African Catfish Freshwater RAS Filtration System Project Case

1. Case Basic Information

1.1 Project Subject

• Provider: HELLA WATER, a professional supplier of high-performance water treatment product, specializes in customized RAS (Recirculating Aquaculture System) solutions for aquaculture industries.
• Core Product: Freshwater RAS Filtration System for African Catfish
• Project Objective: Maintain stable water quality in high-density African catfish farming, supporting daily feeding of 350kg high-protein feed and a circulating flow rate of 80–90m³/h.

1.2 System Specifications & Key Parameters

Core Operating Parameters

Parameter	Specification
Circulating Flow Rate	80–90m³/h
Daily Feeding Amount	350kg high-protein feed (40% protein content)
Target Farming Density	≈30kg/m³
Optimal Water Temperature	25–28℃
Key Water Quality Thresholds	Ammonia nitrogen <0.5mg/L; nitrite <0.1mg/L; turbidity <5NTU

Core Equipment Parameters

Equipment	Model/Key Specifications	Quantity	Core Function
Drum Filter (Mechanical Filtration)	ZLJ-900 (150–500m³/h); 60μm 316L stainless steel screen; power ≤1.5kW	1 set	Remove solid particles (residual feed, feces)
MBBR Biofilter	K5 medium (>800m²/m³ specific surface area; nitrification efficiency 500–1200g NH₄-N/m³·d)	7m³	Degrade ammonia nitrogen and nitrite
UV Sterilizer	Triogen SLP/TX-UVC-160; ≥160W UV-C output; supports 100m³/h flow	1 set	Inactivate pathogenic microorganisms
Aeration Blower	3HP; flange interface; nano-bubble aerator	2 sets (1 for use, 1 for backup)	Maintain dissolved oxygen ≥5mg/L
Filtration Pump	30m³/h flow rate; head ≥15m	2 sets (1 for use, 1 for backup)	Provide circulating power
Heat Pump	Temperature control range 25–28℃	1 set	Stabilize water temperature and preheat MBBR inflow

1.3 Design Standards & Compliance

The system adheres to industry-specific standards and quality requirements, including:

• GB/T 18407.4-2001: Safety Requirements for Aquatic Products – Aquaculture Environment
• NY 5051-2001: Pollution-Free Food – Freshwater Aquaculture Water Quality
• Technical Specifications for Recirculating Aquaculture Systems (SC/T 1135-2021)
• ISO9001: Quality Management System Certification

1.4 Application Scenarios

• High-density freshwater farming of African catfish
• Industrial aquaculture parks requiring water recycling
• Areas with limited water resources (realizing 95%+ water reuse rate)
• Aquaculture projects with strict water quality and disease control requirements, aligning with agricultural water purification goals

2. Project Core Pain Points & Requirements

2.1 Industry Common Pain Points

1. High Nitrogen Waste Load: High-protein feed (40% protein) generates significant ammonia nitrogen (≈7kg/d) and nitrite, which are toxic to fish and easily cause mass mortality.
2. Solid Waste Accumulation: Residual feed and feces accumulate rapidly, leading to increased water turbidity, reduced oxygen transfer efficiency, and secondary pollution.
3. Temperature Sensitivity: African catfish require stable water temperature (25–28℃); temperature fluctuations >3℃ significantly affect growth and survival.
4. Disease Transmission Risk: High-density farming creates favorable conditions for pathogenic microorganisms, and traditional disinfection methods are inefficient or cause drug residues.
5. High Energy Consumption: Conventional RAS systems have poor equipment matching, resulting in high energy consumption for circulation, aeration, and temperature control.

2.2 Customer Core Requirements

• Efficient Pollution Removal: Reduce ammonia nitrogen by ≥90% and solid particles by ≥95%, ensuring compliance with aquatic product safety standards.
• Stable Operation: Maintain consistent water temperature, dissolved oxygen, and water quality; adapt to fluctuations in feeding amount and farming density.
• Low Energy & Maintenance Costs: Optimize equipment configuration to reduce energy consumption; simplify maintenance procedures and extend equipment service life.
• Disease Prevention: Achieve efficient sterilization without drug residues, reducing disease occurrence rate by ≥80%.
• Water Conservation: Maximize water reuse rate (≥95%) to adapt to water-scarce environments.

3. Hella Water Customized Solutions

3.1 Process Design: Integrated Filtration-Degradation-Sterilization System

The solution adopts a “mechanical filtration → biological degradation → temperature control → sterilization → circulation” integrated process, tailored for high-density catfish farming:

1. Mechanical Filtration Stage:
   • Drum Filter (ZLJ-900): Equipped with a 60μm 316L stainless steel screen to remove 95% of solid particles (residual feed, feces), reducing the load on subsequent biological treatment. The water level/time dual-control mode and external gear drive design minimize energy consumption (power ≤1.5kW).
2. Biological Degradation Stage:
   • MBBR Biofilter with K5 Medium: The K5 medium (specific surface area >800m²/m³) forms a stable biofilm, efficiently degrading ammonia nitrogen and nitrite through microbial metabolism. The 7m³ medium volume meets the treatment demand for 7kg/d ammonia nitrogen load.
   • Heat Pump Collaboration: Preheats inflow to MBBR to 25–28℃, increasing nitrification efficiency by 30% compared to room temperature.
3. Oxygenation & Temperature Control Stage:
   • Nano-bubble Aeration System: 3HP blowers (one for use, one for backup) provide sufficient oxygen, maintaining dissolved oxygen ≥5mg/L and improving oxygen transfer efficiency by 40% compared to traditional aerators.
   • Heat Pump: Stabilizes water temperature within 25–28℃, avoiding growth inhibition caused by temperature fluctuations.
4. Sterilization & Circulation Stage:
   • UV Sterilizer (Triogen SLP/TX-UVC-160): Uses medium-pressure UV-C technology to inactivate 99.9% of pathogenic microorganisms (bacteria, viruses, parasites) without drug residues. The intelligent control system automatically adjusts UV intensity, saving 30% energy.
   • Redundant Filtration Pumps: Two 30m³/h pumps ensure continuous circulation, avoiding system shutdown due to single pump failure.

3.2 Core Technical Advantages

System Module	Technical Highlights
Mechanical Filtration	60μm high-precision screen + automatic backwashing; corrosion-resistant 316L material; low power consumption (≤1.5kW)
Biological Treatment	K5 medium with high specific surface area; long service life (>15 years); no hardening or clogging; stable nitrification efficiency
Temperature Control	Heat pump precise temperature control (±0.5℃); preheats MBBR inflow to enhance biological activity
Sterilization	Medium-pressure UV technology; broad-spectrum sterilization; intelligent energy-saving control
System Integration	PLC centralized control; linkage of water quality sensors (NH₃, DO, pH) with alarms and automatic water change functions

3.3 Intelligent Control System

• Integrates PLC controller and online water quality sensors (ammonia nitrogen, nitrite, DO, pH, turbidity) to monitor water quality in real time.
• Automatically triggers alarms and adjusts equipment operation (e.g., increasing aeration when DO is low, starting backwashing when drum filter pressure is high) to reduce manual intervention.
• Supports remote monitoring via mobile app, enabling real-time access to system operating status and water quality data.

4. Project Effectiveness Verification

4.1 Water Quality Improvement Efficiency (Based on Industry Similar Cases)

Pollutant/Indicator	Inlet Concentration	Effluent Concentration	Removal Rate/Stabilization Effect
Ammonia Nitrogen	3–5mg/L	<0.5mg/L	≥90%
Nitrite	0.5–1.0mg/L	<0.1mg/L	≥90%
Solid Particles (≥60μm)	500–1000mg/L	<25mg/L	≥95%
Turbidity	10–20NTU	<5NTU	≥75%
Pathogenic Microorganisms (E. coli)	10⁵–10⁶ CFU/mL	<10² CFU/mL	≥99.9%
Water Temperature	20–32℃ (fluctuating)	25–28℃ (stable)	±0.5℃ control precision

4.2 Operational Performance

• Stability: Continuous operation for 12 months with stable water quality; no fish mortality caused by water quality issues.
• Energy Efficiency: Total energy consumption ≤8kW·h/m³, 20% lower than conventional RAS systems (10kW·h/m³).
• Water Reuse Rate: ≥95%, saving 30,000–35,000m³ of freshwater annually (based on 80m³/h flow rate and 365 working days/year).
• Maintenance Cycle: Drum filter screen cleaning (daily); UV lamp replacement (annual); K5 medium activation (once every 2–3 years); MBBR inspection (quarterly).

4.3 Economic & Environmental Benefits

• Economic Benefits: Reduces feed coefficient by 15% (stable water quality improves feed conversion rate); lowers disease mortality by ≥80%, increasing annual output by 20–30%.
• Environmental Benefits: Reduces wastewater discharge by 95%+; avoids pollution from residual feed and feces; eliminates drug residues in aquaculture products.

5. Case Corresponding Product Quotation Description

5.1 Quotation Overview

Item	Description	Quantity	Unit Price (USD)	Total Amount (USD)
Drum Filter	ZLJ-900, 150–500m³/h, 60μm 316L screen	1 set	18,500	18,500
MBBR Biofilter System	K5 medium (7m³) + filter tank + supporting pipelines	1 set	12,000	12,000
UV Sterilizer	Triogen SLP/TX-UVC-160, ≥160W UV-C output	1 set	6,800	6,800
Aeration System	3HP blowers (2 sets) + nano-bubble aerators	1 set	5,200	5,200
Filtration Pumps	30m³/h flow rate, head ≥15m (2 sets)	2 sets	2,100	4,200
Heat Pump	Temperature control 25–28℃	1 set	9,500	9,500
Intelligent Control System	PLC controller + water quality sensors (NH₃, DO, pH, turbidity)	1 set	7,800	7,800
Installation & Commissioning	On-site installation, pipeline connection, system debugging	1 project	8,000	8,000
Total Quotation	–	–	–	72,000

5.2 Quotation Terms

Term Type	Details
Validity Period	30 working days from the date of quotation
Payment Terms	30% advance payment, 50% before shipping, 20% after acceptance
Production & Delivery Cycle	45 days (from receipt of advance payment to equipment delivery)
Incoterms	DAP (Delivered at Place)
Warranty Period	1 year from the date of acceptance (free repair/replacement for non-human damage)
Country of Origin	China
Product Condition	Brand new, factory-tested qualified products

5.3 Additional Notes

• The quotation includes core equipment, control system, and on-site installation/commissioning; civil engineering (filter tank foundation, machine room) is excluded.
• Spare parts (UV lamps, screen filters, aerator membranes) are provided at 10% of the equipment price for long-term use.
• Customization: Equipment specifications (flow rate, medium volume) can be adjusted according to actual farming scale and local water quality.

6. Frequently Asked Questions (FAQ)

6.1 Installation & Commissioning

Q: What are the on-site installation requirements for the system?

A: The system requires an indoor machine room (≥30m²) and outdoor equipment installation area (≥50m²). It needs access to 380V AC power supply (installed capacity ≥20kW) and a water source for supplementary water (≤5% of circulating flow rate). We provide detailed installation drawings and send 2–3 technicians for on-site installation and commissioning, which takes 7–10 days.

6.2 Maintenance & Upkeep

Q: How to activate and maintain the K5 medium in the MBBR biofilter?

A: During the start-up period, add nitrifying bacteria agents to accelerate biofilm formation (2–3 weeks to reach stable treatment efficiency). The K5 medium has a service life of >15 years and requires no replacement; only annual inspection for sediment accumulation is needed, and backwashing can be performed if necessary.

Q: What is the service life of key components such as UV lamps?

A: The UV lamp has a service life of about 12,000 hours (≈1 year of continuous operation) and needs annual replacement. The drum filter screen (316L stainless steel) has a service life of 5–8 years; the aerator membrane needs replacement every 2–3 years. We provide preferential prices for spare parts for long-term supply.

6.3 Warranty & After-Sales

Q: What is covered under the 1-year warranty period?

A: Within the warranty period, we provide free repair or replacement for faults caused by design, manufacturing, or material defects, including core equipment (drum filter, MBBR tank, UV sterilizer), pumps, blowers, and control system components. Human damage, improper operation, and natural disasters are not covered.

Q: How to get after-sales technical support?

A: You can contact our after-sales team via email or phone. We respond to inquiries within 2 hours and provide remote technical guidance; for on-site maintenance needs, technicians can be dispatched within 72 hours (additional fees apply for non-warranty services). We also conduct quarterly return visits to monitor system operation.

6.4 Operational Cost

Q: What is the estimated monthly operating cost of the system?

A: The main operating costs include electricity and spare parts. The monthly electricity cost is about USD 1,800–2,200 (based on 80m³/h flow rate, 8kW·h/m³ energy consumption, and 0.1USD/kW·h electricity price). The annual spare parts cost is about USD 1,500–2,000, with a total monthly operating cost of about USD 2,000–2,400.

6.5 Safety & Compliance

Q: Will the UV sterilizer affect fish or aquatic product quality?

A: No. The UV-C output of the system is designed to inactivate pathogenic microorganisms without generating harmful by-products or drug residues. The treated water meets NY 5051-2001 “Pollution-Free Food – Freshwater Aquaculture Water Quality” standards, ensuring the safety of aquatic products.

Q: How to handle sudden water quality deterioration (e.g., sharp increase in ammonia nitrogen)?

A: The intelligent control system will automatically trigger an alarm and start the emergency plan: increase aeration intensity to improve dissolved oxygen, start the backup pump to enhance circulation, and open the supplementary water valve to dilute pollutants. At the same time, our technical team will provide remote guidance to adjust feeding amount and activate emergency biological treatment measures.