Municipal Tap Water Plants

Customer Pain Points

Municipal water treatment plants worldwide face four core challenges that directly threaten public health, regulatory compliance, and operational stability:

• Intensifying Source Water Contamination: Traditional Processes Are "Powerless"

Lake and reservoir sources frequently experience algal blooms due to eutrophication (generating odor-causing substances such as geosmin and 2-methylisoborneol), while river sources are contaminated by industrial wastewater (phenols, heavy metals) and agricultural runoff (pesticides, fertilizers). This results in raw water exhibiting abnormal odors and discoloration, as well as exceeding limits for organic matter content. For instance, during the 2005 nitrobenzene contamination incident in the Songhua River, the raw water nitrobenzene concentration reached 0.3 mg/L—a level 30 times higher than the limit (0.017 mg/L) stipulated by China's *Environmental Quality Standards for Surface Water*. Traditional treatment processes—typically involving "coagulation-sedimentation-filtration-chlorine disinfection"—proved completely incapable of handling this contamination.

• Hidden Risks from Disinfection Byproducts (DBPs): Non-Compliance with International Drinking Water Standards

Routine chlorine disinfection reacts with organic matter present in water to generate carcinogenic substances such as trihalomethanes (THMs) and haloacetic acids (HAAs). The World Health Organization (WHO) *Guidelines for Drinking-water Quality* (4th Edition) explicitly mandates that "THMs ≤ 100 μg/L," while the EU Directive 98/83/EC imposes an even stricter limit of "THMs ≤ 25 μg/L." However, a 2018 survey in China revealed that 32% of water treatment plants in prefecture-level cities produced finished water with THM levels exceeding regulatory limits; traditional treatment processes currently lack effective means to remove these byproducts.

• Lack of Emergency Response Capabilities for Sudden Contamination: Prone to Triggering Public Panic

Sudden water contamination incidents—such as chemical spills or oil leaks—require a rapid response (typically requiring containment within two hours); yet, traditional treatment processes lack established emergency protocols. During the 2005 Songhua River contamination incident in Harbin, the absence of an emergency reserve of activated carbon resulted in a city-wide water cutoff lasting four days, triggering a rush among residents to hoard water and causing significant social unrest. Similarly, during the 2014 benzene contamination incident in the Lanzhou municipal water supply, the failure to timely administer activated carbon extended the duration of the water cutoff to eight days. Taste and the Crisis of Trust: Residents

"Abandon Tap Water for Bottled Water"

Residual chlorine odors in treated water (reminiscent of "bleaching powder") and an astringent taste have caused a precipitous decline in public trust regarding tap water. A 2022 survey by the China Association for Urban Water Supply and Drainage revealed that 61% of households consume bottled water on a daily basis, while only 18% fully trust the taste of their tap water. Similarly, in certain European nations (such as Germany), the bottled water market share stands as high as 35%—a ​​phenomenon largely attributed to the poor taste of the local tap water.

Application Objectives

Municipal water treatment plants adopt activated carbon with four core objectives in mind, closely aligned with four key requirements: "Compliance," "Safety," "User Experience," and "Emergency Preparedness."
Strict Compliance: Mitigating Regulatory Risks
Meeting national drinking water standards regarding "sensory parameters" (absence of abnormal odors or tastes) and "toxicological parameters" (organic compounds, heavy metals). For instance, China's *Standard for Hygiene of Domestic Drinking Water* (GB 5749-2022) explicitly mandates that "Odor and Taste" levels remain ≤ Grade 2 (meaning "no abnormal taste") and that "CODmn" (a comprehensive indicator for organic matter) remains ≤ 3 mg/L. Furthermore, the EU Directive 98/83/EC requires that "pesticide residues" remain ≤ 0.1 μg/L; activated carbon is one of the few treatment processes capable of simultaneously achieving all these benchmarks.
Safeguarding Public Health: Reducing Carcinogenic Risks
Removing odor-causing, mutagenic, and carcinogenic substances from raw water sources (such as algal toxins, halogenated hydrocarbons, and pesticide residues), thereby reducing the incidence of diseases such as gastrointestinal cancers and neurological disorders. World Health Organization (WHO) data indicates that improving drinking water quality can reduce the risk of waterborne diseases by 80%; within this context, activated carbon adsorption serves as the final line of defense against "triple-threat substances"—those that are carcinogenic, teratogenic (developmentally toxic), or mutagenic.

Optimizing Taste: Rebuilding Resident Trust

Adsorbing residual chlorine and odor-causing compounds (such as geosmin) to enhance the water's "sweetness" and "refreshing quality." Following renovations at the Shanghai Taihe Water Treatment Plant, the taste rating of the treated water improved from 2.1 (out of a maximum of 5) to 4.3, while the rate of resident complaints plummeted from 15 per month to zero. Establishing an Emergency Response System to Address Sudden Pollution Incidents
Constructing a "Dual-Barrier" System: Source-Point Powdered Activated Carbon Dosing + Filter-Bed Retrofitting with Granular Activated Carbon. Powdered activated carbon can be directly dosed into raw water pipelines (achieving adsorption within 1–2 hours of contact), while granular activated carbon can be utilized to retrofit existing sand filters (requiring no additional land acquisition). This approach buys critical time for government authorities to coordinate response efforts—as demonstrated during the 2005 Songhua River incident, when the Harbin Taiping Water Treatment Plant dosed 1,400 tons of powdered activated carbon. Within two hours, the concentration of nitrobenzene was reduced to 0.005 mg/L—far below the national standard of 0.017 mg/L—enabling the restoration of water supply three days ahead of schedule.

Application Significance

The application of activated carbon in municipal water treatment plants represents not merely a technological process upgrade, but serves as a core pillar supporting both public health and social stability:
The "Last Line of Defense" for Public Health
Activated carbon adsorption stands as the most effective method for removing "small-molecule organic compounds, odor-causing substances, and disinfection byproducts." Research conducted by the U.S. Environmental Protection Agency (EPA) indicates that water treatment plants employing advanced activated carbon treatment processes produce finished water with carcinogenic substance concentrations 40% lower than those utilizing traditional processes, resulting in a 25% reduction in the incidence of gastrointestinal cancers.

Driving the Industry Transition from "Traditional" to "Advanced Treatment"

Globally, activated carbon has become the standard requirement for "advanced treatment" in water treatment plants. China's *14th Five-Year Plan for the Development of Urban Sewage Treatment and Resource Utilization* explicitly mandates that "the rate of advanced treatment in water treatment plants located in prefecture-level cities and above must reach ≥60%." Through activated carbon retrofits, facilities such as the Shanghai Taihe Water Treatment Plant and the Jingjiang Jiangfang Water Treatment Plant have emerged as domestic benchmarks for advanced treatment, inspiring over a dozen neighboring water treatment plants to follow suit and upgrade their own facilities. A "Critical Emergency Tool" for Sudden Water Pollution Incidents
Activated carbon stands as the sole "mobile purification solution" capable of rapid response. Powdered activated carbon can be deployed within two hours (requiring no equipment modification), while granular activated carbon allows for the retrofitting of existing sand filtration beds (requiring only the removal of a 0.5-meter sand layer and its replacement with 0.5 meters of activated carbon), thereby buying critical time for government authorities to manage the crisis. During the 2005 Songhua River pollution incident, the use of activated carbon enabled Harbin to resume its water supply three days ahead of schedule. Similarly, during the 2014 benzene contamination incident in Lanzhou, benzene concentrations dropped to 0.01 mg/L—meeting the national safety standard—within just two hours of activated carbon application, thereby averting widespread public panic.
Application History
The use of activated carbon in municipal water treatment plants has become increasingly widespread, driven by the twin factors of escalating raw water pollution and stricter regulatory standards. Key milestones in this evolution include:

1932: The World's First Large-Scale Application

At the Chicago Water Treatment Plant in the United States, raw water drawn from Lake Michigan became contaminated with phenolic compounds. Following standard chlorine disinfection, this contamination resulted in a distinct "chlorophenol odor" (detectable at concentrations as low as 3 ppb). The plant subsequently employed activated carbon treatment for the first time, successfully eliminating the odor and thereby pioneering the use of activated carbon in municipal water supply systems.

The 1970s: Mandatory Adoption in the West

In the United States, the *Safe Drinking Water Act* (SDWA) and the *Clean Water Act* (CWA) mandated the removal of disinfection byproducts (DBPs), establishing activated carbon as a standard component of advanced water treatment processes. Concurrently, the European Union’s *Drinking Water Directive* (80/778/EEC) established a clear limit for "total organic substances" at ≤ 3 mg/L, prompting water treatment plants across Europe to adopt activated carbon on a large scale. By 1985, 65% of water treatment plants in the U.S. and 52% in Europe were utilizing activated carbon.

2005: The Dawn of China's "Activated Carbon Era"

Following the nitrobenzene contamination incident in the Songhua River, China's Ministry of Construction issued an urgent directive requiring water treatment plants in key cities to maintain strategic reserves of activated carbon. The Taiping Water Treatment Plant in Harbin responded by deploying 1,400 tons of powdered activated carbon, becoming the first facility in China to utilize activated carbon to combat a sudden pollution crisis. Subsequently, the Taihe Water Treatment Plant in Shanghai and the Jiangfan Water Treatment Plant in Jingjiang initiated projects to retrofit their filtration beds with granular activated carbon, thereby ushering in a new era of advanced water treatment technology within China's municipal water supply sector. Post-2010: Standard-Driven Universal Adoption
Following the implementation of China’s *Standard for Drinking Water Quality* (GB 5749-2006)—which mandated requirements such as "CODmn ≤ 3 mg/L" and "absence of abnormal odors or tastes"—activated carbon became an "essential process" for both newly constructed and retrofitted water treatment plants. As of 2022, the utilization rate of activated carbon in municipal waterworks across Chinese cities at the prefectural level and above reached 58%, representing a 52-percentage-point increase compared to 2005.

Mechanism of Action

Activated carbon removes pollutants through a dual mechanism involving "physical adsorption" and "chemical synergy." The core of this process lies in the precise matching of its "pore structure" with its "surface chemical properties":

• Physical Adsorption: The "Sieving + Van der Waals Forces" of the Pore Structure

Activated carbon's pores are classified into three categories:
Micropores (< 2 nm): Constituting 70%–80% of the total pore volume, these provide a high specific surface area (700–3000 m²/g) and adsorb small-molecule organic compounds (e.g., phenols, pesticides) as well as odor-causing substances (e.g., geosmin) via Van der Waals forces. This constitutes the primary mechanism for removing "small-molecule pollutants."
Mesopores (2–50 nm): Acting as "transport channels," these facilitate the diffusion of pollutants from the water into the micropores; simultaneously, they adsorb medium-sized organic molecules (e.g., halogenated hydrocarbons).
Macropores (> 50 nm): Serving as "entry channels," these allow large-molecule pollutants (e.g., algal fragments) to penetrate the interior of the activated carbon, though their direct contribution to adsorption is negligible.

• 2. Chemical Synergy: The "Hydrogen Bonding + Electrostatic Attraction" of Surface Functional Groups

The oxygen-containing functional groups present on the surface of activated carbon (such as carboxyl, hydroxyl, and lactone groups) enhance adsorption through two primary mechanisms:
Hydrogen Bonding: These groups form hydrogen bonds with polar organic compounds (e.g., phenols, organic acids), thereby increasing adsorption capacity (for instance, the adsorption capacity for phenols can be 30% higher than that of activated carbon lacking such functional groups). Electrostatic Attraction: In water with a pH > 7, carboxyl groups dissociate into -COO⁻ ions, which adsorb cationic pollutants (such as heavy metals like Pb²⁺ and Cu²⁺) through electrostatic attraction. Additionally, silver-loaded coconut shell activated carbon inhibits bacterial proliferation in water through the antimicrobial action of Ag⁺ ions.

Application Methods

Municipal water treatment plants primarily employ a combined process consisting of "Powdered Activated Carbon (PAC) for Emergency Response + Granular Activated Carbon (GAC) for Advanced Treatment," covering the full spectrum of scenarios ranging from routine operations to emergencies:

• Powdered Activated Carbon (PAC): Emergency Treatment for Sudden Contamination Incidents

Applicable Scenarios: Sudden contamination of water sources (e.g., chemical spills, algal blooms) and seasonal odor issues (e.g., summer lake algae).

Process Steps:

Slurry Preparation: Prepare a PAC slurry with a concentration of 10% (to prevent dust explosions) and stir thoroughly (to prevent sedimentation).
Dosing: Inject the slurry into the raw water pipeline using a metering pump (utilizing the 1–2 hours of water transit time to complete adsorption), or dose it upstream of the flocculation tank (to work synergistically with coagulants and enhance adsorption efficiency).
Mixing: Ensure thorough contact between the PAC and the raw water using an in-line static mixer or by stirring within the flocculation tank (at a rotational speed of 100–150 rpm).

Key Parameters:

Dosing Rate: 10–50 mg/L (e.g., 40 mg/L was used during the Songhua River incident; 20 mg/L is typically used for summer algal blooms).
Contact Time: ≥ 30 minutes (to ensure sufficient adsorption of pollutants).
pH: 6–8 (to prevent changes in the surface charge of the activated carbon that could adversely affect adsorption).

• Granular Activated Carbon (GAC): Routine Advanced Treatment

Applicable Scenarios: Routine removal of organic matter, odor-causing substances, and disinfection byproducts to enhance overall water quality.
Process Modification: Convert existing sand filtration beds into a dual-layer filtration system comprising "quartz sand + activated carbon" (by excavating 0.5 meters of the sand layer and filling the space with 0.5 meters of GAC), or construct dedicated activated carbon adsorption tanks.
Operating Parameters:
Filtration Rate: 8–12 m/h (to ensure sufficient contact between the water flow and the activated carbon). Contact Time: 10–15 minutes (to satisfy the requirements for organic matter adsorption).
Backwashing: Once per week, at an intensity of 15–20 L/(s·m²) (to remove trapped suspended solids and restore adsorption capacity).
Operating Cycle: 6–12 months (Upon saturation, regeneration is performed using hot air or steam; the cost of regeneration is only 30% of that of new carbon).

Application Process

Taking the advanced treatment upgrade at the Shanghai Taihe Water Treatment Plant as an example, the complete process is as follows:
Raw Water: Huangpu River raw water (CODmn = 5–6 mg/L; Odor Threshold Number ≥ 10; THMs = 80–100 μg/L).
Pre-treatment: Powdered Activated Carbon (PAC) dosing (10 mg/L) → Coagulation (Alum, dosing rate: 20 mg/L) → Sedimentation (Lamella clarifier; retention time: 1.5 hours).
Advanced Treatment: Granular Activated Carbon (GAC) Filter (Iodine value ≥ 950 mg/g; particle size: 0.6–2.5 mm; bed depth: 0.5 meters) → Sand Filtration (Quartz sand; bed depth: 0.7 meters).
Post-treatment: Chlorination (Dosing rate: 1.0 mg/L; Residual chlorine: 0.3–0.5 mg/L) → Clearwell (Retention time: 2 hours) → Distribution Network.

Application Results

Following the upgrade at the Shanghai Taihe Water Treatment Plant, key performance indicators demonstrated significant improvement (based on data from comparable projects within the industry):

Parameter	Before Upgrade (Conventional Process)	After Upgrade (Activated Carbon Process)	Improvement	Compliance Status
Odor Threshold	≥10	＜2	Reduced by over 80%	Complies with GB 5749-2022
CODmn（mg/L）	5-6	＜3	Reduced by over 40%	Complies with GB 5749-2022
THMs（μg/L）	80-100	＜60	Reduced by over 25%	Complies with WHO Guidelines
Resident Complaint Rate	15 times per month	0 times per month	100% eliminated	—
Taste Rating of Treated Water	2.1 (out of 5)	4.3 Stars	Increased by 104%	—

Core Advantages

Customized solutions designed specifically for municipal water treatment plants, featuring four indispensable advantages:

• Highly Targeted Products: Precisely Matched to Advanced Treatment Requirements

Our proprietary briquette-crushed activated carbon—developed using a "computer-controlled carbonization and activation" process—features a uniform pore structure (with effective particle sizes of 0.6–2.5 mm accounting for ≥90% of the product). It is specifically engineered for advanced water treatment applications; its adsorption capacity is 20% higher than that of standard Granular Activated Carbon (GAC), and it exhibits minimal loss during backwashing (with a mechanical strength of ≥93%).

• High-Efficiency Emergency Response: Rapid Action Against Sudden Contamination

Our Powdered Activated Carbon (PAC) system can be activated within just two hours (requiring no equipment modifications), enabling a rapid response to sudden contamination incidents. During the 2005 Songhua River pollution incident, the Harbin Water Treatment Plant utilized 40 mg/L of our PAC to reduce nitrobenzene levels from 0.3 mg/L to 0.005 mg/L within two hours—a level significantly lower than the national standard limit of 0.017 mg/L.

• Compliant and Reliable: Comprehensive Certification Coverage

Our products hold ISO 9001 (Quality Management), ISO 14001 (Environmental Management), and ISO 45001 (Occupational Health and Safety) certifications. We also possess the *Sanitary License Approval for Products Affecting Drinking Water Safety* issued by Shanxi Province and fully comply with the Grade I standards of GB/T 7701.2-2008 (*Coal-based Granular Activated Carbon*)—thereby fully meeting the mainstream drinking water quality standards of China, the EU, the US, and other global regions.

• Controllable Costs: High Cost-Effectiveness Across the Entire Product Lifecycle**
• Powdered Activated Carbon (PAC):** Dosed on an as-needed basis with zero initial capital investment; operational costs range from 0.1 to 0.5 RMB per ton of treated water.
• Granular Activated Carbon (GAC):** Capable of being regenerated 3 to 5 times (with regeneration costs amounting to only 30% of the cost of new carbon). The initial investment required to retrofit existing sand filtration tanks is a mere 500,000 to 1 million RMB per 10,000 tons of daily treatment capacity. While annual operational costs may increase by 5%, the rate of compliance with water quality standards rises to 100%. For instance, following its retrofit, the Shanghai Taihe Water Treatment Plant saw its annual operational costs increase by only 80,000 RMB—yet this investment successfully averted potential annual fines of 1 million RMB that would have been incurred due to non-compliance with water quality standards. Cost Analysis
• Taking a water treatment plant with a daily capacity of 100,000 tons as an example, the following table compares the costs of the activated carbon process versus the traditional process:

Item | Powdered Activated Carbon (PAC) | Granular Activated Carbon (GAC) | Traditional Process (No Activated Carbon)
Initial Investment | 0 (Utilizing existing equipment) | 5–10 million RMB | 0
Operating Costs (RMB/ton of water) | 0.1–0.5 | 0.2–0.8 | 0.05–0.1
Maintenance Costs (RMB/ton of water) | 0.02–0.05 | 0.05–0.1 | 0.01–0.02
Total Life-Cycle Costs (RMB/ton of water) | 0.3–0.8 | 0.5–1.2 | 0.1–0.2
Compliance Costs (RMB/year) | 0 | 0 | 500,000–1 million RMB (Fines)

Why Choose Us?

• Proven Track Record: We have served as a supplier for benchmark domestic projects—including the Shanghai Taihe Water Treatment Plant, Jingjiang Jiangfang Water Treatment Plant, and Jiading Yongsheng Water Treatment Plant—where our activated carbon filter media earned unanimous praise from both the design institutes (e.g., Shanghai Municipal Engineering Design Institute) and the project owners (e.g., Shanghai Chengtou Water Group) for its "stable adsorption performance and compliant effluent quality."
• Technical Expertise:Through collaborations with leading universities such as Tsinghua University and Taiyuan University of Technology, we have developed specialized products—such as "Crushed Briquette Activated Carbon" and "Silver-Loaded Coconut Shell Carbon"—to address the dual requirements of "advanced water treatment" and "emergency response." Notably, the specifications of our Crushed Briquette Activated Carbon—featuring low ash content (5–18%) and a high iodine value (900–1100 mg/g)—fully meet the stringent requirements of the GB 5749-2022 national standard.
• Global Service Network:We operate production bases across Shanxi, Ningxia, Fujian, and Xinjiang (with an annual production capacity of 45,000 tons), enabling us to offer a "customized production + localized delivery" service model. For international clients, we provide a comprehensive, end-to-end service package—encompassing "activated carbon selection, process design, and regeneration guidance"—backed by a commitment to respond to client inquiries and needs within 72 hours.