BACKGROUND The present study aimed to optimize the removal efficiency of ammonia nitrogen (NH3‐N) and total kjeldhal nitrogen (TKN) from domestic wastewater as a function of hydraulic loading rates (HLRs) (0.16–5.44 m3 m–3 day–1) and the aeration rate (3, 5 and 10 L min–1) in a vertical flow aerated steel slag filter (VFASSF) system with nitrifier bacteria. The nitrifier bacterial cell morphology was determined using scanning electron microscopy (SEM) analysis. RESULTS The HLRs affected the performance of the VFASSF in removing TKN and NH3‐N from domestic wastewater. The optimal air flow rate for removing NH3‐N and TKN was recorded with 10 L min–1 and HLR 2.72 m3 m–3 day–1, at which the removal efficiency was >91% compared to 90% and 88% with 3 L min–1 and 5 L min–1 air flow rate, respectively. The high removal was a consequence of the high aeration which enhances the nitrification process performed by the nitrifying bacteria in the VFASSF. CONCLUSIONS These findings reflected the applicability of VFASSF in the treatment and removal of nutrients from domestic wastewater. © 2020 Society of Chemical Industry
Nitrogen is a naturally occurring element that is essential for growth and reproduction in both plants and animals. Excessive concentrations in the water body can cause excessive growth of algae and other plants, leading to accelerate eutrophication of lakes, and occasional depletion of dissolved oxygen. To remove nitrogen conventionally from domestic wastewater requires a high cost technology due to consumption of chemicals, high operational and maintenance cost. Therefore, an alternative low cost treatment technology particularly for nutrient removal including nitrogen removal system has been developed to improve the final effluent quality that is an aerated rock filter system. However, the optimization study under warm climate has not yet been developed. Hence, the present study was carried out to investigate the removal of ammonia nitrogen (AN) from domestic wastewater through nitrification process using a lab-scale vertical aerated limestone filter. Domestic wastewater sample used in this study was collected from Taman Bukit Perdana Wastewater Treatment Plant (WWTP), Batu Pahat, Johor owned by IWK. The experiment has been carried out for 10 weeks. The influent and effluent of the vertical aerated limestone filter system have been sampled and analyzed on biweekly basis for selected parameters including AN, Total Kjedhal Nitrogen (TKN), pH, alkalinity, temperature and dissolved oxygen to monitor the effectiveness of the filter. Results from this study show that nitrification process has took place within the aerated limestone filter as the results from laboratory experiments show that AN in wastewater was oxidized to nitrate and efficiently removed as the removal of AN was ranged from 85 % to 92 % and the removal percentage of TKN was ranged from 83.52 % - 91.67 %. The temperature was in the average of 26.3oC±0.75, pH value average of , DO was from 6.64 mg/L to 7.75 mg/L , and the alkalinity was from 15 to 110 mg / l as CaCO3 . Therefore, from this study it can be concluded that aerated rock filter system has high potential in removing AN and TKN. It is also able to produce a good final effluent quality which is comply with the effluent requirement for nutrient removal in wastewater under the Environmental Quality Act (Sewage) Regulations, 2009 that is safe to be released to the water body.
Excessive nitrogen in domestic wastewater discharge accelerates eutrophication in an aquatic ecosystem. To treat wastewater high in nitrogen conventionally are more expensive, complex and generate high amount of sludge. In line with this situation, rock filters (RF) emerged as one of attractive natural wastewater treatment method to treat wastewater high in nutrient because this filter system is easier to maintain, using low-cost filter media, and environmentally-friendly technology. However, studies on the removal of nitrogen in the system are still limited due to nitrification study under warm climate. Thus, an aerated rock filter system has been designed in this study to remove ammonia nitrogen from domestic wastewater using the recommended hydraulic loading rate in warm climate condition. The laboratory aerated rock filter system has been in operated for 2 months with 5 weeks of sampling. The filter influent and effluent samples have been collected and analyzed twice a week for Total Kjeldhal Nitrogen (TKN), ammonia nitrogen (AN), nitrates ,pH, temperature, DO and alkalinity to monitor the filter performance in removing nitrogen. Results from the laboratory experiments show that AN in wastewater was oxidized to nitrate and efficiently removed as the removal of ammonia nitrogen was ranged from 66.05 % to 91.30 % and the removal percentage of TKN was ranged from 63.23 % to 87.68 %. The temperature was in the range of 25°C to 27.5°C, pH value was in the range of 6.34 to 8.04, DO was from 6.64 mg/L to 7.75 mg/L, and the alkalinity was from 15 to 110 as mg /L CaCO3. Therefore, from this laboratory experiment it can be concluded that aerated rock filter system has high potential in removing AN and TKN. The system also able to produce a good final effluent quality which is comply with the effluent requirement for nutrient removal in wastewater under the Environmental Quality Act (Sewage) Regulations, 2009 that is safe to be released to the water body.
Abstract. Nitrogen removal from wastewater often requires a highly cost of chemical treatment to prevent over loading of nutrient in effluent discharge to the surface water body. However, to remove nitrogen it requires a complex process. Therefore, the aim of this study is to develop an aerated rock filter (ARF) system design under Malaysia condition. A pilot-scale VFARF with 2.0 m height and 0.3 m diameter and a HFARF with 1.0 m long and 0.3 m wide and 0.5 m height has been developed at Taman Bukit Perdana Wastewater Treatment Plant (WWTP) Batu Pahat, Johor to monitor the performance of the ARFs for nitrogen removal from domestic wastewater. The optimum value of HLR and aeration rate was 2.72 m 3 /m 3 .day and 10 L/min, respectively. For monitoring the effectiveness of the VFARF and HFARF, influent and effluent twice a week grab samples have been collected and analysed for TKN, Ammonia Nitrogen, BOD5, COD, TSS, Alkalinity, E-coli, pH, Dissolved Oxygen and Temperature. From the study, it was found that the VFARF system has outperformed as the removal efficiency of TKN, AN, TSS, and E-coli was 89%±7%, 97%±2%, 86%±17%, and 97%±2%. The removal efficiency was slightly lower in the HFARF as their removal was 78%±11%, 71%± 12%, 88%±15%, and 91%±16% for TKN, AN, TSS, and E-coli. However, their performance insignificant in removing organic matter, BOD5, COD as the removal efficiencies in the VFARF and HFARF were 84%±13%, 65%±23% and 85%±12%, 75%±21%, respectively. Alkalinity, pH and DO profiles for VFARF and HFARF systems effluent values were average at 107.08±28.35 mg/L, 7.14±0.27, 5.20±0.84 mg/L, 147.24±16.20 mg/L, 6.99±0.15 and 3.75±0.37 mg/L, respectively. Temperature value for this VFARF and HFARF system was 31.1±1.1ºC. From monitoring study between VFARF and HFARF, it found that VFARF system was outperformed than the HFARF in removing nitrogen from domestic wastewater.
Water pollution is closely related to the Water Quality Index (WQI). One of the parameters in classifying WQI is dissolved oxygen (DO) that can be improved by introducing the surface and subsurface aerations. Herein, the Perlis River’s water quality was investigated by evaluating the DO’s improvement based on various aeration systems. The changes of DO (mg/L) and DO improvement (%) were evaluated during both low and high tide conditions. A total of 9 sets of data collection had been studied by comparing base DO (without running of aeration) and measured DO (with running of aeration) of river. The DO sensor was used to measure the changes of DO in the aeration measurement system. Results found that the DO improvement managed to achieve 74.89%, 10.18%, 35.58%, and 52.45% for water jet, air compressor, commercial venturi, and DIY venturi, respectively. Besides, different behaviour of DO’s improvement was observed during low and high tide conditions.
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