Review on Landfill Leachate Treatments

Municipal solid wastes (MSW) in China contain a large fraction of food waste and have high moisture content. MSW is usually held in waste pits for a few days to reduce moisture content before combustion in an incineration plant. In this study, leachate from the Tongxing MSW incineration plant was characterized and a combined anaerobic–aerobic–coagulation system was proposed and investigated. Optimal operation conditions for the processes in the proposed system were identified. The performance of the treatment process was assessed by monitoring the removal of organic matter (COD) and ammonia nitrogen (NH₃-N). The results showed that the optimal volume ratio of leachate and sewage was 1:6. During the initial anaerobic treatment, 62.1% COD and 49.5% ammonia were removed (optimal reaction time: 20 h, hydraulic retention time: 4 d). During the subsequent aerobic treatment (optimal aeration time of 14 h, dissolved oxygen of 4 mg/L), up to 94.0% COD and 89.4% ammonia could be removed. The coagulation process served as a polishing step. The optimal dose of Fe₂(SO₄)₃ was 600 mg/L at a pH of 5.0. The COD and ammonia concentrations in the final effluent after the combined treatment were 138 mg/L and 22 mg/L, respectively, which meet the Chinese integrated wastewater discharge standards.

Recently, the Shatt Al-Arab River has suffered from increased salinization of its water due to the reduction of freshwater from its tributaries, mainly from the Tigris River, which has resulted in long-distance salinity intrusion. Therefore, there is a need to establish a regulator in the Abu-Flus district to prevent salt intrusion. The aim of the study is to investigate the effect of a proposed regulator on the Shatt Al-Arab River with simulations using the Hydrologic Engineering Center’s River Analysis System (HEC-RAS) model. The upstream boundary conditions were the daily discharges of Tigris River and the downstream boundary conditions were the hourly water stages of the Shatt Al-Arab River. The river model was operated by using the daily discharges recorded in 2014 for calibration and verification of the model. Then, a program operated with a suggested regulator and a flood wave assumed a 200 m³/s peak flow for a duration of 27 days. The flooding occurrence period of the flood wave was investigated under the effect of three study cases of regulator gates, which were fully open (case B1), tide gate (case B2), and fully closed (case B3). The results showed that flooding inundation occurred only in two cases (B2 and B3). These results will encourage the construction of the regulator considering certain precautions.

This study aims to apply Water Quality Index (WQI) to evaluate quality of groundwater samples collected from Basrah governorate south of Iraq. The samples were collected from (29) wells located in different districts of Basrah governorate (Safwan, Zubair, and Um-Qasr) during Summer Season of 2015. The groundwater samples were analyzed for pH, electrical conductivity, total dissolved solids and other major ions. For calculating WQI, eleven parameters; pH, EC, TDS, Total hardness as CaCO3, Calcium, Magnesium, Sulphate, Chloride, Nitrate, Sodium, and Potassium have been considered. The suitability of groundwater in the study area for human drinking purpose was achieved by WQI depending on guideline values of World Health Organization (WHO 2011) for chemical parameters. Then, the weights (Wi) were assigned to the parameters based on their influence on human health. The results showed that the (WQI) values for the groundwater of study area varied from poor to unsuitable for human drinking purpose.