Hypothesis: Municipal wastewater can be used for crop irrigation in periurban areas.
Wastewater reuse has not yet started in a greater way in Bangladesh. Only a part of the wastewater is currently used and almost more than 90 % is diverted to nearby canal, river or ponds. It is usually believed that diverting the wastewater into the natural places is usual and this water cannot create abnormalities in water system but for the past few years, fishes in the natural water bodies are dying and no prevention measure is being taken either by government level or private sectors. Some people are using wastewater without any treatment for vegetable production. In Mymensingh periurban areas, wastewater is used for the production of paddy, horticultural crops, raintrees and vegetables. This wastewater contains high level of nitrogen and phosphorus thus increases soil fertility and lowers dependence on chemical fertilisation in crop production.
Field Level Experiment and description of Equipment Used:
Measurement of field data by using Ph, TDS and EC meter and test strips (Reflectoquant) for NH4, PO4, NO3, etc.
Materials and Methods:
• Literature review and site selection
• Field Level Experiment and Descriptoon of Equipment Used:
pH: pH may be defined as the negative value of the logarithm of the hydrogen ion concentration (strictly speaking hydronium ion concentration), i.e.
The normal pH range for irrigation water is from 6.5 to 8.4; pH values outside this range are a good warning that the water is abnormal in quality. Normally, pH is a routine measurement in irrigation water quality assessment. A digital pH meter (Milwaukee Smart pH system SM100, accuracy at (250C) range ±0.2 pH) uses an electrode to measure the pH of a solution. Before taking a pH measurement, the meter must be "calibrated".
Electrical Conductivity (EC): Electric Conductivity is defined as the ability of a substance to conduct an electric current and it is the reciprocal of electrical resistivity. The unit of measurement commonly used is the Siemens/cm (S/cm), microSiemens/cm (µS/cm), or milli-Siemens (mS/cm). In aqueous solutions conductivity is directly proportional to the concentration of dissolved solids, therefore the higher the concentrations of solids, the greater the conductivity. The relation between conductivity and dissolved solids is expressed, depending on the application, with a good approximation, by: 1.4 S/cm = 1 ppm or 2µS/cm = 1 ppm (part per million of CaC03) Where, 1 ppm = 1 mg/L is the measuring unit for dissolved solids.
In addition to conductivity meters, there are TDS instruments that automatically convert the conductivity value into ppm, thus providing a direct reading of the dissolved solids concentration. DiST 3 (HI 98303, range 1999 µS/cm) was used in the field experiment.
Total Dissolved Solids (TDS): TDS is a common measurement of freshwater. When TDS is determined by summing the results of separate analyses for all major ions, it is analogous to salinity. When TDS is measured gravimetrically (by weight), it can be greater or less than salinity, depending on whether loss of bicarbonate (H2CO3) in the gravimetric analysis is more than offset by the presence and, consequently, measurement of dissolved organic carbon. A gravimetric measurement of TDS in water in an alkaline media would probably indicate lower TDS than if TDS were measured by summation or salinity because not enough organic matter would be present in the water to make up the H2CO3 weight loss. DiST 2 (HI 98302, range 10.00 ppt (g/L)) was used in the field experiment.
Test kids for onfarm analysis: The concentration of NH4+, NO2-, NO3- and PO43- are measured semi-quantitatively by visual comparison of the reaction zone of the strip with the fields of a colour scale. The sample material may be wastewater, soils, fertilizers and food. A wide range of colorimetric and titrimetric rapid testes and ion-specific Merckoquant® test strips are available for the determination of many other ions and compounds.
• Soil Analysis: Soil sample will be collected in the different time and season such as before cultivation, during cultivation, after cultivation, etc.
Soil will be analyzed in BAU or BINA's Soil Science Lab by using the appropriate method.
• Types and yields of Crops grown in the area
To make questionery for the end users of ww, to visit the research area for conducting the PRA survey, collecting information by asking or requesting farmers opinion about the ww irrigation, comparing farmers who use ww for irrigation with others who doesn't use ww.
• Stablishin Demonstration Plot:
After identifying the farmer who wish to give land for establishing demonstration plot, a contract will sign with him. He will work in his field under the supervisor direction and project will compensate his all of cost like hiring land, preparing land, supplying fertilizer if required, insecticides if required, seeds and others. We then able to get details data about the influence of ww irrigation on crop production, selection of the type of crops, soil condition, farmers socio economic condition, etc.
• Statistical analysis:
The data were analyzed using MSTAT and SPSS in accordance with the principle of one-way technique (The one way ANOVA procedure produces a one way analysis of varience for a quantative dependent variable by a single factor (independent) variable). Mean, Standard error, Standard Deviation, coefficient of variation, the correlation coefficient, ANOVA (Analysis of Varience) and multiple regression will be used for data analysis.
Result and Discussions:
A proper PRA survey, KAP study, field and laboratory level experiment and demonstrating plot will help to get a real assesment of the impacts of ww irrigation on crops and soil and also will able to show the economic benefit of the farmers.
Development of Guidelines: After getting the results by analysing the data and arranging seminar or workshop about the findings, a guideline for farmers for the safe use of ww irrigation in the crop field will be developed.