HYDROPHYTE WATER PURIFICATION UNDER CONDITIONS OF “ ZHYTOMYRVODOKANAL ” COMMUNAL ENTERPRISE

58 Biological purification is the most common way for removing organic substances from municipal wastewater [1]. Biological wastewater treatment plants are about 55% of the total number of treatment facilities [2]. In recent decades, there is a tendency of the urban wastewater quality changes due to the increase of nitrogen and phosphorus containing organic substances proportion, of heavy metals concentrations, synthetic surfactants, etc. Many biological sewage treatment plants were designed in 50 years of the last century and meet the environmental standards of that time, thus at present time for technical reasons they cannot provide the compliance of maximum allowable discharges of pollutants into natural water bodies [2]. The actual effectiveness of treatment of urban wastewater from nutrients in biological treatment plants does not exceed 20–40% for phosphates and 30–90% for ammonia nitrogen [1]. Revenues of biogenic elements into the natural reservoir in concentrations that exceed the maximum allowable ones cause the water body’s europhication and death of aquatic flora and fauna. In this context the development of methods and technologies aimed at the reduction of biogenic elements content during the municipal wastewater biological purification process becomes relevant. According to the literature data the higher aquatic plants (HAP) use is the biogenic elements removal effective method [3–5]. There is information about the use of separate HAP in technological process of municipal wastewater biological purification [6–9]. The significant amount of aquatic and coastal aquatic plants is characterized by high phyto-meliorative effects, as well as they are an excellent juicy fodder for animal nutrition [10]. At the same time the removal patterns of pollutants based on technical parameters are not provided by literature, there is no information about HAP selection and their use under climatic conditions of Zhytomyr region, there is not enough information about UDC 504.064.3:574 (477.42) https://doi.org/10.15407/biotech9.06.058

Biological purification is the most common way for removing organic substances from municipal wastewater [1].Biological wastewater treatment plants are about 55% of the total number of treatment facilities [2].In recent decades, there is a tendency of the urban wastewater quality changes due to the increase of nitrogen and phosphorus containing organic substances proportion, of heavy metals concentrations, synthetic surfactants, etc.Many biological sewage treatment plants were designed in 50 years of the last century and meet the environmental standards of that time, thus at present time for technical reasons they cannot provide the compliance of maximum allowable discharges of pollutants into natural water bodies [2].The actual effectiveness of treatment of urban wastewater from nutrients in biological treatment plants does not exceed 20-40% for phosphates and 30-90% for ammonia nitrogen [1].Revenues of biogenic elements into the natural reservoir in concentrations that exceed the maximum allowable ones cause the water body's europhication and death of aquatic flora and fauna.
In this context the development of methods and technologies aimed at the reduction of biogenic elements content during the municipal wastewater biological purification process becomes relevant.According to the literature data the higher aquatic plants (HAP) use is the biogenic elements removal effective method [3][4][5].There is information about the use of separate HAP in technological process of municipal wastewater biological purification [6][7][8][9].The significant amount of aquatic and coastal aquatic plants is characterized by high phyto-meliorative effects, as well as they are an excellent juicy fodder for animal nutrition [10].
At the same time the removal patterns of pollutants based on technical parameters are not provided by literature, there is no information about HAP selection and their use under climatic conditions of Zhytomyr region, there is not enough information about technical devices for HAP placement on the biological wastewater treatment plants.Therefore the research of growth conditions, the issue of number regulation and Eichhornies practical application use opportunities causes significant economic interest.Considering high nutrients content these plants can be included into the farm animals' nutrition actions as valuable nutritional feed.
The aims of the conducted research are hydrophyte water purification method testing, water purification effect determination, determination of the allowable loads of the most toxic pollutants on higher aquatic plants under conditions of modeling laboratory systems and determination of advanced ways of processed phytomass use.

Materials and Methods
Representatives of various HAP groups belonging to different plant divisions were selected as test objects for research.There are water surface free-floating representatives among them: Eichhornia crassipes (Mart.)Solms (fam.Pontederiaceae) and Pistia stratiotes L. (fam.Araceae).The object choice was caused by in vitro and in vivo cultivation opportunity.All listed test facilities were previously successfully used for phyto-meliarative purposes [3,[5][6][7][8].Plants were selected from populations fed in artificial reservoirs of the Botanic garden of Zhytomyr National Agroecological University (Fig. 1).
The industrial experiment planning was conducted according to the methodology of Gorski [11].Plants were placed into the model installations (with 0.25 m 3 capacity), in which the water coming on the pumping station of the first lifting of "Zhytomyrvodokanal" Communal Enterprise was loaded.
Laboratory model systems containing the hydrophilic load were used by conducting of the experiments.Each model system contained plants of one HAP species and one variant with the mixed phytocoenoses of two types.The total biomass of the plants placed (raw weight) was 30-50 g (E.crassipes) and 10-20 g (P.stratioites) for 1.5 l of water.
In the experiments with hydrocoles use the water amount was 200 l.In the experiments the plants number was calculated so that the phytomass amount in all the variants was approximated.Each model system contained plants of one HAP species as well as of their grouping.The variant without plants was taken as for control (Fig. 2).
These studies were carried out to obtain information concerning the resistance of the HAP species used to pollutants contained in natural waters coming on the pumping station of the first lifting of "Zhytomyrvodokanal" Communal Enterprise, as well as to determine the influence of hydrocoles on physical and chemical properties of the quality of the water studied.
The duration of the experiments ranged from 0 to 40 days depending on the timing of influence signs of substances on the plants vitality.Every 10 days during the research period the water samples were selected in accordance with the methodology [11,12] to determine their physical and chemical composition.
Physical properties and chemical composition of wastewater before and after the cultivation of P. stratiotes and E. crassipes were determined by unified Y. Lurie methodology (1984) [13], as well as generally accepted methods.The water temperature was measured by a thermometer at the moment of sampling in situ.Color and smell

Results and Discussion
Significant seasonal temperature variations -from 0.1 to 30 С in average are inherent for the Zhytomyr region water surface.During the research considering the relatively hot period (July-August 2015) the highest water temperature of the Teteriv River was recorded from 12 th to 15 th August at the 25 С, the lowest during periods from 1 st to 4 th July, from 13 th to 18 th July and from 20 th to 23 rd August at the 19 С.In such hot periods of the year, as July-August 2015, natural waters, especially surface ones, are seldom transparent.Given this in our opinion the most important water indicator index of turbidity and chrominance appeared, and its smell.The water turbidity control is very important and also from a toxicological point of view.So in the river waters with moderate turbidity the vast majority of aluminum is located in suspended condition, more than 90% of lead, 30-35% of arsenic and cadmium, and more than 20% of mercury [2].
Under research conditions when loading water in biofilters it was defined as "turbid".10 days later the water turbidity reduced significantly and this water could be characterized as "little turbid".In the next weeks, water quality for this indicator improvement was observed and by the end of the experiment, water was characterized as "clear" (Fig. 3).
While water selection and before their loading wastewater was characterized by the IV score smell (distinctive smell that draws attention; can force to refrain from drinking).After 10 days of hydrocole in bioreactors residence, the smell decreased by two points to the II score.By the end of experiment, it was characterized as faint smell with the score -I, so the hydrophyte purification use had a positive trend on the turbidity and unpleasant smell indexes reduce.
The content of suspended particles (SP) under experimental conditions during the whole research period had a tendency to decrease, particularly in the first 10 days of the experiment their content in N1 option cultivating hydrophytes E. crassipes (Mart.)Solms species, decreased by 10%; in option N2 with growing hydrophytes P. stratiotes L. species by 13%; in mixed phytocoenoses (option N3) -only 3%.But during the next sampling after a 10-day period indicators for all options almost had been leveled and constituted 16-11% of their original content (Fig. 4).At the time of the experiment completion the greatest general suspended SP content decrease was shown by the option N2 with P. stratiotes L. -30%, slightly loweron option N1 -27%, and even lower SP removal rate appeared on option N3 -22%.On the control check SP decrease almost was not recorded that constituted only 3% of its initial value.
Therefore the positive trend by the SP exclusion indicator when using the hydrophyte purification was observed, in particular their con tents decreased by 22-30% compared with control check.
In addition to the organoleptic indicators basic groups (physical-organoleptic), while conducting research we paid attention to a group of chemical and organoleptic indicators.The active water reaction is one of the most important its quality indicators that determines the nature of chemical and biological in natural waters and wastewater treatment facilities processes implementation.While hydrocole on wastewater sewage treatment facilities cultivation water, рН in all the studied period was 7.0-7.9that corresponds to the maximum permissible criteria values.However in options with hydrobionts use in first 10 days of experiment implementation we observed movement of the рН to the left to the waste water neutralizing direction (Fig. 5).
After 10-day periods overcome the pH value began to shift to the right and in 24-25 days (option N1 and N3) crossed its initial value and began to shift to the right.However, it should be noted that at the end of the experiment this indicator in the studied waters meets the requirements that exist to the drinking water reservoirs points' water composition and properties (6.5-8.5).In option N2, unlike the other options, towards neutralization recession have not taken place (10 days period), but at the moment of experiment conclusion pH indicators were virtually identical to the value obtained in option N1.Such intensive indicators variation while control was not found, obviously this is related to the less intensive biochemical processes which took place there.
In addition to pH indicator we observed the general alkalinity indicators.As in the majority of natural waters including Communal Enterprise "Zhytomyrvodokanal" first water intake, carbonate compounds are dominating (mainly НСО 3 -ions), we took into account only hydrocarbonate and carbonate alkalinity (Fig. 6).
During the entire experiment conduction period water alkalinity had a tendency to minor fluctuations.Only in the first option this indicator fluctuations were the most  visible.In particular, in the first 10 days of experiment implementation the alkalinity indicator increased from 3.4 ± 0.10 mf (mean frequency)-eq/dm 3 to 4.8 ± 0.10 mf-eq/dm 3  however, within the next 20 days it reduced again to a 3.2 ± 0.10 mf-eq/dm 3 value, and then to the end of the experiment again increased to the 4.0 ± 0.10 mf-eq/dm 3 mark.Such alkalinity fluctuations were observed on other options.The highest alkalinity value was recorded in the option N3 with mixed phytocoenoses after a month of beginning of the experiment -4.4 ± 0.10 mf-eq/dm 3 .The alkalinity value ranged slightly less on the control; however, the instability tendency persists there during the whole research period.Therefore, we can assume that the hydrocole in biological treatment facilities presence does not significantly affect this index dynamics.
The nitrogen and phosphorus content has got special importance for biological wastewater purification.All forms of nitrogen compounds deep removal, as well as their content in wastewater is always high, task is set for wastewater purification facilities [1].In household wastewater before its purification, oxidized forms of nitrogen (nitrites and nitrates) are absent as usually [1,2].The anaerobiosis processes when wastewater is transported by the water disposal system, bacteria activities that denitrify the oxidized forms of nitrogen to the molecular forms can explain wastewater impurities denitrification.The oxidized nitrogen forms appear after biological wastewater purification indicating the full process completeness.That is why we performed complex, taking into account possible nitrogen content forms transformation processes, nitrogen exchange indicators analysis.
Based on the results of our research, the nitrogen metabolism indicators had significant fluctuation tendency throughout the research period, which is quite typical for biological purification facilities (Fig. 7).Obviously, this is due to high ammonia nitrogen content (0.79-0.83 mg/l) at the beginning of the experiment and its conversion from ammoniac to nitrite and, subsequently, to nitrate forms.The ammonia content decrease was especially appreciable while E. crassipes (Mart.)Solms cultivation (option N1).The most intense ammonia nitrogen oxidation was observed in the first 10 days of experiment, during this period about a third of its total content collapsed -38% (option N1), 28% -option N2 and 21%option N3.It should be noted that ammonia content remained practically unchanged during the control.So while E. crassipes (Mart.)cultivation the ammonia value decreased more intensively than while Р. stratiotes L. and both cultures mixed phytocenosis cultivation.
Fig. 8 proves nitrogen ammoniac forms intense oxidation while hydrophyte purification.The sharp increase of nitrate ions concentration after a 10-day period is closely connected with nitrogen ammoniac forms concentration decrease.As we see on graphics, oxidized forms appearance for all options with hydrobionts is almost equal.In the first 10 days of nitrite ions content indicators variation was within 10%, but from 10 th to 20 th day nitrites amount increased by 6.6-8.75 times.The amount of nitrates increase for all options lasted about a month and further their contents started to decrease that demonstrates oxidized forms by hydrobionts assimilation which they took in the purification process.Over the last 10-days period (from 30 th to 40 th day) the nitrite amount decreased by 14-15%.In the control starting from the 10 th day nitrite concentration increased at significantly lower pace in comparison with hydrophyte purification options (only by 3 times).The nitrates amount decrease tendencies at the end the experiment were not observed.In general, under control nitrates concentration increased by 4.5 times.
We also closely associate appearance of nitrates under hydrophyte purification conditions with nitrogen ammonium and nitrate forms conversion because on the second phase of autotrophic nitrification the nitrite ions are oxidized with the help of microorganisms -Nitrobacter, Nitrospina, Nitrococcus into the nitrate ions [1].As we see on Fig. 9 in first 10 days of experiment conclusion phosphates exclusion on all the options was approximately on the same level, 86% -on option N2, slightly lower than this indicator appeared on option N1 and N3 -83 and 82% respectively.
On the control phosphates content varies insignificantly and decreased in the first 10-20 days of the experiment by 4%, phosphates content changed only by 7%, which is 75-79% less than on hydrophyte purification options.
To characterize the water under experiment conditions we also determined dichromate oxidation (Fig. 11).Because, it in comparison with permanganate oxidation, more accurately describes the organic pollutants content as potassium dichromate oxidizes about 90% or organic substances of those present in the water including hard oxidative.Under the experiment conditions chemical oxygen demand (COD) indicator (dichromate oxidation) provided by hydrophyte purification in all options tended to decrease.Moreover, dichromate oxidation decreased most intensively during the period between 10 th to 20 th day -42%, further the process intensity decreased and before the end of the experiment COD decreased by 55% on option N1.
This indicator decreased slightly faster on option with Pistia during the period from 10 th to 20 th day use -45% however, the final indicator was lower in comparison with option N1, mixed phytocoenosis (option N3) the influence on COD decrease was the lowest -41% -during the period from 10 th to 20 th day and 47% at the end of the experiment.Also on the control COD had a decrease tendency but this process occurred at extremely low paceonly 7% during the period from 10 th to 20 th day and only 10% at the end the experiment was observed.
Biochemical oxygen demand (BOD) during the period of the experiment had a similar trend with COD indicator fluctuations (Fig. 12), in particular significant variation of this indicator was not observed in the first 10 days of the experiment conduction.But, from 10 th to 20 th day on all hydrophyte purification options a sharp decrease of this indicator was observed: from 4.6 ± 0.46 mg О 2 /l to 2.26 ± 0.226 mg О 2 /l that is 53% from its initial value on the Eichhornia option (N1); from 4.5 ± 0.451 mg О 2 /l to 2.5 ± 0.254 mg О 2 /l that is 46% from its initial value on the option with Pistia (N2); from 4.4 ± 0.443 mg О 2 /l to 2.3 ± 0.235 mg О 2 /l that is 45% from its initial value on the option with both cultures mixed phytocoenoses (N3).
Starting from 20 th day of experiment BOD5 conduction the water was not practically changed and remained at previous level.Only on N2 option a further slight decrease of this indicator was observed and at the end of the experiment its general decrease reached 50%, which is 3% lower than in N1 option.On the For both indicators (COD and BOD5) there is a positive trend concerning water quality improvement.Despite presence of hardly oxidizing organic compounds in water, experimental biological purification facilities hydrophyte loading reduced the value of these indexes by 40-53%.In this case, we can recommend including the preliminary hydrophyte purification into the waste water purification technology.
The general iron is the important indicator especially while the wastewater analysis.Under the experiment conditions in the first 10 days concentration of iron on all the hydrophyte purification options, except the control one, decreased (Fig. 13).The most intensively this process took place on option N2 with Pistia -17%, and from 10 th to 20 th day the iron removal process intensity increased and was 43%, at the end the experiment general iron concentration decreased by 53%.
Slightly lower iron removal process intensity was observed on option N1 with Eichhornia use, in first 10 days concentration of iron decreased by 16%, from 10 th to 30 th day about 39% was extracted, iron content at the end of research decreased more than by a half (52%).
Some slightly lower iron removal process intensity was observed on option N3 with mixed phytocoenoses only 10% in first 10 days, in next 20 days iron content decreased only by 22% which represents one fifth, at the end of research with mixed phytocoenoses a little more than a third of total iron content was extracted (38%).
Iron concentration varied a little on the control, only by 2% in first 10 days of research.After the end of research iron content decreased General water mineralization decreased quite slowly during the hydrophyte purification process and in the first 20 days of conducted research mineral share content decrease was only 6-7% on the hydrophyte purification options and only 2% on the control (Fig. 14).
At the time of the experiment completion dry residue content decrease on the hydrophyte purification options was about at the same level and constituted 11-12%.This indicator changed only by 3% on the control that is 7-8% less than on the hydrophyte purification options.
To substantiate the dry residue in drinking tap water normative primarily we need to consider its influence on organoleptic properties.
Chlorides and sulfates content remains virtually unchanged in urban wastewater treatment plants and their concentrations in wastewater do not have significant values neither for physicochemical, nor for biological water purification processes.The microorganism existence threshold was discovered during the research: 150-300 mg/l for urban sewage.
Chlorides content variation was insignificant under the experiment conditions.Water hydrophyte purification use did not significantly affect the chlorides content indicator (Fig. 15).
During the entire research period their content decreased only by 11% on option N1 with hydrophyte purification load by E. crassipes (Mart.)Solms species, slightly lo wer on the option with mixed phytocoenoses -10%, on the option with Р. stratiotes L. chlorides content decrease was within 9%.Sulphates concentration may vary only under anaerobic conditions while wastewater treatment in two tiered sediment bowls and sludge in methane tanksfermentation.This sustainability can be a kind of the executed analysis accuracy level controller.Sulfates in water concentration also had a slight decrease tendency during the conducted research period (Fig. 16).
On option N1 with E. crassipes (Mart.)Solms use in first 10 days of experiment sulfates concentration decreased by 18% and then their content was stabilized and before the end of the experiment remained at the same level.On option N2 with Р. stratiotes L. use sulfates concentration varied slightly less, 17% in total.Nevertheless, their removal process was slower, only 10% in first 10 days.Mixed phytocoenoses on option N3 use caused sulfates concentration only by 5% decreased during first 20 days of conducted experiment and at the time of experiment completion sulfates concentration decreased by 10% from its general initial content.
Sulfates decrease by 5% on the control occurred on the 20 th day of conducted experiment, but at the time of experiment completion their concentration returned to the initial level.
Therefore, as for sulfates content decrease, hydrophyte purification also had a positive trend compared with control.
Phosphates nitrites, ammonia nitrogen high concentrations are the most acute problem at wastewater treatment caused by modern synthetic anionic detergent anionic surface active substances (ASAS) composition use that are presented in the Ukrainian detergents market.
In the studied waters ASAS was detected in the concentration of 0.1 mg/dm 3 .Water in the bioreactors load showed positive trend to this indicator improvement.
The best biopurification process took place in the option of E. crassipes (Mart.)Solms species were ASAS content decreased by 40% during the first 10 days of experiment.ASAS content decreased twice in option N1; it occurred on the 30 th day of conducted research and before the experiment completion their concentration decreased by 60%.On options N1 and N2 in the first 10 days ASAS were removed only by 20-22%, at the moment of the experiment completion ASAS concentration decreased by 40-44% in general.This indicator decrease on the control without hydrocoles practically does not occur during a month period, however, at the moment of the experiment completion, 10% of them had oxidized as a result of natural physical and chemical processes (Fig. 17).
Aquatic plants biomass could be used not only as wastewater meliorant but also in different economic sectors -as a feed additive food for livestock and poultry.We have analyzed the biochemical composition of aquatic plant mass that was used in wastewater purification processes.Furthermore, biomass biochemical composition varies greatly in different parts of plants, therefore, the composition water surface and underwater plants parts were monitored simultaneously.
E. phytomass is characterized by a fairly high nitrogen content.This is one of the key elements -organogenes, its plant tissues content is usually about 1.5% of dry substance, however in Eichornia green mass Fig. 16.Sulfates content under hydrophyte purification concentration change its content was higher -2,69 ± 0,019% and 2,48 ± 0,112% -in the roots (Table ).Phosphorus in green mass and roots content also had minor differences -0.74 ± 0.002% and 0.87 ± 0.011% accordingly.
Potassium in studied plants content did not deviate from conventional indicators.In general, the majority of plants are characterized by a high potassium content (0.9-1.2% of plant tissue dry mass) and it also did not exceed 2% in water hyacinth phytomass content during the studied period.While this minimum general potassium content indicators are typical for underwater part -0.46 ± 0.044% and maximal -for green mass -1.93 ± 0.004%.
Fairly high content of ash elements is inherent for Eichornia phytomass, their higher land part content is 17.68 ± 0.832% of dry substance, which is 2.3% more than in the roots.
Calcium content in Eichornia organs in different options is less variable in both cases.In leaves and roots its content was at the level of 1.86-1.87% of dry substance.However, it should be noted that in comparison with other plant species, where calcium content usually was at the 0.02% level, Eichornia has got almost 9 times more of it.Regarding the cellular tissue plant phytomass distribution their high concentrations in both leaves should be noted -18.19 ± 1.020%, as well as in the roots -21.82 ± 1.440%.

Fig. 1 .
Fig. 1.Places for selection of plant material for conducting plants phyto-meliarative properties research: lake of the Botanic garden of Zhytomyr National Agroecological University

Fig. 3 .Fig. 4 .
Fig. 3. Water turbidity during the period of the experiment with hydrophyte purification dynamics At the start of experiment Through 20 days of the experiment Through 10 days of the experiment