Dewatered alum sludge: a potential adsorbent for phosphorus removal
Y Yang1, D Tomlinson, S Kennedy
1Centre for Water Resources Research, School of Architecture, Landscape and Civil Engineering, University College Dublin, Earlsfort Terrace, Dublin 2, Ireland. yongzhe.yang@ucd.ie
Summary
Alum sludge, a byproduct of drinking water treatment, effectively removes phosphorus from wastewater. This study found pH significantly impacts phosphorus adsorption capacity, with optimal removal occurring at lower pH levels.
Area of Science:
- Environmental Engineering
- Water Treatment Technologies
- Adsorption Science
Background:
- Alum sludge is a significant byproduct of drinking water purification.
- Wastewater phosphorus removal is crucial for preventing eutrophication.
- Investigating alum sludge as a sustainable adsorbent is of environmental interest.
Purpose of the Study:
- To characterize dewatered alum sludge for phosphorus adsorption.
- To evaluate the influence of operational parameters on phosphorus removal efficiency.
- To determine the adsorption capacity and isotherm model for alum sludge.
Main Methods:
- Batch experiments using dewatered alum sludge and synthetic phosphorus-rich wastewater.
- Investigation of adsorption as a function of alum sludge amount, particle size, solution pH, and contact time.
- Analysis of adsorption data using the Langmuir isotherm model.
Main Results:
- pH significantly influences both the phosphorus adsorption process and capacity.
- The Langmuir isotherm model accurately describes the experimental data (R2 = 0.98-0.99).
- Maximum adsorption capacities ranged from 0.7 to 3.5 mg-P/g across tested pH values (4.3-9.0).
Conclusions:
- Dewatered alum sludge demonstrates significant potential as an effective adsorbent for phosphate removal from wastewater.
- Optimizing pH is critical for maximizing phosphorus adsorption by alum sludge.
- Alum sludge offers a sustainable and cost-effective solution for wastewater phosphorus remediation.
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