Please cite this article in press as: D.E. Meeroff, et al., Application of photochemical technologies for treatment of landfill leachate, J. Hazard. Mater.
Please cite this article in press as: D.E. Meeroff, et al., Application of photochemical technologies for treatment of landfill leachate, J. Hazard. Mater. (2012), doi:10.1016/j.jhazmat.2012.01.028 ARTICLE IN PRESS G Model HAZMAT-13921; No. of Pages 9 D.E. Meeroff et al. / Journal of Hazardous Materials xxx (2012) xxx– xxx 3 Table 2 Initial water quality of simulated leachate samples. Constituent Model compound Source Range Units COD KHP Fisher Scientific (Pittsburgh, PA) 1050–10,900 mg/L BOD5 Glucose/glutamic Acid Hach Company (Loveland, CO) 55–425 mg/L Lead Pb(NO3)2 Hach Company (Loveland, CO) 0.03–0.30 mg/L Ammonia NH4Cl Fisher Scientific (Pittsburgh, PA) 110–930 mg/L as NH3–N Alkalinity NaHCO3 Carolina Biological Supply Company (Burlington, NC) 200–4330 mg/L as CaCO3 were created from dry stock or standards of individual or mixed components of leachate dissolved in sterile buffered reagent water . For each constituent, the range of concentrations tested is listed in Table 2. These levels were determined according to the leachate water quality data collected from various sources [1–9]. The minimum, maximum and a level in between were tested to determine concentration dependence. Prior to testing, samples were mixed vigorously overnight and were initially buffered to pH 7.5 using sodium bicarbonate and hydrochloric acid. Color and odors are not present in synthetic leachate and were not evaluated until the processes were tested with real leachate. 2.2. Real leachate Synthetic leachate provides the substrate for bacteria, but does not contain a significant microbial population. Actual field sam-ples of leachate were also collected from a variety of landfill sites located in Florida, USA. Actual leachate samples were collected on site in plastic containers and stored at 4 ◦C until use. Samples were collected from the following locations: 1. Solid Waste Authority of Palm Beach County in West Palm Beach, FL. 2. North Polk County Landfill Site 201 (bioreactor landfill) in Lake-land, FL. 3. Broward County Central Disposal Sanitary Landfill in Deerfield Beach, FL. The leachate collected from the Solid Waste Authority of Palm Beach County is a composite sample from municipal solid waste, waste-to-energy ash, wastewater sludge, yard waste, and construc-tion and demolition waste, combined with leachate from a separate closed landfill, plus condensate water from a refuse-derived fuel waste-to-energy plant. This facility was sampled from the wet well prior to deep well injection disposal. The North Polk County Landfill was sampled directly from the leachate storage tank. The Broward County Central District Sanitary Landfill facility has leachate from Table 3 Initial water quality of real leachate samples. Constituent Range Units COD 140–5200 mg/L BOD5 290–720 mg/L Lead BDL–0.0054 mg/L Ammonia 800–2500 mg/L as NH3–N Color >500 PCU Alkalinity 200–4330 mg/L as CaCO3 active municipal solid waste cells and waste-to-energy ash com-bined with condensate water. A summary of the constituent levels from the real leachate samples is reported in Table 3. Specific con-centration levels used in selected experiments are found in Table 4 for PIMA experiments and Table 5 for TiO2 experiments. 2.3. PIMA bench reactor The bench scale pilot reactor for PIMA consisted of a photo-chemical safety cabinet, a sample tube holding chamber, quartz immersion well, plug flow water cooling system for the lamp, humidified aeration system, and quartz test tube PIMA reac-tors (2.8 cm ID × 20 cm tall, volume = 123 mL), as described in [11,26,27]. The ultraviolet source was an axially mounted 450 W medium pressure mercury vapor lamp and power supply from Ace Glass Incorporated (Vineland, NJ). The bulb length was 0.244 m and diameter was 0.025 m with a radiation zone of 0.13 m in height. Of the total energy radiated, 40–48 percent is in the ultraviolet portion of the spectrum (from 220 nm to 400 nm), 40–43 percent in the vis-ible, and the balance in the infrared. A traceable UV light meter with range of 5 _W/cm2–19.99 mW/cm2 (VWR, Suwanee, GA) was used to measure the UV light intensity transmitted (_ = 320–390 nm). This is the range at which 16% of the lamp power is radiated. The intensity of the incident radiation entering the inner wall of the annulus (I(_,R),z*) is also reported following the method described in . Table 4 First order kinetics analysis for PIMA experiments. Parameter Leachate Type Co (mg/L) Fe (g/L) UV intensity ( _W/cm2) I(_,R),z* ( _W/cm2) Time (min) Removal (%) k (h−1) r2 Theta* (h) COD Simulated individual 1050 16 8 125 1440 44% 0.020 0.81 230 COD Simulated individual 1050 16 19 238 1440 51% 0.024 0.77 200 COD Simulated individual 1050 16 49 502 1440 54% 0.026 0.82 180 COD Simulated mixture 740 16 19 238 960 38% 0.029 0.77 158 COD Simulated mixture 11,600 16 19 238 960 33% 0.024 0.96 190 COD Real leachate (Solid Waste Authority) 2950 16 19 960 10% 0.004 0.44 1220 BOD5 Simulated individual 200 16 19 238 960 39–44% 0.034 0.99 135 BOD5 Simulated mixture 470 16 19 238 960 52–89% 0.100 0.99 45 BOD5 Real leachate (Solid Waste Authority) 666 16 19 238 960 20% 0.014 0.99 322 Ammonia Simulated Individual 930 16 8 125 960 13% 0.006 0.99 813 Ammonia Real leachate (Solid Waste Authority) 9304.1 19 238 960 21% 0.010 0.61 464 Lead Simulated individual 0.30 16 19 238 960 >99.97% 0.484 0.99 9.5 Lead Simulated mixture 0.35 16 19 238 960 77–99.95% 0.477 0.99 10 Lead Real leachate (Solid Waste Authority) 0.0029 8.1 19 238 960 91% 0.149 0.99 31 Color Real leachate (Solid Waste Authority) >500 PCU 8.1 19 238 240 88–98% 0.188 0.79 27 * The value of theta is the estimated time required to achieve 99% removal.