Model Based Optimization of Nitrogen Removal in a Full Scale Activated Sludge Plant

Abstract

This paper evaluates model-based upgrading of an activated sludge plant treating wastewaters of leather tanning industrial district with an average capacity of 13,000 m 3 /d. Significant impact of temperature changes on biochemical processes, such as nitrification and denitrification were quantified and used in setting the aeration control for process optimization in terms of total nitrogen removal. Model evaluation based upon kinetic and stoichiometric parameters specifically determined for the tannery wastewater, indicated that an intermittent aeration type of an operation strategy was suitable for achieving the required effluent total nitrogen level of 100 mgN/L under all operating conditions at the process temperature range of 21°C-35°C. The simulation study also showed that the nitrification performance of the plant was improved by increasing the aeration intensity. The application of intermittent aeration provided a competitive advantage in meeting the total nitrogen standards, improving the total nitrogen removal to around 60%.

Nitrogen and cod removal from tannery wastewater using biological and physicochemical treatments

“…The low organic nitrogen transformation is related to the results obtained by Insel et al [12] who determined that the limiting step in the removal of nitrogen in tannery effluent is the ammonification. They reported residual organic nitrogen concentration between 12 and 25 mg·L .…”

“…This probably corresponds to recalcitrant or non-biodegradable nitrogen that could not be hydrolyzed [32]. In this regard, Boursier et al [33] and Insel et al [12] reported that the organic nitrogen present in industrial effluents from slaughterhouses and tanneries was in the particulate form of organic complex polymers and are probably not nitrificable, severely limiting the process of ammonification.…”

“…Ammonification is recognized as a specific feature of the tannery effluents due to the high content of organic nitrogen present in proteins [12,18,34]. Thus, the low rate of ammonification was considered one of the main reasons that impeded a higher total nitrogen removal from the tannery effluent in the SBR.…”

“…Tannery wastewater contains an important amount of colloidal and/or biorefractory organic matter and nitrogen [11][12][13][14]. Many of these compounds are resistant to biological degradation and/or can inhibit the activity of the biomass in treatment plants.…”

Effects of C/N Ratio on Nitrate Removal from PU Synthetic Leather Wastewater Treated by Anoxic Moving Bed Bio-film Reactors

“…T hERE are more than 2,000 synthetic leather factories located in Southeast China, discharging off 10,000 thousands tons of wastewater per year, in which N,N-Dimethylformamide (DMF) was usually found, it was used for surface modification of PU (poly urethane) synthetic leather as a kind of solvent, and toxic and inhibitive to bacteria's activities [1,2,3]. Many kinds of physic-chemical or biological processes, such as Extraction, Sequencing Batch Reactor, Integrated Anoxic-aerobic Biochemical Process and etc, are applied to treat synthetic leather wastewater [4,5], and these experimental results shows that, some main water quality index parameters, such as CODCr (chemical oxygen demand), SS (suspended solid), Cr and sulfide in effluent, are usually measured with the National Wastewater Discharge Standard (NWDS), but the residual total nitrogen (TN) is hardly up to standard [6].…”