Assessment of the influence of continuous and intermittent irrigation on greenhouse gas emissions from paddy rice

The impact of two water management practises on Greenhouse Gases (GHGs) emissions from paddy rice fields was investigated. New Rice for Africa (NERICA 2) lowland variety was planted under intermittent irrigation (II) and continuous flooding (CF) water management practises. Two closed gas chambers (GCs) were developed and used for gas sampling from paddy fields and measurement was done conventionally in all the four growing stages of rice. Gas Chromatograph (GH200-9) was used analysing GHGs such as Methane (CH4), Nitrous oxide (N2O), Hydrogen Sulphide (H2S) and Oxygen (O2). Soil analyses were carried out to determine the presence of the following parameters viz: nitrogen (N), phosphorus (P), potassium (K), magnesium (Mg), Manganese (Mn) and calcium (Ca). Others are Organic Carbon (OC), Moisture Content (MC), Iron (Fe), Chloride (Cl) and Electrical conductivity (EC) using standard laboratory procedures and ascertain effects of their availability on GHGs concentration levels. From the study, no appreciable CH4 emissions was detected during the four growing stages and under the two water management practises but other GHGs emitted were higher in CF compared with II. Soil nutrients such as N, OC, K and P also contributed considerably to emissions recorded on the two rice fields. The detection of H2S was also an indication that other gases apart from the common GHGs were present in rice fields. Although, CH4 was not detected, other GHGs emitted were more in CF when compared with II which suggested that II be encouraged as a mitigation strategy for reducing impacts of its emissions

Production and purification of antibody by immunizing rabbit with rice tungro bacilliform and rice tungro spherical viruses

Rice tungro disease is the major disease caused by infection with the rice tungro bacilliform virus (RTBV) and rice tungro spherical virus (RTSV). In this study, New Zealand White rabbits were immunized with pure viruses for the production of antibodies against both species. The production of polyclonal antibodies against Tungro viral disease using ammonium sulfate precipitation and a protein A affinity column and their assessment are described. Two peaks were found from the protein A affinity column. Peak 1 represents the unbound compounds from the extracted serum and peak 2 represents antibody that bound to protein A, which was eluted using elution buffer. Peak 2 was collected for antibody titration. The amount of pure antibody in the titers was quantified by enzyme-linked immunosorbent assay (ELISA) to capture the tungro viruses. Antibody titer was analyzed by the ELISA method. For anti-RTBV, 1.696 mg/mL was highest at the second bleed and anti-RTSV was 2.3225 mg/mL was highest at the first bleed. These antibodies detected the tungro viral disease well and proved to be a potential probe for the detection of rice tungro disease

Quantification of chlorine and hydrogen chloride in air using chemically treated filter

Air pollution is a major cause of environmental health problems with devastating effects all over the world. In recent years, new techniques of air sampling have been developed for the assessment of air pollutants. In this study, a simplified technique based on the US EPA Test Method 26 was developed to quantify the concentration of Chlorine (Cl2 ) and Hydrogen chloride (HCl) in indoor air. The collection of acid gases was compared by liquid absorption between impingers and the chemically treated filter. Results show that there was a linear relationship between the concentration of the acid gases collected and their flow rates in both cases. The chemically treated-filter method was found to quantify both Cl2 and HCl to a certain sensitivity compared to the impinger method. Errors are inherent in the measurement system. Although the uncertainties cannot be reduced to zero, by quality assurance study, the new methods are viable. Small-sized apparatus, portable, simple to operate and exclusiveness of any volatility are some of the advantages of the developed filter. It was also shown that chemical reaction of Cl2 with Sodium hydroxide (NaOH), and HCl with Sulphuric acid (H2 SO4 ) produced ion chlorides that can be determined instrumentally

Pre-treatment ammonia removal of scheduled waste leachate with hydrated lime and caustic soda

Leachate is known to be hazardous wastewater in terms of its organic matter and ammonia content. Various methods have been studied extensively for the treatment of different types of leachate. However, scheduled waste leachate is rarely studied due to its complex characteristics and highly contaminated nature compared to other types of landfill leachates. In this study, hydrated lime (Ca(OH) 2 ) and caustic soda (NaOH) as softener agent were used for increasing the pH of the treatment process of scheduled waste leachate to remove ammonia-nitrogen (NH 3 -N). Chemical oxygen demand (COD) and colour removal were also evaluated. Jar test experiments was performed using Ca(OH) 2 and NaOH at varying dosages ranging from nil to 12 g L -1 . A Historical Data Design (HDD) of Response Surface Methodology (RSM) was employed to optimize the parameters affecting NH 3 -N, COD and colour removal efficiency. The optimal conditions obtained from desirable response were predicted at 5.9 g L -1 of Ca(OH) 2 dosage, where the maximum NH 3 -N, COD and colour removal efficiency would be 49%, 18% and 66%, respectively. Meanwhile for NaOH, dosage of 6.4 g L -1 was predicted to remove NH 3 -N, COD and colour up to 32%, 4% and 42%, respectively. The predicted values concurred with the experiments, in which Ca(OH) 2 successfully reducing NH 3 -N, COD and colour up to 52%, 17.5% and 65%, while NaOH could only remove NH 3 -N, COD and colour by up to 35%, 2% and 49%, respectively. The results obtained from this study suggest that hydrated lime (Ca(OH) 2 ), is more feasible to be used for the pre-treatment process of scheduled waste leachate as less dosage is required with higher removal efficiencies of NH 3 -N, COD and colour. This study demonstrates that RSM was a reliable tool to predict the optimum dosage and suitable types of chemicals for the removal of NH 3 -N, COD and colour from the available data