{"id":21157,"date":"2023-04-04T13:35:49","date_gmt":"2023-04-04T12:35:49","guid":{"rendered":"https:\/\/www.vtei.cz\/2023\/04\/odvodneni-cistirenskych-kalu-pomoci-kalovych-poli-s-mokradni-vegetaci-tzv-reed-bed-jednotek\/"},"modified":"2024-08-19T17:56:37","modified_gmt":"2024-08-19T16:56:37","slug":"odvodneni-cistirenskych-kalu-pomoci-kalovych-poli-s-mokradni-vegetaci-tzv-reed-bed-jednotek","status":"publish","type":"post","link":"https:\/\/www.vtei.cz\/en\/2023\/04\/odvodneni-cistirenskych-kalu-pomoci-kalovych-poli-s-mokradni-vegetaci-tzv-reed-bed-jednotek\/","title":{"rendered":"Dewatering sewage sludge using sludge drying beds with wetland vegetation, the so-called Sludge Treatment Reed Bed units"},"content":{"rendered":"

At present, the\u00a0problem of\u00a0waste disposal is\u00a0growing worldwide; its secondary use is\u00a0therefore more than desirable. A\u00a0pressing problem for\u00a0many small municipalities that need to\u00a0build or\u00a0reconstruct a\u00a0wastewater treatment plant (WWTP) is\u00a0solving the\u00a0issue of\u00a0processing the\u00a0resulting sludge and its stabilization, sanitation, and further application. It is\u00a0not unusual for\u00a0small municipal WWTPs to\u00a0lack a\u00a0complete in-situ<\/span> sludge management (including dewatering etc.). Sewage sludge is\u00a0thus often pumped out at high cost and transported to\u00a0a\u00a0large WWTP. The\u00a0main\u00a0goal for\u00a0the\u00a0real application\u00a0of\u00a0sewage sludge is\u00a0to\u00a0prevent future damage to\u00a0soils, plants, and the\u00a0health of\u00a0animals and people. For\u00a0this\u00a0reason, taking into\u00a0account the\u00a0substances currently present in\u00a0the\u00a0sludge (e.g., organic micropollutants), it is\u00a0advisable to\u00a0sufficiently pre-treat the\u00a0sludge, not just sanitize it to\u00a0eliminate above-limit microbial pollution.<\/span><\/p>\n

Since 1 January 2021, the\u00a0possibility of\u00a0direct application\u00a0of\u00a0sludge is\u00a0newly established under the\u00a0Waste Act No. 541\/2020 Coll., and Decree No. 445\/2022 Coll., which amends Decree No. 273\/2021 Coll., on\u00a0the\u00a0details of\u00a0waste management, as\u00a0amended by\u00a0Decree No. 78\/2022 Coll., and other related Decrees in\u00a0the\u00a0field of\u00a0waste management. This\u00a0Decree is\u00a0valid from 1 January 2023.<\/span><\/p>\n

Conversely, the\u00a0correct use of\u00a0sludge can be very useful for\u00a0the\u00a0soil because treated sludge is\u00a0a\u00a0rich source of\u00a0organic matter, basic nutrients (nitrogen, phosphorus, potassium, calcium, etc.), and trace elements.<\/span><\/p>\n

The\u00a0Sludge Treatment Reed Bed (STRB) technology of\u00a0so-called \u201cReed Bed\u201d (RB) units is\u00a0intended for\u00a0the\u00a0passive dewatering of\u00a0sewage sludge, taking into\u00a0account the\u00a0economic point of\u00a0view directly at the\u00a0place of\u00a0their origin. The\u00a0principle of\u00a0the\u00a0technology is\u00a0the\u00a0gradual dosing of\u00a0raw sewage sludge originating from activation\u00a0tanks of\u00a0mechanical-biological WWTP, or\u00a0from objects of\u00a0mechanical pre-treatment of\u00a0water (sand traps, septic tanks, settling tanks of\u00a0various types), so-called constructed wetland, and its gradual dewatering based on\u00a0filtration\u00a0through the\u00a0drainage layer and evapotranspiration\u00a0with the\u00a0help of\u00a0planted wetland plants. Sludge is\u00a0dosed in\u00a0certain\u00a0periods and, in\u00a0the\u00a0period between dosing, both the\u00a0humidity of\u00a0the\u00a0sludge is\u00a0reduced and it is\u00a0gradually stabilized. After filling the\u00a0sludge field to\u00a0the\u00a0operational maximum, the\u00a0system is\u00a0shut down and the\u00a0phase of\u00a0mineralization\u00a0of\u00a0the\u00a0matrix and reduction\u00a0of\u00a0the\u00a0sludge volume occurs, so that \u201cfresh\u201d sludge can be dosed again. In\u00a0this\u00a0way, the\u00a0maximum operating capacity of\u00a0the\u00a0sludge field is\u00a0gradually reached after several years, and it must be shut down. The\u00a0final stage is\u00a0stabilization\u00a0and, as\u00a0has\u00a0been proven to\u00a0a\u00a0certain\u00a0extent, sanitation\u00a0of\u00a0the\u00a0mixture of\u00a0sludge and decomposable biomass of\u00a0wetland plants, after which the\u00a0mixture can be extracted for\u00a0use. The\u00a0time required for\u00a0the\u00a0entire filling cycle is\u00a0several years but, based on\u00a0experience, a\u00a0maximum of\u00a0ten, depending on\u00a0the\u00a0projected volume. The\u00a0resulting material resembles compost.<\/span><\/p>\n

As\u00a0part of\u00a0research supported by\u00a0TA CR, this\u00a0technology was\u00a0tested in\u00a0semi-operation\u00a0both for\u00a0mechanical-biological (activation) WWTP up to\u00a01,000 p.e. and for\u00a0the\u00a0so-called constructed wetland of\u00a0the\u00a0same size category. Research has\u00a0shown that the\u00a0use of\u00a0technology based on\u00a0extensive dewatering of\u00a0sludge and its stabilization\u00a0in\u00a0sludge fields with suitable wetland vegetation, possibly with the\u00a0use of\u00a0protection\u00a0against dilution\u00a0of\u00a0the\u00a0dried mixture by\u00a0precipitation\u00a0(greenhouse, canopy), can represent an alternative to\u00a0other technologies, especially in\u00a0combination\u00a0with a\u00a0constructed wetland. A\u00a0condition\u00a0is\u00a0a\u00a0sufficiently large area of\u00a0land, which is\u00a0often an example of\u00a0small municipalities that use constructed wetland.<\/span><\/p>\n

The\u00a0following diagram (Tab. 1<\/span>) shows a\u00a0simplified SWOT analysis\u00a0for\u00a0the\u00a0possible use of\u00a0STRB unit technology in\u00a0the\u00a0Czech Republic. A\u00a0detailed analysis\u00a0of\u00a0the\u00a0possible use in\u00a0a\u00a0specific case will be tailored to\u00a0local conditions as\u00a0part of\u00a0the\u00a0decision-making analysis\u00a0to\u00a0solve the\u00a0issue of\u00a0sludge management in\u00a0a\u00a0given location.<\/span><\/p>\n

The\u00a0described sewage sludge dewatering technology can be the\u00a0first stage of\u00a0treatment which, by\u00a0ensuring subsequent appropriate steps (e.g., standardization\u00a0of\u00a0substrates by\u00a0the\u00a0addition\u00a0of\u00a0other additives or\u00a0processing into\u00a0pellets) opens the\u00a0way for\u00a0the\u00a0sensible use of\u00a0sludge on\u00a0arable land.<\/span><\/p>\n

Tab. 1. Simplified SWOT analysis for the possible use of STRB unit technology in\u00a0the\u00a0Czech Republic\"\"<\/a><\/span><\/h5>\n

The\u00a0following photos show examples of\u00a0the\u00a0use of\u00a0STRB units for\u00a0sludge dewatering:<\/p>\n

\"\"<\/a>Fig. 1. STRB unit with controlled pipe system for filling and ventilation, larger WWTP with SBR reactor, France<\/h6>\n
\"\"<\/a>Fig. 2. STRB unit for\u00a0village WWTP, size below 200 p.e., Austria<\/h6>\n
\"\"<\/a>Fig. 3. An example of the construction of the basic structure of two STRB units to ensure the alternating operation of filling, dewatering, and stabilization of sludge from the settling tank of the constructed wetland, Czech Republic<\/h6>\n

More information\u00a0can be found on\u00a0the\u00a0website of\u00a0Dekonta [5]. The\u00a0site also contains e-learning material that was\u00a0processed as\u00a0part of\u00a0project TH02030532. It includes basic information\u00a0about the\u00a0research and presentations on\u00a0the\u00a0subject in\u00a0PDF format, which are free to\u00a0download and can serve as\u00a0educational material for\u00a0the\u00a0professional public and operators of\u00a0small municipal sewage sludge sources, as\u00a0well as\u00a0basic information\u00a0about the\u00a0certified methodology for\u00a0the\u00a0practical implementation\u00a0and operation\u00a0of\u00a0RB unit systems.<\/p>\n

\"\"<\/a>Fig. 4. Structure of\u00a0the\u00a0dewatered and stabilized mixture of\u00a0sludge and wetland vegetation\u00a0after 7 years of\u00a0operation\u00a0of\u00a0the\u00a0STRB unit and after shutdown for\u00a0one season\u00a0to\u00a0complete the\u00a0process of\u00a0stabilization\u00a0and sanitation\u00a0of\u00a0the\u00a0mixture<\/h6>\n

In\u00a0case of\u00a0further interest in\u00a0practical use or\u00a0implementation, do not hesitate to\u00a0contact Ing. Petra Najmanov\u00e1, Ph.D., Head of\u00a0the\u00a0R&D Department at Dekonta, a. s. (najmanova@dekonta.cz) or\u00a0Mgr. Michal \u0160ere\u0161 (michal.seres@gmail.com). If you are interested in\u00a0the\u00a0theoretical and research part of\u00a0the\u00a0issue, do contact the\u00a0authors of\u00a0the\u00a0article.<\/em><\/p>\n

Acknowledgements<\/h3>\n

The\u00a0article was\u00a0written as\u00a0part of\u00a0the\u00a0practical implementation\u00a0of\u00a0the\u00a0results of\u00a0the\u00a0project TH02030532 \u201cNew procedures for\u00a0treatment and stabilization\u00a0of\u00a0sewage sludge from small municipal sources\u201d.<\/em><\/p>\n

This informative article has not been peer-reviewed.<\/p>\n","protected":false},"excerpt":{"rendered":"

At present, the\u00a0problem of\u00a0waste disposal is\u00a0growing worldwide; its secondary use is\u00a0therefore more than desirable. A\u00a0pressing problem for\u00a0many small municipalities that need to\u00a0build or\u00a0reconstruct a\u00a0wastewater treatment plant (WWTP) is\u00a0solving the\u00a0issue of\u00a0processing the\u00a0resulting sludge and its stabilization, sanitation, and further application. It is\u00a0not unusual for\u00a0small municipal WWTPs to\u00a0lack a\u00a0complete in-situ sludge management (including dewatering etc.). Sewage sludge is\u00a0thus often pumped out at high cost and transported to\u00a0a\u00a0large WWTP. The\u00a0main\u00a0goal for\u00a0the\u00a0real application\u00a0of\u00a0sewage sludge is\u00a0to\u00a0prevent future damage to\u00a0soils, plants, and the\u00a0health of\u00a0animals and people. For\u00a0this\u00a0reason, taking into\u00a0account the\u00a0substances currently present in\u00a0the\u00a0sludge (e.g., organic micropollutants), it is\u00a0advisable to\u00a0sufficiently pre-treat the\u00a0sludge, not just sanitize it to\u00a0eliminate above-limit microbial pollution.<\/p>\n","protected":false},"author":8,"featured_media":18600,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[91,2,89],"tags":[3118,3119,2624,3116,3117],"coauthors":[187,1806],"class_list":["post-21157","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-applied-ecology","category-from-the-world-of-water-management","category-water-technology-water-supply-waste-water-treatment","tag-dewatering","tag-reed-bed-units","tag-sewage-sludge","tag-sludge-drying-beds","tag-wetland-vegetation"],"acf":[],"_links":{"self":[{"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/posts\/21157","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/users\/8"}],"replies":[{"embeddable":true,"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/comments?post=21157"}],"version-history":[{"count":4,"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/posts\/21157\/revisions"}],"predecessor-version":[{"id":32070,"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/posts\/21157\/revisions\/32070"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/media\/18600"}],"wp:attachment":[{"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/media?parent=21157"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/categories?post=21157"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/tags?post=21157"},{"taxonomy":"author","embeddable":true,"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/coauthors?post=21157"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}