Swedish Experience of the Deammonification Process in a Biofilm System

Abstract

Treatment of supernatant from dewatering of digested sludge was performed in a pilot plant scale at Himmerfjärden wastewater treatment plant in the Stockholm region. A moving bed biofilm reactor was used with Kaldnes rings as support material. Deammonification is a two-step process technology in which the first step involves oxidation of part of the ammonium to nitrite followed by oxidation of remaining ammonium with the formed nitrite into nitrogen gas (anammox). The two processes can be performed in two separate reactors or in one-stage biofilm reactor there the outer biofilm layer performs nitritation and an inner layer the anammox reaction. One-stage technology was started by seeding anammox bacteria into a step with partial nitritation and deammonification was rapidly established with an average nitrogen removal between 55 and 88% with influent ammonium concentrations between 350 and 720 g N m-3. A removal rate of about 15 g N m-3 d-1 could be reached. The process could be monitored by pH and conductivity measurements. Nitrititation was the rate limiting step.

Oxidation-reduction potential (ORP) as a control parameter in a single-stage partial nitritation/anammox process treating reject water

“…The nitrogen removal efficiency was 83.9% ± 5.8%, with a maximum value of 98.3% (Table ). These values are comparable with results obtained in a full‐scale partial nitritation/anammox process . The same reject water was used throughout the whole experiment and the proportions of COD, nitrogen and alkalinity were the same.…”

Advances in wastewater nitrogen removal by biological processes: state of the art review

“…Intermittent aeration supporting partial nitritation and anammox reactions is provided by coarse bubble diffusers. Alternance of aeration/anoxic periods limits nitrite accumulation and restrict the growth of aerobic nitrite-oxidizing bacteria (Plaza et al, 2011;Thöle, 2007). DO concentration of 3 mg L -1 during aeration is considered appropriate for design and operation, but higher concentrations are avoided to prevent potential for NOB growth, and limit anammox inhibition.…”

“…duration of aeration cycles). Inorganic nitrogen removal efficiency is usually in the range 70-85% and in the temperature range 25-30˚C (Plaza et al, 2011). Minimum process operating temperature is 20˚C, after which substantial performance deterioration occurs (Thöle, 2007).…”

Three-Dimensional Stratification of Bacterial Biofilm Populations in a Moving Bed Biofilm Reactor for Nitritation-Anammox

“…Furthermore, there is a need for quantitative image analysis to reveal the actual distribution patterns of the biofilm microorganisms. For moving bed biofilm reactors (MBBRs), which are used today in full-scale nitritation-anammox [ 15 , 16 ], a recent investigation has indicated a more orderly biofilm structure [ 17 ], but detailed analysis of biofilm establishment and stratification is still lacking for these systems. One probable reason for this is the challenge to retreive and analyze undisrupted biofilms from the protected carrier compartments.…”