International Journal of Civil Engineering and Technology (IJCIET) Volume 6, Issue 9, Sep 2015, pp. 08-19, Article ID: IJCIET_06_09_002 Available online at http://www.iaeme.com/IJCIET/issues.asp?JTypeIJCIET&VType=6&IType=9 ISSN Print: 0976-6308 and ISSN Online: 0976-6316 © IAEME Publication ___________________________________________________________________________ COLUMN STUDY OF THE ADSORPTION OF PHOSPHATE BY USING DRINKING WATER TREATMENT SLUDGE AND RED MUD Prof. Dr. Alaa Hussein Al-Fatlawi College of Engineering / Babylon University/Iraq Mena Muwafaq Neamah College of Engineering / Babylon University/Iraq ABSTRACT The present study investigates the efficiency of phosphate removal from wastewater by the Drinking Water Treatment Sludge (DWTS), and Red Mud (RM) sorbent. Wastewater was taken from the effluent channel of Almuamirah wastewater treatment plantin at Al-Hilla city/Iraq. Drinking Water Treatment Sludge (DWTS), was taken from the sedimentation tanks of Al-Tayara drinking water treatment plant, in the same city. Column experiment was carried out to study the adsorption isotherm of phosphorus at 25±1⁰C and solution of different pH and adsorbent dosages. The effects of (DWTS) dose, bed height (H), contact time (T), agitation speed (S), hydrogen ion concentration (pH), (DWTS –RM) ratio, were studied. All continuous experiments were conducted at constant conditions, bed depths 25 cm, initial phosphate concentration 4 mg/L, flow rate 5 mL/min, particle size (1mm) for (DWTS), and (0.425mm) for (RM) and solution pH of 4. The results show that the use of (RM) reduces the operating time by about 21% compared to the use of (DWTS).Increasing (RM) ratio increasing the removal efficiency and decreasing the equilibrium time in about 57% and 38% for 50% and 33% (RM) ratio respectively. At the highest phosphate concentration of 4 mg/l, the (DWTS) bed was exhausted in the shortest time of less than 9 hours leading to the earliest breakthrough. Percent of phosphate removal decreased with the increase in initial concentration. Both the breakthrough and exhaustion time increased with increasing the bed height. The results show that a significant increase in the operating time is achieved by adding different ratios of (RM) to (DWTS). Adding 33%, and 50 % (RM) weight ratios to the (DWTS) bed decreases the operating time by about 18%, and 30% respectively. http://www.iaeme.com/IJCIET/index.asp 8 [email protected] Column Study of The Adsorption of Phosphate by Using Drinking Water Treatment Sludge and Red Mud Key words: Column Study, Adsorption, Drinking Water Treatment Sludge (DWTS), and Red Mud (RM), phosphate. Cite this Article: Prof. Dr. Alaa Hussein Al-Fatlawi and Mena Muwafaq Neamah. Investigating Column Study of The Adsorption of Phosphate by Using Drinking Water Treatment Sludge and Red Mud. International Journal of Civil Engineering and Technology, 6(9), 2015, pp. 08-19. http://www.iaeme.com/IJCIET/issues.asp?JTypeIJCIET&VType=6&IType=9 1. INTRODUCTION Phosphorus (P) is an essential nutrient for the growth of organisms in most ecosystems, but superfluous phosphorus can also cause eutrophication and hence deteriorate water quality. Phosphorus is released into aquatic environments in many ways, of which the most significant are human industrial, agricultural, and mining activities. Although phosphorus removal is required before discharging wastewater into bodies of water, phosphorus pollution is nevertheless increasing. Therefore, there is currently an urgent demand for improved phosphorus removal methods which can be applied before wastewater discharge. In wastewater treatment, enhanced biological phosphorus removal (EBPR) is becoming an increasingly popular alternative to chemical precipitation (CP) because of its lower costs and reduced sludge production. Much water treatment sludge is produced in the production of service water and drinking water. It is impossible to prevent the production of water treatment sludge. The water treatment sludge is liquid and solid and is regarded as a waste. Consequently, the water treatment sludge must be handled in accordance with regulations in forces. The quantity of the water treatment sludge is rather high. The water treatment sludge is placed mostly in landfills. In some countries, for instance in the Netherlands, about 25 per cent of the produced water treatment sludge is re-used, (Miroslav, 2008). It is still an issue to choose a disposal or liquidation method for the water treatment sludge that would be reasonable in terms of technology and economy. According to environment protection regulations it is required to minimise the quantity of wastes produced. If possible, the wastes should be re-used or processed as secondary raw materials as much as possible. If this is not possible, the solid wastes should be put back in the environment where the space occupied should be as little as possible and minimum costs should be incurred, (Moldan et al., 1990). Phosphorus removal from wastewater has been widely investigated and several techniques have been developed including adsorption methods, physical processes (settling, filtration), chemical precipitation (with aluminum, iron and calcium salts), and biological processes that rely on biomass growth (bacteria, algae, plants) or intracellular bacterial polyphosphates accumulation (de-Bashan et al., 2004). Recently, the removal of phosphate from aqueous solutions via adsorption has attracted much attention. The key problem for many phosphorus adsorption methods, however, is finding an efficient adsorbent. Several low-cost or easily available clays, waste materials and by-products. http://www.iaeme.com/IJCIET/index.asp 9 [email protected] Prof. Dr. Alaa Hussein Al-Fatlawi and Mena Muwafaq Neamah 2. MATERIAL AND METHODS 2.1 Adsorbate Phosphate was selected as a representative of a contaminant because the it is the main nutrient for the growth of aquatic microorganisms like algae but the excess content of phosphorus in receiving waters leads to extensive algae growth (eutrophication). The samples was collected from the effluent channel of Almuamirah wastewater treatment plant in Al-Hilla city, Iraq. These samples were immediately transported to the laboratory for processing. The total amount of plant nutrients and other pollutants present in a sewage plant effluent is subjected to seasonal, daily, and hourly variation. Table 1 summarizes the composition and variability of the effluent under study. The wastewater sample was used as stock solution to provide the specific value of phosphate concentration. Where necessary, pH adjustment was made on each sample by addition of 0.1 M HNO3 and NaOH solutions using a HACH-pH meter. Table 1 Physico-chemical analysis of secondary wastewater effluent sample, (Almuamirah wastewater treatment plant, 2014) parameters Quantitative composition E.C, µs/cm 3.5 T.D.S, mg/L 1288 Salinity, mg/L 2.18 Total hardness, as CaCo3, mg/L 1200 pH 7.9 Mg, mg/L 232.8 Ca, mg/L 160.3 So4, mg/L 769.4 Cl, mg/L 289.9 Po4, mg/L 2.7 No3, mg/L 0.46 T.S.S, mg/L 40 BOD5, mg/L 32 COD, mg/L 54 DO, mg/L 2.3 Fecal coliform, mpn/100 ml 120000 Total coliform, mpn/100 ml 128000 2.2 Adsorbent Two types of adsorbent were used in the present study for adsorption of phosphate from secondary effluents of wastewater treatment plant they are: 1. Drinking Water Treatment Sludge (DWTS), 2. Red Mud (RM). 2.2.1. Drinking Water Treatment Sludge (DWTS) The composition and properties of the water treatment sludge depends typically on the quality of treated water as well as on types and doses of chemicals used during the http://www.iaeme.com/IJCIET/index.asp 10 [email protected] Column Study of The Adsorption of Phosphate by Using Drinking Water Treatment Sludge and Red Mud water treatment. Depending on the quality of the treated water, the water treatment sludge contains suspensions of inorganic and organic substances. The (DWTS) used in this study was taken from the sedimentation tanks of Al- Tayara drinking water treatment plant, in Al-Hilla city, Iraq. This sludge was dried at atmospheric temperature for 5 days, and then sieved on 2 mm mesh to achieve satisfactory uniformity. The sludge had a particle size distribution ranged from 150 μm to 10 mm (Fig. 1) with an effective grain size, d10, of 250 μm, a median grain size, d50, of 460 μm and a uniformity coefficient, Cu= d60/d10, of 2.24. 120 100 80 60 40 % of cumulative passing cumulative of % 20 0 0.1 1 10 Partical size (diameter , mm) Figure 1 Gradation curve for (DWTS) used in the present study. The geometric mean diameter (1.19) is given by where d1 is the diameter of lower sieve on which the particles are retained and d2 is the diameter of the upper sieve through which the particles pass (Alexander and Zayas, 1989). Table 2 presents the physical and chemical characteristics of this (DWTS). Table 2 Physical and chemical characteristics of DWTS Element Quantitative composition T.O.C, mg/L 4.29 E.C, µs/cm 620 T.D.S, mg/L 312 Salinity, mg/L 0.2 pH 8.1 L.O.I, mg/L 15.76 Fe2O3, mg/L 3.6 CaO, mg/L 15.32 SO3, mg/L 0.63 MgO, mg/L 3.66 Al2O3, mg/L 11.56 R2O3, mg/L 15.16 SiO2, mg/L 45 2.2.2. Red Mud (RM) The Red Mud (RM) used in this study was supplied by the Iraqi commercial markets. It is a solid waste produced in the process of alumina production from bauxite following the Bayer process. Red mud, as the name suggests, is brick—red in colour and slimy, having an average particle size of <10μm. A few particles greater than http://www.iaeme.com/IJCIET/index.asp 11 [email protected] Prof. Dr. Alaa Hussein Al-Fatlawi and Mena Muwafaq Neamah 20μm are also available [Liu et al., 2011].The mesh size of red mud used in the study was of 1mm.