations in Nigeria. Samples of soil were collected at 0.5m depth from the selected dumpsite, and a free land (uncontaminated soil) which served as control. The properties of the soils investigated include: particle size distribution, natural moisture content, consistency limits, maximum dry density, optimum moisture content and specific gravity. Test results revealed that the contaminated soils possess lower plastic limit, maximum dry density and specific gravity than the uncontaminated soil. However, the contaminated soil yielded higher natural moisture content, liquid limit, plasticity index, optimum moisture content and fine particles content than the uncontaminated soil. Therefore, within the limit of this study, it can be inferred that the geotechnical properties of the contaminated soil were reduced due to the influence of the municipal solid waste, and this makes the soils unsuitable for engineering applications

SLUDGE DEWATERING SUBJECTED TO CONSTANT VACUUM PRESSURE: A MODELLING APPROACH

Sludge is often generated from the treatment of wastewater and it is essential to reduce its volume before disposal into the environment through dewatering. This helps to reduce the cost of final sludge disposal. This study was therefore aimed at developing a model for the draining time of sludge through the application of vacuum pressure. A vacuum filtration experiment was performed on sewage sludge collected from the wastewater treatment plant situated at the University of Nigeria, Nsukka. The sludge sample was poured into Buchner funnel apparatus and the volume of the filtrate collected was noted at a certain time interval until the end of the experiment. The specific resistance values were obtained using the newly derived-, modified-, and Carman’s-equation, respectively. A comparative study was carried out on the three values obtained and the results showed that the newly derived equation gave the best result. Overall, the newly derived equation demonstrated conformity with Carman’s equation and can be used for sludge dewatering investigation. This paper covers a relevant subject within the field of waste treatment processes, namely the dewatering of sludge from wastewater treatment system and on a large scale, can aid in producing cost effective mechanism that makes it more possible for developing nations to incorporate adequate and effective sanitation

Life Cycle Assessment of Environmental Impacts of Using Concrete or Timber to Construct a Duplex Residential Building

Traditionally, the choice of construction materials depended principally on the strengths of materials, cost of material, availability of materials, simplicity of erection, aesthetics and technical expertise available to the society. This meant that little attention was paid to the environment impacts of materials adopted for civil construction. After centuries of speedy advancement accompanied by deteriorating ecosystem as evidenced by the global climate change and the accompanying gap between the rich and the poor, the world is becoming more conscious of the ecosystem and the future of mankind. This has led to the growing quest for sustainable development. In the more recent years, environmental and sustainability factors are becoming compelling factors in the choice of construction materials. Researches focused on materials for affordable houses for the increasing low income masses are on the increase. This research focuses on the environmental impact performance of concrete and timber applied to a modest duplex residential building. It explores using Athena Impact Estimator software to model the greenhouses gases expressed in terms of carbon dioxide equivalents, sulphur dioxide equivalents, phosphate equivalents and ethane equivalents potentials obtainable from using concrete or timber to build a duplex residential building. From the various results obtained, it is very evident that timber construction is more eco-friendly in terms of carbon emission reduction which translates to reducing global warming, thermal insulation and energy efficiency. This will be helpful in making choice for building materials to be adopted for affordable houses developing countries

PREDICTION OF FRESH AND HARDENED PROPERTIES OF NORMAL CONCRETE VIA CHOICE OF AGGREGATE SIZES, CONCRETE MIX-RATIOS AND CEMENT

Concrete is the most commonly used building material for building most of the world’s buildings and infrastructure. After centuries of usage, it still remains the most widely adopted construction material worldwide. But in many developing nations, the frequent occurrence of building collapse has been mostly ascribed to poor quality concrete. As Nigeria is noted for frequent building collapse, this research reproduces standard concrete practices commonly adopted in Nigerian construction industry with the intent to predict design strength via choice of coarse aggregate sizes ( 12.5 mm, 19 mm, 30 mm and mixed), concrete mix-ratios (1:2:4, 1:3:6, 1:2:3) and ordinary Portland cement types (42.5R and 32.5N). Cement compound’s composition tests, fresh property tests and hardened property tests were conducted on samples. Test results from building cites of different Local Government Areas of Lagos State, Nigeria obtained in 2010 are compared with the compressive test results of this research via statistical tools. Results indicate that the fresh properties and hardened properties are influenced in a proportional manner by the sizes of aggregates and that the choices of aggregate sizes, concrete mix-ratios and cement types can be used to predict the fresh and hardened properties of normal concrete. This study also show that poor concrete production is one of the principal cause of frequent building collapse in Nigeria

Toxicity, Growth And Survival Of Clarias Gariepinus Juveniles Exposed To Different Concentrations Of Crude Oil Fractions-Polluted Water

Studies were carried out on the toxicity, growth and survival of Clarias gariepinus juveniles exposed to different concentrations of oil-polluted water. Thirty-nine aerated aquaria (60 × 30 × 30 cm3), arranged in a 4 × 3 Complete Randomized Block Design were used for the study. Three oil types: the Bonny light crude oil (BLCO), the premium motor spirit (PMS) and kerosene (DPK) at oilconcentrations of 1.00, 1.50, 2.00 and2.50 ml L -1 were used in triplicates of 5 ml to contaminate 15L of dechlorinated tap water and 20 fingerlings o Clarias gariepinus (22 ± 0.24 g) exposed to it. A control treatment (0.00 ml L-1) of non-oil contamination was aso used in riplicates. A 96-hour toxicity phase in the oil-polluted water preceded a 42 days recovery phase. 38% crude proein dietwas fed to fish during exposure and recovery phases at 3% and 5% body weight per day respectively. Water temperature, pH, fish mortality and normalized biomass index (NBI) of each aquarium were monitored. The total organic nitrogen, soluble organic nitrogen and colloidal organic nitrogen in addition to soluble and adsorbed ammonia in the aquaria water and sediments were analyzed using standard methods. Results showed that the water temperature was 26 ± 2.04° C, pH was 6.50 ± 0.30 and fortnighty eed intake of fish increased between days 14 and 42. This increase, which corresponded wth the increase in the fortnightly weight gain, could be attributed to the reduction of stress caused during the 96-h toxicity phase. The increase in the soluble ammonium and the exchangeable ammonium concentrations o water correlated with the increase inthe concentrations (1.50 – 2.50 ml L-1) ofBLCO, PMS and DPK. Percent mortality of fsh reduced between days 14 and 42 irrespective o oil treatment while fish exposed to the control treatment had lower percent mortality than those exposed to the oil treatments. This trend was corroborated by the relatively higher NBI for the control during the exposure (-0.02) and recovery{0.08 (14 days), 0.08 (38 days) and 0.21 (42 days)} periods than those of oi treatments (-49.64 to-0.10). Keywords: Clarias gariepinus, Toxicity, Soluble ammonium, Feed intake, Weight gainAnimal Research International Vol. 3 (2) 2006 pp. 466-47