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Large volumes of pavement de-icing and anti-icing fluids, collectively termed de-icing agents, are used at airports to facilitate wintertime safe air travel. After use, most of the them get typically mixed with storm water runoff and may enter soil and waters near the airports. Wastewater resulting from airports&rsquo, winter operations is contaminated mainly with nitrogen and carbon compounds. Previous research results have shown that the use of biofilters filled with lightweight aggregates prepared from fly ash from sewage sludge thermal treatment (FASST LWA) could be an effective method for removing nitrogen and organic compounds at low temperatures, i.e., 0&ndash, 8 &deg, C. For this to be possible, it is necessary to maintain a proper ratio between the amounts of carbon and nitrogen in the treated wastewater, through the simultaneous application of de-icing agents containing urea and carbon compounds. Biofilter technology is part of the concept of sustainable development. Their filling is made of waste materials and one of the pollutants (organic compounds) present in the wastewater is used to remove other pollutants (nitrogen compounds). In this study, technological systems for the treatment of wastewater containing airport runway de-icing agents with biofilters were proposed, which allow for the treated wastewater to be discharged into natural waters, soil, and sewerage network.

In this study, we determined the effectiveness of removal of nutrients (nitrates and orthophosphates) from greenhouse wastewaters (GW) using non-cross-linked chitosan (CHs) and chitosan cross-linked with epichlorohydrin (CHs-ECH) in the form of hydrogel beads. GW used in the study had the following parameters: N-NO3 621.1 mg/L, P-PO4 60.8 mg/L, SO42− 605.0 mg/L, Cl− 0.9 mg/L, Ca2+ 545.0 mg/L, Mg2+ 178.0 mg/L, K+ 482.0 mg/L, hardness 113° dH, and pH 6.2. The scope of the study included determination of the effect of pH on wastewater composition and effectiveness of nutrient sorption, analyses of nutrient sorption kinetics, and analyses of the effect of sorbent dose on percentage removal of nutrients from GW. CHs-ECH was able to sorb 79.4% of P-PO4 and 76.7% of N-NO3 from GW, whereas CHs to remove 92.8% of P-PO4 and 53.2% of N-NO3. Electronic supplementary material The online version of this article (10.1007/s11356-018-2078-z) contains supplementary material, which is available to authorized users.

The annual global production of milk is approximately 630,000 million litres and the volume of generated dairy wastewater accounts for 3.2 m3·m−3 product. Dairy wastewater is characterized by a high load of chemical oxygen demand (COD). In many wastewater plants dairy wastewater and municipal wastewater are co-treated. The effect of dairy wastewater contribution on COD fraction changes in municipal sewage which has been treated with a sequencing batch reactor (SBR) in three wastewater treatment plants in north-east Poland is presented. In these plants the real contribution of dairy wastewater was 10, 13 and 17%. In raw wastewater, SS fraction (readily biodegradable dissolved organic matter) was dominant and ranged from 38.3 to 62.6%. In the effluent, SS fraction was not noted, which is indicative of consumption by microorganisms. The presence of dairy wastewater in municipal sewage does not cause changes in the content of the XI fraction (insoluble fractions of non-biodegradable organic matter). SBR effluents were dominated by non-biodegradable dissolved organic matter SI, which from 57.7 to 61.7%. In raw wastewater SI ranged from 1.0 to 4.6%. Xs fraction (slowly biodegradable non-soluble organic matter) in raw wastewater ranged from 24.6 to 45.5% while in treated wastewater it ranged from 28.6 to 30.8%. In the control object (fourth wastewater plant) which does not process dairy wastewater, the SS, SI, Xs and XI fraction in inflow was 28.7, 2.4, 51.7 and 17.2% respectively. In the effluent the SS, SI, Xs and XI fraction was below 0.1, 33.6, 50.0 and 16.4% respectively.

The study was conducted in a one-stage rotating electrobiological disk contactor (REBDC) and a rotating electrochemical disk contactor (RECDC). Synthetic wastewater with characteristics similar to the wastewater from soil-less cultivation of tomatoes was used in the experiment. Current efficiency (CE) values, that express the denitrification performance of bio- and electrochemical reactors, were higher in the electrobiological contactor than in the electrochemical one. Combining biological processes with electrochemical processes in the electrobiological contactor resulted in almost 20% higher current efficiency in the contactor operated at a density of 0.63 A/m2 and hydraulic retention time (HRT) = 4 h. The study showed that, in both the electrochemical and the electrobiological contactor, current density increase and hydraulic retention time extension increased electric power consumption (E) during phosphorus compounds removal and simultaneously lowered current efficiency.

Soilless plantations under cover constitute a significant part of horticulture. This study aimed at determining the qualitative composition of wastewater generated from the soilless cultivation of tomato under cover. This is important for managing the wastewater, which may be recirculated to allow the or employ a partial or complete recovery of minerals. Two plantations located in north-eastern Poland, which differed in the type of substratum (coconut fiber or rockwool), were studied. The generated wastewater was characterized by a low content of organic matter and a high concentration of total nitrogen (TN), total phosphorus (TP), and salinity (EC). Over 99% of the TN was constituted by nitrates. The chemical oxygen demand (COD) changed from 50.07 to 75.82 mgO2&middot, L&minus, 1 (greenhouse 1), and from 37.35 to 78.12 mgO2&middot, 1 (greenhouse 2), the content of TN changed from 403.59 to 614.89 mgN&middot, 1 (greenhouse 1), and from 270.00 to 577.40 mgN&middot, that of TP changed from 35.44 to 78.00 mgP&middot, 1 (greenhouse 1), and from 54.10 to 104.00 mgP&middot, and the EC changed from 3.53 to 6.93 mS&middot, cm&minus, 1 (greenhouse 1), and from 4.94 to 6.94 mS&middot, 1 (greenhouse 2). No statistically significant correlations were noted between TN and TP, or between TP and EC.

There is a growing global environmental problem of agricultural wastewater from soilless plant cultivation systems. In most countries dominate open fertilization systems, in which excess of nutrient solution is discharged in an uncontrolled way into the ground inside greenhouses or adjacent areas. Wastewater from such systems is characterized by a very high concentration of nitrogen and phosphorus compounds and their discharge into the environment causes significant pollution of the water and soil environment. The goal of the research was to determine the contribution of electrochemical reduction of nitrogen, hydrogenotrophic and heterotrophic denitrification in the process of nitrogen removal in a rotating electrobiological contactor (REBC) depending on hydraulic retention time (HRT) and electric current density (J). Synthetic sewage with characteristics corresponding to wastewater from soilless cultivation of tomatoes was the subject of the research. The first part of the experiment included determination of the effect of HRT on the effectiveness of bio-processes of nutrients removal in a rotating biological contactor (RBC). The second concerned the effect of HRT and J on the effectiveness of nutrients removal in a rotating electrochemical contactor (RECC), while the third part - the effect of HRT and J on the effectiveness of nutrients removal in REBC. RBC was characterized by low efficiency of denitrification (6.2 to 9.2%). The effectiveness of nitrogen removal in RECC was determined by both electric current density and hydraulic retention time. The highest efficiency was 53.4%. REBC nitrogen removal effectiveness was higher than in RBC and in RECC. The nitrogen removal efficiency increased along with increasing values of HRT, reaching the maximum value of 68.6% for J=10.0A/m2 and HRT=24h. The contribution of hydrogenotrophic denitrification in total nitrogen removal increased with the increase of electric current density.

The basic factors determining the efficiency of the removal of nitrogen and carbon compounds from airport wastewater containing de-icing agents are low temperature and the C/N ratio (carbon to nitrogen ratio). Biofilm reactors (biofilters) create better conditions for nitrification and denitrification than suspended biomass reactors. The scope of the study included determination of the influence of the C/N ratio in the wastewater on nitrification, denitrification and organic compound removal in biofilm reactors depending on the temperature. The experiment was performed in 24 circular laboratory biofilters with LECA (Light Expanded Clay Aggregates) filling. The study was divided into three series differing in organic carbon loading. In each series, carried out at the same hydraulic retention time, biofilters were operated at 25, 8, 4 or 0 &deg, C. The study showed the effective removal of nitrogen compounds across a very wide temperature range. The applied filling and properly selected operating parameters of the reactors resulted in effective simultaneous nitrification and denitrification. The highest efficiency of nitrogen removal at 0 &deg, C (34.57 &plusmn, 4.54%) was obtained at the C/N ratio of 0.5 gC/gN. The efficiency of denitrification (the lowest at the temperature of 0 &deg, C) increased as the temperature and C/N ratio increased in the wastewater.

The influence of light weight aggregate made of fly ash from sewage sludge thermal treatment (FASSTT LWA) on ammonia nitrogen metabolism, and on quantitative and qualitative changes of microorganisms colonizing the filling, was investigated. Two reactors were used in the experiment. The first was filled with gravel, the other with FASSTT LWA. The reactors were operated with a wastewater hydraulic loading rate of 5 mm(3) mm(-2) d(-1). During the eleven-week experiment, high efficiency of ammonia removal was observed. The lower concentrations of nitrites and nitrates in the effluent indicate that ammonia nitrogen removal resulted not just from nitrification. Nitrate concentration increase was reflected in a decrease in nitrogen removal efficiency. One possible explanation for this phenomenon is that in the period when ammonia nitrogen and nitrites were present in the reactor's FASSTT LWA filling, facilitating conditions occurred for the deammonification process.

The aim of the study was to supplement the information missing in the literature on the influence of organic compounds speciation (percentage of chemical oxygen demand (COD) fractions, readily biodegradable and non–biodegradable dissolved organic matter; slowly biodegradable and non‒biodegradable insoluble organic matter) in wastewater on chemically assisted primary sedimentation process and its potential impact on the energy and economic balance of the plant. The statistical modelling of the chemically assisted primary sedimentation process using artificial neural networks (ANN) was a novelty. It was also important to check the differences resulting from the use of coagulants, polyelectolites and their doses. For both large wastewater treatment plants (>500,000 people equivalent) located in the various regions of the country in Central Europe only ferric chloride had a positive balance. The addition of polyelectrolyte in the Wroclaw wastewater did not affect the chemically assisted primary sedimentation process but in the Bialystok wastewater it strengthened the process effect. In both plants only doses from 10 to 40 mgFe/dm3 are cost-effective. The results indicate that the addition of polyelectrolyte should be taken into account in this application and was correlated with the amount of colloidal COD fractions in wastewater. The developed ANN models reflected well the effectiveness of COD removal in both large WWTP while the sensitivity analysis of individual ANN models showed differences in the variables affecting the calculation process of both models, despite similar values of parameters characterizing wastewater in both wastewater treatment plants.

The hydraulic loading of biofilter (HL), temperature and C/N ratio - these factors influence on nitrogen and carbon removal efficiency from airport wastewater containing de-icing agents. The vast area of airports and significant fluctuations in atmospheric precipitation contribute to huge differences in wastewater flows discharged to treatment systems. The aim of the study was to determine the influence of the hydraulic loading on nitrogen and organic compounds removal in biofilters in low temperatures. The novelty of the paper results from low temperatures (0, 4 and 8 °C), specific wastewater and biofilter filling (light weight aggregates prepared from fly ashes from sewage sludge thermal treatment (FASST LWA). The study was divided into four series differing in the hydraulic loading (1.0, 3.0, 5.0, and 10.0 L·m−2·d−1). In each series, biofilters (filled with FASST LWA) were operated at the temperature of 0, 4, 8 °C and 25 °C. The organic carbon to nitrogen ratio was 0.5. The study showed the effective removal of nitrogen at low temperatures, even at high HL. The highest efficiency of nitrogen removal at the temperature of 0 °C (34.93 ± 4.54%) was obtained at 5.0 L·m−2·d−1. The hydraulic loading and temperature affected the efficiency of nitrogen and COD removal. The presented experiment demonstrated that the use of biofilters filled with FASST LWA may offer an effective and sustainable method for the treatment of airport de-icing wastewater.

Wastewater from households wastewater treatment plants (HWWTP) is discharged to the ground or to the surface waters. Special consideration should be given to the improvement of HWWTP effectiveness, particularly in relation to nutrients. The addition of biodegradable carbon sources to biofilm reactor, can enhance microbial activity but may also lead to filling clogging. The study aimed to compare 3 different organic substrates: acetic acid (commonly applied)and two untypical - citric acid and waste beer, under the same operational conditions in a post-denitrification biofilm reactor. The study investigated the impact of a type of organic substrate, low pH and time on: (1) biofilm growth, (2) the characteristics of extracellular polymeric substances (EPS), (3) the kinetics of nutrients removal and (4) reactor clogging. Results were referred to (5) the effectiveness of nutrients removal. The study demonstrated that low pH assured the development of a thinbiofilm. Citric acid ensured the lowest biomass volume, being by 53% lower than in the reactor with acetic acid and by as much as 61% lower than in the reactor with waste beer. The soluble EPS fraction prevailed in the total EPS in all reactors. The content of the tightly bound EPS fraction ranged from 26.93% (citric acid) to 36.32% (waste beer). Investigations showed also a high ratio of exoproteins to polysaccharide in all fractions, which indicated a significant role of proteins in developing a highly-proliferating biofilm. The treated wastewater met requirements of Polish regulations concerning COD and nitrogen concentrations.

One of the key elements in the operational management of airports is effective de-icing of surfaces. The run-off of precipitation water loaded with pollutants from de-icing is a considerable and costly problem. The aim of our research has been to evaluate the applicability of biofilters filled with light expanded clay aggregate (LECA) generated from incineration of sewage sludge and now serving as a matrix for the development of microorganisms. The tested biofilters treated precipitation water polluted with agents used to de-ice airports. The solution was tested on a laboratory scale, in a range of temperatures from 0 to 25°C, and at concentrations of pollutants from airport de-icing expressed as COD and varying from 503.30 to 3827.50 mg O2·L-1. The tested filling allowed nitrifying as well as denitrifying bacteria to grow and develop even at low temperatures. Biofilters provide simultaneous nitrification and denitrification, as well as removal of organic compounds, even at 0°C. Biofilters based on the granulate prepared from fly ash from sewage sludge thermal treatment can be a cost-efficient and low-maintenance technology to treat airport surface runoff.

The operators of wastewater treatment plants in Poland have been observing an increase in the concentration of raw sewage for several years. In particular for organic substances. This is the effect of water consumption reduction, restoration of the sewerage networks, growing wealth, widespread waste of food. The most serious adverse, influencing on the municipal wastewater composition is colloid mills application in gastronomical objects and the discharge of shredded food waste to sewer. That widespread behavior has been noticed and negated, in 2010 year, by the common position of GIS and the ME. Far too late, which confirms the situation observed at the Olsztyn wastewater treatment plant, where the biggest increase of COD values ​​was observed in 2008–2010. The average concentration of COD of sewage in the period 2011–2014 was almost twice higher than in 1996, real PE is close to the design value, despite the fact that the hydraulic load of the object slightly exceeded 50% of design value. Removing such large organic pollutant loads generates high costs, that could be avoided by reasonable food waste management.

This study reports results of respirometric measurements of activated sludge biodegrading the substrate in wastewater originating from the following brewery plant production departments: malt house, brewhouse, fermentation house and racking house. The process was conducted at two temperatures: 10 and 20°C with activated sludge adapted to brewery wastewaters. The loading of activated sludge reached 0.25 g chemical oxygen demand per gram dry matter per day, which assured complete degradation of organic matter. The physicochemical characteristics of the wastewaters are provided. The study demonstrates a correlation between the site of wastewater generation, the specific character of a unitary technological process and the quality of the wastewater discharged to the sewage system, including biodegradability. Despite significant differences in the quality of the wastewaters, they were characterized by high biodegradability at a temperature of 10 and 20°C and by the C:N:P ratio being beneficial for biological treatment, irrespective of their source of origin. Copyright © 2013 The Institute of Brewing & Distilling

This study aims to determine the effect of volatile fatty acids on nitrates and orthophosphate removal in a sequencing batch reactor (SBR) with activated sludge biomass adapted to process dairy wastewater. The research also determine whether it is the type of fatty acid applied that is responsible for the effectiveness of denitrification and dephosphatation at varying nitrate:orthophosphate ratios, or whether these processes are additionally affected by the presence of microorganisms that have adapted to the specific carbon composition of the wastewater being treated. At the beginning of an operating cycle SBRs were dosed with VFAs to provide a source of carbon. A comparative analysis was performed of nitrate and orthophosphate removal at initial nitrate concentrations of 1.22, 7.3 and 15.2 mgN(NO3)L⁻¹. Doses of fatty acids were approximately 10.5 mg⁻¹COD·mgP(PO4). They consisted of acetic, propionic, butyric, isobutyric, valeric, isovaleric and caproic acids. Increases of nitrate concentration from 1.22 to 15.2 mg N(NO3)L⁻¹ were observed to reduce the quantity of removed orthophosphate depending on the fatty acid applied, from 7.2-9.2 mgP(PO4)L to 4.5 - 6.7 mgP(PO4)L. Every increase in the removed nitrates by 5.0 mgN(NO3)L⁻¹ was accompanied by a decrease in the removed orthophosphate of around 1 mgP(PO4)L⁻¹. The reactor containing acetic acid was found to remove the highest amount of orthophosphate irrespective of the nitrates concentration. Acids present in significant amount in dairy wastewaters (i.e. acetic, propionic and butyric) were more effective source of carbon in the denitrification process compared to low concentration acids.

RBC effluent needs further treatment because of water-quality standards requiring low nitrogen and phosphorus concentrations. It may be achieved by using reactors with biomass immobilized on the filling's surface as post-denitrification biofilm reactors. Due to the lack of organic matter in treated wastewater, the introduction of external carbon sources becomes necessary. The new attached growth bioreactor--anaerobic rotating disc batch reactor (ARDBR)--was examined as a post-denitrification reactor. The impact of selected volatile fatty acids on nutrient removal efficiency in an ARDBR was studied. The biofilm was developing on totally submerged discs mounted coaxially on a vertical shaft. Acetic, propionic, butyric and caproic acids were applied. Wastewaters were removed from the reactors after 24-h treatment, together with the excess solids. In the ARDBR tank, there was no biomass in the suspended form at the beginning of the treatment process. Acids with a higher number of carbon atoms (butyric and caproic) were the most efficient in denitrification process. The highest phosphorus removal efficiency was noted in the ARDBR with butyric and propionic acids. The lowest unitary consumption of the external source of carbon in denitrification was recorded for acetic acid, whereas the highest one for caproic acid.