CC BY
31
UDK 621.317.08
RENDERING SURFACE RUNOFF HARMLESS IN STATIONARY PETROL
STATION DESIGN
G. Walter, Associate Professor, Candidate of Biological Sciences, Ye. Voronova, Associate Professor, E. Davidyants, magister, KhNAHU
Abstract. Different methods of surface runoffpurification are studied in laboratory conditions. During the experiment it has been revealed that the purification of modeled runoff which is carried out according to the scheme: sedimentation-electrocoagulationfiltration is optimum.
Key words: stationary petrol station, surface runoff, suspended matters, petroleum derivatives, sedimentation, electrocoagulation, filtration.
ОБЕЗВРЕЖИВАНИЕ ПОВЕРХНОСТНОГО СТОКА В ПРОЕКТЕ СТАЦИОНАРНОЙ АВТОЗАПРАВОЧНОЙ СТАНЦИИ
Г.А. Вальтер, доцент, к.б.н., Е.М. Воронова, доцент, Е.А. Давидянц, магистр,
ХНАДУ
Аннотация. В лабораторных условиях были изучены различные методы очистки поверхностного стока. В результате эксперимента было установлено, что очистка моделированных стоков, которая осуществляться по схеме: отстаивание-электрокоагуляция-фильтрация, оптимальная.
Ключевые слова: стационарная АЗС, поверхностный сток, взвешенные вещества, нефтепродукты, отстаивание, электрокоагуляция, фильтрация.
ЗНЕШКОДЖЕННЯ ПОВЕРХНЕВОГО СТОКУ В ПРОЕКТ СТАЩОНАРНО1
АВТОЗАПРАВНО1 СТАНЦП
Г.А. Вальтер, доцент, к.б.н., С.М. Воронова, доцент, К.О. Давщянц, магктр,
ХНАДУ
Анотаця. У лабораторних умовах були вивчет р1зт методи очищення поверхневого стоку. В результатi експерименту було визначено, що очистка модельованих стоюв, яка зд1йснюеться за схемою: вiдстоювання-електрокоагуляцiя-фiльтрацiя, е оптимальною.
Ключов1 слова: стащонарна АЗС, поверхневий стт, зави^i речовини, нафтопродукти, вiд-стоювання, електрокоагулящя, фтьтращя.
Introduction
For surface runoff purification where its rate which limiting pollutants are petroleum derivatives and suspended matters it is conceivable to use different methods of purification.
As the sedimentation method doesn't provide enough effective purification of oil products and suspensions there for it is necessary to use additional other purification methods (coagulation, flotation, sorption and so forth). A quite good effect is provided by chemical and reagent coagulation.
Analysis of publications
At present the operational experience of similar sewage works is practically lacking. Only after acquisition of concrete research results relative to surface runoff purification it is possible to devise a process diagram and surface runoff purification technology of a stationary petrol station [1].
Purposes and objectives of investigation
In laboratory conditions different methods of surface runoff purification have been studied. In the first stage investigations on purification of runoffs by simple sedimentation then chemical coagulation and electrocoagulation have been carried out.
All experiments have been performed using modeled runoffs [2].
Rendering surface runoff harmless by an sedimentation method
Necessary sedimentation time is known to depend on the initial content of suspended matters and it is determined by kinetics of their separation in water. The content of suspended matters in initial samples constituted 100, 200, 500 mg/dm3, being determined by the weight method. The content of petroleum derivatives constituted 100-150 mg/dm3.
Data processing by sedimentation kinetics of rain water made it possible to set up the following:
- with an increase of suspended matters in initial content from 100 to 200 and 500 mg/dm3 respectively the purification efficiency from 83,9 %, to 96,2 % (after two-hour sedimentation) increases;
- only prolonged sedimentation (24-hours) in the content of suspended matters in the initial sample up to 600 mg/dm3 provides the ultimate content of suspended matters corresponding to circulating water standards and the resulting concentration of petroleum derivatives constitutes not less than 40 mg/dm3;
- with sedimentation time increasing from 1 to 2 hours the purification effect of suspended matters and oil products changes slightly that is the residence time, in the settling tank can be re-
duced to 1-hour in a number of cases. The content of suspended matters after 1-hour sedimentation on the average is 70-90 mg/dm3, petroleum derivatives 50-90 mg/dm3;
- the purification effect from petroleum derivatives depends on the initial content of suspended matters by this means with the content of suspensions increasing from 200 to 1180 mg/dm3 the resulting content of petroleum derivatives after sedimentation is roughly diminished 1,5 times.
Laboratory investigations have been carried out by the clemical coagolation of preliminary settled, modelled runoffs. Aluminium sulphate and iron sulphate in advance were used as coagula-tors. PH value has a great impact on their capacity for coagulating.
PH optimum value has been set with the use of lime milk. The aluminium sulphate dose was 20-30 mg/dm3 by Al2O3, the iron sulphate dose comprises 50-120 mg/dm3 by Fe2O3. Coagula-tors were added in the form of the 5% solution. For increasing of purification effect injections of coagulators were conducted with addition of polyacrilamide flocculant in amounts of 0,51,5 mg/dm3.
For investigations runoffs with a different initial content of suspended matters (100, 200, 500) have been modelled. The content of petroleum derivatives was varied in the range of 120170 mg/dm3.
The optimum dose a coagulator being determined, experiments have been made with the aim of revealing sedimentation dynamics by suspended matters and petroleum derivatives. Samples were selected from cylinders in 15, 30, 60, 120 minutes.
The best result on wastewater purification by coagulation has been obtained in treatment of modelled runoffs by aluminium sulphate in a dose of 50,0 mg/dm3; polyacrilamide flocculant in a dose of 1,5 mg/dm3 and by alkalization in pH=7-8. The resulting content of oil products and suspended matters was 4,6 and 6,0 mg/dm3 respectively. In coagulation by iron sulphate in a dose of 80,0 mg/dm3, polyacrilamide flocculant in a dose of 1,5 mg/dm3, the resulting content of petroleum, derivatives and suspended matters ranged from 25,7 to 54,0 mg/dm3.
Rendering surface runoff harmless by an electrocoagulation
Investigation of the modelled storm runoff by electrocoagulation purification has been carried out using a plant of a running type. The electro-coagylation has been conducted in the following parameters: current density /=0,5; 1,0; 2,0 A/dm2; the residence time in the interelec-trode space was /=15, 30, 60 seconds.
The content of suspensions in the initial sample varied in the range of 100-500 mg/dm3 and the contend of petroleum derivatives was up to 200 mg/dm3. After two- hour sedimentation samples were taken for content determination of suspended matters and petroleum derivatives.
The data analysis allowed to make a conclusion that treated water indices are improved with an increase of current density and residence time in the interelectrode space.
Increasing current density when /=1,0 A/dm2 reduces the resulting content of petroleum derivatives up to 4,0 mg/dm3, the resulting content of suspended matters - up to 45 mg/dm3 (all factors being equal).
Wastewater has the best indices when it is treated in current density /=2, 0 A/dm2 and treatment time /=30, 60 seconds. The resulting content of oil product doesn't exceed 5,0 mg/dm3 and suspended matters - 20 mg/dm3.
Treatment parameters of modelled surface runoffs are as follows: the current density /=2,0 A/dm2; the residence time of runoffs in the interelectrode space was 15 seconds. The filtration in the interelectrode space easted 15 seconds. The filtration was carried out from the
bottom upwards at the rate of a speed of 5, 10, 30 m/h.
Conclusions
By obtained data it comes that purification of modelled runoffs which is carried out according to the scheme: sedimentation - electrocoagulation - filtration provides:
- purification on suspended matters and oil products according to sanitary standards;
- in direction of filtration from the bottom upwards the enhancement of the initial velocity results in reduction of the filter cycle. The optimum filtration velocity 5,0 m/h;
- increasing suspended matters in the initial sample in the range of 100-700 mg/dm3, all factors being equal, the performance of filtration doesn't affect on a purification effect from suspended matters [3].
References
1. Вальтер Г. А. Прикладна пдро еколопя:
метод. вк^вки до практичних занять з дисциплши для студенев спещальносп 7.070801 / Г. А. Вальтер. - Харюв : ХНА-ДУ, 2007. - 41с.
2. http://www.hydroeco.zp.ua/
3. http://www.ogmi.farlep.odessa.ua/add_html/
gideko/index.html
Рецензент: В. К. Жданюк, професор, д.т.н., ХНАДУ.
Стаття надшшла до редакци 28 грудня 2009 р.
