Safe Drinking Water: Concepts, Benefits, Principles and Standards

Water is connected to every forms of life on earth. As a criteria, an adequate, reliable, clean, accessible, acceptable and safe drinking water supply has to be available for various users. The United Nation (UN) and other countries declared access to safe drinking water as a fundamental human right, and an essential step towards improving living standards. Access to water was one of the main goal of Millinium Development Goals (UN-MDGs) and it is also one of the main goal of the Sustainable Development Goals (SDGs). The UN-SDG goal 6 states that “Water sustains life, but safe clean drinking water defines civilization”. Despite these facts, there are inequalities in access to safe drinking water in the world. In some countries, sufficient freshwater is not available (physical scarcity); while in other countries, abundant freshwater is available, but it is expensive to use (economic scarcity). The other challenge is the increasing population of the world at an alarming rate, while the available freshwater resources almost remains constant. This chapter presents aspects of safe drinking water - background information, definition of water safety and access, benefits, principles and regulations, factors challenging the sustainable water supply and water quality standards and parameters

Quality composition and irrigation suitability of various surface water and groundwater sources at Matahara Plain

Abstract: This study highlights the physico-chemical compositions of different water sources available at Matahara Plain and evaluates their suitability for irrigation purpose. Various surface- and ground-water samples were collected and then analysed for important major physic-chemical quality parameters (pH, EC, cations and anions) following standard procedures. Other chemical indices were derived from the measured quality parameters. The quality rating for each water type was evaluated against the recommended threshold level for irrigation. Each water sources were rated for irrigation suitability following standard FAO guidelines and others. Overall, the findings emphasize the need to avoid the use of poor quality water for irrigation. Keywords: groundwater, irrigation suitability, Lake Basaka, Matahara, quality parameters

Lake Basaka expansion : challenges for the sustainability of Matahara irrigation scheme, Awash River Basin (Ethiopia)†

Abstract: Matahara Sugar Estate (MSE), after nearly 60 years of irrigation, is experiencing effects of waterlogging and salinization in some fields. The problem is believed to be the result of the expansion of (saline and alkaline) Lake Basaka towards the plantation fields. The objective of this study was to determine the geometry of the lake (area and shape) in the past about a half century (1957-2015) from both Landsat images and local information and then assess its negative effects on MSE's soil and water quality. Monthly groundwater (GW) depth was monitored using piezometer tubes. Water and soil samples were collected from each of the piezometer location and analysed for important physico-chemical parameters. The results indicate that the lake expanded approximately 47.3 km2 in the past about a half century. The soil quality is found to be very poor in plantation sections with very shallow GW depth and severe salinity condition. The lake, as revealed by the results, is intruding into the groundwater system of MSE on the Abadir side. Assuming continuation of the past trends, the lake is expected to inundate parts of MSE in the next few years and hence, challenge the production and productivity of MSE significantly. The Lake has the potential to join Awash River, thereby impacting all downstream irrigation developments in the Basin and the livelihood of the people depending on the water resources. As the area is situated in the uppermost part of MER, other factors are expected to exacerbate its..

Development and Application of Conceptual Rainfall-Altitude Regression Model: The Case of Matahara Area (Ethiopia)

Rainfall data available, in tropical regions with undulating topography, may provide a valuable information for water resource development as well as for predicting and preventing natural disasters. But in developing countries like Ethiopia, rain gauge stations are sparsely populated, and rainfall data are the limiting factor. Hence, estimation of rainfall is extremely important. The current paper deals with the development of a rainfall-altitude relationship for Matahara area, Awash Basin of Ethiopia. A conceptual rainfall-altitude regression model was formulated and its performance evaluated. The relationship between monthly rainfall totals and gauge elevation over Matahara region (including Lake Basaka catchment) was examined using the conceptual regression model (ordinary least square). The regression parameters were identified and estimated and then used to map the spatial rainfall for Lake Basaka catchment in ArcGIS. The regression analysis showed a strong positive correlation (r = 0.85) between the long-term average monthly rainfall and altitude of the region. It is shown that the rate of increase of rainfall with altitude is in the range of 0.020 mm/h at Matahara to 0.067 at Welenchiti, with average value of 0.0475 mm/m/month. The best fit (R2 = 0.9187, p = 0.015) was obtained between observed and estimated rainfall depths for all the stations with total standard error of 12.97 mm. The high R2 reveals that the developed equation is acceptable for the area at 98.5% (p > 0.015) confidence limit. The performance of the developed model is found to be within reasonable accuracy, which is limited by the elevation difference and distance from the base station. Therefore, the spatial and temporal structures of rainfall distribution (daily, monthly or annual) for Matahara region (including Basaka Lake catchment) can be determined from the available records of rainfall data at the Matahara Research Station (Merti) meteorological station with acceptable reliability. In general, the performance of the developed model is found to be within reasonable accuracy, which is limited by the elevation difference and distance from the base station

Evaluating the adequacy performances of sprinkler irrigation system at Finchaa sugarcane plantation, Eastern Wollega Zone (Ethiopia)

Abstract: The success of sprinkler irrigation system largely depends on its actual performance at field condition. Although the uniformity of water application is the most important aspects in the sprinkler systems performance, adequacy better explains the performance of the system. In this study, the adequacy of irrigation performance was measured actually at field condition considering three operating hydrant pressures (4.0, 4.5 and 5.0 bars) and two sprinkler nozzle sizes (2.4 * 4.4 and 2.4 * 4.8 mm). The main objective of this study was to determine the level of current adequacy of irrigation performance in relation to the predicted performance during the design period. Three different adequacy performances (delivery, infiltration and storage) were determined from the measurements of the two important basic sprinkler performance parameters: discharge and uniformity. The study result indicates excess irrigation water application more than the crop net irrigation requirement and soil moisture deficit, especially for the 2.4 * 4.8 mm nozzles sprinkler at all pressure ranges considered. Inline to this, tremendous losses in terms of deep percolation ( 40%) have been observed, the consequence of which is leaching of soluble nutrients, loss of valuable water resources, reduced crop yield and rise of groundwater table. The later one might lead to drainage problems, which requires construction of expensive drainage..

Assessing the performance of Trichardt wastewater treatment plant (South Africa)

Abstract: The main task in treating the wastewater in South Africa is to reduce the pollutants (solids, organic matter, nutrients, and micro-organisms) to meet the standard requirements from Department of Water and Sanitation (DWS). That means the discharged effluent should be without polluting the environment and posing safety risks. The objective of this study was to investigate the performance of the Trichardt Wastewater Treatment Plant (South Africa) and come up with recommendations for the improvement of the wastewater treatment plant. The performance of the plant was evaluated for its compliance with the standard set by the DWS. The water quality parameters tested include: Ammonia (NH3), Nitrate (NO3-), Phosphate (PO4-3), Chemical Oxygen Demands (COD), Turbidity (T) and Total Suspended Solids (TSS). The result indicates that the concentration of most of the considered parameters (TSS, NH4, COD, PO4-3) are above the permissible limit set by DWS throughout the year, except Nitrate. The operating flowrate is below the design capacity (1.8 m3/s) throughout the year, except September. Overall, the final effluent discharged to the stream do not comply with the standard set by DWS. Thus, measures for the improvement of the treatment plants’ performance are highly recommended. The increase of the hydraulic loading capacity and the use appropriate methods of treatment process such as biological nitrification-denitrification processes are suggested. The increase of retention time to 3 hrs and decrease of the screen openings to 12 mm are also highly recommended

Improving Traditional Spate Irrigation Systems: A Review

Although the spate irrigation system is an ancient practice, it is only in the past very few decades the system has undergone little modernization interventions. However, these interventions were mostly in the aspects of heavy investment in the sophisticated head works for improving flood water diversion efficiency. In many cases, the modernization interventions were not successful due to various problems such as heavy sedimentation, high flood, disturbed local water distribution rules, or the new designs were not coherent with home-grown practices. On the other hand, successful improvements incorporate less labor intensive and relatively permanent structures with the advantages of conventional systems without considerably altering the approach of the spate irrigation practice. Thus, in this chapter, the techniques of improving traditional spate irrigation systems were reviewed. Farmer-implemented improved traditional spate irrigation systems: flow diversions; canals and control structures; management of sediment, field water, and soil moisture and agronomic practices; reactive water rights and distribution rules were assessed. Therefore, this chapter helps as a reference material for teaching, training and research activities, and it plays a great role in the efforts of sustainable spate irrigation systems development, rehabilitation and management programs

Suitability of shallow groundwater for irrigation purpose : The case of Wonji Shoa sugar estate (Ethiopia)

Abstract: This study evaluated the possibility of conjunctive use (CU) of shallow ground water (SGW) and surface water for irrigation use at Wonji Shoa Sugar Estate (WSSE)(Ethiopia). Irrigation suitability was investigated by taking 46 SGW samples from piezometers and hand-dug wells. Many physicochemical parameters (Mg2+, Na+, Ca2+, K+, CO3-, SO42-, HCO3-, Cl-, TH, EC, TDS and pH) and other indices (MAR (magnesium adsorption ratio), SSP (soluble sodium percentage), SAR (sodium absorption ratio), RSC (residual sodium carbonate), KR (Kelly’s ratio) and permeability index (PI)) were analyzed following standard procedures. The salinity and infiltration problems of SGW were found to be none to moderate with none chloride and boron ion toxicity. The sodium ion toxicity problems are slight to moderate. The SGW is generally categorized under C3S1 (high salinity and low sodium hazard). However, a high value of SSP and RSC indicate a high possibility of occurrence of infiltration problem when using the SGW. Hence, the CU of SGW and surface water must be practiced to minimize the potential problems of infiltration, salinization and their associated problems on soil and sugarcane productivity. Therefore, during CU planning, the optimum irrigation scheduling that considers the in situ use of groundwater table must be practiced

The application of magnetite biochar composite derived from parthenium hysterophorus for the adsorption of methylene blue from aqueous solution

The removal of toxic and harmful dyes like methylene blue (MB) from textile wastewater is necessary to reduce environmental pollution. Therefore, this study is aimed at removing MB from an aqueous solution using magnetite-doped biochar of parthenium hysterophorus. Biochar was prepared through pyrolysis techniques at 500 ℃ for 2 h whereas the magnetite and composite material were developed using coprecipitation methods. Herein, NaNO3 and FeSO4. 7H2O were utilized as precursor materials and NaOH as a precipitating agent for preparation of magnetite. Furthermore, pH point of zero charge (pHpzc), Scanning Electron microscope (SEM), Fourier Transform Infrared Spectroscopy (FTIR), and X-ray Diffraction (XRD) are characterization techniques used to evaluate the nature of the composite material. On the other hand, a full factorial design involving four factors at two levels (24) such as pH (3 and 9), contact time (10 and 40 min), initial dye concentration (100 and 150 mg/L) and adsorbent dosage of 0.01 and 0.04 g/100 mL was used to design and optimize the batch adsorption of MB from an aqueous solution. As a result, a maximum removal efficiency of 99.99% was attained at optimum operating conditions of pH 9, contact time 40 min, initial MB concentration 100 mg/L and adsorbent dosage of 0.04 g/100 mL. Langmuir, Freundlich and Temkin isotherm models were used to investigate the adsorption isotherm in which Freundlich isotherm with a maximum R2 of 0.98 was found to describe the adsorption process inferring multilayer and heterogeneous surface interaction. Additionally, the thermodynamics study depicts that the nature of the adsorption is spontaneous, endothermic and feasible. On the other hand, the chemosorption nature is revealed by the pseudo second kinetics model with a maximum R2 of 0.99. Finally, the remarkable reusability ranging from 99.98% to 97.6% for five consecutive cycles proved that the magnetic biochar derived from parthenium hysterophorus can be used as an effective adsorbent for the decolourization of MB saturated effluent at an industrial scale

Setting Time and Workability of Geopolymerized Fly Ash-Phosphogypsum Paste and Mortar

Geopolymer is no longer viewed as a concept for a greener society but rather as a pragmatic solution for reducing CO2 emissions in the construction industry. It is commonly produced using industrial waste materials such as fly ash (FA) and phosphogypsum (PG). Globally, FA has an estimated annual production of around 1 billion tonnes and that of phosphogypsum is around 300 million tonnes, of which utilization stands at 50% and 15% of the total generated, respectively [1]. Geopolymers have been extensively studied as an alternative to ordinary Portland Cement (OPC) [2], [3] but to date, no study has been done to investigate the setting time and workability of geopolymerized fly ash-phosphogypsum paste and mortar. This research investigates the setting time and workability of geopolymerized fly ash-phosphogypsum paste (GPP) and mortar (GPM) using a Vicat needle procedure per ASTM C191 and the flow table test per ASTM C1437, respectively. The materials used were PG, Class F FA, silica sand, NaOH pellets of 99% purity, and Na2SiO3 solution of the composition Na2O = 8.3%, SiO2 = 27.7%, H2O = 64%, and Ms (SiO2/Na2O) = 3.34. The dissolution of NaOH pellets in water is an exothermic process [4] therefore the prepared NaOH solution was kept in a sealed glass bottle for 24 hours at room temperature to allow sufficient cooling before mixing with the Na2SiO3 solution. The specimens were prepared at 10M NaOH + Na2SiO3 Ms of 3.34, Na2SiO3/ NaOH ratio of 1.5, Alkaline Liquid/Precursor ratio of 0.4, Binder/Aggregate ratio of 1.0, and varying PG at 10 wt% increments. As per ASTM C305 for mixing pastes and mortars, the preparation of the specimens started with dry mixing the FA with PG in a conventional pan mixer for 3 minutes, followed by the gradual addition of alkaline solution and wet mixing for 5 minutes. Soon after wet mixing, the manufactured paste and mortar were tested for setting time and workability. It was found that an increase in the PG wt% led to a decrease and/or acceleration in the initial setting time (INSET) and final setting time (FINSET) attributed to the rapid dissolution of Ca2+ in low alkaline concentrations outnumbering that of Al3+ and Si4+ and thus forming ettringite and C-A-S-H gel that facilitates hardening shortening the setting time [5], [6]. The INSET of GPP decreased from 37 min (at 10wt% PG) to 27 min (at 30 wt% PG) while the FINSET of GPP decreased from 155 min (at 10wt% PG) to 125 min (at 30 wt% PG). The INSET of GPM decreased from 29 min (at 10wt% PG) to 23 min (at 30 wt% PG) while the FINSET of GPM decreased from 142 min (at 10wt% PG) to 113 min (at 30 wt% PG). Furthermore, the workability of GPP and GPM decreased with an increase in PG wt% attributed to faster hydration activity, accelerated setting, and increased viscosity. The workability of GPP decreased from 176 mm (at 10 wt% PG) to 138 mm (at 30 wt% PG) while that of GPM decreased from 137 mm (at 10 wt% PG) to 112 mm (at 30 wt% PG). The development of GPP and GPM offers a sustainable circularity construction solution to minimize OPC usage and prevent the disposal of FA and PG in landfills. Future research should investigate the mechanical properties of GPP and GPM