EP4486705A1 - Verfahren zur wiederverwertung von klärschlamm aus der behandlung von zivilem abwasser in die landwirtschaft unter verwendung einer mischung mit natriumchlorit unter bildung von chlordioxid - Google Patents

Verfahren zur wiederverwertung von klärschlamm aus der behandlung von zivilem abwasser in die landwirtschaft unter verwendung einer mischung mit natriumchlorit unter bildung von chlordioxid

Info

Publication number
EP4486705A1
EP4486705A1 EP23714607.1A EP23714607A EP4486705A1 EP 4486705 A1 EP4486705 A1 EP 4486705A1 EP 23714607 A EP23714607 A EP 23714607A EP 4486705 A1 EP4486705 A1 EP 4486705A1
Authority
EP
European Patent Office
Prior art keywords
treatment
sludge
sewage sludge
civil
treating sewage
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP23714607.1A
Other languages
English (en)
French (fr)
Inventor
Giacomo Mencarini
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Individual
Original Assignee
Individual
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Individual filed Critical Individual
Publication of EP4486705A1 publication Critical patent/EP4486705A1/de
Withdrawn legal-status Critical Current

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F11/00—Treatment of sludge; Devices therefor
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2209/00—Controlling or monitoring parameters in water treatment
    • C02F2209/06—Controlling or monitoring parameters in water treatment pH
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2303/00—Specific treatment goals
    • C02F2303/04—Disinfection

Definitions

  • the present invention relates to a method for recycling sewage sludge from the treatment of civil wastewater to agriculture, after treating the sludge with a mixture containing sodium chlorite, with the formation of chlorine dioxide.
  • sewage sludge from the treatment of civil wastewater constitutes a major environmental problem, because, once produced, it must be disposed of in landfills.
  • About 3 tons of sewage sludge (data from ISPRA - Higher Institute for Environmental Protection and Research) are produced in Italy alone every year, and 56% must be disposed of in landfills, with consequent evident problems connected to the population’s opposition to this type of solution, which is particularly understandable if one considers that the sludge currently produced by many civil wastewater treatment plants emits foul odours and has high levels of bacterial colonies, above all of salmonella and Escherichia coli.
  • waste-to-energy process enables energy to be produced from the combustion of sludge, this process likewise entails environmental problems due to the production of pollutants that are released into the atmosphere, besides being costly for businesses.
  • circular economy In recent years, growing attention has been paid to the problems connected to environmental pollution. In this context, an economic system called circular economy has been conceived; it aims to ensure development compatible with eco- sustainability through a model of production and consumption attentive to reducing the waste of natural resources and consisting in the sharing, reuse, repair and recycling of existing materials and products for as long as possible.
  • the solution according to the present invention fits into this context; it aims to provide a method for recycling sewage sludge from the treatment of civil wastewater to agriculture, following treatment with sodium chlorite.
  • the method according to the present invention proposes using sludge in the agricultural sector, in accordance with the following requirements:
  • the number of bacterial colonies present in the sludge must be below with the limits set by law; in particular, two types of bacteria, salmonella and Escherichia coli, must be kept under control, as must helminth eggs.
  • the aim of the present invention is thus to provide a method for treating sewage sludge from the treatment of civil wastewater which makes it possible to overcome the limits of the methods according to the prior art and to obtain the previously described technical results.
  • a further aim of the invention is that said treatment method may be carried out with substantially low costs.
  • Yet another aim of the invention is to propose a method for treating sewage sludge from the treatment of civil wastewater that is simple, safe and reliable.
  • a specific object of the present invention is a method for treating sewage sludge from the treatment of civil wastewater, comprising the following steps:
  • said acid solution is added until pH values less than or equal to 1 are obtained, and more preferably equal to 0.5.
  • said acid can be chosen from HCI and H 2 SO4 and more preferably it is HCI.
  • the added amount of said sodium chlorite is such as to obtain an excess of at least 300% of the amount of acid over the amount of NaCIO 2 .
  • said NaCIO 2 can be added in solution or powder form, preferably in a 25% aqueous solution.
  • said 25% solution of NaCIO 2 is added in an amount of at least 0.5g per gram of sludge, considered dry, corresponding to about 0.12g per gram of wet sludge, with a degree of moisture corresponding to a value of 76.4%, which corresponds to the average moisture value of sewage sludge from the treatment of civil wastewater.
  • chlorine dioxide is also an oxidising agent, capable of causing the oxidation of some organic compounds present in the sludge, thus leading to a reduction or to the disappearance of the unpleasant odours caused by these compounds.
  • the hydrochloric acid present in the sludge reacts with sodium chlorite to give CIO 2 (chlorine dioxide), NaCI (sodium chloride) and water, according to the reaction:
  • the necessary pH value must be very acidic (with a pH of less than or equal to 2, preferably a pH equal to 0.5). This pH range enables the maximum conversion of sodium chlorite to chlorine dioxide (CIO 2 ) to be obtained.
  • hydrochloric acid at different concentrations, or other types of acids, such as, for example, sulphuric acid.
  • the maximum amount of acid to be added there is no actual limit.
  • the important thing is for the pH to remain less than or equal to two and preferably less than or equal to one.
  • the amount of hydrochloric acid must be a good deal above the stoichiometric ratio determined by the reaction indicated previously, and it is preferably necessary to work with an excess of hydrochloric acid equal to at least 300%.
  • sodium chlorite As regards sodium chlorite, it can be used at various concentrations or even in powder (after putting in place the necessary measures to counter the safety problems due to the high corrosiveness of sodium chlorite powder) and reacted with a suitable amount of acid. As regards the ratio between the amount of sludge and the amount of sodium chlorite to be added, it can be varied according to needs.
  • the minimum amount of solution to be added is about 0.12g of 25% solution of sodium chlorite per gram of wet sludge.
  • this reaction can be carried out using suitable chlorine dioxide generators, already existing on the market, to be applied to the tank containing the sludge to be treated, since these devices enable an optimal, more uniform generation of chlorine dioxide compared to the simple manual addition of reagents to the sludge suspension.

Landscapes

  • Life Sciences & Earth Sciences (AREA)
  • Hydrology & Water Resources (AREA)
  • Engineering & Computer Science (AREA)
  • Environmental & Geological Engineering (AREA)
  • Water Supply & Treatment (AREA)
  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Treatment Of Sludge (AREA)
EP23714607.1A 2022-03-01 2023-03-01 Verfahren zur wiederverwertung von klärschlamm aus der behandlung von zivilem abwasser in die landwirtschaft unter verwendung einer mischung mit natriumchlorit unter bildung von chlordioxid Withdrawn EP4486705A1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
IT102022000003794A IT202200003794A1 (it) 2022-03-01 2022-03-01 Procedimento di riciclo in agricoltura dei fanghi di depurazione derivanti dal trattamento delle acque civili utilizzando una miscela contenente sodio clorito con sviluppo di diossido di cloro
PCT/IT2023/050062 WO2023166539A1 (en) 2022-03-01 2023-03-01 Method for recycling sewage sludge from the treatment of civil wastewater to agriculture using a mixture containing sodium chlorite with the formation of chlorine dioxide

Publications (1)

Publication Number Publication Date
EP4486705A1 true EP4486705A1 (de) 2025-01-08

Family

ID=81648621

Family Applications (1)

Application Number Title Priority Date Filing Date
EP23714607.1A Withdrawn EP4486705A1 (de) 2022-03-01 2023-03-01 Verfahren zur wiederverwertung von klärschlamm aus der behandlung von zivilem abwasser in die landwirtschaft unter verwendung einer mischung mit natriumchlorit unter bildung von chlordioxid

Country Status (3)

Country Link
EP (1) EP4486705A1 (de)
IT (1) IT202200003794A1 (de)
WO (1) WO2023166539A1 (de)

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3642516B2 (ja) * 2001-10-02 2005-04-27 株式会社荏原製作所 水中のｃｏｄ成分の除去方法及び除去装置
JP2005254056A (ja) * 2004-03-09 2005-09-22 Hitachi Plant Eng & Constr Co Ltd 余剰汚泥の減容化方法
AU2011218724A1 (en) * 2010-09-08 2012-03-22 Southwell Ip Limited Stabilised Chlorine Dioxide Solution

Also Published As

Publication number Publication date
WO2023166539A1 (en) 2023-09-07
IT202200003794A1 (it) 2023-09-01

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