Removal Efficiency Of SS Research Articles

Evaluation of Horizontal Subsurface Flow Constructed Wetland for Treatment of Tannery Wastewater in Kaduna, Nigeria

Tannery wastewater is often characterized by their complexities in terms of contaminants and require specialized treatment technologies. Hence, the objective of this paper is to explore the performance evaluation of a laboratory-scale horizontal subsurface flow constructed wetland (HSSFCW) in the treatment of tannery wastewater in Kaduna, Nigeria using appropriate standard techniques. Out of the tree replica systems, two were respectively vegetated with Phragmites australis and Polygonum salicifolium + Ipomoea carnea, while the last was left un-vegetated and used to treat tannery effluent. Characteristics such as Biological Oxygen Demand (BOD), Chemical Oxygen Demand (COD), Nitrates (NO-3), phosphates (PO43-), suspended solids (TSS) and chromium (Cr) analyzed using standard methods were used as indicators of the treatment efficiency under a 6-day Hydraulic Retention Time. The results showed that the system vegetated with Phragmites australis had the best performance in the removal of BOD, COD, NO-3, PO43- and Cr (97.9%, 94.2%, 54.4%, 44.1% and 98.4% respectively). The system vegetated with Polygonum salicifolium + Ipomoea carnea on the other hand had the best performance for SS removal (92.6%) while the system vegetated with Phragmites australis had a SS removal efficiency of 92.3%. The performance indices for unvegetated cell, Phragmites australis vegetated cell and Polygonum salicifolium + Ipomoea carnea vegetated cell were respectively, 4, 9 and 8 which shows that the cell vegetated with Phragmites australis had the best performance in the treatment of tannery wastewater. It also showed that the performance of the cell vegetated with Polygonum salicifolium + Ipomoea carnea was also comparable with that of Phragmites australis. This study demonstrated that the HSSFCW vegetated with both Phragmites australis and Polygonum salicifolium + Ipomoea carnea can effectively treat tannery wastewater. There is however a need to investigate the efficiency of the system over a longer period with consideration of microbial characteristics.

Pollution Mitigation in Vermicelli Wastewater: Integrated Fenton and Aerobic Sludge Treatment for Water Quality Improvement.

Vermicelli production generates wastewater that is rich in organic and nutrient pollutants, which poses significant environmental challenges. Conventional biological treatments, either alone or in combination with other methods, often fail to achieve high efficiency and operational stability. This study explored the potential of the Fenton process, followed by aerobic activated sludge treatment, to enhance the biodegradability and mineralization of organic substances in vermicelli wastewater. Orientation experiments were performed to examine the effects of operating variables such as pH, reaction time, settling time, and ratio H2O2/Fe2+ on COD removal in order to select the optimal conditions for operating the model in a batch of 20 L, that is, pH = 3, reaction time of 90 min, settling time of 90 min, and ratio of H2O2/Fe2+ used 3 : 1 (4.5 : 1.5 g/L). The removal efficiencies of COD, BOD5, TN, TP, and SS reached 75.83%, 67.26%, 28.24%, 26.63%, and 91.9%, respectively. The BOD5/COD increased from 0.52 to 0.63, facilitating aerobic activated sludge, which had batch conditions of 15 L with pH of 6.5-8.5, DO ≥3 mg/L, additional nutrients with a dose of 12 mg/L, retention time of 14 h, and settling time of 2 h. As a result, the removal rate of those parameters climbed quite notably, except in SS (95.6%, 96.0%, 84.6%, 84.1%, and 83.6%), and their concentration parameters remained within the allowance levels of the National Technical Regulation in Vietnam before being discharged into the environment. However, the efficiency of treatment in the aerobic activated sludge stage for removing COD and BOD5 was not as high as anticipated (83% and 87.33%, respectively) owing to the influence of the high TDS concentration. Thus, additional research is required to address this challenge. The integrated treatment system combining the Fenton process with aerobic activated sludge demonstrated significant potential for the effective reduction of organic and nutrient pollutants in vermicelli wastewater, thereby achieving compliance with regulatory standards. However, the observed limitations in COD and BOD5 removal efficiency, likely due to elevated TDS levels, indicate the need for further investigation and optimization to enhance the overall treatment performance.

Optimizing biogas production from palm oil mill effluent utilizing integrated machine learning and response surface methodology framework

This study presents a novel approach to optimize the anaerobic digestion of palm oil mill effluent (POME) for maximum biogas production on an industrial scale. Unlike most optimization studies which are limited to laboratory scale, this study utilized data from a real-world industrial setting to simulate the anaerobic digestion (AD) process. The processes include feedstock pre-treatment, biogas scrubbing, wastewater treatment, and sludge handling. The impact of process conditions such as hydraulic retention time (HRT), organic loading time (OLR), anaerobic sludge recycling ratio (RRAS), treatment effluent recycling ratio (RRTE), and reaction temperature on chemical oxygen demand (COD) removal and methane yield was analysed. An integration of response surface methodology (RSM) and artificial neural network (ANN) is applied to predict the optimal values for the process conditions. The results showed that the optimal values for HRT, temperature, OLR, RRAS, and RRTE are 38.58 days, 45 °C, 1.033 g COD/(L∙day), 0.052, and 0.95, respectively. The optimization improves the COD removal efficiency, SS removal efficiency, and biogas production by 7.38%, 8.37% and 16.18%, respectively when processing 24,134 L/h of POME feed. The optimized AD process is economically viable with a payback period of 5.34 years and a net present value (NPV) of $5,079,000.

Response Surface Optimization and Floc Structure Analysis of Magnetic Flocculation Technology for Anaerobic Digestion Reject Water

In order to improve the removal efficiencies of SS and Fe3+ in anaerobic digestion reject water for the subsequent biological treatment process, on the basis of the single factor test in the early stage, the response surface method was used, and the structure of the formed floc was analyzed by magnetic flocculation. The optimum amounts of magnetic powder, polyaluminum chloride (PAC) and polyacrylamide (PAM) were 40.51 mg/L, 31.31 mg/L and 4.05 mg/L, respectively. At this time, the removal efficiencies of SS and Fe3+ were 97.84% and 98.35%. The effects of floc particle size, scanning electron microscopy, infrared spectroscopy and two-dimensional fractal dimension of flocs on the flocculation ability showed that: compared with conventional coagulation, the average particle size of flocs treated by magnetic flocculation was 76.56 μm, the Fe-O-Al absorption peak appeared at 984 cm−1, the flocculation ability was significantly improved, the surface of the floc was rough and porous, and the structure was dense, and the sedimentation performance was significantly improved also.

Application of Deep-bed Denitrification Filter in Sewage Treatment

The combined process of A2/O oxidation ditch, high efficiency sedimentation tank and denitrification deep bed filter was adopted in Sewage Treatment Plant of Hefei City to treat municipal domestic sewage. The effluent quality could meet the discharge limit of major water pollutants in urban sewage treatment plants and industrial industries of Chaohu Lake Basin (DB34/2710-2016). In addition to the parameters of design and operation, the effect of SS and deep denitrification was summarized in detail in this paper. The results showed that the combined process SS and denitrification effect was removed very well. The operational results demonstrated SS removal efficiency 74.3%,TN removal efficiency (92.3％) in the biosystem ,in which 80.0％ and 12.3％ of TN in influent were removed in the pre-denitrif ication in oxidation ditch and post-denitrification in deep bed denitrification filter, respectively. The deep bed denitrification filter could be used as the safeguard for effluent TN with the addition of external carbon source to ensure the efficiency of TN less than 5 mg/L.

폐 패각을 이용한 다공성 여과재의 수질정화 성능평가

In this study, in order to evaluate the water purification performance of media filter using shell recycling, specific surface area and water purification experiments were performed after fabricating a filter medium mixed with fine oyster shell powder, zeolite, cement, water, and effective microorganims (EM). A comparative experiment was performed on the amount of change in specific surface area and BOD, SS, and T-P according to the blending amount of the media filter material. When zeolite was added to the media filter using shell recycling, the specific surface area increased, which was twice that of the meida filter using shell recycling without the addition of zeolite. In terms of water purification performance, the removal efficiency of SS and T-P was very high regardless of the type of media filter, but the BOD removal efficiency was different depending on the blending amount of the media filter. The BOD removal efficiency of MF-3 (120 g of fine oyster shell powder, 40 g of zeolite, 40 g of cement, 140 g of water and 10 g of EM based on 350 g) was 86.8 % after 3 and 4 weeks. So it is suitable for use. If the media filter using shell recycling is developed using the optimal blending amount of the media filter obtained in this experiment, it is expected that it can replace the existing media filter and become a new utilization method of the neglected shells.

Study on household micro-mesh anerobic digester followed by vegetable garden fertilization for resources oriented sanitation of toilet and kitchen

The household three chamber anaerobic digester(3CAD)with its final products being used as fertilizers is the main way for harmless and resourceful treatment of traditional toilet liquids in rural China. When the residents changed their waterless toilets into water-flush toilets, the design volume of the existing 3CADs is far from meeting the requirements of the national mandatory standards regarding the hydraulic retention time (HRT). In this study, a multiple-step micro-mesh anaerobic digester (MMAD) was advanced, aiming to greatly shorten the HRT requirement of the anaerobic digestion. Based on health risk assessment and phytotoxicity assessment of the effluent, the feasibility of MMAD method was verified. According to the results of the comprehensive evaluations, the optimization of the setting parameters of the multi-step micro-meshes and the HRT of the digester were also obtained. Setting four-step micro-meshes with apertures of 150 μm,75 μm,50 μm and 5 μm along the water flow direction, the effluent quality obtained when the HRT is 10 days is as follows: the SS5 (>5 μm) was less than 0.5 mg L−1, representing that the effluent index of parasite eggs was qualified; the fecal coliform value of the effluent was greater than 10−4; the removal efficiency of SS and COD were 82.28% and 67.27%, which were much better than those of the 3CADs. After continuous operation for 236 days, the reactor showed no sign of clogging. The system with MMAD + vegetable garden fertilization can not only meet the needs of modern sanitation in rural areas at low cost, but also help to achieve the goal of carbon peak and neutrality, which are in line with the concept of sustainable development.

Physiochemical Treatment of Wastewater Utilizing Polyaluminum Chloride for Khartoum North Wastewater Effluent

This paper focuses on the possibility of applying physiochemical treatment for industrial wastewater combined with domestic wastewater that are currently treated by the conventional activated sludge process in Khartoum North Treatment plant at Haj Yousif (Wad Dafeah). A lab-scale experiment was carried out utilizing Poly aluminum chloride (PAC) as a coagulant for determining the optimum dose to reduce the turbidity of the wastewater sample to the lowest level. The results of the lab-scale model showed that a dose of 0.8 ml/l of the PAC achieved significant removal of turbidity (from turbidity >1000 NTU of raw sewage to turbidity level of 18 NTU of the treated effluent). This dose of 0.8ml/l obtained from the lab-scale experiment was applied in a pilot plant of capacity 30 m3/d erected at the site of the treatment plant (Wad Dafeah). The process units utilized in the pilot plant were of minimum or negligible electrical power consumption. They include an inverted hydro cyclone for flash mixing of the coagulant, pipes arrangement to achieve hydraulic gentle mixing as flocculation process, vertical sedimentation tank to enhance efficient settling of particles and tertiary treatment using a rapid sand filter. Raw sewage of BOD5 = 5000 mg/l was introduced into the pilot plant and excellent quality of treated effluent was obtained. Removal efficiencies of both BOD5 and SS were high (97 % & 98% respectively).Treated effluent had BOD5 = 23 mg/l & SS = 22 mg/l. The high dose of PAC utilized for the treatment (0.8 ml/l= 1040 mg/l) can be reduced significantly if raw wastewater of lower BOD content such as domestic wastewater is treated. In a parallel study with the domestic sewage of BOD5 =350 mg/l, the PAC dose required was 0.1 ml/l (130 mg/l). Recycling of residual PAC in the sludge is recommended to decrease the cost of treatment. The approach & methodology followed in this study can be further adopted using other coagulant material such as ferric salts or other similar local product which can achieve high efficiency in reducing the load of organic substances in the wastewater with minimum cost.Keywords: Physiochemical; Poly aluminum chloride; inverted hydro cyclone

Efficiencies and mechanism of enhanced coagulation pre-treatment on domestic sewage with PAC-HCA compound.

Poly dimethyl diallyl propyl ammonium chloride (HCA) and poly aluminum chloride (PAC) were used to prepare complex coagulants for the enhanced coagulation (EC) pretreatment of domestic sewage. The influences of hydraulic conditions, the dosage ratio of PAC-HCA complex coagulants, initial pH value, and dosage on the removal efficiency of SS, COD, and TP in domestic sewage were investigated. The fractal dimension and Zeta potential were used to verify and characterize the experimental results. The results showed that the optimum coagulant conditions were as follows: G1 = 200.0-265.0 s-1, T1 = 1.5 min, G2 = 40.0 s-1, T2 = 5 min, PAC: HCA = 25:1, dosage = 15 mL/L, pH = 8. At the mentioned point, the removal rates of SS, COD, and TP are 98.74%, 44.63%, and 89.85%, respectively. In addition, through comparative tests, PAC-HCA compound coagulants show better treatment efficiency than PAC and HCA used alone. When the HCA dosage was 15 mg/L, Zeta potential and flocs fractal dimension was 2.29 mv and 0.9844, respectively. This indicates that PAC-HCA has a good treatment effect on domestic sewage, and the mechanism of enhanced coagulation to remove nutrients is mainly electrical neutralization.

Zeolite fly ash-enhanced coagulation treatment of oil recovery wastewater from polymer flooding.

Herein, an enhanced coagulation model is proposed in which zeolite is used as a crystal nucleus to promote flocs. The zeolite is prepared from fly ash by microwave-assisted hydrothermal synthesis. Scanning electron microscopy (SEM), X-ray diffraction (XRD), and specific surface area and pore size analysis (BET) characterization confirmed the successful synthesis of ZFA, and improved the surface properties. Thus, the adsorption capacity of ZFA as crystal nucleus was improved, which enabled it to achieve better results in the process of enhanced coagulation. Compared with those of conventional coagulation, the oil content and SS removal rate of ZFA-enhanced coagulation increased by 85% and 44%, respectively. Compared with that of CFA-enhanced coagulation, the oil removal efficiency increased by 4%, and the SS removal efficiency increased by 9%. The optimal conditions of ZFA-enhanced coagulation were as follows: ZFA dosage of 100mg/L, pH value of 5-8, ZFA particle size range of 60-75μm, temperature of 40-50 ℃, and precipitation time of 30min.

Engineering application of an improved AAO process

An improved AAO process was designed in this study, in which the pre-anaerobic section was prepositioned and water inlet by two-points method was utilized. A regulating section was added between the anaerobic and aerobic sections, and could be switched to anaerobic or aerobic sections as needed to enhance the performance of nitrogen and phosphorus removal. On this basis, the process was applied to the Xihai Sewage Treatment Plant Project (Phase III), aiming to the treatment of domestic sewage with a scale of 8×104 m3/d. Characteristics, mechanisms and design parameters of the process were introduced and the operation results were analyzed in this study. It could be found that the removal efficiencies of COD, NH3-N, TP and SS were 89.36%, 96.89%, 95.99% and 96.78%, respectively. All the effluent indicators meet the first-level A standard in the “Pollutant Discharge Standard for Urban Wastewater Treatment Plant” (18918-2002).

An improved primary wastewater treatment system for a slaughterhouse industry: a full-scale experience.

The effluent streams from individual slaughtering operations were segregated based on the degree of similarity and were treated separately. The wastewater from lairage and paunch sections was dominant in suspended solids (SS: 6,000-25,000 mg/L) and was separated using a hydrasieve (500 μm) and externally fed rotary drum filter (EFRDF, 200 μm), respectively. The SS removal efficiency of the hydrasieve and EFRDF was 75% and 55%, respectively, and remaining solids were removed through a primary clarifier. The fats, oils and grease (FOG: 12,000-35,000 mg/L) containing streams from the hide fleshing, rendering, intestine, and tripe washing were routed through a skimming tank. The SS and FOG removal efficiencies through the skimming tank were 75% and 90%, respectively. Any FOG remaining after the skimming tank was removed using dissolved air flotation which achieved 95% FOG removal. In addition, the efficiency of chemical oxygen demand removal through the primary treatment system was more than 80%. The effluent obtained after primary treatment was SS and FOG ≤ 200 and 100 mg/L. The segregation of streams and their separate treatment offered benefits such as resource recovery, reduced waste load on downstream secondary treatment and overall ease in slaughterhouse wastewater treatment.

Experimental Study on Flocculation Effect of Tangential Velocity in a Cone-Plate Clarifier

A large number of particles with small size and light density in mine water are difficult to remove by traditional separation equipment. In order to improve the efficiency of mine water treatment, a cone-plate clarifier is proposed in this paper. The particle size distribution and their fragmentation fractal dimension were studied in 15 sampling points of the cone-plate clarifier to elucidate the process of floc growth and settling. The influence of the tangential inlet velocity size distribution characteristics was also studied. The results showed that the cone-plate clarifier can effectively improve suspended solids and turbidity removal efficiency. The floc growth and settlement courses are shown in the charts. The cone-plate clarifier was divided into four zones: micro flocculation, floc growing, settlement, and exit pipe. Because the fluid enters the cone-plate clarifier tangentially, the value of the inlet velocity and the tangential velocity are equal at the inlet feed. With the increase in tangential velocity, the flocculation efficiency first increased and then decreased. Comprehensive analysis of the particle greater than 50 μm in the effluent showed that the optimal inlet was qual to 1.63 m/s. By fitting the equations, the optimal SS and turbidity removal efficiency reached the maximum values of 92.04% and 80.18% at the inlet velocity of 1.86 m/s and 1.77 m/s, respectively.

Full Scale Sanitary Landfill Leachate Treatment by MBR: Flat Sheet vs. Hollow Fiber Membrane

The aim of this study was to find a cost-efficient leachate treatment system by comparing two MBR systems, flat sheet and hollow fiber. Data collected through continuous monitoring and laboratory analysis over the last two years has been evaluated in terms of treatment performance and economic analysis. MBR systems were found to be as effective and economical in terms of color, SS removal, and total treatment efficiency. It has been observed that the flat sheet membranes were clogged up in six weeks, while the hollow fiber membranes took 12–16 weeks to clog. Moreover, the hollow fiber module was less clogged and needed shorter washing times, resulting in lower amounts of chemical consumption. Hollow fiber membrane systems, compared to flat sheet membrane systems, have higher operational availability and lower maintenance costs. For the first time, the advantage of using submerged hollow fiber for the treatment of high-strength landfill leachate has been clearly demonstrated.

Upflow Filtration System Using Fiber-Ball Filter Media for the Treatment of Nonpoint Pollution

Objectives : The objective of this study is to investigate the performance of the fiber-ball media upflow filtration system for non-point pollutants treatment.Methods : The additional air backwashing nozzle were installed between upper and lower fliter media cartridge. The effect of feed SS concentration, surface overflow rate, retention time, head loss on the removal efficiency were investigated respectively. Particle size distribution, SEM, and backwashing effect were also analyzed.Results and Discussion : The operated of upflow filter mean retention time, mean head loss were 1.99 min, 7.2 cm. On condition of SOR 480 m<sup>3</sup>/m<sup>2</sup>/day, results indicate that the range of removal efficiency of turbidity and SS were 76.8 ~ 93.21% (mean 88.3%) and 85.4 ~ 97.9% (mean 92.7%), respectively. The effluent turbidity and SS were under 15 NTU, 20 mg/L, respectively.Conclusions : Since turbidity can be continuously monitored in a filtration non-point pollution treatment system, turbidity can be used as a operation factor in evaluating operating conditions. The particle size the effluent larger than the influent was due to bonding, collision and adsorption between particles in the pores of the filter media. SEM analysis showed that after backwashing, very fine particles in the filter medium were not removed but adhered to the fiber yarn and remained. The average recovery rate of fiber-ball media filtration was 88.7%, which is evaluated as excellent in backwashing.

Development of Primary Sludge Control Technology Based on Solids Loading Rate in Sidestream MLE Process

Objectives:By measuring the solids loading rate for the sidestream, it was intended to achieve increased treatment capacity and improved process performance by developing control technologies for primary sludge removal, recirculation, and input.Methods:The pilot plant was manufactured by the primary clarifier+MLE process similar to the full-scale plant and was configured to control the amount of sludge withdrawal based on the inflow solids loading rate. The state point analysis was used to determine removal underflow withdrawal rate and the total underflow withdrawal rate for the primary sludge. The operation was divided into manual withdrawal, automatic withdrawal, automatic withdrawal+recirculation, and automatic withdrawal + input methods. The performance evaluation items for primary sludge control technology were primary sludge concentration and SS removal efficiency for primary and secondary clarifiers. The improvement in the performance of the bioreactor by recirculation and input was judged through the removal efficiency of ammonium nitrogen, TIN (Total Inorganic Nitrogen) and phosphate phosphorus, SNR (Specific Nitrification Rate), and SDNR (Specific Denitrification Rate). The cause of the performance improvement was analyzed by comparing the acetic acid concentration changed by recirculation and the microbial community characteristics.Results and Discussion:The average value of SS monitoring of the sidestream influent was 2.2 (0.7~6.3) g/L and the primary clarifier needed treatment in response to high concentration SS and fluctuations. It is judged that the state point analysis based on the actual settling rate can accurately suggest whether the stable operation of primary sludge removal, recirculation, and input is the possible and specific design and operation standards. The automatic withdrawal that controls the underflow withdrawal rate according to the change of the inflow solids loading rate could stably draw out the high-concentration sludge and maintain the SS removal efficiency. It is believed that stable operation is possible even in the sludge recirculation operation, and the treatment capacity of the primary clarifier can be increased more than two times in a full-scale plant. By recirculation of the primary sludge, the TIN removal efficiency in the bioreactor was improved by 24.2~52.3%, and the phosphate phosphorus removal efficiency was improved by up to 20.1%. The TIN removal efficiency in the bioreactor was improved by 32.6% by the input of primary sludge. VFAs (Volatile Fatty Acids) including acetic acid was produced and the removal efficiency was improved because it was in contact with primary sludge by recirculation and the ratio of major fermentation microorganisms was present at 2.0%. It is determined that 26.4% of the main species of microorganisms treated with nitrogen and phosphorus exist in the sidestream inflow and the removal efficiency was improved by supplying microorganisms through the input of primary sludge.Conclusions:Technology that controls primary sludge removal, recirculation, and input by measuring the solids loading rate for the sidestream is believed to increase the treatment capacity of the primary clarifier and improve the nitrogen and phosphorus removal efficiency of the bioreactor.

Two-stage hybrid constructed wetland-microbial fuel cells for swine wastewater treatment and bioenergy generation

A newly emerged alum sludge-based hybrid constructed wetland-microbial fuel cells (CW-MFCs), i.e. vertical upflow CW coupled MFC as 1st stage and horizontal subsurface flow CW coupled MFC as 2nd stage (VFCW-MFC + HSSFCW-MFC), was firstly developed for swine wastewater treatment and electricity generation. Swine wastewater and multi-set air-cathodes were applied to investigate the pollutants removal behavior and the power production. Six-month trial suggested that the overall removal efficiency of SS, COD, NH4+-N, NO3−-N, TN, TP and PO43--P was 76 ± 12.4, 72 ± 7.4, 59 ± 28.3, 69 ± 25.6, 47 ± 19.7, 85 ± 9.5 and 88 ± 8.7%, respectively. The two stages hybrid system (VFCW-MFC + HSSFCW-MFC) continuously generated electrical power with average voltages of 0.44 ± 0.09 and 0.34 ± 0.09 V, and power densities of 33.3 ± 13.81 and 9.0 ± 2.5 mW/m³ in 1st and 2nd stage, respectively. The average net energy recovery (NER) of 1st stage and 2nd stage is in turn 0.91 ± 0.16 and 2.76 ± 0.70 Wh/kg·COD. It indicates that the hybrid CW-MFCs has higher removal efficiency than single stage CW-MFC, while 1st stage plays the major role both in pollutants removal and power generation.

Evaluation on Performance and Backwashing Effect of Filter Media for Treatment of Nonpoint Pollution

The stormwater is a typical urban non-point source. About 80% of pollutants in stormwater are present in particulate phase and attached to particles transported in suspension, with under 100 µm particle size. Therefore, various pollutants are associated with particles, it has been suggested that the removal of SS is critical for the treatment of a wide range of stormwater pollutants. This study has been carried out to evaluate the applicability of three filter media and backwashing effect for treatment of stormwater micro-particle pollutants. Upflow type column filter was used for to treat micro particles. Three filter materials were selected for this study: PP, Ball type fiber media, and Ceramic media. SEM image analysis was performed to view of three media surface structure. As the results of PP, Ball, Ceramic media filtration, the mean removal efficiency of SS were 80.5%, 78.4%, 80.0%, respectively. The range of mean particles size, D_Mean for influent and effluent were 12.35~42.32 µm and 1.58~31.16 µm, respectively. Based on SS load mass balance, the results of filter recovery rate for PP, Ball, Ceramic media were 95.0%, 92.0%, 89.7%, respectively. Key words: Stormwater, Filter media, Backwashing effect, SEM

Potential Use of Dimocarpus longan Seeds as a Flocculant in Landfill Leachate Treatment

Landfill leachate is a highly polluted and generated from water infiltration through solid waste produced domestically and industrially. In this study, a coagulation–flocculation process using a combination of Polyaluminium chloride (PACl) as a coagulant and Dimocarpus longan seed powder (LSP) as coagulant aid was used in treating landfill leachate. LSP has been tested as the main coagulant and as coagulant aid with PACl. As the main coagulant, the optimum dosage and pH for PACl were 5 g/L and 6, respectively, with removal efficiencies of 67.44%, 99.47%, and 98% for COD, SS, and color, respectively. For LSP as the main coagulant, results show that LSP is not effective where the removal efficiencies obtained for COD, SS, and color were 39.40%, 22.20%, and 28.30%, respectively, with the optimum dosage of 2 g/L and pH 4. The maximum removal efficiencies of COD, SS, and color were 69.19%, 99.50%, and 98.80%, respectively, when LSP was used as coagulant aid with PACl. Results show that using LSP as coagulant aid was found to be more effective in the removal of COD, SS, and color with less PACl dosage. The PACl dosage was decreased from 5 to 2.75 g/L when LSP was used as a coagulant aid. Cost estimation for using PACl alone and using LSP as the coagulant aid showed a reduction in the cost of approximately 40% of the cost of using PACl alone. Overall, this study confirmed the efficiency of LSP to be used as a natural coagulant aid in leachate treatment.

Photocatalytic oxidation of dairy effluent with UV lamp or UV light-emitting diode module and biological treatment processes

The objective of this study was to develop a novel and simple-operated treatment system for refining dairy farm effluent after conventional dairy wastewater treatment system. Experimental results showed that average removal efficiency of COD, BOD, and SS in the effluents of a dairy farm was 72, 98, and 79%, respectively, using a combined photocatalytic and biological reactors. Removal efficiency of calculated conductivity value seems to be closely related to the removal efficiency of NH4+, PO43−, and Mg2+ when using the photocatalytic UV lamp reactor only. However, average removal efficiency of COD, BOD, and SS in the dairy farm effluent was 53, 62, and 62%, respectively, with the photocatalytic UV LED reactor. In summary, removal efficiency of BOD, COD, SS, and EC in photocatalytically treated dairy farm effluent with UV lamp reactor was higher than that with photocatalytic UV LED reactor. In addition, removal efficiency of COD and BOD with a combined photocatalytic and biological treatment system was higher than that using a photocatalytic oxidation reactor only. Thus, the combined system can provide dairy cattle farmers to refine and recycle their effluents.