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The research focuses on ammonia and phosphate removal from wastewater by using a novel metal and microwave-treated clinoptilolite. For increasing adsorption capacity, the samples were calcinated or microwave irradiated in the solutions of Fe(III), Cu (II), or Ca(II) chlorides. BET-specific surface area measurement revealed that the calcination led to a decrease from 18.254 to 11.658 m2/g. The adsorption results were fitted to theoretical models. The PO43− adsorption in all samples as well as NH4+ adsorption in natural and Fe- and Ca-modified samples is best described using the Langmuir–Freundlich model, but in calcinated and Cu-modified clinoptilolite the NH4+ sorption is better characterized by the Freundlich model. The PO43− adsorption in natural and all modified samples is best described using the Langmuir–Freundlich model. Fe-modified and calcinated clinoptilolite showed the highest NH4+ adsorption capacity of 4.375 and 2.879 mg/g. Ca-modified samples demonstrated the lowest adsorption capacity of 0.875 mg NH4+/g. The metal-modified samples exhibit a significantly higher phosphate sorption capacity (from 800.62 for Cu-sample to 813.14 mg/g for the Fe-modified sample) than natural (280.86 mg/g) or calcinated samples (713.568 mg/g). Experimental studies in dynamic conditions revealed high NH4+ and sufficient PO43− ions captured on modified clinoptilolite. This study provides a feasible approach for the synchronous removal of the main eutrophication agents for implementation in additional (tertiary) wastewater treatment facilities.

Wastewater treatment plants (WWTPs), which operate due to the vital activity of microorganisms, often do not achieve high nitrogen and phosphorus removal from wastewater. Nitrogen and phosphorus compounds in treated wastewater enter surface water bodies and cause their eutrophication. The effective treatment of wastewater is essential for creating a sustainable environment. Three WWTPs were selected with similar effluent discharges (10 m3/d) and the removal of pollutants was analyzed. ...

Phosphorus is important in the environment and its recovery and recycling is necessary. Sewage wastewater is one of the substances in which a high amount of phosphorus and its compounds are found. Phosphorus in water is one of the causes of environmental problems such as eutrophication. The utilization of sewage sludge is a main prob- lem in both large and smaller towns. This research investigates how much and how to use sewage sludge biochar as an adsorbent to remove phosphorus compounds from wastewater. This article highlights the sorption capacity of the filler to absorb phosphorus compounds.

Nuotekų valyklos dažnai nepasiekia aukšto azoto ir fosforo šalinimo iš nuotekų lygio. Išvalytose nuotekose esantys azoto ir fosforo junginiai patenka į paviršinio vandens telkinius ir sukelia jų eutrofikaciją. Siekiant aukštesnio azoto ir fosforo junginių išvalymo lygio, rekomenduojamas papildomas – tretinis valymas. Eksperimentiniai tyrimai atlikti su nuotekomis iš nuotekų valyklos po biologinio nuotekų valymo. Nuotekų valyklos patalpoje buvo įrengtas filtravimo kolonų stendas. Filtravimo kolonos buvo užpildytos skirtingų filtrų užpildų (kvarcinio smėlio su geležies bei mangano oksidų plėvele, natūralaus ceolito ir Purolite (jonų mainų derva)) sluoksniais. Nustatytos nuotekų teršalų (BDS7, ChDS, NO3–N, NH4–N, PO4–P) koncentracijos į filtravimo kolonas tiekiamose nuotekose ir po jų išleidžiamose nuotekose. Taip pat nustatyti nuotekų pH, filtravimo greitis, slėgio nuostoliai. Tyrimo rezultatai yra naudingi kuriant ir tobulinant tretinio nuotekų valymo įrenginius.

This research investigated the ability of two materials, which are waste generated during water treatment and wastewater treatment, to remove phosphates from water. The selected materials were quartz sand used in drinking water treatment plants (OQS) and incinerated (600 °C) sewage sludge (ISS). The materials were chosen for their composition: both contain aluminium, iron, and calcium. The experiments were carried out in the laboratory (in batch and in columns stand). Modelling of the sorption processes was performed on the basis of results from experiments in batches. The maximum adsorption capacity of the OQS was 1.14 mg/g obtained using the linearized Langmuir model and the maximum adsorption capacity of the ISS was 0.86 mg/g for the linearized Langmuir model (in batch). A pseudo-first-order model obtained using a nonlinear fit can accurately explain phosphate adsorption kinetics using both adsorbents: OQS and ISS. During the column filtration experiment, a higher sorption capacity of the ISS filter media was achieved −2.1 mg of phosphate phosphorus per gram of filter media. The determined adsorption capacity of the investigated materials was average, but the reuse of this waste would help to solve the issues of the circular economy.

After biological wastewater treatment, ammonium nitrogen (NH4-N), nitrate nitrogen (NO3-N), and phosphate phosphorus (PO4-P) remain in the effluent, which is discharged into natural water bodies. For further removal of these wastewater compounds, three selected materials were used as filter media: quartz sand used in drinking water treatment plants, Purolite A502PS resin, and natural zeolite. After placing all selected materials in the first filtration column (height of each layer-30 cm), the concentration of NH4-N in the wastewater was reduced by 5 times (from 8.22 to 1.5 mg/L), the concentration of NO3-N by 6 times (from 2.46 to 0.44 mg/L), and the concentration of PO4-P by 3 times (from 1.56 to 0.45 mg/L). The second column was without a Purolite A502PS layer, so the concentration of NO3-N in the filtrate from the second column was not reduced. The filtration columns were operated for about 2 months, and the filtration was stopped due to clogging with suspended solids (TSS) with an average concentration of 53.2 mg/L. The preliminary removal of TSS from wastewater before filtration through sorbents is recommended. The tested materials effectively treat wastewater of nitrogen (average efficiency 80–83%) or phosphorus (average efficiency 65–67%) and do not pollute the wastewater with environmentally hazardous substances, so they can be used in the development of tertiary wastewater treatment filters.

Šiuo metu apie 24 % Lietuvos gyventojų nuotekas tvarko individualiai, iš jų 74 % nuotekas tiesiog kaupia specialiose surinkimo duobėse. Per pastaruosius penkerius metus, atlikęs patikrinimus, Aplinkos apsaugos departamentas nustatė apie 30 % netinkamo individualaus nuotekų tvarkymo atvejų. Jei dėl aplinkosauginių ar ekonominių priežasčių netikslinga nuotekų tvarkyti centralizuotai, jos gali būti tvarkomos individualiai. Tam reikalingi efektyvūs nuotekų valymo įrenginiai, kuriais išvalytos nuotekos atitiktų LR nuotekų tvarkymo reglamento reikalavimus. Šiame straipsnyje analizuojamas dviejų mažo našumo (0,9 m3/d.) Lietuvoje gaminamų įrenginių efektyvumas šalinti iš nuotekų azoto junginius. Pastebėta, kad mažo našumo įrenginiais išvalytose nuotekose likdavo nedidelė amonio azoto arba nitratų azoto koncentracija, jų koncentracija priklauso nuo pradinės nevalytų nuotekų Kjeldalio azoto koncentracijos. Abu tirtieji įrenginiai azoto junginius iš nuotekų šalino 75–80 % efektyvumu, bendrojo azoto likutinė koncentracija (

Nuotekų valymo įrenginių veikliojo dumblo darbas gali būti projektuojamas, optimizuojamas ir vertinamas taikant matematinį modeliavimą. Šio darbo tikslas – ištirti ilgalaikius (10 mėn. trukmės) mažojo individualaus NVĮ darbo duomenis, rasti priklau-somybes tarp parametrų ir patikrinti, ar yra galimybė optimizuoti vykstančius nuotekų valymo procesus taikant įprastus ASM (angl. Activated Sludge Model) modelius. Modeliuojant svarbiausi yra trys kinetiniai ir stechiometriniai kalibravimo parametrai: maksimalus heterotrofinis mikroorganizmų augimo greitis, aerobinis endogeninis heterotrofinės biomasės kvėpavimas ir aerobi-nis heterotrofinės biomasės prieaugis. Tarp šių parametrų turi būti dinaminė pusiausvyra, veikliojo dumblo koncentracija įrengi-nyje turi būti pastovi ir optimali. Išanalizavus gautus duomenis paaiškėjo, kad mažo našumo NVĮ-102 aeracinėje kameroje išma-tuota veikliojo dumblo koncentracija nėra pastovusis dydis. Tyrimo metu ši koncentracija kito nuo 3 iki 6,9 g/l. Kintant veikliojo dumblo koncentracijai, kinta jo apkrova organinėmis medžiagomis (g BDS5/g dumblo sausosios medžiagos), tūrinė apkrova, grąžinamojo veikliojo dumblo debitas (m3/d.), grąžinamojo veikliojo dumblo koncentracija, grąžinamojo veikliojo dumblo pro-centinis kiekis, deguonies poreikis. Apibendrinus galima teigti, kad mažojo NVĮ darbui optimizuoti įprasti ASM modeliai nėra pritaikyti.

Nowadays, the problem of water pollution with phosphorus compounds is especially important. Wastewater treatment plants do not always meet the strict requirements for the residual total phosphorus concentration – 1 mg/l in the treated wastewater. Usually individual wastewater treatment plants have a poorer removal of phosphorus from the wastewater because they are more sensitive to fluctuations in wastewater flow and environmental conditions. Research results in the scientific literature shows that only 30–50% of the phosphorus is removed from the wastewater by conventional methods. Additional wastewater treatment is recommended for higher phosphorus removal efficiency achievement. One of the ways to remove phosphorus from wastewater is filtration through sorbents filter media. The efficiency of three sorbents – Filtralite P, foam-glass and crushed shells to remove phosphorus from biologically treated wastewater is investigated in this article. A phosphate phosphorus concentration was reduced by filtering wastewater through sorbents filter media during the experiment. Concentrations of treated wastewater pollutants, filtration rate, efficiency of sorbents to remove phosphorus from the wastewater were measured and evaluated. Experiment results showed that phosphate phosphorus was effectively removed by Filtralite P sorbent (removal efficiency 97–98%), less effective were foam-glass (removal efficiency 66–95%) and crushed shells sorbents (removal efficiency 39–50%). DOI: https://doi.org/10.3846/enviro.2020.620

Sludge digestion process can be optimized applying the methods of sludge disintegration. This article analyses the efficiency of the digestion process of disintegrated sludge by methods of ultrasound or high voltage in comparison to the digestion process of non-disintegrated sludge. The sewage sludge from two Lithuanian wastewater treatment plants as used for the research. Both wastewater treatment plants use analogous sludge treatment technology, in both of them the municipal wastewater is treated and the influence of industry on the quality of sewage is analogous. Due to this it has been assumed that the quality of excess sludge is also analogous. The results showed that both analysed methods of disintegration had the same effect on the increase of specific destruction of volatile solids (VSS) and increase of specific biogas production with the maximum values of 22% and 12–13% respectively. In case of digestion of disintegrated excess activated sludge applying both methods, the maximum methane content in biogas was 71.9%, whereas in case of digestion of non-disintegrated sludge it was 58.3% only. The total operation expenses and capital expenditures of ultrasonic disintegration method are more than 8 times higher comparing to the total expenses and expenditures of high voltage disintegration method.

Small individual household wastewater treatment plants not always operate well. Consequently, the concentrations of ammonium nitrogen and phosphate phosphorus are exceeded. The aim of the work was to examine the zeolite as a wastewater tertiary treatment material and propose environmentally friendly ways to solve fresh water problem. During experiment zeolite filter material was tested. In the article is analyzed zeolite filtering efficiency of nutrient removal from wastewater. Zeolite filler most effective was against ammonium nitrogen (99.9–10.1%) and relatively less effective against phosphate phosphorus (51.2–4.9%).

Net maži, individualūs buitinių nuotekų valymo įrenginiai turi būti efektyvūs ir salinti is nuotekų azoto bei fosforo junginius. Aplinkosauginiai reikalavimai griežtėja, nuo 2019 m. lapkricio mėnesio įsigalios Nuotekų tvarkymo reglamento pataisos, pagal kurias mažuosiuose (kurie per dieną isvalo iki 5 m3 nuotekų) valymo įrenginiuose bus privaloma is nuotekų pasalinti azoto junginius iki 25 mgN/l, o fosforo junginius – iki 5 mgP/l. Individualiais įrenginiais isvalomų nuotekų likutinė tarsa beveik nekontroliuojama, nėra sukaupta duomenų apie tokių įrenginių darbo efektyvumą. Reikalingi isvalytų nuotekų kokybės tyrimai ir jų analizė. Straipsnyje analizuojami keleto gamintojų (,,Traidenio‘‘, ,,Dinaito‘‘ ir ,,August‘‘) platinamais mažiausiais biologinio valymo įrenginiais pasiekiami nuotekų isvalymo rodikliai, esant realioms įrenginių eksploatavimo sąlygoms. Tiriami isvalytų nuotekų mėginiai (matuojamos ChDS, BDS7, nitritų azoto, nitratų azoto, amonio azoto ir fosfatų fosforo koncentracijos) bei įrenginių veiklusis dumblas (atliekama mikrobiologinė analizė). Tyrimų rezultatai lyginami su norminiais reikalavimais. DOI: https://doi.org/10.3846/aainz.2019.004

Lietuvoje apie 700 tūkst. gyventojų vis dar iš šachtinių šulinių tebevartoja geriamąjį vandenį, kurio kokybė neužtikrina saugaus jo vartojimo. 2017–2018 metais tirta Šiaulių miesto, rajono ir apskrities šachtinių šulinių vandens kokybė. Nustatytos geležies, fosfatų, fluoridų, chloridų, bromidų, nitritų, nitratų, sulfatų jonų koncentracijos ir bendrasis vandens kietis. Nustatyta, kad 60 % tirtųjų Šiaulių miesto ir apskrities šachtinių šulinių vandens kokybė pagal nitratų ir geležies jonų koncentracijas neatitinka HN 24:2017 higienos normos reikalavimų. Didžiausia geležies jonų koncentracija nustatyta Šiaulių rajone, sodų bendrijos šulinio vandenyje (214 μg/l), kur iš viso 10 % tirtųjų mėginių viršijo HN 24:2017 higienos normos reikalavimus. Šiaulių miesto gyventojai, vartojantys vandenį iš šachtinių šulinių, turėtų atkreipti dėmesį į vandens kokybę dėl didelės (daugiau, kaip 300 mg/l) nitratų jonų koncentracijos, iki 6 kartų viršijančios HN 24:2017 higienos normos reikalavimus. Gyventojams rekomenduojama aktyviau jungtis prie centralizuotų vandentiekio tinklų arba periodiškai tikrinti geriamojo vandens kokybę.

Siandien itin svarbi vandens tarsos fosforo ir azoto junginiais problema. Kai reikiamas nuotekų isvalymo lygis nepasiekiamas pagrindinio valymo grandyje, taikomas tretinis valymas. Straipsnyje tiriamas trijų sorbentų – gamtinio ceolito, kriauklelių ir Filtralite P – efektyvumas salinti is nuotekų biogenines medžiagas. Biologiniu būdu isvalytos nuotekos is eksploatuojamų įrenginių tirtos VGTU Aplinkos apsaugos ir vandens inžinerijos katedros laboratorijoje, jų tarsa amonio azoto bei fosfatų fosforo junginiais mažinta filtruojant per sorbcinius filtrų užpildus eksperimentiniame stende. Matuojamos ir vertinamos valomų nuotekų tersalų koncentracijos, filtravimo greitis, sorbcinių medžiagų geba sulaikyti NH4-N ir PO4-P. Atlikus eksperimentinius tyrimus nustatyta, kad fosfatų fosforą geriausiai salino Filtralite P užpildas (salinimo efektyvumas iki 70 %), o amonio azotą – ceolito užpildas (salinimo efektyvumas iki 95 %). DOI: https://doi.org/10.3846/aainz.2019.011

It is important to control not only the large wastewater treatment plants work, but also the work of individual small wastewater treatment plants for the protection of environment. Individual small wastewater treatment plants can become the local sources of pollution, when they are not functioning properly. Sewage purification indicators are not always the same as declared at wastewater treatment plants documentation in real conditions, so it is important to control the properly work of individual small wastewater treatment plants. The work of the small wastewater treatment plant AT-6 was analyzed by the treated sewage results (BDS7, SM, NH4-N, NO3-N, NO2-N, PO4-P), the quality of activated sludge, biological indicators and enzymatic activity in this article. The nitrification process was not going very well by the results of research, because there was the 72 mg/l concentration of ammonium nitrogen remaining in the cleaned wastewater. The morphological study of the activated sludge has confirmed the hypothesis that the necessary conditions for nitrification process were not established. The oxygen supply was increased and the small wastewater treatment plant functioning become more efficient, because nitrification process started working properly – there was less than 1 mg/l of ammonium nitrogen remaining in the cleaned wastewater. Santrauka Aplinkosaugos požiūriu svarbu kontroliuoti ne tik didelių, bet ir mažų, individualių nuotekų valymo įrenginių darbą. Maži nuotekų valymo įrenginiai, netinkamai veikdami, gali tapti vietiniais tarsos saltiniais. Gamyklinių įrenginių dokumentuose deklaruojami nuotekų isvalymo rodikliai ne visada pasiekiami realiomis sąlygomis, todėl reikalinga jų darbo kontrolė. Straipsnyje tiriamas mažo buitinių nuotekų valymo įrenginio AT-6 darbas (pagal isvalytų nuotekų BDS7, SM, NH4-N, NO3-N, NO2-N, PO4-P koncentracijas), vertinama veikliojo dumblo sudėtis, fermentinis aktyvumas. Tyrimų metu buvo pastebėtas nitrifikacijos proceso sutrikimas, dėl kurio is įrenginio istekanciose nuotekose amonio azoto koncentracija siekė 72 mg/l. Veikliojo dumblo morfologinės sudėties tyrimas patvirtino hipoteze, kad nitrifikacijai vykti reikalingos sąlygos nesudarytos. Issiaiskinus priežastis ir padidinus deguonies tiekimą, įrenginys ėmė veikti efektyviau ir is jo istekanciose nuotekose likdavo mažesnė nei 1 mg/l amonio azoto koncentracija. Reiksminiai žodžiai: veiklusis dumblas; buitinės nuotekos; individualus įrenginys; BDS7; SM; amonio azotas; nitratų azotas; ortofosfatų fosforas.

Hydrolysis-acidogenesis of primary sludge is a suitable method to produce readily biodegradable organic matter. Sludge retention time (SRT) is a significant technological parameter: when it...

The article analyses the results of ten months of operations of two small-scale wastewater treatment plants. Both wastewater treatment plants were one-block facilities, operating on the basis of activated sludge in accordance with the same technological scheme and having an identical hydraulic load. The difference between the plants was that one was 1.3 times smaller than the other, was better insulated and had a longer sludge retention time, with excess sludge having to be removed less often. The smaller plant purified waste more effectively in terms of the parameters of chemical oxygen demand, biochemical oxygen demand over five days, suspended solids, ammonium nitrogen, and total phosphorus. The efficiency level in regard to removing ammonium nitrogen in the small plant given the winter temperature conditions was high (98–99%). In the treated effluent, the amount of remaining ammonium nitrogen was just 0.1–0.6 mg/L. Helpful factors were the long sludge retention time and the concentration of activated sludge, which reached up to 6.5 g/L. Excess sludge was removed from the small plant only twice in ten months. The amount of phosphorus remaining in the treated effluent was on average 1.06 mg/L. Comparing the two plants, a 20% greater effectiveness in elimination of phosphorus (82%) was achieved in the smaller plant, which used four times less electrical energy. The analysis results are useful for the further improvement of small biological wastewater treatment plants.

The anaerobic sludge digestion is a widely used method for sludge stabilization in wastewater treatment plant. This process can be improved by applying the sludge disintegration methods. As the sludge disintegration is not investigated enough, an analysis of how the application of thermal hydrolysis affects the sludge digestion process based on full-scale data was conducted. The results showed that the maximum volatile suspended solids (VSS) destruction reached the value of 65% independently on the application of thermal hydrolysis. The average VSS destruction increased by 14% when thermal hydrolysis was applied. In order to have the maximum VSS reduction and biogas production, it is recommended to keep the maximum defined VSS loading of 5.7 kg VSS/m(3)/d when the thermal hydrolysis is applied and to keep the VSS loading between 2.1-2.4 kg VSS/m(3)/d when the disintegration of sludge is not applied. The application of thermal hydrolysis leads to an approximately 2.5 times higher VSS loading maintenance comparing VSS loading without the disintegration; therefore, digesters with 1.8 times smaller volume is required.

The demand for wastewater treatment plants purposed for a single household or groups of households continues to increase as the quality requirements for wastewater treatment become increasingly rigorous. Researchers are constantly searching for new methods to remove phosphorus compounds from wastewater that do not require the use of chemicals. This article describes a newly designed tertiary wastewater treatment unit that increases the effectiveness of the main small-scale (up to 1 m3/d) biological wastewater treatment unit. The tertiary treatment unit is filled with the sorbent material Filtralite P., after the main treatment wastewater flows through the filler without the use of electric power. A compact system consisting of a main (secondary) treatment unit and the newly designed tertiary wastewater treatment unit was tested in accordance with the harmonised European Standard EN 12566-3. During the testing period, no surplus sludge was discharged from the system, no reagents were dosed into it, the system only consumed 119 kW of electric power, and the treated wastewater contained

With stricter requirements for wastewater treatment, small-scale individual wastewater treatment plants can provide a financially attractive alternative to a sever connection in locations far from the existing sewer network. Systems operating under the basis of active sludge are considered advanced, and their producers declare high levels of wastewater treatment not only according to BOD, but also under biogenic materials. However, there are hardly any data on how small-scale individual household wastewater treatment facilities operate. This article presents an analysis of the main parameters of wastewater biologically treated in three small-scale household wastewater treatment plants (which operate under the basis of active sludge), namely TSS, COD, BOD7, Nt, NO3-N, NH4-N, Pt, and PO4-P concentrations. The research lasted for 5.5 months during a cold period. According to TSS, COD, and BOD7 concentrations in effluent, the wastewater treatment level in the study plants was good. The concentrations of these substances in effluent (TSS

Petroleum products that have leaked into the natural environment are very hazardous. They are particularly dangerous for aquatic ecosystems. The major part of oils is carried into natural water bodies together with the surface outwashes from urban areas. One of the most inexpensive and easiest methods of the removal of oil contaminants from runoff is filtering. The authors of this study examined several synthetic substances (Duck and Reo-dry), and several vegetal materials (shredded stems of reeds, bulrush and lesser bulrush) and compared their filtration characteristics with the characteristics of the synthetic substance Fibroil now widely used for filtration. The authors of this study feel that the materials tested are suitable for the petroleum removal filter medium. Industrialists submit specifications of their products that were recorded under ideal conditions, at a low filtration rate. The authors studied filter material of natural origin as well as synthetic ones by simulating actual condit...

The tertiary wastewater treatment experiment was performed on the experimental stand which was installed in a wastewater treatment plant and which consisted of three filters of the diameter of 380 mm with a non-submerged media. Biologically treated wastewater was constantly supplied to these filters. Tertiary wastewater treatment process was aggravated due to low temperature of wastewater (6 °C) and high fluctuations of load according to individual pollutants – the difference between the minimum and maximum values ranged from 3 to 10 times. The productivity of removal of pollutants according to individual contamination rates reached 8 to 43%.

One of the reasons for inefficient wastewater treatment is easily degradable organic material shortages. Hydrolysis increased readily biodegradable organic matter content is beneficial - sewage cleanup by all indicators become more efficient. The primary sludge hydrolysis take place the conditions necessary for the installation of the pumps allows wastewater treatment plants and precipitator while keeping the original sludge in it for 6-8 days. Preliminary experimental in one of the treatment plant primary settling tanks, installation of pumps, has been given appropriate hydrolysis conditions: hydraulic load q ~ 1.3 m 3 /m 2 /h, sludge age ~ 6 days, the temperature about 15° C, pH of approximately 8. Effluent after hydrolysis of COD concentration was 17%, and BOD 5 concentration - 18% higher than runoff from the normal working (without hydrolysis) settler. Waste water from the settling tank (with hydrolysis) obtained higher (better) COD and BOD 5 relationship with phosphorus and nitrogen compounds than the effluent from the settling tank which worked without hidrolysis. Preliminary studies have shown good results in the future to continue the true primary sludge hydrolysis optimization experiments. DOI: https://doi.org/10.3846/enviro.2017.076

The article analyses Lithuanian rivers, 32 of which have been selected as non-complying with the require-ments of good condition. Furthermore, 15 discharge facilities that discharge wastewater to the aforementioned rivers from agglomerations with population equivalent (PE) greater than 2,000 have been selected. The assessment of the quality of treated wastewater according to the allowable impact on the reception facility has been carried out and has been compared with the currently regulated minimum allowable values of concentrations of pollutants. The analysis of the impact of quality of treated wastewater on the ecological status of rivers has been presented. It has been established that the pollution of rivers would be decreased by an average 8% (organic pollutants and total nitrogen) and by 22% (total phosphorus), if the allowable concentrations of pollutants according to the impact on the reception facility were ensured in the analysed treatment plants with PE greater than 10,000.

Globalization of nowadays education and science promoted by various international programmes provides with unique opportunities to renew some old educational approaches connected with linear application of education within higher educational institutions in Lithuania. Nowadays Nature science development confirms fact, that there are more approaches to reality, than finding the only one epistemological truth. In parallel there are several aspects, dimension of the same truth in the complex systems of the reality. Educational process regarding its complexity largely belongs to the complex, non- liner, opened and non-reversal systems. That's why we must be focused on the dynamics of educational components rather than on its components alone, that are at the second rate of importance. Those relations have influence on the whole system change largely. That is the reason why authors employ the theory of Synergy, that‘s focused on such kinds of relations. Authors explore the roots of Synergy theory its approaches of application in Educational systems. Project-based learning is kept as one of active forms in the complex education systems. There are emphasized problem solving competences in project-based learning, the synergy of separate cognitive steps in learning process that are reflected in two higher educational institutions within bachelor degree students in Vilniaus kolegija/University of Applied Sciences and master degree students in Vilnius Gediminas Technical University. Peculiarities of Project- based learning are revealed through review of problem solving application methodology to promote students ‘cognitive and meta-cognitive skills, connected to decision making, social, group working skills. Authors emphasize on College level students ‘shortages of competences related to finding the right information, structuring of problems components, modelling of project solving strategy. This reveals students paternalistic manner of thinking that impede learning process due to the lack of habits of thinking systemically. That shows shortage of applying innovative educational methods in the College. Respectively, educational experiment revealed, that Master degree students in the University demonstrated much higher achievements in operation of cognitive and meta-cognitive competences in completing problems solving tasks, what demonstrated their success in whole project implementation more, comparing to the Colleges‘ones. Authors of this work emphasize the importance of treating all students across the different subjects with problem based learning methodologies in order to improve project implementation skills in Higher educational institutions.

Tirtas biologinio valymo įrenginio AT-6 darbas žiemos laikotarpiu, oro temperatūrai svyruojant nuo –23 iki +6oC. Nustatyti šiuo įrenginiu pasiekiami pagrindiniai nuotekų išvalymo rodikliai (ChDS, BDS7, SM, N bei P junginių koncentracijos). Tuo lai-kotarpiu buvo imami ir tiriami veikliojo dumblo mėginiai. Tyrimų laikotarpiu analizuotame įrenginyje išvalytų nuotekų BDS7 koncentracija nė karto neviršijo 17 mg O2/l. Žiemos sąlygomis organiniai teršalai (pagal SM, ChDSCr, BDS7,) iš nuotekų buvo išvalomi 2–5 % geriau, nei deklaruoja įrenginio gamintojai. Azoto bei fosforo junginių šalinimas nebuvo efektyvus. Iki –17– –23oC naktimis atvėsdavęs oras neigiamai veikė jautrių nitrifikuojančiųjų bakterijų veiklą, todėl sutriko nitrifikacijos procesas.

Tirtas mažų buitinių nuotekų valymo įrenginių (AT-6) darbas. Tyrimo metu nustatyta, kokios tersalų koncentracijos lieka isvalytose nuotekose. Atlikta veikliojo dumblo mikroskopinė analizė. Tyrimų laikotarpiu visuose tirtuose įrenginiuose efektyviai (>95 %) is nuotekų buvo salinami SM bei BDS7 rodikliais apibūdinami tersalai. BDS7 rodiklis isvalytose nuotekose nevirsijo 17 mg O2/l ir buvo 2 kartus mažesnis už vidutine metine DLK mažosioms (iki 5 m3/d) nuotekų valykloms. Tiriamieji įrenginiai užtikrino aplinkosauginiais norminiais dokumentais reikalaujamą valytų nuotekų kokybe. Mikroskopinė veikliojo dumblo mėginių analizė patvirtino nuotekų valymo įrenginiuose rezultatus. Vieno įrenginio darbas buvo sutrikes dėl erlifto užsikimsimo, todėl tuo metu azoto junginiai nebuvo efektyviai salinami is nuotekų. DOI: https://doi.org/10.3846/aainz.2016.09

Water samples were collected from Vilnius drinking water distribution system fed by treated and different groundwater. Parameters related to bacterial growth have been measured considering these samples: temperature, concentration of free residual chlorine, ammonium, nitrates and nitrites. Results showed that treated groundwater was less susceptible to favour bacterial growth in the pipelines. The obtained results also showed that the potential growth induced by the distribution of treated water could be reduced if: ammonium levels were below 0.5 mg/l at the outlet of the water treatment plant; biological ammonium removal treatment implementation should reduce the levels of the nitrates and nitrites of the treated supplied water. Article in Lithuanian

In Lithuania centralized municipal wastewater treatment technologies are applied quite effectively, but there is little evidence of the functioning of individual small wastewater treatment plants. The paper presents the small device AT-6, in the city of Vilnius, and the treated sewage results (BDS7, nitrate, ammonium, total nitrogen, total phosphorus and phosphate concentrations). Studies have shown that treated sewage indicators based on ammonium and nitrate ion concentrations are good. These substances are 2–10 times less than it can be in drinking water according to HN 24: 2003. Concentration of phosphates in the treated sewage ranged from 3.57 to 9.33 mg/L and exceeded the indicators, which were compared. The phosphorus environmental aspect is not dangerous, because treated sewage is not discharged into surface water bodies. Dealing from the pattern of biological indicators and enzymatic activity, the quality of activated sludge is good. Treated sewage does not impair the natural state. Santrauka Lietuvoje centralizuoto buitinių nuotekų valymo technologijos yra taikomos gana efektyviai, tačiau beveik nėra duomenų, kaip veikia maži individualaus buitinių nuotekų valymo įrenginiai. Straipsnyje analizuojami mažu buitinių nuotekų biologinio valymo įrenginiu AT-6 pasiekiami pagrindiniai išvalymo rodikliai (BDS7, nitratų azoto, amonio azoto, bendrojo azoto, bendrojo fosforo ir fosfatų fosforo koncentracijos). Nuotekų išvalymo laipsnis pagal amonio azoto ir nitratų azoto koncentracijas yra aukštas. Šių medžiagų yra 2–10 kartų mažiau, nei gali būti geriamajame vandenyje pagal HN 24:2003. Fosfatų fosforo (PO4-P) koncentracijos išvalytose nuotekose svyravo nuo 3,57 iki 9,33 mg/l ir viršijo rodiklius, su kuriais buvo lygintos. Šis fosforas aplinkosaugainiu aspektu yra nepavojingas, nes nuotekos nėra išleidžiamos į paviršinį vandens telkinį. Sprendžiant iš rastų biologinių indikatorių ir fermentinio aktyvumo, veikliojo dumblo kokybė yra gera. Išvalytos nuotekos nepablogina gamtos būklės. Raktiniai žodžiai:buitinės nuotekos, mažas namų ūkio įrenginys, biologinis valymas, BDS7, nitratų azotas, amonio azotas, fosfatų fosforas, veiklusis dumblas.

Straipsnyje analizuojami individualaus buitinių nuotekų biologinio valymo (IBNV) įrenginiu pasiekiami pagrindiniai išvalymo rodikliai (BDS7, nitratų azoto, amonio azoto ir fosfatų fosforo koncentracijos). Tiriamas Vilniaus mieste esantis, mažų valymo įrenginių grupei priklausantis AT-6, kurio projektinis našumas 0,54 m3 /h, vidutinė apkrova teršalais – 0,24 kg BDS5/d. Tyrimai parodė, kad išvalytų nuotekų BDS7 koncentracija nė karto neviršijo 17 mg O2/l, o tai yra aukštas išvalymo rodiklis (du kartus mažesnė koncentracija, nei vidutinė metinė DLK mažosioms (iki 5 m3 /d) nuotekų valykloms. Pagal nitratų azoto ir amonio azoto koncentracijas yra pasiekiamas aukštas nuotekų išvalymo laipsnis. Šių medžiagų yra 10–11 kartų mažiau, nei gali būti geriamajame vandenyje pagal HN 24:2003 (tai svarbu, nes valytos nuotekos yra infiltruojamos į gruntą ir gali užteršti gruntinius vandenis). Fosfatų fosforo (PO4-P) koncentracijos išvalytose nuotekose buvo 2–3 kartus didesnės, nei nurodomos bendrojo fosforo DLK didesnėms (nuo 5 m3 /d iki 10000 GE) valykloms (2 mg/l). Šis fosforas aplinkosauginiu aspektu yra nepavojingas, nes nuotekos nėra išleidžiamos į paviršinį vandens telkinį. Likutinės 3,6–6,6 mg/l PO4-P koncentracijos išvalytose nuotekose gali būti paaiškinamos ilgu veikliojo dumblo amžiumi (30 parų) ir retu (1–2 kartai per metus) perteklinio dumblo pašalinimu iš įrenginio. Bendrai tirtasis įrenginys pagal išmatuotus rodiklius aplinkosauginiu požiūriu yra saugus ir išvalytos nuotekos nepablogina gamtos būklės.

The capability of organic (plant) sorbents: Club-rush and Lesser Bulrush (from the lake shore) for removal of petroleum products (PP) from runoff was investigated. Dynamic process was investigated using filters packed with these materials. The third material analysed, synthetic sorbent Fibroil, was chosen for comparing the results. The laboratory experiments were performed in two stages, with the following being filtrated: tap water with a diesel admixture, road runoff contaminated with PP, and also suspended solids. The significance of this work is due to high runoff filtering rate (~10 m/h) and high PP concentrations in the runoff (>50 mg/L) used in the experiment. In these cases the use of sorbents is limited. Schoenoplectus lacustris and Typha angustifolia fillers are quite efficient (92–98%) in PP removal from runoff at a 10 m/h filtering rate. Use of them for filtration was possible longer than Fibroil, it clogs up quickly. Schoenoplectus lacustris and Typha angustifolia are a natural source for the production of PP sorbents. The results obtained in this experimental work can be used in the design of equipment for the treatment of PP contaminated runoff.