Keeping a Completely Autotrophic Nitrogen Removal over Nitrite System Effective in Treating Low Ammonium Wastewater by Adopting an Alternative Low and High Ammonium Influent Regime

Abstract

An alternative low and high ammonium influent regime was proposed and adopted to keep a completely autotrophic nitrogen removal over nitrite (CANON) effective when treating low ammonium wastewater. Results show that, by cyclic operating at an alternative low and high ammonium concentration for 10 days and 28 days, the CANON system could effectively treat low ammonium wastewater. Excessive proliferation of nitrite oxidizing bacteria (NOB) under low ammonium environment was still the challenge for the stable CANON operation; but with 28 days of a high ammonium treatment combined with a sludge retention time control, the NOB overproliferated in the low ammonium operational period could be under control. Specifically, when the nitrite oxidation rate reached 8 g N/m3/h, the CANON system should enter the high ammonium influent operating mode. 16S rDNA high-throughput sequencing results show that the appropriate sludge discharging provided an environment favoring Candidatus Jettenia.

Ammonia Recovery with Sweeping Gas Membrane Distillation: Energy and Removal Efficiency Analysis

“…However, that does not necessarily translate to reduced plant costs. , In biological treatment, aeration is an essential element and accounts for about 60% of energetic costs. , Because aeration is highly energetically intensive, improvements can be achieved by favoring oxygen efficient bacteria. Previous research has focused on using environmental controls to reduce nitrite oxidizing bacteria (NOB) and favoring ammonia oxidizing bacteria (AOB), or anammox bacteria to reduce oxygen consumption by 63%. , In Sweden, a pilot moving bed bioreactor (MBBR) was designed to treat wastewater effluent with a load of 200 kg N/day and concentration of 1 g/L NH 4 -N and achieved a 90% nitrogen removal with energetic consumption at 1.45–1.75 kWh/m 3 with no pH or temperature control . Although MBBR provides lower operating and maintenance costs, the biological process still yields emissions of N 2 O, a potent greenhouse gas. , Environmental sustainability and cost benefits to wastewater reclamation facilities and industries are strong incentives to promote the recovery and reuse of ammonia while limiting the amount of pollution …”