Optimization of nickel removal from electroless plating industry wastewater using response surface methodology

Optimum pH and coagulant dosage for chemical precipitation in wastewater treatment plants is conventionally obtained through repeated jar test. In this research, optimization of the performance of polyacrylamide in the treatment of industrial wastewater was carried out using response surface methodology. The individual linear and quadratic effect of coagulant dosage and pH on the degree of removals of nickel, total suspended solids, Chemical Oxygen Demand and turbidity were investigated. The optimum pH and polyacrylamide dosage were found to be 10.5 and 1.6 ml/L respectively and the optimum percentage nickel removal was 96.9%. The model used in predicting the precipitation process gave a good fit with the experimental variables and hence the suitability of response surface methodology for the optimization of polyacrylamide performanc

Coagulation-flocculation in water treatment using calotropis procera leaves: a case study of river in Kaduna, Nigeria

This research was carried out to evaluate the effectiveness Calotropis procera leaves as an alternative to the use of chemicals as coagulants in water treatment. Calotropis procera leaves were plugged, washed with distilled water, cut into small pieces and then dried in an oven to a constant weight. After which the leaves were grinded into various particle sizes of 1 mm, 2 mm and 0.71 mm. Raw water from River Kaduna at Kabala and Kakuri areas within Kaduna metropolis were treated with different samples classified based on the dried Calotropis procera leaves particle size and weight, sampling location and the treatment time. The physico-chemical characteristics of the treated samples were all within the allowable standard by World Health Organization (WHO). The results show that the treated water sample D with 0.71 mm particle size and 40 g weight of the dried Calotropis procera leaves gave the highest percentage reduction in turbidity. Treatment of the samples with Calotropis procera leaves gave a significant reduction in coliform count from 21 per 100 ml to 1 per 100 ml in treated water samples E and F. This study shows that Calotropis procera can be used as a low-cost, environmentally friendly substitute coagulant for water and wastewater treatmen

Application of a packed column air stripper in the removal of volatile organic compounds from wastewater

Addressing environmental degradation and ensuring environmental sustainability are inextricably linked to all methods of reducing volatile organic compounds (VOCs) from the environment. A packed column air stripper is a typical example of such technologies for the removal of VOCs from polluted water. The present review is devoted to the applications of a packed column air stripper and, in comparison with previous reviews, presents further elaborations and new information on topics such as modeling and simulation of the dynamic behavior of the air stripping process in a packed column air stripper. The paper observed that a knowledge gap still exists in the synthesis of this knowledge to formulate practically applicable mathematical relationships to describe the process generally. Therefore, further researches are still required in the area of air stripper performance optimization, particularly in the development of a mathematical model and the optimization of an air stripper using a statistical experimental design method. Such a determination is critical to the understanding of the interactive effect of process variables such as temperature, air-to-water (A/W) ratio, and height of packing on air stripper performanc

Temperature and air-water ratio influence on the air stripping of benzene, toluene and xylene

Volatile organic compounds in water and wastewater can be removed using air stripping. The effects of temperature and air-water ratios on the air stripping of benzene, toluene and xylene (BTX) from wastewater have been examined at a temperature range of 30–50°C and air-water ratios of 20–100. Removal efficiencies of >99%, >93% and 93% for BTX, respectively, were obtained at 50°C and air-water ratios of 100. The removal efficiencies increase non-linearly with temperature and air-water flow ratio. The effects of increasing temperature on the removal efficiency were found to be more significant at temperatures between 30 and 35°C than at 45 and 50°C. The effects of increasing water-air ratios on the removal efficiency were more significant at air-water ratios of 20–60 than at 80–100. The results indicate that a high removal of BTX can be achieved by operating the air stripper at high temperature conditions even at relatively low air-water ratios and vice versa

Effect of temperature and air flow rate on xylene removal from wastewater using packed column air stripper

In this research, the effects of temperature and air flow rate on the removal efficiency of xylene from wastewater using packed column air stripper were investigated at a temperature range of 30 to 500C and air-water ratios of 20 to 100. The quantities of xylene in effluent from the air stripper were determined using UV-visible spectrophotometer. The effects of increase in temperature on the percentage removal of xylene were found to be more significant at low temperatures (30-400C) than at higher temperatures (45-500C). Also, the effects of increase in water-air ratio on percentage removal of xylene were less significant at higher G/L ratio (80-100) and more significant at low G/L ratios (20-60), thus revealing a non-linear trend in the effect of temperature and air-water ratio on xylene removal.The result also indicates that xylene removal efficiency is greatly affected by column temperature and G/L ratio with the highest removal efficiency of 99.93 at temperature of 500C and at G/L ratio of 10

Preparation, Characterization and Adsorption Study of Granular Activated Carbon/Iron oxide composite for the Removal of Boron and Organics from Wastewater

Boron and organics maybe in high concentration during production of oil and gas, fertilizers, glass, and detergents. In addition, boron added to these industrial processes may require to be removed by the wastewater treatment plant. The preparation, characterization and application of iron oxide-activated carbon composite for removal of boron and COD was studied. The one variable at a time (OVAT) method was implemented to obtain desirable operating conditions (adsorbent dosage 5 g/L, reaction time 2 h, agitation speed 100 rpm, pH 5 for COD removal and pH 9 for boron removal). It was found that boron and organics present in a sample wastewater may require to be treated separately to remove the contaminants. The study achieved 97 and 70% for boron and COD removal, respectively. Adsorption as an alternative cheap source of treatment and its practicability for small communities is recommended as effective in removal of contaminants from river water

Preparation, Characterization and Adsorption Study of Granular Activated Carbon/Iron oxide composite for the Removal of Boron and Organics from Wastewater

Boron and organics maybe in high concentration during production of oil and gas, fertilizers, glass, and detergents. In addition, boron added to these industrial processes may require to be removed by the wastewater treatment plant. The preparation, characterization and application of iron oxide-activated carbon composite for removal of boron and COD was studied. The one variable at a time (OVAT) method was implemented to obtain desirable operating conditions (adsorbent dosage 5 g/L, reaction time 2 h, agitation speed 100 rpm, pH 5 for COD removal and pH 9 for boron removal). It was found that boron and organics present in a sample wastewater may require to be treated separately to remove the contaminants. The study achieved 97 and 70% for boron and COD removal, respectively. Adsorption as an alternative cheap source of treatment and its practicability for small communities is recommended as effective in removal of contaminants from river water

Integrated air stripping and non-thermal plasma system for the treatment of volatile organic compounds from wastewater: statistical optimization

This study examined the treatment of toluene and m-xylene from wastewater using integrated air stripping and non-thermal plasma (NTP) reactor system. Toluene and m-xylene concentrations, before and after plasma treatment, were determined using Fourier transform infrared spectroscopy. The performance of the NTP reactor was optimized using the central composite design of the response surface methodology. The optimum discharge gap, applied voltage, and flow rate for the decomposition were found to be 22.34 mm, 15 kV, 3.56 L/min and 20.10 mm, 15 kV, 3.34 L/min for toluene and m-xylene, respectively. Experimental removal efficiencies and model predictions were in close agreement with 1.25 and 2.16% errors for toluene and m-xylene, respectively. The developed model could fit the experimental data with acceptable values of percentage errors