The Effect Of Temperature And Salinity On PN-ANAMMOX Process With Internal Reflux Device And Control

The partial nitritation-anammox process?PN-ANAMMOX?is a new type of biological denitrification process.The application of anammox would lead to a significant saving of aeration cost and external electron donor.Present researches show that nitrogen removal rateas of lab scal Anammox process was high than 76.5 kg·m^-3·d^-1.Anammox process has attracted much attention in recent years,with low energy consumption,less sludge production and higher nitrogen removal rateas compared with the conventional nitrification–denitrification process.PN-ANAMMOX process are very sensitive to environmental parameters.In order to make the function of both bacteria play its maximum efficiency,need to heat the waste water from room temperature to 35?,this part of the energy consumption as much as traditional biological nitrogen removal process.In order to give a full play to the superiority of the PN-ANAMMOX process,the optimization of temperature control on PN-ANAMMOX process is particularly important.Industrial wastewaters often containing salinity.Defined amount salts could speed up the enzymatic reaction,maintain the important roles of membrane osmotic balance and mediation.But high concentration of salts material will cause waste water higher osmotic pressure,high osmotic pressure will reduce microbial activity,and even killed microbes.Therefore need to study the process of the optimum salinity.The main purpose of this study is to improve the nitrogen removal rate by reacting the PN-ANAMMOX process in suitable temperature and salinity.Determine the temperature tolerance of each areas by determination of nitrogen conversion efficiency under gradual cooling process.Determine the key area influence by temperature,and concluded the temperature control measures.Explicit the influence of salinity on the nitrogen removal rate of each areas in PN-ANAMMOX process by determination of nitrogen conversion efficiency under different salinity,determine the salinity tolerance of each areas,and concluded t the salinity control measures.The effect of gradual cooling on the nitrogen removal rate of each areas in partial nitrification anaerobic ammonia oxidation?PN-ANAMMOX?process reactor was studied by using a series of partial nitrification and ANAMMOX process with reflux device as the seasons change.The results showed that,when temperature reduced to 25 ?,the total nitrogen removal rate droped from 1 kg·m^-3·d^-1 down to 0.5 kg·m^-3·d^-1 in combined process;nitrogen removal rate declined obviously from 18 kg·m^-3·d^-1down to 9 kg·m^-3·d^-1in anaerobic zone.When the temperature reduced to 19?,nitrite produce rate declined obviously from 0.9 kg·m^-3·d^-1 to 0.2 kg·m^-3·d^-1 in aerobic zone,the total nitrogen removal rate declined a bit.At this point,the NO₃—N concentration in effluent increased quickly,shows that the advantage of AOB growth was broken,NOB started to grow a lot.The temperature coefficient of Arrhenius law for nitrogen rem oval rate in anaerobic zone was higher than aerobic zone,shows that temperature has more influence on ANAMMOX process.The nitrogen removal rate in combined process was more close to nitrogen removal rate in anaerobic zone.ANAMMOX process was the rate limiting step of combined process.The nitrogen removal rate of each areas in PN-ANAMMOX process The effect of salinity on the nitrogen removal rate of each areas in PN-ANAMMOX process reactor was studied by using synthetic wastewater.5 g.L^-1 salinity has a promoting effect on nitrogen removal rate of each areas in PN-ANAMMOX process reactor.10 g.L^-1 salinity has a promoting effect on nitrogen removal rate of aerobic areas in PN-ANAMMOX process reactor.10 g.L^-1 salinity has an inhibitory effect on nitrogen removal rate of anaerobic areas in PN-ANAMMOX process reactor.20 g.L^-1 salinity has an inhibitory effect on nitrogen removal rate of aerobic areas in PN-ANAMMOX process reactor.25 g.L^-1 salinity has a strong inhibitory effect on nitrogen removal rate of PN-ANAMMOX process reactor.The nitrogen removal rate under 25 g.L^-1 salinity was below the half of without salinity.Take control measure when the nitrogen removal rate of aerobic areas in PN-ANAMMOX process reactor decreased obviously under 25 g.L^-1 salinity.The initial aeration rate is 340 L.h^-1,the nitrogen removal rate of aerobic areas in PN-ANAMMOX process reactor is 0.7 kg.m^-3.d^-1.The nitrogen removal rate of aerobic areas in PN-ANAMMOX process reactor rise to 0.9 kg.m^-3.d^-1 when aeration rate rising to 500 kg·m^-3·d^-1.When salinity was as high as 25 g.L^-1,rise aeration rate can not improve the reaction rate.The recovery experiment start after the salinity effect on PN-Anammox process experiment finished.The nitrogen removal rate of aerobic areas in PN-ANAMMOX process reactor was 0.8 kg.m^-3.d^-1 without salinity.The nitrogen removal rate of aerobic areas in PN-ANAMMOX reactor increased from 0.2 to 0.6 kg.m.d by recovery 11 days.The nitrogen removal rate of aerobic areas in PN-ANAMMOX reactor increased to 1 kg.m^-3.d^-1in the 20 th day of the recovery experiment.The nitrogen removal rate of PN-ANAMMOX reactor increased from 0.4 to 0.8 kg.m^-3.d^-1 by recovery 20 days.