Effect of chloride concentration on nitrogen removal from landfill leachate in sequencing batch reactor after MAP pretreatment

Abstract

Leachate generated from landfill is becoming a great environmental challenge to China as it contains high concentration of COD, ammonium and some other substances. Nitrogen removal through the conventional nitrification-denitrification process is hampered by the low C/N ratio especially for the old age landfill sites and the high energy consumption for aeration. In this study, the combination of magnesium ammonium phosphate (MAP) precipitation and Sequencing batch reactor (SBR) was suggested as a new process for the treatment of high strength ammonium, and the effect of high concentration of Cl 2 after MAP precipitation because of the use of MgCl 2 was investigated on SBR performance. The practical upper limit of Cl 2 for nitrification was found to be 12,000 mg/L, above which resulted in significant accumulation of ammonium in SBR system. It is suggested that an ammonium removal of 70% was suitable for the MAP treatment to achieve a balance between increasing the C/N ratio and avoiding detrimental effect from high concentration of Cl 2 in the succeeding SBR system. DGGE analysis indicated that high diversity of Ammonium oxidizing bacteria (AOB) could be maintained at a Cl 2 concentration of 12,000 mg/L.

Sequencing batch reactor technology for landfill leachate treatment: A state-of-the-art review

“…Magnesium Ammonium Phosphate (MAP) Precipitation increases C/N ratio by decreasing NH4-N concentration. Thus, high concentration of Cl2 after pretreatment with MAP will adversely affect the microbiological function of the successor SBR system (M. Chen, He, Yi, & Yang, 2010). Attaching a trickling filter (TF) to an SBR system, the mean concentration of NO3 in effluents of the mature leachate increased owing to activities of nitrifying microorganisms (Aluko & Sridhar, 2013).…”

Recovery of Phosphorus from Waste Water Profiting from Biological Nitrogen Treatment: Upstream, Concomitant or Downstream Precipitation Alternatives

“…This is, for instance, the case of the BOD/N ratio (BOD is biochemical oxygen demand) before applying the NDN process. By considering MAP precipitation as pre-treatment, Maekawa et al [66], treating raw swine waste water, achieved a rise in the BOD/N ratio from 1.6 to 7 g O 2 g −1 N before biological treatment, or similarly, Chen et al [116], treating digested landfill leachate, increased this ratio from 1.5 to 6.5 g O 2 g −1 N (a minimum value of 5-6 g O 2 g −1 N is needed to ensure complete denitrification, according to Henze et al [127]). When processing complex industrial waste waters with moderate N load, such as those produced by the leather tanning industry, the appropriate addition of chemicals for precipitating MAP, together with an optimised management of source separated streams, may allow decreasing the concentration of ammonium to typical levels for urban waste water.…”

“…Integrative waste water treatment alternatives, considering P-recovery by chemical precipitation before biological N oxidation or removal, have conceptually been analysed under different scenarios [103,104] and also experimentally studied [66][67][68][69][105][106][107][108][109][110][111][112][113][114][115][116][117][118][119][120][121][122], as summarised in Table 2 (an extended version of this table is provided as Supplementary Material). Chemically induced phosphate precipitation before BNR from waste water-and also in the case of not considering BNR-typically requires to increase the pH (preferably above 8.0-8.5) by dosing an alkaline reagent (e.g., sodium hydroxide, NaOH) or by applying CO 2 stripping [93,123], and to adjust the amount of alkaline-earth metal ions (i.e., Mg 2+ or Ca 2+ ) available to effective concentrations according to the accessible phosphate-typically slightly above the theoretically needed ratios.…”

Sizinti Suyu Aritiminda Strüvi̇t Çöktürme Opti̇mi̇zasyonu

“…2002;Zhang et al 2011;Tonetti et al 2016). As a chemical precipitation technique MAP is a promising and successful treatment option (Chen et al 2010;Yetilmezsoy and Sapci-Zengin, 2009;Farrow et al 2017). Ammonia removed from the leachate by struvite precipitation (MAP), having an inhibitory effect on the methane bacteria (Di Iaconi et al 2010), can be used in agricultural field as fertilizer (Uysal and Kuru, 2013).…”