Research and evaluation of iron impact on sludge digestion process

Abstract

The dissertation examines impact of iron salts and ochre (iron sludge from water treatment plant) on digestion of sludge mixture from wastewater treatment plants with biological phosphorus removal process. Research object was anaerobic digestion of sludge mixture with traditional and alternative iron sources added. The aim of work was to examine the potential of ochre as an alternative iron source and to investigate factors governing anaerobic digestion process: methane production rate, hydrogen sulphide removal process and reduction of internal phosphates recycling at wastewater treatment plants with biological treatment plants. Dissertation consists of introduction, three chapters, general conclusions and recommendations, references and list of author's publication on the topic of dissertation. In introduction main problem is discussed; topicality of work, object of research, aim and objectives of work are formulated, of the work are described; research methodology, scientific novelty of research, practical significance of results and defended propositions are presented. In the end of introduction author's articles, structure of dissertation and acknowledgements are presented. In the first chapter literature concerning with the studied topic is analysed. Information about sludge sources, types and characterisation, anaerobic digestion process and previous research on results on impact of aluminium and iron. In the end of chapter conclusions and tasks are reformulated. Second chapter presence methodologies used for the research. Laboratory and pilot-scale anaerobic reactors and characteristics of sludge and ochre used for the experiments are described. In third chapter results on impact of iron salts and ochre are presented and discussed, comparison with other researchers obtained results is made. Proposed technological scheme for use of ochre at the wastewater treatment plants with biological phosphorus removal presented and described. Ten articles have been published on the topic of thesis: two-in scientific journal referred in the other databases, two-in International Conference material, three-in Lithuanian Conference material. 12 presentations were made at the Republic and International Conferences and Seminars. vi Reziumė Disertacijoje nagrinėjama geležies druskų ir geležies paplavų (ochra) iš geriamo vandens paruošimo įrenginių įtaką dumblo pūdymo procesui. Tyrimo objektas-dumblo mišinio pūdymas, į jį įterpiant tradicinį arba alternatyvų geležies šaltinį. Pagrindinis disertacijos tikslas-ištirti geležies paplavų, kaip alternatyvaus geležies šaltinio, panaudojimo galimybes ir nustatyti faktorius, įtakojančius pūdymo proceso kokybę: metano susidarymą, sieros vandenilio pašalinimo procesą ir vidinės fosfatų recirkuliacijos sumažinimą nuotekų valymo įrenginiuose su biologiniu fosforo šalinimu. Disertaciją sudaro įvadas, trys skyriai, bendrosios išvados ir rekomendacijos, naudotos literatūros ir autoriaus publikacijų disertacijos tema sąrašas. Įvadiniame skyriuje aptariami tiriamoji problema ir darbo aktualuma...