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The adsorption characteristics of phosphate adsorption on the dewatered alum sludge were identified as a function of pH and ion strengths in solution. In addition, adsorption mechanisms were investigated by conducting batch tests on both the hydrolysis and P-adsorption process of the alum sludge, and making a comparative analysis to gain newer insights into understanding the adsorption process. Results show that the adsorption capacity decreased from 3.5 to 0.7 mg-P/g-sludge when the solution pH was increased from 4.3 to 9.0, indicating that adsorption capacity is

showed a maximum P adsorption capacity of 31.9 mg-P g -1 and significant P removal was 41 achieved in column tests. Overall, results showed that Al-WTR can be a low-cost, easily 42 and locally available substrate for enhanced P removal in engineered wetlands and it carries 43 the benefits of reuse of a by-product that promotes sustainability.

For the purpose of synthesizing a compendium of efforts aimed at environmental pollution control through the use of constructed wetlands systems (CWs) in Ireland, a detailed review of CWs was undertaken. Emphasis was placed on the diverse range of development, practice and researches on CWs technology, placing them in the overall context of the need for lowcost and sustainable wastewater treatment systems. The potential use of CWs in protecting estuarine quality within the current legislative framework is considered, as well as the emerging concept of integrated constructed wetlands (ICWs). In addition, an assessment of the efficiency of CWs in operation in Ireland towards abating environmental pollution was done, and compared with CWs operating in other European countries. The need for sufficient and appropriate data to assist in further development of CWs and modelling studies, and instilling confidence in the public is also highlighted.

Publication informationProcess Biochemistry, 46 (1) In this study, beneficial reuse of the alum-contained drinking water treatment sludge is 14 extended into developing a novel constructed wetland system (CWs) using the alum 15 sludge as main substrate. The study reports on the first pilot field-scale alum sludge-based 16CWs operated in the tidal flow mode with enhanced capacity for phosphorus and organic 17 matter removal from animal farm wastewater. The concept of the development is 18 presented and this is followed by the performance analysis of the first CWs of its kind. 19The CWs consists of four identical compartments in series operated using a tidal flow 20 strategy with a hydraulic loading rate of 0.29 m 3 /m 2 .d. First year analysis of the system's 21 performance shows that it is a unique and promising low-cost wastewater treatment 22 system. The mean monthly removal efficiencies obtained was determined to range from 23 57%-84%, 36%-84%, 11%-78%, 49%-93%, 75%-94%, 73%-97% and 46%-83% for 24 BOD 5 , COD, TN, NH 4 -N, TP, P (inorganic phosphorus) and SS. The system showed a 25 distinct phosphorus removal and also, the system was effective in reducing levels of 26 organics and ammonium-nitrogen. More importantly, the system showcases a novel reuse 27 alternative for the alum sludge as opposed to its landfilling, demonstrating a win-win 28 technique with a great potential for larger-scale application. 29 30

Excess phosphorus (P) in wastewaters promotes eutrophication in receiving waterways. A cost-effective method such as use of novel low-cost adsorbents for its adsorptive removal would significantly reduce such impacts. Using batch experiments, the intrinsic dynamics of P adsorption by waste alum sludge (an inevitable by-product of drinking water treatment plants)was examined. Different models of adsorption were used to describe equilibrium and kinetic data, calculate rate constants and determine the adsorption capacity. demonstrates that alum sludge -hitherto thought of as undesirable waste, can be used as novel adsorbent for P removal from wastewater through various applications, thus offsetting a portion of the disposal costs while at the same time improving water quality in sensitive watersheds.

Water samples, sediments, tilapia and cat fishes from each of Epe and Badagry lagoons in Lagos State, Nigeria were analyzed quantitatively for the presence of zinc, nickel and iron using Perking Elmer atomic absorption spectrophotometer. The sediment contains higher concentration of Fe with a value of 13.30 µg/g against 8.400 µg/g in fishes and 7.30 mg/L in water. Studies on the different parts of the fish revealed higher concentrations of 4.00 µg/g Ni on the head of tilapia fish followed by 2.40 µg/g Ni in the intestine of cat fish. The highest concentration of 1.95 µg/g Zn was detected on the head of the cat fish while the lowest concentration with a value of 0.16 µg/g was recorded in tilapia head. The concentration of Zn in the water is within the limits permitted by the Lagos State Environmental Protection Agency (LASEPA) of 1.0 mg/L Zn set for water. None of the trace metals investigated was above the maximum permissible level set by world health organization ( WHO).

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