| Anaerobic ammonium oxidation (Anammox) process is a novel, and energy efficient biological nitrogen removal technology. One of the major challenges in developing Anammox process is the treatment with wastewater in which exist complicated compositions(high salinity) and environmental conditions(low temperature). In order to perfect the full-scale application of Anammox process, the effects of low temperature(<25℃) and high saline on Anammox process and the corresponding control strategies were studied in this investigation. The conclusions are as follows:(1) The performance of Anammox starting-up period was investigated.The reactor seeded with Anammox sludge by ambient temperature preservedand the start-up periodonly lasted for4days. During the operation of Anammox, sludge floatation turned up twice. First sludge floatation happened when sludge in flocculent condition, then by shortening (HRT), this phenomenon disappeared. Granular sludge floatation came out, due to the inanition inside of granular. To maintain the stability of Anammox process, the appropriate particle size is needed.(2) The effects of low temperature on Anammox process and corresponding control strategies were studied in this investigation.It was found that, Seeded with Anammox sludge by ambient temperature preserved, the reactor showed to be more adaptation to low temperaturewith activation energy of39.5kJ·mol-1. The SAA were decreased with decreased temperature, when temperature reduced from35to15℃, SAA decreased from6.12to2.05mgN·g-1VSSh-1. After several times of temperature shocks, Anammox bacteria slowly adapted to low temperature and the effluent of reactor became stable. Sequential biocatalyst addition was used to relieve the inhibition of low temperature on Anammox. With25ml high rate Anammox sludge addition every three days, NRR was increased as high as6.25±1.51kg·m-3·d-1, comapared with the NRR of the control was approximately5.40±0.59kg·m-3·d-1. The appropriate glycine betaine addition could promote the performance of Anammox. When under the temputure of9.2±0.5℃, NRR of the reactor with0.1mmol·L-1glycine betaine addition was 5.94±0.79kg·m-6·d-1. increased with4%compared with the control.(4) The effects of salinity on Anammox process and corresponding control strategies were studied in this investigation.Batch tests were applied to study the effects of salinity on Anammox and feasibility of glycine betaine addition for alleviating high salinity inhibition was investigated. The results indicated that different types of salt inhibited Anammox with different degrees. When under the same molar concentration, the inhibitiondegrees as follow:Na2SO4> KC1> NaCl. Meanwhile the50%inhibiting concentration of osmotic pressure on Anammox was1.24Mpa. The most important factor affected Anammox was the spices of iron which led to different Anammox activity. Low concentration of salt (NaCl<10g·L-') could promote Anammox activity, thespecific Anammox activity (SAA) increased by49%under5g·L-1NaCl.While high salt concentration would reduce the activity of Anammox. When NaCl concentration was upper to50g·L-1, it resulted in a low activity in Anammox. After a60g l-1NaCl shock, the SAA was3.55mg·g-1VSS·h-1. The response to the shock loading can be divided into three stages:a sensitive period, an interim stable period and a recovery period. The performance was more stable at low-concentration NaCl shocks. Sequential biocatalyst addition can promote the performance of Anammox under high salinity environment.(5) The combine effects of salinity and low temperature on Anammox process was studied in this investigationUnder lower than10g·L-1NaCl with temperature higher than25℃, the combine effects of those two factors on Anammox was slight. With temperature maintained as35℃, SAA increased. While as low as15℃and higher as30g·L-1NaCl would inhibit the SAA serious. |
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