Application of response surface methodology (RSM) for optimization of ammoniacal nitrogen removal from semi-aerobic landfill leachate using ion exchange resin (original) (raw)

Various advanced waste disposal methods are available, nevertheless, landfilling is still widely adopted in most countries, due to its low cost and simplicity. However, the generation of a highly complex and polluted liquid leachate from landfill is a major concern as it threatens human health and environment. The presence of different constituents in leachate had made it difficult to be treated, and different treatment approach is needed dependent on the target pollutants. Despite the increasing number of documented scientific literatures in various wastewater and leachate treatment, the understanding of the leachate characteristics and treatment methods from scheduled waste landfill (SWL) are limited. Besides, SWL treatment need different approach as direct biological treatment is not suitable, due to its high NH3-N concentration that inhibits microorganism’s activity. These limitations have led to a thorough investigation in finding improved SWL leachate pre-treatment process on ...

Ammonia stripping from landfill leachate has been investigated. The main objectives were to enhance biodegradability and to overcome ammonia toxicity to further biological treatment steps. The stripping process was carried out at various pH values ranging from 8.5 to 11. To investigate the impact of initial ammonia concentration on the stripping process, raw as well as diluted leachate (1 leachate: 1 water) were used for the present study. The efficiency of the treatment process was monitored by chemical analyses and Vibrio fischeri toxicity test. The chemical analyses covered ammonia nitrogen (NH4–N) and organic pollutants (COD and BOD5).The improvement in biodegradability was measured by the BOD/COD ratio. The highest removal efficiency of ammonia nitrogen (NH4-N) was obtained at pH value of 11 after air stripping for 24 hr. Average removal values were 94.5% for raw leachate and 96.9% for diluted leachate. The biodegradability, as expressed by the BOD/COD ratio, increased from 0.34 for raw leachate to 0.38 after ammonia stripping for 24 hr at pH values of 10 and 11. Kinetics of the rate of reaction for raw and diluted leachate indicated the preference of the use of raw leachate.

The treatability of stabilized sanitary landfill leachate via synthetic anion exchange resin (INDION FFIP MB) was investigated. An ideal experimental design was conducted based on central composite design using a response surface methodology to assess individual and interactive effects of critical operational variables (i.e., anionic dosage; contact time; shaking speed) and pH on treatment performance in terms of color, chemical oxygen demand (COD), suspended solid (SS), and turbidity removal efficiencies. Optimum operational conditions were established as 30.9 cm3 anionic dosage, 90 min contact time, 150 rpm shaking speed, and pH 3.1. Under these conditions, the color, COD, SS, and turbidity removal efficiencies of 91.5, 70.3, 93.1, and 92.4% were experimentally attained and were found to fit well with the prediction model. According to these results, stabilized leachate treatment using INDION FFIP MB could be an effective alternative in the administration of color, COD, SS, and turbidity problems of landfill leachates.

The efficiency of nitrogen removal from leachate by different chemical and biological methods was explored. The leachate was derived from Filborna landfill (NSR AB, Helsingborg, Sweden) and was characterized as an old leachate with pH = 8.0 and comparatively low concentrations of nitrogen and organic compounds (ca. 150 mg/l NH4-N and 500 mg/l COD). Three treatment processes were tested in lab-scale experiments; combined nitrification and denitrification in a sequencing-batch reactor (SBR), one-reactor nitritation-anammox process in a moving-bed biofilm reactor (MBBR) in sequencing-batch configuration and nitrogen precipitation in the form of magnesium-ammonium-phosphate (MAP). State-of-the-art of these processes is described. The conventional combined nitrification/denitrification process allowed 99% removal of inorganic nitrogen with 23 mg NH4-N/(l·h) being the highest nitrification rate achieved. Aeration during nitrification step and addition of carbon source according to the sto...

The aim of this work was to investigate the efficiency of nitrogen removal from municipal landfill leachate with a microbial culture in 3 L batch bioreactor. The microbial culture, originating from landfill leachate, was prepared by an enrichment culture technique. Organic compounds measured as chemical oxygen demand (COD) of 400–600 mg L–1 and high concentrations of ammonium nitrogen (NH4 +-N) 270–312 mg L–1 characterized the landfill leachate as a mature leachate. The rate of ammonium nitrogen removal was 24.5 mg NH4 +-N L–1 h–1. Nitrification rate was 20.1 mg NOx–-N L–1 h–1. Denitrification was performed with the addition of sodium acetate as external carbon source in ratio C/N 2 and 4. Sodium acetate was insufficient for complete denitrification at C/N 2. Complete denitrification at C/N 4 was performed at denitrification rate 8.3 mg NO3–-N L–1 h–1.

A lab-scale ammonia stripping reactor was used to treat raw and diluted (1:1) scheduled waste landfill (SWL) leachate containing ammonia-nitrogen (NH 3-N). Operating parameters such as air-liquid ratio, hydrated lime [Ca(OH) 2 ] dosage, types of packing materials and packing heights were investigated with central composite design (CCD) of response surface methodology (RSM) was used to optimize the parameters affecting NH 3-N removal from the leachate. The percentage removal on turbidity, colour and phosphate were also evaluated in this study. It was observed that the optimal conditions obtained from desirable response (NH 3-N removal) for raw leachate were predicted at air–liquid ratio of 70, Ca(OH) 2 dosage of 5 gL-1 , packing height of 60 cm and types of packing material was number 3 (non-woven polyester) while for diluted leachate these were 70, 6 gL-1 , 60 cm and Type 3 (non-woven polyester), respectively. Quadratic RSM predicted the maximum NH 3-N removal to be 78% for raw leachate and 81% for diluted leachate at these optimal conditions concurred with the experiment which successfully removed 76% and 80% of NH 3-N, respectively. However, higher removal efficiencies of turbidity (97%), colour (88%) and phosphate (93%) was observed in the treatment with diluted leachate compared to raw leachate merely up to 55%, 34% and 49%, respectively. The finding showed that the difference in the removal of NH 3-N in diluted and raw SWL leachate was insignificant. However, turbidity, colour and phosphate showed a significant reduction in the diluted leachate during the treatment. The study suggests that the dilution of SWL leachate does not present a significant effect on the removal of ammonia in the stripping reactor.