Simultaneous precipitation in an ECF kraft pulp mill : Long-term experiences

Sakari Toivakainen*, Heikki Hannukainen, Timo Laukkanen, Olli Dahl

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

Abstract

Long-term experiences of simultaneous precipitation (SP) of phosphorus using ferric sulfate in the secondary treatment of softwood E C F kraft pulp mill wastewater were examined from a time period of 7 years. Phosphorus reduction in an activated sludge process (ASP) was improved from monthly average level 43%-67% to 72-84% by adding ferric iron in the aeration basin. Due to periodic changes in wastewater qualities, the demand for iron addition to wastewater varied between 0 and 10 mgFe/L, depending mainly on influent P/BOD7 ratio. Introduction of SP has not caused any notable disadvantages to daily wastewater treatment plant operation, excluding minor increase of total sludge production. Experiences and conclusions from long-term operation were similar to our preliminary findings from pilot-scale and short-term full-scale studies. Thus, it can be verified, that SP offers an alternative to decrease phosphorus discharges from pulp mill ASP instead of more expensive tertiary treatments.

Original languageEnglish
Title of host publicationPulping, Engineering, Environmental and Recycling Sustainability Conference, PEERS 2019
PublisherTAPPI Press
Pages372-377
Number of pages6
ISBN (Electronic)9781510896857
Publication statusPublished - 2019
MoE publication typeA4 Article in a conference publication
EventTAPPI PEERS Conference - St. Louis, United States
Duration: 27 Oct 201930 Oct 2019

Publication series

NamePulping, Engineering, Environmental and Recycling Sustainability Conference, PEERS 2019

Conference

ConferenceTAPPI PEERS Conference
Abbreviated titlePEERS
CountryUnited States
CitySt. Louis
Period27/10/201930/10/2019

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