Miloslav Drtil

The use of upflow anaerobic filter and AnSBR for wastewater treatment at ambient temperature

This research was carried out in order to study the effect of the temperature and hydraulic retention time (HRT) on the start-up and steady-state performance of upflow anaerobic filter (UAF) and anaerobic sequencing batch reactor (AnSBR). A mixture of synthetic substrate (glucose and sodium acetate) and real municipal wastewater was used as a laboratory substrate. The temperature (in the range 9-23 degrees C) and HRT (in the range 6-46 h) were selected as the most decisive technological parameters for a practical application. Average removal efficiency of COD found for tested anaerobic reactors were 56-88% (AnSBR) and 46-92% (UAF) depending on used temperature and HRTs. Based on the observed results, the use of AnSBR and UAF in practice seems to be a potential technology for (pre)-treatment of wastewater produced by small communities.

Acidobasic balances in the course of heterotrophic denitrification

Abstract Acidobasic balances are discussed to define the influence of organic substrate composition on CO2, HCO−3, CO2−3 production and pH value changes in the course of heterotrophic denitrification. The decisive parameter for these balances for undissociated substrates is average oxidation number of carbon (AONC). For dissociated substrates the balances are influenced by the composition of organic compounds (the number of C, H, O atoms and the oxidation number). The rules for determination of pH value changes according to substrate composition are discussed both for dissimilative and assimilative reactions. The theoretical conclusions are verified in kinetic denitrification tests with selected organic compounds (glucose, glycerine, ethanol, methanol, acetate, endogenous substrate). Furthermore, indication of nitrates and nitrites removal (the end of denitrification) by continuously measured pH is described (when denitrification has been finished, pH value begins to decrease).

Increase of biogas production from pretreated hay and leaves using wood-rotting fungi

Wood-decaying mushrooms can be applied for the pretreatment of lignocellulosic substrates such as leaves, hay and straw. The use of wood-decaying fungus Auricularia auricula-judae for the decomposition of sweet chestnut (Castanea sativa) leaves and hay is discussed in the proposed paper. Such pretreated substrate was employed in the anaerobic processes for biogas production. Comparison of pretreated and non-pretreated substrate revealed that an increase of 15 % in the biogas production can be achieved using the pretreated substrate. Composition of organic compounds in the sludge during the anaerobic process was identified by HPLC. The obtained results show that the utilization of pretreated leaves and hay leads to a gradual increase of the concentration of formic, acetic, and volatile fatty acids as well as to the formation of some aldehydes, ketones, and alcohols.

Treatment of industrial wastewater with high content of polyethylene glycols by Fenton-like reaction system (Fe0/H2O2/H2SO4)

Abstract The Fenton-like reaction (FLR) as advanced oxidation process system was successfully applied in the industrial wastewater pre-treatment with high content of polyethylene glycols (PEGs). Our effort was focused on the monitoring of efficiency of chemical oxygen demand (COD) removal in untreated and pre-treated wastewater using FLR (Fe0/H2O2/H2SO4) and also identification of products after treatment process. The influence of FLR pre-treatment on the biological treatment step was also studied. It was found that the COD value removal in untreated wastewater was only 37%, whereas in pre-treated wastewater the COD removal achieved 84%. High-performance liquid chromatography data have shown that during FLR the low-molecular fragments of PEGs are formed. It was also observed that high initial COD value was considerably decreased.

Long-term operation of a domestic wastewater treatment plant with membrane filtration

Possibilities of membrane technology and the use of membrane processes in wastewater treatment were investigated. The main focus was the monitoring of the starting phase of a domestic wastewater treatment plant. Experimental part of the study was realized at the municipal wastewater treatment plant (WWTP) Devínska Nová Ves — Bratislava during the period from February 2005 to September 2006. The system was stable without any external chemical treatment of the membrane modules and the permeate quality was very high. Observed decrease of COD and BOD5 values ranged between 91 % and 98 %. The process of nitrification was very successful considering its high efficiency (> 95 %).

Granulation of activated sludge in a laboratory upflow sludge blanket reactor

The creation of anoxic granulated biomass has been monitored in a laboratory USB (Upflow Sludge Blanket) reactor with the volume of 3.6 L. The objective of this research was to verify the possibilities of post-denitrification of residual NO3-N concentrations in treated wastewater (denitrification of 10-20 mg L−1 NO3-N) and to determine the maximum hydraulic and mass loading of the granulated biomass reactor. G-phase from biodiesel production and methanol were both tested as external organic denitrification substrates. The ratio of the organic substrate COD to NO3-N was 6. Only methanol was proven as a suitable organic substrate for this kind of reactor. However, the biomass adaptation to the substrate took over a week. The cultivation of anoxic granulated biomass was reached at hydraulic loading of over 0.35 m h−1. The size of granules was smaller when compared with results found and described in literary reports (granules up to 1 mm); however, settling properties were excellent and denitrification was deemed suitable for the USB reactor. Sludge volume indexes of granules ranged from 35-50 mL g−1 and settling rates reached 11 m h−1. Maximum hydraulic and mass loadings in the USB reactor were 0.95 m3 m−2 h−1 and 6.6 kg m−3 d−1. At higher loading levels, a wash-out of the biomass occurred.

Comparison of illicit drug use in three selected towns in Slovakia by wastewater analysis

The aim of this study was to analyse illicit drugs and their metabolites in wastewater from three selected wastewater treatment plants: Bratislava-Central, Bratislava-Petržalka and Piešťany. Urinary bio-markers of methamphetamine, cocaine, amphetamine, cannabis and ecstasy use were analysed by LC-MS/MS. The presented study shows that the highest consumption of methamphetamine among the surveyed sites is in Petržalka (149 mg/day/1000 inhabitants), followed by Piešťany (124 mg/day/1000 inhabitants) and Bratislava (119 mg/day/1000 inhabitants). It was determined that the consumption of cocaine increases over the weekend and that the drug is consumed mainly in areas with a higher population like Bratislava (86 mg/day/1000 inhabitants) and Petržalka (56 mg/day/1000 inhabitants), compared to areas with fewer inhabitants such as Piešťany (9 mg/day/1000 inhabitants). Ecstasy consumption in areas with higher population also significantly increased over the weekend (e.g. Bratislava on Wednesday - 2 mg/day/1000 inhabitants, on Sunday - 9 mg/day/1000 inhabitants).

Operation Of Household Mbr Wwtp – Operational Failures

The aim of this research is to get a practical experience with operating of a household MBR plant under real conditions with real domestic wastewater that differs from the municipal wastewater. For household MBR plant is typical that the system must to cope with a long-time zero load or vice-versa with more concentrated wastewater in big amounts (i.e. on weekends).

Comparison of anoxic granulation in USB reactors with various inocula

Anoxic granulation process with four different inocula was monitored in a laboratory post-denitrification up-flow sludge bed (USB) reactor. Wastewater containing 20 mg L−1 NO3-N and methanol as an organic carbon source was used. Gradual increase of mass volumetric loading (Bv) and hydraulic loading (γ) resulted in spontaneous granulation of anoxic biomass both from flocculant activated sludge and from anaerobic granulated sludge. With flocculant activated sludge as the inoculum, anoxic granules sedimentation properties and maximum loadings of the USB reactor depended on the sludge volume index (SVI) of the inoculum. Bv,max achieved in the USB reactor with flocculant inoculum from a municipal wastewater treatment plant (SVI = 208 mL g−1) was only 4.2 kg of COD per m3 per day and 0.7 kg of NO3-N per m3 per day. Bv,max using flocculant inoculum from an industrial wastewater treatment plant (SVI = 170 mL g−1) was 8.1 kg of COD per m3 per day and 1.35 kg of NO3-N per m3 per day. With anaerobic granulated inoculum (SVI range 8–11 mL g−1), markedly higher loadings in the USB reactor and lower SVI values of anoxic granulated biomass were achieved. Values of Bv,max were in the range of 16.1–22.4 kg of COD per m3 per day and of 2.7–3.7 kg of NO3-N per m3 per day (depending on the inoculum and the granulation procedure). It was proved that anaerobic granulated sludge is not just an inoculum, it is also a carrier for new denitrification biomass.

Degradation and toxicity changes in aqueous solutions of chloroacetic acids by Fenton-like treatment using zero-valent iron

Three priority pollutants, i.e. mono-, di-, and trichloroacetic acids, were degraded by the conventional Fenton AOP system (Fe2+ and H2O2). The results obtained suggest that the degradation decreased in the order: monochloroacetic, dichloroacetic, and trichloroacetic acid. The best of advanced oxidation processes (AOPs) for the degradation of trichloroacetic acid was reductive dechlorination with the use of zero-valent iron (Fe°). The results of Escherichia coli toxicity tests revealed that the reagents’ toxicity after the Fenton treatment process was decreased.