Research Paper EAEF 4(2) : 47-53, 2011

Treatment of Swine Wastewater using Sequencing Batch Reactor*

Mohammad N. ISLAM*1 Keum J. PARK*2 Md. J. ALAM*3

Abstract The swine wastewater from Sunchon swine farm was decomposed using a sequencing batch reactor (SBR). The reactor body was fabricated using a plexi glass cylinder and its total volume was 20L with 15L of working volume. Each operating cycle consisted of five phases (fill, react, settle, draw and idle) with a total cycle time of 8 hours, thus resulting in three cycles per day (with 5 days of hydraulic retention time and 41 days of solid retention time). The cycles of the SBR system were controlled by a designed on-site computer and custom software. The results showed removal efficiencies of 85.5%, 80.3% and 87.2% for BOD, COD and TP respectively. It was found however that there were some - non-satisfactory results, only attaining removal efficiencies of 61.0%, 31.2% and 54.5% for TN, NH3-N and NO3 -N respectively. This was possibly due to the lack of enough carbon source and the inadequate aeration rate. It was also observed that removal efficiencies of 61.4%, 62.8%, 77.6% and 73.2% could be obtained for TS, TVS, TSS and TVSS respectively. The study showed that the SBR system could be used to attain good removal efficiencies of BOD, COD and nutrients in swine if it is supplied with sufficient carbon source for de- and optimum aeration for nitrification. [Keywords] sequencing batch reactor (SBR), COD removal, BOD removal, swine wastewater, wastewater treatment, removal efficiency

I Introduction de-nitrification using alternation of oxic and anoxic periods. Due to its operational flexibility, it is simple to increase The sequencing batch reactor (SBR) has gained wide SBR efficiency in treating wastewater by changing the acceptance for the removal of the biochemical timescale of each phase. Several researchers have used demand (BOD), (COD), and SBR to remove , , COD and BOD from different nutrients from wastewater (Imura et al., 1993, swine wastewater (Bicudo et al., 1999; Kim et al., 2000; Rusten and Eliassen, 1993). Wastewaters from pig farms Kim et al., 2004; Tilche et al., 1999). Despite this SBR is are characterized by their high BOD, COD and other not widely utilized to treat swine farm wastewater in Korea. nutrient contents. Many pig farms in Korea typically use an This research was conducted to evaluate the performance treatment system for the decomposition of of an oxic-anoxic SBR system according to a specific time wastewaters. The activated sludge system however has schedule in terms of reduction of COD, BOD and nutrients problems with high energy consumption and biomass in treating slurry manure from swine farm. production, leading to a relatively high operation cost and the disposal of a large amount of sludge. It has been found II Materials and Methods that biological processes based upon a sequencing batch 1. SBR construction and set-up reactor (SBR) are effective for organic nutrient removal in The experiment was carried out using a lab scale domestic and industrial wastewater (A Mohseni and Bazari, sequencing batch reactor (SBR), having a total volume of 2004). In recent years sequencing batch reactors have 20L with a working volume 15L. The SBR system was become of great interest for wastewater treatment due to installed at the farm power lab in Sunchon National their simple configuration (all necessary processes take University, Korea. The SBR body was fabricated using a place within a single time sequence in a single basin). SBR transparent plexi glass cylinder with an inner diameter of can achieve nutrient removal by the nitrification and 190mm.

* This paper was supported by Sunchon National University Research fund in 2007. *1 Department of Industrial Machinery Engineering, College of Bio-industry Science, Sunchon National University, South Korea *2 KSAM Member, Corresponding author, Professor, Department of Industrial Machinery Engineering, College of Bio-industry Science, Sunchon National University, Jeonnam 540-742, South Korea, E-mail: [email protected], Tel: +82-617503267 Fax: +82-617503260 *3 Department of Animal Science & Technology, Sunchon National University, South Korea

48 Engineering in Agriculture, Environment and Food Vol. 4, No. 2 (2011)

LabVIEW data logger

Air pump

Mixer Influent pump Mixer Draw pump

Effluent tank

Air flow controller Influent tank

Surplus sludge

Fig. 1 A schematic diagram of the experimental arrangements for the

sequencing batch reactor treatment system.

The system consisted of the reactor body, two peristaltic Table 1 Basic properties of the influent wastewater fed pumps (7524-45, Cole-Parmer Instrument Co.) for feeding into the sequencing batch reactor. influent and discharging effluent and 3 probes for the Parameters Concentration measurement of pH, temperature and the dissolved oxygen content (DO). Air was supplied into the reactor via two pH 7.47 porous stone diffusers. Supplemental mixing was provided Biochemical oxygen demand, mg/L 1500 by turbine stirrers with four blades (radius 6 cm). The SBR Chemical oxygen demand, mg/L 1972 system operation and data acquisition were accomplished Total phosphorus (TP), mg/L 1058 by an on-site computer using LabVIEW software (National Total nitrogen(TN), mg/L 1720 - Instrument Corporation). A schematic diagram of the -nitrogen(NO3 -N), mg/L 377 design of the SBR system is shown in Fig. 1. -nitrogen(NH3-N), mg/L 948 Total solids(TS), % 1.20 2. Collection of swine wastewater Total volatile solids(TVS), % 0.67 Wastewater for the experiment was collected from (TSS), % 0.67 Suncheon swine farm located near Suncheon city. The Total volatile suspended solids 0.33 collected wastewater was sieved to remove coarse materials (TVSS), % o (particles greater than 600 µm) and then stored at 4 C if not used immediately. The original wastewater had about 7% of 3. Sampling and analytical method total solids (TS), so it was diluted seven times with fresh During the experimental period (June 20–July 31; 2009), water to decrease the quantity of total solids for this sampling was carried out every day for the first four days, experiment. The characteristic compositions of the diluted one time every two days from the 5th to the 27th day and wastewater are presented in Table 1. once every three or four days after that.

ISLAM, PARK, ALAM : Treatment of Swine Wastewater using Sequencing Batch Reactor 49

FILL REACT SETTLE DRAW IDLE

40 min 360 min 40 min 20 min 20min

Oxic Anoxic Anaerobic (40 min) (20 min)

Fig. 2 The time frame for one cycle tested on the SBR.

All analytical measurements were undertaken according to this sludge was removed during the IDLE phase to keep the the standard methods of the American Public Health SRT of 41 days. In the DRAW phase, the supernatant was Association (APHA, 1998). The parameters analyzed removed by the peristaltic pump with a flow rate of 50 include: total solids (TS), total volatile solids (TVS), total mL/min resulting in 5 days of HRT. Finally, the decanted suspended solids (TSS), total volatile suspended solids effluent was collected and analyzed. A detailed operating

(TVSS), 5-day biochemical oxygen demand (BOD5), time frame for one cycle is shown in Fig. 2. chemical oxygen demand (COD), total phosphorus (TP), total nitrogen (TN), ammonia nitrogen (NH3-N) and nitrate III Results and Discussion - - nitrogen (NO3 -N). The COD, TP, TN, NH3-N, NO3 -N contents were measured using a DR/2800 1. BOD removal spectrophotometer (“Hach company”, 1993). Suspended The BOD concentration is used to assess the organic solids were measured using a glass micro fiber filter (Cat. 5 matter removal (Zhu et al., 2006). Because the experiment No. 1822-047, Whatman). The pH, temperature and the started after filling 14 L of raw wastewater into the SBR dissolved oxygen content (DO) of the mixed liquor in the tank, effluent concentrations for all items during the first 5 SBR tank were measured manually every day using days had high values and decreased continuously towards CX-401(Sechang, Korea). constant values. In this present study, the influent had a

BOD5 concentration of 1500 mg/L. This reduced to 190 4. Experimental procedure mg/L by the 9th day and fluctuated from 110 mg/L to 390 The SBR experiment was performed for 41 days at mg/L during the rest of the testing period with a mean of 23.7±1oC liquid temperature. At the beginning the SBR was 216.9 mg/L as shown in Fig. 3. The removal rates of the filled with 14 L of influent wastewater and started regular effluents were obtained using the data from the 9th day to operation according to the time schedule. Previous research the end of the experiment. indicates that the cycle regime and hydraulic retention time (HRT) are the two critical parameters that affect the performance and economics of an SBR. The HRT was 5 days for this experiment, following that indicated by previous research (Ra et al., 2000). Each operating cycle consisted of five phases, i.e. FILL, REACT, SETTLE, DRAW and IDLE, and lasted for a total of 8 hours, thus resulting in three cycles per day. During the FILL phase, the main reactor received influent wastewater from the storage basin at a feeding rate of 25 mL/min resulting in a fill rate of 1 L of influent per cycle. The REACT phase was composed of an oxic-anoxic process. The liquid in the tank was mixed by a 4 bladed propeller and air was supplied

(1-1.5 L/min) during the oxic period in the reaction basin. Fig. 3 Variation of BOD concentration and removal During the SETTLE phase a thick sludge was formed and efficiency with time.

50 Engineering in Agriculture, Environment and Food Vol. 4, No. 2 (2011)

Removal efficiency was calculated by the difference between the influent and effluent concentration in the wastewater. BOD removal efficiency was 85.5±4.5% during this period with a slight increase towards the end of the experiment. This reduction rate is slightly lower than the BOD removal rate of 93% found in previous research (Lo et al., 1999), possibly due to inadequate aeration. A study for pig wastewater treatment was conducted by Lo et al. (1999) using an aerobic SBR with SRT and HRT of 14 days and 23h, respectively.

2. COD removal

The removal efficiency for COD and BOD5 depends on the reactor cycle working with or without the anoxic phase, at different hydraulic retention times (HRT) in the SBR Fig. 5 Variation of TP concentration and removal (Kulikowska et al., 2007). A study of an aerobic bench efficiency with time. scale SBR with an influent COD concentration of 2000 mg/L for dairy wastewater treatment was conducted by Mohseni-Bandpi and Bazari (2004). In the experiment one cycle was composed of 8 hours with a 6 hour aeration period. In this study, COD removal efficiency was between 85 and 90%, similar to the presented experiment. In the presented experiment COD concentration decreased from the initial value of 1972 mg/L to 499 mg/L at the 9th day and varied in the range of 280-499 mg/L with a mean value of 388.1 mg/L from the 9th day to the end of testing. COD removal efficiency during this period was 80.3±2.6% with a slight increase towards the end of the experimental period as shown in Fig. 4.

Fig. 6 Variation of TN concentration and removal efficiency with time.

Fig. 4 Variation of COD concentration and removal efficiency with time.

Fig. 7 Variation of NH3-N concentration and removal efficiency with time.

ISLAM, PARK, ALAM : Treatment of Swine Wastewater using Sequencing Batch Reactor 51

3. Phosphorus removal Figure 5 presents the changes of total phosphorus content in the effluent liquid. The influent concentration of total phosphorus was 1058 mg/L and effluent concentrations decreased to 130 mg/L by the 9th day and varied from 89 mg/L to 165 mg/L with a mean of 135.4 mg/L after this. During this period the average removal efficiency of total phosphorus was 87.2±2.0%. DO concentration was varied from 1.7 mg/L to 2.1 mg/L with a mean value of 1.9 mg/L during the FILL phase. During the FILL phase, the anaerobic environment forced a group of microbes (phosphorus-accumulating microorganisms) to expend energy to obtain readily biodegradable carbon substrates and store them as poly hydroxyl alkanets (PHAs) causing a - Fig. 8 Variation of NO3 -N concentration and removal release of phosphorus into the liquid (Lee et al., 2001). efficiency with time. High phosphorus removal was possibly due to phosphorus release under anoxic condition and the phosphorus uptake during the following oxic period (Zhu and Xiao, 2007).

Table 2 Performance of SBR. Parameters Influent Effluent Removal Conc. Range of efficiency, ppm concentration % after 9th day BOD, mg/L 1500 110-390 85.5 COD, mg/L 1972 280-499 80.3 TP, mg/L 1058 89-165 87.2 TN, mg/L 1720 500-800 61.0

NH3-N, mg/L 948 564-758 31.2 - NO3 -N, mg/L 377 153-191 54.5 TS, % 1.20 0.30-0.53 61.4 Fig. 9 Variation of TS concentration and removal TVS, % 0.67 0.06-0.36 62.8 efficiency with time. TSS, % 0.67 0.08-0.20 77.6 TVSS, % 0.33 0.00-0.2 73.2

4. Nitrogen removal Total nitrogen (TN) is composed of organic nitrogen,

ammonia nitrogen (NH3-N) including ammonium nitrogen + - (NH4 -N), nitrogen (NO2 -N) and nitrate nitrogen - (NO3 -N). High mixed liquor suspended solid (MLSS=2.5%) concentration in the reaction tank helps to create anoxic condition as soon as the air supply is cut after the aeration phase to achieve de-nitrification for nitrogen removal. DO concentrations were varied from 6.9 to 5.1 mg/L with a mean value of 6 mg/L during the oxic phase. Nitrogen tied up in high energy compounds such as amino acids and amine is organic nitrogen. One of the intermediate compounds formed during biological Fig. 10 Variations of pH and temperature with time. metabolism is ammonia nitrogen. Aerobic decomposition

52 Engineering in Agriculture, Environment and Food Vol. 4, No. 2 (2011)

- - changes NH3-N into NO2 -N and finally into NO3 -N. The IV Conclusions influent concentration of total nitrogen was 1720 mg/L and The swine wastewater was decomposed using a effluent concentrations decreased to 780 mg/L by the 9th sequencing batch reactor (SBR) with 5 days of HRT and 41 day and varied from 500 mg/L to 800 mg/L with a mean of days of SRT. The removal efficiencies of BOD, COD and 670.0 mg/L after this as shown in Fig. 6. During this period TP were 85.5%, 80.3% and 87.2% respectively, indicating the average removal efficiency of total nitrogen was good removal rates. However, the removal efficiencies of 61.0±5.7%. The influent concentration of NH3-N was 948 TN, NH -N and NO --N were 61.0%, 31.2% and mg/L and effluent concentrations decreased to 664 mg/L by 3 3 54.5%,respectively, exhibiting poor performance, possibly the 9th day and varied from 564 mg/L to 758 mg/L with a due to the lack of enough carbon sources and an inadequate mean of 651.9 mg/L after this (Fig. 7). During this period aeration level for nitrification and de-nitrification during the average removal efficiency of NH -N was 31.2±6.8%. 3 the oxic and anoxic periods. It was also observed that The low reduction efficiency for ammonia nitrogen was removal efficiencies of TS, TVS, TSS and TVSS were possibly due to the continuous transformation of organic 61.4%, 62.8%, 77.6% and 73.2% respectively. This study nitrogen to ammonia nitrogen despite the fact that showed that an SBR system can be used to get good results nitrification occurred. The influent concentration of NO --N 3 for BOD, COD and nutrient removal in swine wastewater was 377 mg/L and effluent concentrations decreased to 191 treatment if supplied with enough carbon source for mg/L by the 9th day and varied from 153 mg/L to 191 mg/L de-nitrification and optimum aeration for nitrification. with a mean of 171.6 mg/L after this as shown in Fig. 8.

During this period the average removal efficiency of - References NO3 -N was 54.5±2.8%. APHA. 1998. Standard methods for the examination of water and 4. Changes of others parameters in this study wastewater, 21th Edition, American Public Health Association, Total solids (TS) varied from the initial value of 1.2% to Washington D.C. 0.48% on the 9th day of the experiment and the average Bicudo, J. R, J. J. Classen, C.D. Goldsmith and T. Smith. 1999. reduction rate of TS from the 9th day to the end of testing Effects of aeration cycles and hydraulic retention time on the was 61.4% as shown in Fig. 9. A similar tendency appeared sequencing batch treatment of flushed swine manure. Advances in TVS, with marginally higher reduction being observed in in Environmental Research, 3 (1), 58-73. TSS and TVSS as shown in Table 2. Oxic/anoxic SBR Hach Inc. 1993. Procedure Manual. Loveland, CO. experiments for treating swine wastewater (Ra et al.,2000) Imura, M., E. Suzuki., T. Kitao and S. Iwai. 1993. Advanced showed that removal efficiencies for TS, TVS, TSS and treatment of domestic wastewater using sequencing batch TVSS were 75.3%, 84.9%, 95.2% and 96.4% respectively, reactor activated sludge process. Water science and Technology, indicating higher removal efficiencies than those obtained 28, 267-274. during this study. The solids and hydraulic retention time Jun Zhu and W. Xiao. 2007. Full-scale sequencing batch reactor (SRT and HRT) employed for their SBR were 10 days and treatment for milking center wastewater. Presentation at the 4.7 days respectively. Lo et al. (1991) decomposed pig ASABE Annual International Meeting, (American Society of wastewater using an aerobic SBR with 23 hours of HRT Agriculture and Biological Engineers). and 14 days of SRT and achieved only about 23% and 31% Kulikowska D., E. Kliminuk and A. Drzewicki. 2007. BOD5 and of TS and TVS reduction respectively, indicating a much COD removal and sludge production in SBR working with or lower efficiency than this experiment possibly due to the without anoxic phase. Bioresource Technology, 98, 1426-1432. low HRT and SRT. Another experiment was also conducted Kim, C. W., M. W. Choi, J. Y. Ha and T. J. Park. 2000. using an anaerobic SBR to treat swine wastewater in which Optimization of operating mode for sequencing batch reactor the removal efficiency was found to be 59% for TVSS (Ng, treating Piggery wastewater. Presented at the 2nd International 1989) showing marginally lower efficiency than for this symposium on sequencing batch reactor technology, experiment. It was found that the effluent appeared to have International Water Association. very low although this was not measured. The pH Kim, J. H., M. Chen., N. Kishida and R. Sudo. 2004. Integrated of the solution inside the reactor increased over the real time control strategy for nitrogen removal in swine experiment with fluctuation from the initial value of 7.47 to wastewater treatment using sequencing batch reactors. Water the maximum value of 8.68 as shown in Fig. 10. Research, 38 (14-15), 3340-3348. Lee D. S., C. O. K. Jeon and J. M. Park. 2001. Biological nitrogen removal with enhanced phosphate uptake in a sequencing batch

ISLAM, PARK, ALAM : Treatment of Swine Wastewater using Sequencing Batch Reactor 53

reactor using single sludge system. Water Research, 35 (16), 3968-3976. Lo K. V., P. H. Liao and R. J. Van Kleeck. 1999. A full-scale sequencing batch reactor treatment of dilute swine wastewater. Canadian Agricultural Engineering, 33, 193-194. Mohseni-Bandpi, A. and H. Bazari. 2004. Biological treatment of dairy wastewater by sequencing batch reactors. Iranian J. Env. Health sci Eng, 1(2), 65-69. Ng W-J. 1989. A sequencing batch anaerobic reactor for treating piggery wastewater. Biological Wastes, 28, 39-51. Ra C. S., K. V. Lo., J. S. Shin and B. J. Hong. 2000. Biological nutrient removal with an internal organic carbon source in piggery wastewater treatment. Water Research, 34(3), 965-973. Rusten, B. and H. Eliassen. 1993. Sequencing batch reactors for nutrient removal at small wastewater treatment plants. Water Science and Technology, 28, 233-242. Tilche A., E. Bacilieri., G. Bortone., and L. Stante. 1999. Biological phosphorus and nitrogen removal in a full scale sequencing batch reactor treatment piggery wastewater. Water Science and Technology, 40(1), 199-206. Zhu J., Z. Zhang and C. Miller. 2006. A laboratory scale sequencing batch reactor with the addition of acetate to remove nutrient and organic matter in pig slurry. Biosystems Engineering, 93(4), 437-446. (Received: 5.November. 2009, Accepted: 9.March. 2011)