Residual seawater from salt production (bittern) as a coagulant to remove lead (Pb2+) and turbidity from batik industry wastewater

Eddy Setiadi Soedjono; Agus Slamet; Nurina Fitriani; Mega Soekarno Sumarlan; Agus Supriyanto; Dwi Ratri Mitha Isnadina; Norzila Binti Othman

doi:10.1016/j.heliyon.2021.e08268

Residual seawater from salt production (bittern) as a coagulant to remove lead (Pb²⁺) and turbidity from batik industry wastewater

Heliyon. 2021 Oct 25;7(11):e08268. doi: 10.1016/j.heliyon.2021.e08268. eCollection 2021 Nov.

Authors

Eddy Setiadi Soedjono¹, Agus Slamet¹, Nurina Fitriani², Mega Soekarno Sumarlan², Agus Supriyanto², Dwi Ratri Mitha Isnadina², Norzila Binti Othman³

Affiliations

¹ Department of Environmental Engineering, Faculty of Civil, Engineering, and Planning, Institut Teknologi Sepuluh Nopember, Kampus ITS, Sukolilo, Surabaya, 60111, Indonesia.
² Department of Biology, Faculty of Science and Technology, Universitas Airlangga, Kampus C UNAIR, Jalan Mulyorejo, Surabaya, 60115, Indonesia.
³ Department of Water and Environmental Engineering, Faculty of Civil and Built Environment, University Tun Hussein Onn Malaysia, 86400, Parit Raja, Batu Pahat, Johor, Malaysia.

Abstract

Coagulation and flocculation using bittern coagulant are effective methods for processing batik industrial wastewater containing heavy metals and high turbidity. Bittern as residual seawater product from salt production can be used as a natural coagulant as it contains magnesium (Mg²⁺), chloride (Cl^-), and sulfate ions (SO₄ ^2-) which can react with Pb²⁺ and turbidity to produce precipitation. This study focused on Pb²⁺ and turbidity removal from batik wastewater by introducing different variations of coagulant doses and variations in fast-stirring speed. Bittern coagulant dosage (v/v) of 5%, 15%, 25%, and 35% were used while fast-stirring speed were 55 rpm, 90 rpm, and 125 rpm. Results of this experiment showed that variations of coagulants and stirring speed to give Pb²⁺ maximum removal of 99.3% happened when coagulant dose and stirring speed at 35% and 55 rpm, while maximum turbidity removal at 97% happened when coagulant dose and stirring speed was 15 % and 125 rpm, respectively. Optimum dose using Response Surface Methodology (RSM) was at coagulant dose of 25% with 55 rpm, of which Pb²⁺ and turbidity removal were 99% and 93%, respectively.

Keywords: Bittern; Coagulant dose; Fast-stirring speed; Lead (Pb2+); Turbidity.