Solid phosphorus phase in aluminum- and iron-treated biosolids.
Xiao-Lan Huang1, Yona Chen, Moshe Shenker
1Department of Soil and Water Sciences, Faculty of Agricultural, Food and Environmental Quality Sciences, The Hebrew University of Jerusalem, Rehovot 76-100, Israel.
Journal of Environmental Quality
|March 3, 2007
Summary
Stabilizing phosphorus (P) in biosolids with alum or iron sulfate reduces soluble P. This research identifies the specific P compounds formed, crucial for safe land application of biosolids.
Area of Science:
- Environmental Science
- Soil Science
- Materials Science
Background:
- Phosphorus (P) stabilization in sewage sludge (biosolids) is vital to minimize P loss from soils.
- Effective P stabilization enhances the safe use of biosolids as soil amendments.
Purpose of the Study:
- To investigate the chemical forms of phosphorus (P) retained in biosolids treated with aluminum sulfate (alum) or ferrous sulfate (FeSul).
- To understand P stabilization mechanisms for safe and beneficial agronomic use of biosolids.
Main Methods:
- Scanning electron microscopy (SEM) with energy-dispersive X-ray elemental spectrometry (EDXS).
- X-ray diffraction (XRD) analysis.
- Chemical speciation of P in treated biosolids.
Main Results:
- Both alum and FeSul treatments formed a calcium-phosphate phase (likely brushite).
- Alum treatment resulted in aluminum-phosphate precipitation (Al/P molar ratio ~1:1).
- FeSul treatment involved iron-phosphate precipitation (Fe/P molar ratios 1:1 or 1.5:1) and adsorption onto iron hydroxides (Fe/P molar ratio up to 11:1).
Conclusions:
- Alum and FeSul effectively reduce P solubility in biosolids through distinct chemical mechanisms.
- The specific P phases formed influence P reactivity in amended soils.
- Optimal P stabilization strategies for biosolids depend on target soil characteristics.
More Related Videos
10:49Laboratory-determined Phosphorus Flux from Lake Sediments as a Measure of Internal Phosphorus Loading
Published on: March 6, 2014
07:20Discovery and Synthesis Optimization of Isoreticular Al(III) Phosphonate-Based Metal-Organic Framework Compounds Using High-Throughput Methods
Published on: October 6, 2023
Related Concept Videos
01:21The Phosphorus Cycle
Unlike carbon, water, and nitrogen, phosphorus is not present in the atmosphere as a gas. Instead, most phosphorus in the ecosystem exists as compounds, such as phosphate ions (PO43-), found in soil, water, sediment and rocks. Phosphorus is often a limiting nutrient (i.e., in short supply). Consequently, phosphorus is added to most agricultural fertilizers, which can cause environmental problems related to runoff in aquatic ecosystems.
01:19Acid Mine Drainage
Mining activities that disturb sulfide-rich rocks, particularly those containing pyrite (FeS₂), initiate a cascade of geochemical and microbiological processes with serious environmental implications. When exposed to air and water, pyrite undergoes oxidation, releasing sulfate, ultimately forming sulfuric acid and mobilizing heavy metals into surrounding water systems. This phenomenon, known as acid mine drainage (AMD), results in low pH waters laden with toxic elements that threaten aquatic...
04:01Factors Affecting Solubility
Compared with pure water, the solubility of an ionic compound is less in aqueous solutions containing a common ion (one also produced by dissolution of the ionic compound). This is an example of a phenomenon known as the common ion effect, which is a consequence of the law of mass action that may be explained using Le Chȃtelier’s principle. Consider the dissolution of silver iodide:
01:06Coagulation
Colloidal solids are solid particles suspended in solution. They are usually negatively charged, attracting a compact primary layer of positively charged ions, which attract more counterions to form an electrical double layer. Electrostatic repulsion between the charged double layers prevents the particles from colliding, stabilizing the colloids. These solids are often undesirable because they can contain toxins that are difficult to remove. Coagulation is a technique that helps aggregate and...
01:25Microbial Bioremediation of Uranium
Microorganisms play a critical role in the transformation and immobilization of uranium in contaminated environments through four main pathways: bioreduction, biosorption, bioaccumulation, and biomineralization. These mechanisms reduce uranium’s toxicity and prevent its migration through groundwater systems, offering sustainable approaches for in situ bioremediation.Bioreduction of UraniumBioreduction is driven by anaerobic bacteria such as certain strains of Geobacter and Shewanella, which use...
01:27Bioplastics
Bioplastics derived from microbial processes present a sustainable alternative to conventional petroleum-based plastics. Among these, polyhydroxyalkanoates (PHAs), particularly polyhydroxybutyrates (PHBs), have emerged as prominent candidates due to their biodegradability and biocompatibility. These polymers are synthesized by a variety of bacteria, such as Cupriavidus necator and Pseudomonas putida, which naturally accumulate PHAs as intracellular carbon and energy reserves, especially under...