Effluent Quality of Wet Process Coffee Processing Factories in Coffee Growing Ecological Zones in Burundi

Arabica coffee is cultivated by smallholders for commercial purposes, and it is commonly processed using wet Coffee Processing Technology. Burundi has more than 250 Coffee Processing factories which discharge their effluents to water bodies. The goal of this study was to determine the levels of physicochemical parameters in wastewater from Coffee Processing Technology factories in major coffee growing ecological zones in Burundi. Wastewater samples were collected from 19 sites representing private, public and cooperative owned coffee processing stations. Physicochemical analyses were determined in-situ field and laboratory conditions using standard procedures. Results indicate that the wastewater does not meet Burundi Effluent Discharge standards for Total Suspended solids, Chemical Oxygen Demand, Biochemical Oxygen Demand, pH. The data revealed that the wet coffee processing pollutes the environment in terms of pH, Total Suspended solids, Chemical Oxygen Demand, Biochemical Oxygen Demand. There is need to install quality polishing technologies to treat the water before disposal.

On the Use of Iron Chloride and Starch for Clarification in Drinking Water Treatment

In drinking water treatment plants, chemical reagents are employed to aggregate and remove suspended particles. However, not all reagents are eco-friendly and exists concerns over environmental, economic, and health issues. This study shows features of the sustainability of commercial coagulants/flocculants and presents experimental research on floc characterization and settling of dispersed solids with a combination of Ferric Chloride (FeCl3 ) and gelatinized starch. Bench studies were conducted using kaolin suspensions and results were validated with raw water collected from a river (Rio dos Sinos, Brazil). Flocculation indexes, floc structure, and residual turbidities were compared with Polyaluminum Chloride (PAC), as a reference. All techniques showed that the combination of FeCl3 and starch formed well-structured, larger, and more settleable flocs than those produced with PAC. Superficial loadings, in a continuous separation tank (2 to 4 m.h-1) were studied with and without lamellae. Best results were obtained with 15 mg.L-1 Fe3+ and 10 mg.L-1 starch, with a velocity gradient, G, of 60 s-1 in the slow mixing and with 60° inclined lamellae spaced 1.3 cm apart. Best conditions were applied to the clarification of the raw water and again, due to the rapid settling of flocs with FeCl3 and starch, better results were obtained compared to PAC. A turbidity reduction of 94% and a residual value of 2.5 NTU with superficial loadings of 3 m.h-1 were obtained. Results were discussed in terms of interfacial and operating parameters and a promising potential for the combination of FeCl3 with starch for solid/liquid separation was envisaged.

Residual Wastewater Treatment by an Aquatic Plant System in Tropical Area: Assessment of Arundo Donax and Pennisetum Purpureum Schumach

This study examines the potential of two local reed species (Arundo donax and Pennisetum purpureum Schumach) from Uíge province, Angola, to purify wastewater from the Kimpa Vita University Campus, under a vertical flow regime, and in a tropical climate. The assessment performance of these macrophytes is based on an experimental system with three plastic basins, with a capacity of 84 L each, containing a 0.25 m-thick layer of gravel and topped with a layer of sand of 0.1 m. The first basin is planted with Arundo donax, the second with Pennisetum p. Schumach, and the last is without vegetation cover. The obtained results show that the effluent treated by the planted filters has a better mineralization, with a satisfactory Chemical Demand for Oxygen (COD), unlike the unplanted filter. Indeed, the action of the roots and rhizomes allows a significant elimination of nutrients, although the average abatement in Biochemical Demand for Oxygen for five days (BOD5 ) of the whole system is low. In addition, the microbiological elimination of faecal coliforms is good on average and the effluents purified by these filters are clear and odorless. The planted filter of Arundo donax allows better elimination of Escherichia coli (E. coli) and enterococci compared to that of Pennisetum p. Schumach.

Various Absorbents and Parameters Affecting Removal of Water Hardness from Wastewater: Review

Discharges of heavy metals from different sources to the water lead to water hardness which is the major problem of the world due to their toxic and carcinogenic nature. Among several methods to eliminate heavy metals, absorption is the leading technique for the removal of heavy metals from wastewater because it is efficient, available, low-cost, and eco-friend. This review paper gives detail information about adsorbents on both conventional and nanostructured materials, either occur naturally or available commercially. The review also contains properties and parameters which affect the adsorption process with essential clarifications that are given by researchers.

Application of EAFDS/Lime Integrated System for the Removal of Cu and Mn from Industrial Effluent

Metal pollution is one of the significant concerns affecting the environment and the wellbeing of living things. Copper and manganese are the most common metal pollutants with detrimental effects on the health of human beings. Several methods have been proposed and applied for the treatment of industrial effluent and removal of hazardous metals. One of the most common treatment methods is chemical precipitation. This study is about application of chemical precipitation of copper and manganese metals from industrial acidic effluent in the presence of large concentration of other metals using a steel industry solid waste called Electric Arc Furnace Dust Slag (EAFDS) in conjunction with lime. The study proved that EAFDS alone can remove the target metals considerably and reducing the cost associated with the procurement of other costly chemicals. The concentration of Cu in the raw effluent was 47.2 mg/l. The slag reduced the concentration to 7.8 mg/l achieving 81.7 % removal. The concentration of Mn in the raw effluent was 120.8 mg/l, which was reduced to 12.0 mg/l with the slag only. The two metals were removed achieving 99.7 %with the addition of small amount of Ca(OH)2.

Evaluation of Residual Al3+ and Fe3+ Concentration in Blended Alum-Ferric Chloride Coagulant Use

The use of aluminum and iron salts as coagulants in water treatment may cause the rise of aluminum and iron ions concentrations in finished water. Approximately drinking water is responsible for nearly five percent of the aluminum ingested by humans although aluminum accumulation in the brain is associated with neurodegenerative diseases. This study aims to evaluate the residual concentration of Al3+ and Fe3+ upon the use of blended alum-ferric chloride coagulant in clarifier effluent. An experimental study of Jar tests were conducted to evaluate the effect of blended alum-ferric chloride coagulant use on the finished water residual aluminum and ferric ion concentration. All parameters were determined according to APHA standard methods for water and wastewater examination. Data were compiled and analyzed using Microsoft excels 10 and Minitab 16 and presented using tables and graphs. As compared to single coagulant use, 1:1 A-FC (Alum-Ferric chloride) mix-use resulted in an average of 40% aluminum ion concentration and 20% residual ferric ion concentration reduction. At optimal pH and dose, the residual aluminum ion concentration were 0.1 mg/L, 0.06 mg/L and 0.09 mg/L for alum, 1:1 and 3:1 A-FC coagulants, respectively. While, the ferric ion concentration were 0.4 mg/L, 0.32 mg/L and 0.11 mg/L for ferric chloride, 1:1 and 3:1 alum-ferric chloride coagulants, respectively. The study demonstrated a strong correlation (r=0.93) between coagulant dose and residual aluminum ion concentration which was statistically significant (P<0.05). Also, a strong correlation (r=-0.97) was observed between the water pH and residual aluminum ion concentration which was similarly statistically significant (P<0.05). The residual aluminum and ferric ion concentrations were greatly reduced when alum and ferric chloride coagulants were used in combinations than used separately. The regular monitoring of chemical residuals in drinking water and control of coagulant conditions should be considered in the water treatment process.