Views: 0 Author: Site Editor Publish Time: 2026-08-19 Origin: Site
When selecting polyaluminum chloride (PAC) for water treatment, one of the most common questions is whether to choose 28% or 30% product. Many buyers assume that higher Al₂O₃ content automatically means better performance. However, the choice involves more nuanced considerations—including production process, water insoluble matter, heavy metal content, and total cost per unit of active aluminum.
This article provides a practical comparison of 28% and 30% PAC products based on industry data, helping you make an informed selection for your specific application.
The percentage on a PAC product label refers to the Al₂O₃ (aluminum oxide) content by weight—a standard indicator of active aluminum concentration in the product. This allowscomparison across different formulations and water contents.
Important clarification: The Al₂O₃ percentage alone does not determine product quality. Other factors—particularly basicity (OH/Al ratio) , water insoluble matter, and heavy metal content—are equally critical for performance and regulatory compliance.
At Sherlock Chemical, our PAC products are manufactured under strict quality control with typical Al₂O₃ content of 28–30% (solid) to ensure consistent batch performance for large-scale continuous treatment systems.
The difference between 28% and 30% PAC is not merely about content percentages—it reflects fundamentally different production processes:
| Feature | 28% PAC (Drum-Dried) | 30% PAC (Spray-Dried) |
|---|---|---|
| Production Method | Drum drying | Spray drying (atomized in tower) |
| Appearance | Brown or coffee-colored | White or light yellow |
| Particle Uniformity | Less uniform | Uniform, excellent flowability |
| Dissolution Rate | Moderate | Fast |
Drum-drying involves liquid PAC entering a rotating drum dryer where heat evaporates water. This is a lower-cost process, but it produces higher insoluble residue.
Spray-drying atomizes concentrated PAC solution (40–50%) into fine droplets in a spray tower, achieving rapid drying. This produces uniform particles with fast dissolution.
This is one of the most significant practical differences:
| Specification | Industrial Grade (28%) | Drinking Water Grade (30%) |
|---|---|---|
| Water Insoluble Matter | ≤ 0.4% | ≤ 0.1% |
| Iron (Fe) Content | ≤ 1.5% | ≤ 0.2% |
Practical impact: Lower water insoluble matter means less residue in the treated water, reduced equipment fouling, and longer maintenance intervals.
Drinking water grade PAC has significantly stricter limits:
| Heavy Metal | Industrial Grade (28%) | Drinking Water Grade (30%) |
|---|---|---|
| Arsenic (As) | ≤ 0.0005% | ≤ 0.0001% |
| Lead (Pb) | ≤ 0.002% | ≤ 0.0005% |
| Cadmium (Cd) | ≤ 0.0005% | ≤ 0.0001% |
| Mercury (Hg) | ≤ 0.00005% | ≤ 0.00001% |
| Chromium (Cr) | ≤ 0.005% | ≤ 0.0005% |
Critical note: According to the Chinese national standard GB 15892-2020 for drinking water PAC, these heavy metal limits are mandatory. Drinking water applications must prioritize low heavy metal grades.
At Sherlock Chemical, each batch of PAC is supplied with Certificate of Analysis (COA), Technical Data Sheet (TDS), Material Safety Data Sheet (MSDS), batch number, and traceable quality records to ensure regulatory compliance.
A major source of confusion is equating "28%" with "industrial grade" and "30%" with "drinking water grade." While this is generally the pattern, it is not a universal rule.
According to standard specifications:
Drinking water grade PAC requires Al₂O₃ ≥ 29.0% with strict heavy metal and water insoluble limits
Industrial grade PAC typically requires Al₂O₃ ≥ 28.0% with less stringent impurity limits
Therefore:
A 30% product is almost always drinking water grade (spray-dried) with low impurities
A 28% product is typically industrial grade (drum-dried), but 28% drinking water grade products can exist if they meet the heavy metal and insolubles requirements
Always verify the actual quality specification—not just the percentage label—when selecting PAC for your application.
Many buyers compare PAC products on a cost per kilogram basis. This is misleading. The correct metric is cost per unit of Al₂O₃ delivered to the water.
Example:
| Parameter | 28% PAC | 30% PAC |
|---|---|---|
| Price per ton | $450–550 | $520–620 |
| Required dosage to achieve target Al₂O₃ | Higher | ~7% lower |
If the price increase is proportional to the Al₂O₃ content difference, the economics are similar. However, when normalized per kg of Al₂O₃, 30% PAC can actually cost 5–8% less due to higher purity and lower impurity content.
A detailed TCO analysis for a 50 MLD surface water plant (50–100 NTU feed) on an annual basis:
| Cost Factor | 28% PAC | 30% PAC | Savings with 30% PAC |
|---|---|---|---|
| Annual PAC usage | 730 tons | 620 tons | 110 tons (15% less) |
| PAC purchase cost | $400,400 | $384,400 | $16,000 |
| Sludge disposal | $60,000 | $51,000 | $9,000 |
| Mixing/pumping energy | $18,000 | $16,200 | $1,800 |
| Lab testing | $8,000 | $7,000 | $1,000 |
| Total Operating Cost | $486,400 | $458,600 | $27,800 (5.7%) |
The higher unit price of 30% PAC is offset by:
Lower dosage requirements
Reduced sludge generation (10–15% less volume)
Lower residual aluminum, reducing the need for post-treatment
Longer shelf life (18–24 months vs. 12 months for 28% drum-dried)
For more detailed cost comparisons between PAC and traditional coagulants, see our guide on PAC vs Alum for Wastewater Treatment.
30% PAC is the preferred choice for:
Drinking water treatment (municipal, potable water)
Food processing wastewater
Applications with strict regulatory compliance (heavy metal limits)
High-purity process water (pharmaceutical, microelectronics)
Cold climate conditions (higher basicity provides better low-temperature performance)
✅ Medium-to-large operations (≥200 tons/year usage) where TCO advantages are realized
28% PAC remains cost-effective for:
General industrial wastewater treatment (coal washing, leather, textile)
Municipal wastewater treatment
Budget-constrained projects where heavy metal limits are not a concern
High-turbidity raw water where the lower cost per kg is attractive
Facilities with moderate water quality and stable influent conditions
For coagulant selection in wastewater applications, visit our Water Treatment Applications page to explore our full range of coagulation and flocculation solutions.
Yes, but recalibration is required. To deliver the same amount of Al₂O₃, increase the dosage proportionally—approximately 7% more 28% PAC by weight compared to 30% PAC. Always run jar tests after switching to confirm the optimal dosage.
Not necessarily, but in practice, most 30% products are drinking water grade (spray-dried). Always verify the quality specification and test reports, particularly for heavy metals and water insoluble matter.
Not always. Basicity (OH/Al ratio) can be more important than Al₂O₃ content. A 28% PAC with 80% basicity will often outperform a 31% PAC with only 60% basicity.
Basicity affects the charge neutralization capability and floc formation efficiency. Higher basicity generally improves performance in cold water and low-alkalinity conditions. Typical ranges:
28% PAC: 60–75% basicity
30% PAC: 65–80% basicity
31% PAC: 70–85% basicity
Selecting between 28% and 30% PAC is not about picking the "better" product—it is about matching the product to your application requirements and total cost structure.
| Application | Recommendation | Key Consideration |
|---|---|---|
| Drinking water treatment | 30% PAC (spray-dried) | Heavy metal limits, lower residual aluminum |
| Industrial wastewater | 28% PAC (drum-dried) | Lower upfront cost, sufficient for most industrial needs |
| High-purity water | 30% PAC (spray-dried) | Low water insoluble matter |
| Budget-constrained projects | 28% PAC (drum-dried) | Lower cost per kg |
| Cold climate operations | 30% PAC (spray-dried) | Higher basicity improves low-temperature performance |
Final recommendation: For most industrial and municipal applications, 30% PAC with 65–80% basicity offers the optimal balance of performance and total cost of ownership. For drinking water applications, 30% spray-dried PAC is the industry standard due to its lower heavy metal content and reduced residual aluminum.
Always request and review the actual quality test report (COA) before purchasing—not just the product label.
For pricing, samples, or technical support on PAC selection, please contact Sherlock Chemical. We provide:
Fast Response · Flexible MOQ · Export Support
Each batch with COA, MSDS, TDS, batch label, and traceable QC reports
Packaging options: 25 kg PP woven bags with PE inner liner, customized packaging available
Visit our Contact Page to request a quote or free samples.
Disclaimer: The information provided is based on typical industrial experience and laboratory data. Actual performance may vary depending on water quality, operating conditions, and system design. Users are advised to conduct appropriate trials to determine optimal dosage and application methods.
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