Title: Effect of degree of prepolymerisation of coagulant and ratio of phosphate-inorganic metal on coagulated sludge

Authors: Lelum Manamperuma; Harsha Ratnaweera; Arve Heistad; Liubov Vasenko

Addresses: Norwegian University of Life Sciences, IMT, 1432 Aas, Norway ' Norwegian University of Life Sciences, IMT, 1432 Aas, Norway ' Norwegian University of Life Sciences, IMT, 1432 Aas, Norway ' National Technical University of Ukraine KPI, Pl Peremogi, Kiev, Ukraine

Abstract: Phosphates are becoming a limited resource as mineral phosphorus (P) reserves are dropping down and probably will be over within next three to five decades. One of the solutions for this problem is to reuse the wastewater sludge as the P source in plant growth. However, the potential to increase the plant availability of phosphorus (PAP) in coagulated sludge is reported to be 80-90% less than sludge from biological treatment. Effect of OH/Al ratios of coagulants and initial orto-phosphate (OP) levels on growth rate of plants and methods to improve PAP by different coagulants combined with cationic polymers were studied. Plant growth tests confirmed that the sludge obtained from higher OH/Al ratio coagulants has higher growth rates. Also combine dosing of cationic polymer with inorganic coagulants have higher biomass allocation than only with inorganic coagulants.

Keywords: plant availability; phosphorus; cationic polymers; inorganic coagulants; biomass allocation; coagulant repolymerisation; phosphate-inorganic metals; coagulated sludge; phosphates; wastewater sludge; sludge reuse; plant growth rates.

DOI: 10.1504/IJETM.2016.082254

International Journal of Environmental Technology and Management, 2016 Vol.19 No.3/4, pp.278 - 287

Received: 14 Nov 2015
Accepted: 15 Nov 2016
Published online: 13 Feb 2017 *

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