COMPLIANCE INFO_NL STDY - Laserfiche WebLink

Home Browse Search

N%001 SYSTEM OVERVIEW SCIENTIFIC AND ENGINEERING PRINCIPLES The design of the EnviroServer is based on well-known engineering principles in the wastewater field applied in a new way. The system can be described as a hybrid fixed film-suspended growth extended aeration wastewater treatment system with a two stage biological process to optimize denitrification. One main advantage is the capability of removing sludge or dead biomass, which may clog or lower the efficiency of the system. The removal of sludge is done by the Thermal Processor. The Thermal Processor is a patented system'2 that has been optimized to fit the EnviroServer System by the in-house R&D Department(records are available upon request). The EnviroServer removes nitrogen using biological processes, such as ammonification followed by nitrification and denitrification. In ammonification, organic nitrogen (proteins and peptides) is decomposed to ammonia or ammonium ions. About 80% of the ammonification take place in the sewer lines before the wastewater enters the EnviroServer and the balance is ammonified in the first compartment. The ammonification is followed by nitrification. In nitrification, ammonia is removed biologically by a two-step process in which the ammonia is oxidized to nitrite, and the _ nitrite is oxidized to nitrate according to the following formulas3,e,13: NH3+02+ CO2+ HCO3+ Microbes New Microbes+ NO3+ H'+H20 NO2+ 02+ CO2 + HCO3 + Microbes => New Microbes + NO3 The nitrification is affected by temperature, pH, dissolved oxygen (DO), alkalinity, contact time, and mean cell residence time°,5, 73. The temperature and pH are not specifically controlled in the EnviroServer. The temperature is normally kept between 70 to 90°F by the microbial activity and some added heat from the air compressor. The pH is typically between 7 and 8.5 in the EnviroServer, since no chemicals are added to any of the compartments. Therefore, both the temperature and the pH fall well within the optimum range for nitrification. An air compressor continuously supplies air to the two aerobic compartments in the tank to keep the dissolved oxygen above 3 mg/l. The conversion of ammonia to nitrates requires 4.57 kg of oxygen per kg of ammonia converted 12,17,la. Nitrate formed during nitrification is removed by heterotrophic organisms under anaerobic conditions through conversion to gaseous nitrogen species through denitrification13, 17. 18. In this process, nitrate first is reduced to nitrite and then to nitric oxide (NO) followed by nitrous oxide ` (N20) and nitrogen gas (N2). This process requires a carbon sourced. In the EnviroServer, the wastewater exiting the two-stage aerobic section, which is high in nitrates and low in carbon, is recirculated back to the first anaerobic compartment where it mixes with the raw wastewater, which is high in carbon. The biodegradable organic carbon, that causes CBOD5, is converted to carbon dioxide and settleable biomass by heterotrophic organisms13. These microorganisms require oxygen. The process is referred to as aerobic digestion and can be expressed by the following equation? t2: Microbes Organic Matter+ 02 + Nutrients => New Microbes + CO2 + H2O 04/08/2000