Influent Ammonium Concentration Research Articles

Study of nitrifying biofilms in submerged biofilters by experimental design methods

The relative influence of influent ammonium concentration, pH, temperature, filter height and liquid and gas superficial velocities over the biofilm growth and activity in submerged nitrification biofilters has been experimentally studied. The goal is to quantify the relative contributions of the different control parameters over the biofilm growth and the specific activity of ammonia and nitrite oxidizer microorganisms.The use of statistical tools like the experimental design methods, allows to characterize quantitatively the control parameters of the system and the levels providing the most favorable response of the system, in such a way that the noise factor influence is minimized. The experimental period is reduced eight times comparing to the traditional study of parameters influence.

Upgrading of existing sewage treatment plants by computer simulation: game or reality?

From 1 January 1995 in The Netherlands 75% of the phosphorus in the influent has to be removed in the waste water treatment plants (wwtp's). At this moment 40 – 50% is reduced by biological incorporation and some chemical dosing. By additional measures an extra 35% reduction has to be accomplished. A further reduction of total nitrogen to 75% has to be realised from 1 January 1998. Further extension of the activated sludge system is not always possible and in most cases rather expensive. Therefore optimization of the existing treatment plant is considered. For this purpose the advanced simulation model STREAM• is used. With STREAM• almost every waste water treatment plant can be simulated with the computer. In this way, for example, the effect of different control mechanisms and other measures can be studied without costly research. Computer simulation has been applied at the Kralingseveer wwtp of the HH van Schieland (Waterboard in the Netherlands) to optimize aeration control and to evaluate a number of technological process adjustments. Attempts are being made to reduce nitrogen drastically using equipment currently available, supplemented where possible with other limited measures. It can be concluded from the results of simulation, that the use of integrated aeration control, whereby influent flow, and nitrate and ammonium concentrations in the activated sludge are measured on-line, further improves the treatment process. Furthermore, when the sludge content in the aeration tank is raised and nitrogen is removed from the internal return flows, it seems that an average annual effluent quality of 10 mg Ntotal/1 is feasible. Verification of these factors will be carried out in the near future using practical measurements. The Kralingseveer project demonstrates that computer simulation is more than simply a ‘game’. It has become a real means of guiding or even limiting the need for extensive and costly (practical) investigation.

Interpretation of bacterial activities in nitrification filters by a biofilm model considering the kinetics of soluble microbial products

Activities of heterotrophic bacteria in nonsteady-state biofilms were evaluated using a simplified biofilm model in which formation and exchange of soluble microbial products (SMP) by nitrifiers and heterotrophs were considered. The model was applied to experimental results for a trace-level substrate removal. The model predictions indicated that SMP from nitrifiers contributed to supporting heterotrophic growth and their substrate removal potential. The biological interactions were more significant in cases of low influent substrate COD concentrations and increased with higher influent ammonium concentration. The introduction of SMP kinetics into the model captured the key aspects of removal and formation of COD components in biofilms receiving low influent substrate concentrations, such as nitrification filters for drinking water treatment and wastewater reuse.

Aerobic biodegradation potential of photoprocessing wastewaters

ABSTRACT: Currently, over 99% of all photoprocessing laboratories in the U.S. discharge directly to publicly owned treatment works (POTWs) after using various recovery methods. The purpose of this research was to investigate any potential adverse effects of photoprocessing effluents on the activated sludge process. Effluents from two commonly used photoprocesses were tested. These effluents were simulated in the laboratory and fed to fill‐and‐draw activated sludge reactors at loading levels less than or equal to 20% by volume along with a synthetic base feed. Conventional wastewater treatment parameters along with major photoeffluent constituents, such as ethylene diamine tetraacetate (EDTA), sulfur, and nitrogen species, were monitored. Results indicate that EDTA was recalcitrant and accounted for a significant fraction of the effluent COD. A significant fraction of the reduced sulfur species were oxidized to sulfate resulting in alkalinity consumption and a pH reduction. All activated sludge reactors showed a decrease in influent ammonia concentration and production of nitrate or nitrite. Up to 61% photoeffluent COD removal was achieved by the fill‐and‐draw activated sludge reactors. Such results demonstrate the potential of aerobic biological processes in the treatment of photoprocessing wastewaters and warrant further study.

An Analytical Model for Predicting the Carrying Capacity of Submerged Biofilters Used in Aquaculture

Laboratory data and information from the literature were used to develop an equation that models ammonia removal by submerged biofilters. The equation is based on the half-order/zero-order kinetics model and fixed biofilm nitrification, which indicates that the nitrification rate is a linear function of the ammonia concentration at ammonia concentrations <2.0 mg/l. Input data for the equation include easily gathered information of flow rate, biofilter size, maximum permissible ammonia level, biofilter influent and biofilter effluent ammonia concentrations, temperature, and ammonia production rate. The equation can be used to determine the carrying capacity of the submerged biofilters, to estimate biofilter sizes needed to support various fish loads, and to investigate the effects of changes in biofilter system parameters on carrying capacity. Comparisons of the predicted and actual carrying capacities of several experimental biofilters indicated that the equation accurately predicted carrying capacity und...

Temperature effects on biodrum nitrification

Filtration systems are required to maintain recirculated water quality, and are directly related to reliability and profitability in closed-cycle operations. Nitrifying biological filters (biofilters), a necessary component in closed-cycle filtration systems, use nitrifying bacteria to oxidize ammonia to nitrate through a two-step, temperature-related process known as nitrification. Unfortunately, biofilters are often inefficiently incorporated into filtration systems because quantitative design data for aquacultural applications are severely lacking. To assist in future biofilter design, biodrum (a biofilter type) performance was evaluated at controlled air and water temperatures (7°C to 35°C) by measuring influent and effluent ammonia, nitrite and nitrate concentrations. Other variables known to affect nitrification were controlled by delivering a synthetic, inorganic wastewater to two identical bench-scale biodrums in a one-pass arrangement. Flow rate was constant throughout the experimental trials (0·62 liters/min) and pH remained between 7·5 and 8·5. Influent ammonia concentration was maintained between 7·0 and 10·0 mg NH 4 +N per liter. Biodrum performance was found to be linearly related to temperature in this range (140–400 mg NH 4 +N oxidized per liter of filter per day, respectively).

Ammonia removal and recovery from urea fertilizer plant waste

Abstract Air stripping is the most simple method of ammonia removal from fertilizer wastewaters. Herein, studies were carried out for the removal and recovery of ammonia. With experimental data, a nomogram was generated relating the three contrblable variables, namely waste‐water flow rate, air flow rate and percentage ammonia removal. It was found that one litre of commercially available raw grade phosphoric acid was sufficient to absorb the ammonia stripped out from more than 275 litres of wastewater having an influent ammonia concentration 2000 mg 1−1.

Cyclical fluctuations in ammonia and nitrite-nitrogen resulting from the feeding of turbot, scophthalmus maximus (L.), in recirculating systems

Daily and weekly cyclical fluctuations in ammonia (NH 4N μg litre −1) and nitritenitrogen (NO 2N μg litre −1) were shown to occur in marine recirculating systems containing juvenile turbot, Scophthalmus maximus (L.). A stepwise multivariant regression analysis, computed for the prefeeding morning base levels, showed that ammonianitrogen concentration in the fish tanks was related to inflow ammonianitrogen concentration, water flow rate, water temperature, mean fish weight and fish biomass. Influent ammonia concentration and water flow rate were by far the most important variables accounting for 68·0% and 16·7% of the variation in the regression respectively. The fluctuations, which occurred at concentrations thought to be tolerated by the fish, were attributed to the amount and timing of feeding. The significance of the existence of such fluctuations was discussed together with the importance of their amplitude and frequency.

Clinoptilolite Column Ammonia Removal Model

A simple model employing a linear driving force in the particle phase has been successfully employed to model ammonium removal from a synthetic wastewater by a column of clinoptilolite. Batch isotherm studies conducted with the ammonium containing wastewater where shown to follow the form of a Langmuir isotherm for a single solute system but these data predicted better column performance than that observed. This was shown to be caused by incomplete regeneration of the clinoptilolite column. However, the column performance could be modeled effectively using an equilibrium isotherm constructed from column capacity data collected with different influent ammonium concentrations. The column isotherm was only valid for the particular conditions of regeneration employed in this study. Subsequent studies on more completely regenerated clinoptilolite indicate that the initial distribution of ammonium on the clinoptilolite must be identified if the column performance is to be modeled more accurately.

The biological treatment of carbonization effluents—IV

Abstract Biological systems operating the continuous, completely mixed activated-sludge process have been employed to investigate the further benefits obtained from the addition of certain biochemical factors such as p-aminobenzoic acid and glucose, which have been shown to have a significant effect on the rates of removal of constituents of coke-oven wastes such as thiocyanate and cyanide. These “growth factors” have now been shown to encourage the oxidation of ammonia, not only in non-bactericidal wastes, but also in the biological treatment of coke-oven effluents. The results of the investigation show that, in addition to the normal maintenance of neutral conditions in the aeration tank, acidification of a limed liquor before biological treatment, greatly reduces the deposition of calcium compounds in the bacterial sludge. This procedure can enable increases to be made in the organic loadings applied to such systems, with the added likelihood of additional benefits from growth factor application. It has been shown that, if the influent ammonia concentration during this modified treatment of a limed coke-oven waste can be reduced to 100–200 mg 1−1 by efficient operation of the lime still, it may be possible to oxidize the ammonia to nitrate, without any additional aeration stage. Yet another property of glucose and other growth factors is their ability to promote the biochemical oxidation of organic bases such as pyridine, the latter normally being regarded as resistant to bacterial breakdown. Experimental evidence suggests that, when once a particular breakdown pathway has been established, the continued application of an organic additive may not always be necessary.