Coagulation techniques for phosphorus removal from agricultural wastewater

Bailey, Shorma Bianca

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https://hdl.handle.net/2142/113305 Copy

Description

Title

Coagulation techniques for phosphorus removal from agricultural wastewater

Author(s)

Bailey, Shorma Bianca

Issue Date

2021-07-16

Director of Research (if dissertation) or Advisor (if thesis)

Grift, Tony

Doctoral Committee Chair(s)

Grift, Tony

Committee Member(s)

• Maghirang, Ronaldo
• Bhattarai, Rabin
• Zilles , Julie

Department of Study

Engineering Administration

Discipline

Agricultural & Biological Engr

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

Ph.D.

Degree Level

Dissertation

Keyword(s)

• phosphorus
• manure
• eutrophication
• water quality
• agriculture
• clean water

Abstract

Agricultural wastewater runoff is a known pollution source contributing to poor water quality, impending eutrophication, and toxic algal blooms. Best management practices designed to control orthophosphate (OP) pollution in the tile drainage network and cattle manure management are needed to prevent freshwater contamination longterm. To first address OP contamination from tile drain and cattle manure lagoons, this research first evaluated a series of scaled up reactors including batch, plug flow, pilot and farm trial for selecting the industrial by-products (IBPs) feasible for control of OP. To validate proof of concept for the passive filter used to treat tile drainage water and an electrocoagulation device built to purify cattle manure lagoon wastewater (CMLW), OP concentrations were quantified before and after treatment. The five iron-based IBPs in this work include: steel slag (SS), treated steel slag (TSS), iron turnings (IT), goethite powder (GTP), treated iron turnings (TFe), and hematite-clay pellets (MHP). These IBPs were evaluated for their ability to reduce OP in synthetic P solution and tile drainage water from a farm. During batch experiments, steel slag and IT demonstrated no OP removal. However, GTP at initial OP at 1.0 mg PO4 L-1 reduced OP by 32% in 60 min, resulting in a final OP concentration of 0.68 mg PO4 L-1. A second batch experiment used raw tile water and upcycled IBPs; TFe and MHP provided OP reductions of 25.4 ±0.08 % (mg PO4L-1: 0.024 to 0.68) and 72.3 ± 0.04 % (mg PO4 L-1: 0.024 to 0.07), respectively. Treated iron turnings performed better than MHP in plug flow experiments with a 70% reduction of OP (mg PO4 L-1: 0.02 to 0.005) in 3 h with 1.2 ml min-1. After small plug flow experiments, the ability of untreated SS, IT, and GTP to treated IBPs–treated steel slag (TSS), TFe, and MHP to reduce OP was evaluated in a large pilot system. Among the four IBPs in the pilot system, TFe demonstrated the highest capacity at 2 min showing a OP reduction of 68% (mg PO4 L-1: 1185 to 395.3) while, SS showed the second highest OP removal efficiency of 3.33% at 2 min, (mg PO4 L-1: 11400 to 10633 +611). The ideal IBP for OP reduction was TFe, therefore it was selected for in field-scale testing, which resulted in an OP reduction of 49%. In the cow manure lagoon water CMLW electrocoagulation experiments, a batch reactor using two iron electrodes connected to a constant-current power supply circuit was designed. Except for trials with synthetic OP solution, all other trials maintained an operating current of 0.5 A. In less than 2 h, 100% CMLW showed the most promising result, reduction of OP was 94 % to 95% (mg PO4 L-1: 13.7 to 0.73), while turbidity reduction was 56 to 95% (NTU:50 to 850) accomplished in 15 h of operation.The required cumulative energy consumption to accomplish this treatment was 423 kJ g-1-PO4. The conclusion of this work supports proof of concept for utilizing steel iron-based IBPs for OP reduction in an agricultural setting. The TFe suggests there is a cyclical removal of OP over time, suggesting a cumulative removal process. Electrocoagulation worked best for high turbidity wastewater in contrast to tile water. Both results for chemical and electrocoagulation demonstrate as alternative technologies for best management practices that are inadequate in addressing OP leaching from tile and lagoons.

Graduation Semester

2021-08

Type of Resource

Thesis

Permalink

http://hdl.handle.net/2142/113305

Copyright and License Information

Copyright 2021 Shorma Bailey Professor Tony Grift, Chair Professor Ronaldo Maghirang Associate Professor Rabin Bhattarai Assistant Professor Julie Zilles

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