Pollution

The water quality index (WQI) method rather than the conventional water quality standard approach was applied in evaluating the surface water quality of the Jakara basin, Kano, Northern Nigeria. The objective of this study is to provide water quality index reference values and pattern for targeted environment. Thirty surface water samples were collected: twenty three samples along River Getsi and seven surface water samples along the main channel River Jakara. Twenty three quality parameters namely: pH, temperature, turbidity, electrical conductivity, dissolve oxygen, biochemical oxygen demand, Fecal Coli form, total solids, nitrates, phosphates, cobalt, iron, nickel, manganese ,copper, sodium, potassium, mercury, chromium, cadmium, lead ,magnesium, and calcium were analyzed. The study used nine physicochemical and bacteriological parameters converge into single value as suggested by National Science Foundation-Water Quality Index (NSF-WQI). The result reveled that S2,S3,S4,S5,S12,S15,S17 of the River Getsi fall under very bad water quality while other sampling points within the same stream shows Bad water quality. On the other hand out of the seven sampling points within River Jakara, only S25 shows Very bad, others fall within Bad water quality. In general water in the Jakara basin fall under very bad category and pose a danger in any form of water consumption. The water quality index scheme performed better in water quality pollution trend analysis due to its sensitivity to changes in water quality at different point in time.

The most likely process that can lead to the release of radionuclides from a repository to the geosphere is transport by groundwater. Hence, waste disposal-related safety analyses must assess the possibility of the migration of radionuclides in the conservative assumption of leaching by groundwater after the destruction of the engineered barriers. The need to protect groundwater from possible radioactive contamination and the need to investigate radionuclide migration through soils and rocks of the zone of aeration into groundwater has become very urgent at a time when geological disposal of radioactive waste is being considered. This is why the Borehole Disposal Concept (BDC) is being implemented to address the problem. The BDC involve the conditioning and emplacement of disused sealed radioactive sources in an engineered facility of a relatively narrow diameter borehole (0.26 m). This concept is inherent with physical and chemical characteristics such as intrusion barriers, casing, lining materials, back-filling materials and stainless steel waste containers that prevent or delay the movement of radionuclides between components and inadvertent access to humans, animals and plants.

This work assessed the enrichment of lettuce and cabbage on display for sale along some busy roads in Accra with some essential elements using instrumental neutron activation analysis and atomic absorption spectrometry. The background levels of Fe, Mn, Cu and Zn, in lettuce and cabbage harvested from a vegetable farm were determined. The amount of the metals deposited on the vegetables after deliberate exposure along a busy road for three days were also determined. Background levels of elements in the vegetables in mg/kg were, Fe (162.97) > Mn (58.28) > Zn (10.78) > Cu (4.61) for lettuce and Fe (44.91) > Mn (20.95) > Zn (6.69) > Cu (1.16) for cabbage. The levels of all the elements increased in both vegetables after deliberate exposure with the third day recording the highest levels. The total amount of elements deposited on the vegetables after exposure for three days in mg/kg were Fe (22.27), Mn (11.8), Cu (1.68) and Zn (3.17) for lettuce and Fe (18.76), Mn (12.83), Cu (1.59) and Zn (5.58) for cabbage. Rates of enrichment of the vegetables by elements in mg/kg/day were, Fe (9.09) > Mn (3.93) >Zn (1.06) > Cu (0.56) for lettuce and Fe (6.25) > Mn (4.28) > Zn (1.86) > Cu (0.53) for cabbage.

Experimental investigations were carried out to treat industrial dairy wastewater and to minimize BOD and COD values to the required level as stipulated by the environmental standards by employing various surface-active materials like coagulants. This chemical pretreatment was followed by a biological treatment using a lab scale reactor with acclimatized and mixed consortia. Moreover the present study aimed to evaluate various parameters effecting the BOD and COD level mainly during the treatment. From the BOD and COD data for all samples, comparisons of various surface-active materials were carried to suggest the efficient surface-active material during chemical pre-treatment phase and thereby the optimum time of contact, dosage and pH were determined. In this present study chemical agents had been used as a pretreatment to the dairy effluent to reduce the BOD and COD whereas the biological treatment ensures rapid reduction in the BOD and COD values using the bacterial degradation process. The experimental results have been analyzed using Water Quality Index method to compare the efficiency of all the treatment processes.

Copper is one of the essential trace nutrients in all high plants and animals. But it can be toxic in high concentration. In this study a Copper resistant bacteria, Bacillus pumilus was isolated from Marine water. A multi-step response surface methodology was successfully applied for the maximum removal of Cu(II) from the aqueous solutions using the live bacteria to optimize the following factors : pH of the solution(3.50-5.50), concentration of the copper solution(15-50mg l^-1), incubation time (14-46 hours) and to evaluate the effects and interactions of process variables. Based on the statistics analysis the optimum conditions were obtained from pH=6.18, copper concentration=32.50mg l^-1 of the media, contact time=30 hours and the copper removal was 60.264%. The higher value coefficient of determination (R²=0.9991) justified an excellent correlation between the process parameters. Finally the difference between the theoretical value and statistical value was very low.

The use of various fixed beds having higher surface area is effective in removing organic matters and nutrients from municipal wastewater. Due to the higher specific surface area, fibrous materials are often considered a better choice for increased microbial support and treatment efficiency. In the present study two naturally available fibrous materials such as sisal and Oil palm Empty fruit Bunch (OPEFB) fibers having higher specific surface area were used as packing media in two different bio-reactors for sewage treatment, under batch mode and similar experimental conditions. Experimental results obtained were satisfactory at a packing density of 50 kg/m3. The reactors were continuously aerated for different contact times. At a contact time of 72 hours and Mixed Liquor Suspended Solids(MLSS) concentration ranging from 1500-2000 mg/L, the reactors filled with Sisal and OPEFB fibers shows satisfactory COD removal of 69.5% and 73%, BOD5 of 74% and 79.7%, NH3-N of 69% and 72.7%, and Ortho-phosphate of 81% and 82.3% respectively. The study reveals that these fibrous medias could be acceptable for efficient removal of organics and nutrients present in the sewage.

Experimental investigations were carried out to treat tannery wastewater effluent. Various surface-active materials were used to reduce the effect of chromium present in tannery wastewater. This chemical pretreatment was followed by a biological treatment. The aim was to evaluate and optimize the various parameters effecting the chromium removal during the treatment. Different coagulants were used to suggest the efficient surface-active material during chemical pre-treatment phase and thereby the optimum time of contact, dosage and pH were determined. In this present study chemical agents had been used as a pretreatment of tannery effluent to reduce the chromium (VI) whereas the biological treatment ensures rapid reduction in the chromium ions using the bacterial degradation process.

Ground water quality assessment described with 46 samples collected from Thrissur district in Kerala, India. Groundwater samples were anylsed for water quality parameters using standard methods. For the better understanding and simple representation of water types, Piper plot and Schoeller diagrams were employed. Dominant water types in the groundwater are Na-Cl, Ca-HCO3, and Ca-Na-HCO_3. Major quality parameters such as pH, EC, Ca, Mg, Na, K, Cl, SO₄, HCO₃, CO₃, NO₃ and F were analysed. Results were compared with WHO standards. This inferred that the groundwater in the Thrissur district is extremely suitable for the drinking purposes.

Modern wastewater treatment technique is effective in removing inherent contaminants in influent, which leaves the effluent with permissible minimum regulatory standards that would support the demand for water economy, recycling and re-use. Most industrial wastewater (untreated) entering a water body represents a heavy source of environmental pollution. It affects the water quality as well as microbial flora and aquatic lives. With competing demands on limited water resources, awareness of issues involved in water pollution, has led to considerable evaluations concerning environmental effects of industrial effluents discharged into aquatic environments. Effluents rich in decomposable organic matter constitute high level of organic pollution that promotes growth of significantly high coliforms and other microbial forms leading to eutrophication. Finally, this could pose serious health issues to users especially when discharge into water bodies, but could be remedied in the recent times with the advent of modern wastewater treatment techniques.

This study applies multivariate statistical technique to understand the hydro-geochemistry characteristics of pollutants along River Kaduna. Fourteen key monitored parameters that accurately represent the water quality during the rainy season (May-August) were provided by the Kaduna State Water Board. Cluster analysis (CA) grouped the sampled parameters into three independent classes (turbidity (TUR), conductivity (COND) and twelve parameters). As such, correlation of COND and TUR is worked out with the rest of the analyzed parameters based on the result generated in the CA. The findings indicate an excess concentration of TUR and COND with no significant relationship with other observed parameters. This finding is an indication that water quality parameters poses hidden complex characteristics that can only be simplified and understood when subjected to multivariate statistics and effort should be put by stakeholders to checkmate the concentration of the dominant pollutants.