Українська   Русский
DonNTU   Masters' portal

Abstract

Contents

Introduction

The main purpose of the operation of sewage treatment plants is to protect natural water bodies from pollution by sewage of economic, domestic, industrial and mixed origin. Wastewater treatment has a negative side, namely the formation of large volumes of sewage sludge (SL) at the stage of mechanical and biological purification. Sewage sludge is a large pollution, delayed by gratings, a precipitate of sand, a moist sediment falling out in primary sedimentation tanks and spent activated sludge or biofilms formed in biochemical treatment facilities (BT) [1]. The solid fraction of the crude sediment consists of organic and mineral substances, and the spent activated sludge is represented by a complex of microorganisms after the BT process.

In spite of the fact that sewage sludge is classified as low-hazard waste (class IV), the consequences of their storage in waste disposal sites create environmental, economic and social problems. The development and introduction of ecologically safe and economically profitable technology for the utilization of sewage sludge is topical. Utilization of SL will not only reduce their volumes, but, first of all, solve environmental problems accompanying the storage of this type of waste.

1. Topic relevance

Relevance of the choice and justification of the technology for the utilization of sewage sludge at the plant under investigation consists in the fact that in the operation of the sewage treatment plant in the city of Makeyevka, large volumes of SL in the amount of 10 000 tons per year are generated, which accumulate annually in waste disposal sites, occupy huge areas of fertile land an area of 253 000 m² and represent an environmental hazard due to soil pollution, air, surface and groundwater.

2. Goal, objectives, object, subject of study, the planned scientific novelty

The main goal of the study is to develop an optimal technology for the utilization of sewage sludge generated during the operation of the city sewerage treatment plant Makeyevka IM WSSU Water of Donbass.

To achieve this goal the following tasks should be solved:

  1. An analysis of the technological scheme for wastewater treatment and determine the stages in the formation of sewage sludge;
  2. To study the system of handling sewage sludge at the enterprise and to consider their impact on the state of the environment;
  3. An analysis the main methods and technologies of treatment, neutralization and utilization of sewage sludge;
  4. To investigate the qualitative and quantitative composition of sewage sludge, as well as their sanitary and hygienic and toxicological indicators;
  5. To select the technology for secondary use of sewage sludge and develop scientifically based recommendations for its implementation;
  6. To determine the ecological and economic effect of introducing the technology of secondary use of sewage sludge.

Research object: sewage sludge of the sewage treatment plant in Makeyevka.

Research subject: analysis of the possibility of applying vermicomposting technology for the utilization of sewage sludge.

Planned scientific novelty: the use of vermicomposting technology for the secondary use of sewage sludge in urban sewage treatment plants to obtain a valuable commercial product.

3. Characteristics of sewage sludge as a source of environmental hazard of the enterprise

An obligatory condition for the effective operation of sewage treatment plants is the treatment and removal of SL from the territory of treatment facilities for the environmentally safe use or storage of precipitation.

Despite the fact that sewage sludge is classified as a low-hazard waste (class IV), the consequences of their storage create environmental, economic and social problems. Most of the conditions necessary for normal operation of the SL storage sites are not met. Measures to sort and neutralize SL are not carried out [5]. Located on sludge ponds and in ponds, SL occupy large areas of fertile land (253 thousand m² [5]), which are removed from agricultural circulation for the main type of wastewater treatment plant waste disposal, and also require continuous monitoring and control [6] .

Sewage sludge pollutes the soil, surface and groundwater, the atmosphere. Pollution of the environment of the SL occurs as a result of the emission of a number of chemical elements (organic substances, nitrogen and phosphorus compounds, sulfur, heavy metals and other elements) contained in this kind of waste [6].

According to the literature [7], a high content of heavy metals when entering groundwater, which is classified as qunprotected, can be traced in several geological horizons (at a depth of 5-6 m), while a significant proportion of the balance of groundwater is the infiltration from silt sites. A special danger for surface waters (which are located at a distance of 0.05 km and 2 km from the location of storage sites of SL [5]), with unsatisfactory operation of silt areas, represents the flow of pollutants with drainage water, which practically negates the efficiency of the treatment facilities. With long-term storage of SL in sludge areas and ponds, as a result of anaerobic decomposition processes, biogas emissions and atmospheric pollution occur [6].

In addition, the lifetime of storage sites for SL, calculated for 30 years, has long since expired, since the silt areas and ponds of the investigated object were designed as early as 1972 [5]. Most of the silt ponds and ponds fill to the limit of their design capacity and require new areas for sedimentation, which is associated with financial payments for waste disposal and degradation of new areas occupied by sludge ponds and ponds [6].

Warehousing of SL in close proximity to agricultural lands and residential areas at a distance of 2 km creates prerequisites for unauthorized use as a fertilizer and, as a consequence, to contaminate additional arable land. Sewage sludge is a favorable bacteriological environment for the development of various parasitic agents (eggs and larvae of helminths, intestinal protozoan cysts), and stray animals and birds, being carriers of dangerous infections (toxocariasis), create epidemiological adverse situations [7].

The mechanical and physical methods for treating sewage sludge, such as aerobic stabilization, sludge areas and sludge ponds, are associated with significant economic costs, energy consumption, labor and material costs, and do not always ensure environmental safety in wastewater treatment plants.

On the basis of the foregoing, it is necessary to develop measures that will allow the utilization of sewage sludge, and thus reduce their negative impact on the state of the environment, comply with environmental standards for waste management and ensure environmental safety in the operation of the enterprise under investigation.

Conclusion

Review of the literature and preliminary results of experimental studies suggest that for the disposal of sewage sludge, it is necessary to choose a method based on the use of vermitechnologies – vermicomposting, which will solve the problems associated with the secondary use of this type of waste, increase its fertilizer value and obtain a qualitative fertilizer for soils.

This master's work is not completed yet. The term of final completion: May 2018. The full text of the work and materials on the topic can be obtained from the author or his head after this date.

References

  1. Зуб, А. А. Выбор вермикомпостирования как перспективной технологии утилизации осадков сточных вод канализационных очистных
    сооружений / А. А. Зуб, Ю. Н. Ганнова // Материалы 3-й Международной научно-практической конференции «Инновационные перспективы Донбасса». – Донецк: ДонНТУ, 2017, Т.4, С. 157-161.
  2. Коммунальное предприятие «Компания «Вода Донбасса» [Электронный ресурс] / Официальный сайт КП «Компания «Вода Донбасса». – Режим доступа http://www.voda.dn.ua. – Загл. с экрана.
  3. Технологический регламент городских канализационных очистных сооружений Макеевского ПУВКХ КП «Компания «Вода Донбасса» / Макеевское ПУВКХ КП «Компания «Вода Донбасса». – Макеевка, 2016. – 20 с.
  4. Мишуков, Б. Г. Очистка городских сточных вод / Б. Г. Мишуков, С. Ю. Игнатчик. – СПб: СПб ГАСУ, 2014. – 196 с.
  5. Паспорт места удаления отходов Макеевского ПУВКХ КП «Компания «Вода Донбасса»: Отчет годовой / Макеевское ПУВКХ КП «Компания «Вода Донбасса». – Макеевка, 2013. – 20 с.
  6. Гриценко, А. В. Влияние канализационных осадков на экологическое состояние природной среды, обработка и утилизация осадков сточных вод / А.В. Гриценко, Н.С. Горбань, Н.Ю. Ревякина и др. // Проблемы охраны окружающей природной среды и экологической безопасности: сборник научных трудов/ УкрНИИЭП. – Харьков, 2011. – С.111-122.
  7. Храменков, С.В. Комплексное решение проблемы по разработке и внедрению современных технологий рекультивации территорий иловых площадок станций аэрации с возвращением выведенных из оборота земель / С.В. Храменков, А.Н. Пахомов, А.В. Танин // Водоснабжение и санитарная техника. – Ч. 1. – № 12.– 2002. – С. 17-20.
  8. Солодкова, А. Б. Обезвреживание отработанного активного ила с получением материалов для решения экологических проблем химических и нефтехимических предприятий: Диссертация канд. техн. наук: 03.02.08 / Энгельсский техно-логический институт. – Саратов, 2014. – 158 с.
  9. 3oтoв, H. И. K вопросу об использовании осадков бытовых сточных вод в сельском хозяйстве [Текст] / Н.И. 3oтoв, С.P. Сyслoв // Biсник Дoнбaської нац. академії бyдiвництвa і архітектури: зб. наук. праць / М-вo oсвiти i нayки Укpaїни, ДoнHAБA. – Mакiївка, 2010. – Вип. 2010-3(83): Теxнoлoгiя, opганiзацiя, меxанiзацiя та геoдeзичнe забезпечення будівництва. – С. 214-221. – ISSN 1814-3296.
  10. Вермикомпостирование и вермикультивирование как основа экологического земледелия в XXI веке. Сборник научных трудов. – Минск: НПЦ НАН Беларуси, 2013. – 250 с.
  11. Разработка системы обращения с осадками сточных вод, доочистка сточных вод, предочистка поверхностных вод биотехнологическими методами (вермикультура, биоплато и др.: Отчет годовой (программа 17)) / ЦКИПИВЛ КП «Компания «Вода Донбасса». – Донецк, 2015. – 82 с.
  12. ГОСТ 17.4.3.07–2001. Охрана природы. Почвы. Требования к свойствам осадков сточных вод при использовании их в качестве удобрений. – Введ. в действие Постановлением Госстандарта России от 23-01-2001. – М.: Госстандарт России, 2001. – 6 с.