Large‐Scale Biological Nitrate and Ammonia Removal

Abstract

In order to treat water containing nitrogen in excess of the European Drinking Water guideline, an innovative large-scale biological, nitrogen-removal process has been used. After extensive pilot-scale testing and a first full-scale (80 m3/h) demonstration at Eragny (France), a 400 m3/h installation, serving about 50000 people, was built at Guernes-Dennemont, near Paris. The raw water source is a combination of percolation from agricultural plains and river bank infiltration, and contains both nitrates and ammonia.The plant consists of two fixed-bed biological reactors in series. An anoxic filter, using ethanol as a carbon source for heterotrophic bacteria, removes nitrates at filtration rates up to 10 m/h. The denitrified water is then polished on an aerated twolayer filter, packed with activated carbon and sand. Excess carbon from the first stage, together with reduced nitrogen (ammonia and nitrates), is oxidized at this stage before ozonation of the water.Design data and operational performance are given for total nitrogen (NO3 and NH,), total organic carbon (TOC) and chlorinated hydrocarbons. A specific dosing method for biodegradable carbon was developed to monitor the efficiency of the post-treatment. Special attention was paid to (a) nitrate control through improved backwash, and (b) reducing the potential for bacterial contamination and aftergrowth in the distribution network.

Mixed-matrix membranes for efficient ammonium removal from wastewaters

“…A variety of biological and physicochemical methods have been employed for the removal of ammonia nitrogen from the water systems [4,5]. Biological methods are commonly used to remove ammonium via nitrification−denitrification process by the microorganisms [6,7].…”

Biological nitrate removal processes from drinking water supply-a review

“…Methanol has been used as a carbon source for denitrification of drinking water reported by Rogalla et al [ 32 ], Ayyasamy et al [ 46 ] and Hall&Zabel [ 47 ], whereas, extensive use of ethanol and acetic acid has been reported by Ghararah [ 48 ], Mohseni-Bandpi et al [ 49 ], Magram [ 50 ], Green et al [ 51 ] and Roennefhart [ 52 ]. Ghararah showed that ethanol as a carbon source was given better results as compared with methanol and acetic acid in an anoxic static bed column [ 48 ].…”

“…Rogalla [ 32 ] used a pilot-scale packed bed reactor with a mineral medium and ethanol as the carbon source to remove nitrate from groundwater. The results obtained from the pilot scale studies were applied to full scale reactors.…”

“…Denitrified water was passing through a two-layer media. The first layer consisted of aerated activated carbon for the removal of excess carbonaceous pollution, and to increase the available dissolved oxygen, while the second layer was made of fine sand to remove suspended solids [ 32 ].…”

Using carrier surface loading to design heterotrophic denitrification reactors

“…Although various unit processes have been adapted for heterotrophic denitrification of drinking water (Rittmann & McCarty, 2001; Clifford & Liu, 1993; Liessens et al, 1993; Rogalla et al, 1990; Gayle et al, 1989; Richard, 1989; Rittmann & Huck, 1989; Janda et al, 1988; Richard et al, 1980), the most common are packed‐bed reactors in which the biomass carriers consist of plastic modules that are systematically stacked or granular media (e.g., sand, granular activated carbon, expanded clay) that are dumped in the reactor vessel. Packed‐bed reactors can be operated in either downflow or upflow modes.…”