The present study describes the phytoremediation performance of water lettuce (Pistia stratiotes L.) for physicochemical pollutants elimination from paper mill effluent (PME). For this, pot (glass aquarium) experiments were conducted using 0% (BWW: borewell water), 25%, 50%, 75%, and 100% treatments of PME under natural day/light regime. Results of the experiments showed that the highest removal of pH (10.75%), electrical conductivity (EC: 63.82%), total dissolved solids (TDS: 71.20%) biological oxygen demand (BOD: 85.03%), chemical oxygen demand (COD: 80.46%), total Kjeldahl's nitrogen (TKN: 93.03%), phosphorus (P: 85.56%), sodium (Na: 91.89%), potassium (K: 84.04%), calcium (Ca: 84.75%), and magnesium (Mg: 83.62%), most probable number (MPN: 77.63%), and standard plate count (SPC: 74.43%) was noted in 75% treatment of PME after treatment by P. stratiotes. PCA showed the best vector length for TKN, Na, and Ca. The maximum plant growth parameters including, total fresh biomass (81.30 ± 0.28 g), chlorophyll content (3.67 ± 0.05 mg g-1 f.wt), and relative growth rate (0.0051 gg-1 d-1 ) was also measured in 75% PME treatment after phytoremediation experiments. The findings of this study make useful insight into the biological management of PME through plant-based pollutant eradication while leftover biomass may be used as a feedstock for low-cost bioenergy production. PRACTITIONER POINTS: Biological treatment of paper mill effluent using water lettuce is presented. Best reduction of physicochemical and microbiological pollutants was attained in 75% treatment. Maximum production of chlorophyll, plant biomass, and highest growth rate was also observed in 75% treatment.
In this current work, the performance of an aerobic granular sludge (AGS) for real textile wastewater was investigated based on system operational parameters evaluation. The study was performed for 90 days, and sampling was done once a week in which textile dyeing effluent from the textile mill was collected and subjected to laboratory-scale treatment. The samples from the inlet, the outlet of the wastewater plant, and within the bioreactor were collected at various concentrations of MLSS, and hydraulic retention remained the same in the investigated period of 53 hours. The objective of this study was to analyze the AGS system performance assessment by evaluating the effect of different MLSS concentrations on chemical oxygen demand (COD), TSS, and oil/grease removal from real-based textile water. The results showed that removal of organic material from the process water increases with an increase in MLSS concentration in the bioreactor and gradually shifts removal of COD from 91.2% to 94.5%. As the concentration of microorganisms in the reactor (aeration tank) increases, the degradation of waste organics in the wastewater increases as well. Moreover, the % removal of total suspended solids (83.5 to 98 %) and removal of oil/grease (62.5 to 76.4%) were also increased. These results ultimately suggest that the utilization of an activated sludge system can effectively treat complex and highly polluted denim textile wastewater to avoid secondary pollution posed by this industry.
Temperature is known to influence the operational efficiency of enhanced biological phosphorus removal (EBPR) systems. This study investigated the impact of thermal stress above 30°C on the properties of an EBPR community established with tropical inoculum. The results confirmed the stability of the 30°C EBPR system with high P-removal efficiency over 210 days. Accumulibacter was abundant in the community. When the EBPR sludge was subjected to a sudden temperature increase to 35°C under multiple cycles of anaerobic-aerobic phases, each lasting 4 h, high P-removal was maintained over 2 days, before gradually failing when the Competibacter appeared to outcompete Accumulibacter. These data suggested that the EBPR capacity is robust when subjected to occasional thermal stress. However, it could not be maintained even for a short time under temperature stress at 40°C. Thus, the threshold temperature for tropical EBPR failure is between 35°C and 40°C. PRACTITIONER POINTS: EBPR was stably maintained at 30°C with Accumulibacter being dominant. Good EBPR activities persisted for a short period at 35°C. EBPR was deteriorated at 40°C. The threshold temperature for tropical EBPR failure is between 35°C and 40°C.
This study was conducted to evaluate the effect of the toxicity levels of the coagulation and flocculation process on raw and treated leachate using acute toxicity tests. Tin tetrachloride (SnCl4 ) and the Jatropha curcas (JC) seed were used as coagulant and coagulant aid to remove concentrated suspended solids, SS (534 mg/L), color (19,297 Pt-Co), and chemical oxygen demand (COD) (4188 mg/L) in a stabilized landfill leachate. The toxicity effects on local red tilapia fish (Oreochromis niloticus) were investigated, which involved three main steps, namely, acclimatization, range-finding test, and short-term definitive test. The presence of JC seed (0.9 g/L) as a flocculant reduced the dosage of SnCl4 from 11.1 to 8.5 g/L and exhibited good removals of 99.78%, 98.53%, and 74.29%, respectively, for SS, color, and COD. The toxicity test indicated that only five fish died in the first 12 h for the treated sample compared with seven deaths for untreated leachate. In 96 h, a total of 42 and 31 mortality rates were noted for the raw and treated leachate samples, respectively. The treated sample could reduce the toxicity effects to the tested tilapia fish and is safe to be discharged at appropriate dilution concentrations. PRACTITIONER POINTS: Coagulation-flocculation by Tin (IV) chloride and Jatropha Curcas (JC) was investigated. Almost complete reduction of SS was obtained at 8.5 g/L of SnCl4 and 0.9 g/L of JC as flocculant. The toxicity effect was evaluated using red tilapia (Oreochromis niloticus) fish as the indicator. Treated leachate was considered acceptable as the number of dead fish was lower than the untreated leachate.
Landfill leachate can threaten the environment and human life. Therefore, this study aims to investigate the efficiency of ozone (O3 ), O3 with zirconium tetrachloride (O3 /ZrCl4 ), and O3 with tin tetrachloride (O3 /SnCl4 ) in remediating the stabilized anaerobic landfill leachate (SAL) from Alor Pongsu, Perak. Hydroxyl radical (OH•) is an important oxidizing agent in the ozonation process. Its presence was tested using tert-butyl alcohol. Results showed that using ZrCl4 and SnCl4 in ozonation boosted the generation of hydroxyl radical, thereby enhancing the oxidation process and pollutant removal inside the sample. The O3 /ZrCl4 mix at chemical oxygen demand (COD) to ZrCl4 ratio of 1:1.5, pH 8-9, and 90-min reaction time resulted in the highest reduction rates of COD and color at 91.9% and 99.6%, respectively. All results demonstrated that the optimum performance occurred at alkaline conditions (pH > 8), proving that OH radicals primarily oxidized the pollutants through an indirect reaction pathway. The biodegradability (biochemical oxygen demand/COD) ratio was also considerably improved from 0.02 (raw) to 0.37 using O3 /ZrCl4 , compared with using O3 alone and using O3 /SnCl4 , which only recorded 0.23 and 0.28, respectively, after the treatment. The study demonstrated that O3 /ZrCl4 was the most efficient combination. PRACTITIONER POINTS: The O3 /ZrCl4 recorded the highest COD and color removals. The O3 /ZrCl4 combination also recorded higher OH• concentrations. The biodegradability of leachate (BOD5 /COD ratio) improved from 0.02 to 0.37.
Landfill leachate is well known as a hazardous byproduct from dumpling sites that has a negative impact on the environment and human life. Therefore, an effective treatment is imperative to overcome this issue. This research study investigates the effectiveness of zirconium tetrachloride (ZrCl4 ) and tin tetrachloride (SnCl4 ) as a coagulant in leachate treatment. Two parameters selected as a performance indicator in this study are color and chemical oxygen demand (COD). The data obtained showed that SnCl4 performed well as a coagulant with removal percentages of color and COD, which are 97% and 77%, respectively. Furthermore, the potential of integrated treatment using ozonation (O3 ) and the coagulation-flocculation process was also investigated. Four sequences of integrated treatment setup for this study were ozonation followed by jar test (ZrCl4 as a coagulant), ozonation followed by jar test (SnCl4 as a coagulant), jar test (ZrCl4 as a coagulant) followed by the ozonation process, and jar test (SnCl4 as a coagulant) followed by the ozonation process. The experimental data showed that the combination treatment of SnCl4 as a coagulant (jar test) followed by the ozonation process had recorded the highest removal of color (97.1%) and COD (88%) compared to other sequences. Moreover, the biodegradability ratio of this sequence also improved from 0.03 to 0.28, compared with other methods. Comparatively, integrated treatment is more effective in treating stabilized landfill leachate compared to the coagulation flocculation process alone. PRACTITIONER POINTS: Stabilized landfill leachate is difficult to be treated by natural coagulants or biological process. SnCl4 performed well as a coagulant in removing COD and colour from landfill leachate compared to ZrCl4 . However, too much usage of SnCl4 potentially generate secondary pollutant. Therefore, combination with O3 as pre-treatment is investigated. Combination treatment of SnCl4 ( as coagulant) with O3 had recorded the highest removal of colour (97.1%) and COD (88%). The biodegradability ratio of this sequence also improved from 0.03 to 0.28.
The combination of UV and water-soluble Fe(III) complexes is an effective method for generating Fe(II) in situ for activating advanced oxidation processes. This study explored the potential of Fe(III)-diethylenetriaminepentaacetic acid (Fe(III)-DTPA) and Fe(III)-ethylene glycol-bis(2-aminoethylether)-N,N,N',N'-tetraacetic acid (Fe(III)-EGTA) in activating the UV/persulfate (UV/PS) for sulfamethazine removal. The initial screening showed that Fe(III)-EGTA and Fe(III)-DTPA could significantly improve the rate of sulfamethazine removal. The optimum molar ratios of persulfate to Fe(III)-DTPA and Fe(III)-EGTA were 100:1 and 100:2.5. The predicted percentage of sulfamethazine removal under the optimized conditions, obtained using response surface methodology, was ~99% for both catalysts. The pH range of 6 to 8 did not significantly affect the performance of UV/PS in the removal of sulfamethazine. The percentage sulfamethazine removal in the selected water samples was ranged from 93.6% to 99.6%, agreeing with the predicted value. The performance of both catalysts in activating UV/PS is comparable with that of the frequently used Fe(III)-EDDS. PRACTITIONERS POINTS: The potential of Fe(III)-DTPA and Fe(III)-EGTA in activating UV/persulfate (UV/PS) was explored. Fe(III)-DTPA and Fe(III)-EGTA improved the performance of UV/PS in sulfamethazine removal. Fe(III)-DTPA and Fe(III)-EGTA are effective in catalyzing UV/PS under pH 6 to 8. The performance of Fe(III)-DTPA and Fe(III)-EGTA is comparable with well-studied Fe(III)-EDDS.
Produced water (PW) has been generated in a huge amount representing the largest volume waste stream. Membrane technology has found a leading ability in treating PW due to its significant advantages, such as lower cost, easy installation, and being environmentally friendly. Mixed matrix membranes (MMMs) have received significant research interest due to their flexibility, multifunctionality enhances the membrane performance with increasing selectivity, permeability, robustness, mechanical strength, and resistance to fouling. This mini-review paper identifies the utilization of different membranes for treating PW. It also gives a review of different types of MMMs with specific fillers for the application of PW treatment. Lastly, some methods to enhance the performance of mixed matrix membranes have been highlighted. The issues and challenges in membranes are also discussed. PRACTITIONER POINTS: Mixed matrix membranes (MMMs) are a potential membrane type for PW treatment. This mini-review paper identifies the use of several membranes to treat PW. It also examined various types of MMMs containing specific fillers for the application of PW treatment. Methods for improving the performance of mixed matrix membranes have been highlighted, including the use of novel materials, surface modification, and cross-linking. The issues and challenges in membranes are also discussed.
Groundwater is one of the alternatives to surface water that can be used for drinking water; however, it normally exists with high iron and manganese content. In this study, a column study was conducted to observe the elimination of iron (Fe) and manganese (Mn) in the groundwater under different retention times by using zeolite immobilized with iron-oxidizing bacteria (IOB). Rossellomorea sp., representing an IOB, was found from the isolation process and was further cultured in the laboratory for immobilization into the natural zeolite as replacement materials for the sand filter. When the zeolite assisted with the Rossellomorea sp. was used, the elimination of Fe and Mn were 99.34% and 88.92%, respectively, compared to the removal of Fe and Mn, which were 93.62% and 93.73%, respectively, for media without immobilization. The presence of Rossellomorea sp. enhances the Fe oxidation, resulting in high removal of Fe. The Thomas and Yoon-Nelson models were performed in both raw zeolite and zeolite with IOB. The total coliform (most probable number [MPN]) increased from 70.8 to 307.6 MPN/100 mL because of the Rossellomorea sp. present that promotes the growth of coliform bacteria. In conclusion, the immobilization of zeolite with IOB is a potential technique to extract the Fe and Mn in the groundwater. PRACTITIONER POINTS: Zeolite incorporated with Rossellomorea sp. has higher removal performance of Fe, whereas the removal of Mn reduced compared to the raw zeolite. The presence of Rossellomorea sp. enhances the oxidation of ferrous iron and improves the removal of Fe in the groundwater because the ferric iron is the priority ion to be exchanged. The removal of UV254 increase when Rossellomorea sp. present in the zeolite because the Rossellomorea sp. consume the natural organic matter as carbon source.
Malaysia encounters a consistent rise in the generation of solid waste and leachate on a daily basis. It should also be noted that leachate has a low degree of biodegradability (BOD5 /chemical oxygen demand [COD]), as shown by its BOD5 /COD ratio. Its high toxicity levels significantly threaten the environment, water bodies, and human well-being. High concentrations of COD, color, and ammoniacal nitrogen (NH3 -N) in leachate prevent this wastewater from being allowed to be discharged directly into the water body. Therefore, an effective process to remove the pollutant is desired. The aims of this study are to investigate the performance of ozonation with two metallic compounds, ZrCl4 and SnCl4 , and optimize their performance using response surface methodology (RSM). In this study, the performance of ozonation with ZrCl4 (O3 /ZrCl4 ) recorded better pollutant removals compared with the ozonation with tin tetrachloride (O3 /SnCl4 ), as seen in the removals of 99.8%, 93.5%, and 46.3% for color, COD, and NH3 -N, respectively. These removals were achieved by following the experimental model (optimum experiment condition) generated by RSM at O3 dosage of 31 g/m3 , COD and ZrCl4 dosage ratio (COD, mg/L/ZrCl4 , mg/L) of 1:1.35, with the pH solution of 8.78 and reaction time of 89 min. The R2 of each parameter for this model was recorded as 0.999 (COD), 0.999 (color), and 0.998 (NH3 -N), respectively. These data indicated that the model is well fitted as the predicted data by statistical calculation and in good agreement with the actual data. PRACTITIONER POINTS: The performance of O3 /ZrCl4 and O3 /SnCl4 was examined for remediate stabilized landfill leachate. The performance of O3 /ZrCl4 and O3 /SnCl4 was optimized using RSM, and a set of experimental models was generated and tested. O3 /ZrCl4 recorded the higher removal of COD, color, and NH3 -N compared with O3 /SnCl4 . At best condition, both methods recorded removal as 89% to 99.8% of pollutants in leachate and product clear effluent. This finding gives a new approach to treat landfill leachate effectively and efficiently.