Ammonia Nitrogen Removal from Domestic Wastewater via Nitrification Process Using Aerated Rock Filter

Abstract

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.