Aquaculture

Aquaculture Wastewater Management

Challenges and Advanced Solutions

Industry Challenges and Technological Context

Aquaculture wastewater contains high ammonia (NH₃-N), nitrite (NO₂⁻), organic residues (uneaten feed, feces), and antibiotics, posing risks to aquatic ecosystems and farm productivity. Intensive farming practices and climate variability exacerbate these challenges, requiring robust treatment systems to maintain water quality and comply with regulations like the FAO’s Code of Conduct for Responsible Fisheries.

Core Challenges in Aquaculture Wastewater

Ammonia & Nitrite Toxicity

NH₃-N >2 mg/L and NO₂⁻ >1 mg/L can cause fish mortality.

Low Dissolved Oxygen (DO)

High organic loads reduce DO to <4 mg/L, stressing aquatic life.

Antibiotic Resistance

Residual antibiotics promote resistant bacteria in water bodies.

Space Constraints

Limited land for traditional treatment systems in coastal/offshore farms.

Innovative Treatment Processes

High-Surface-Area MBBR for Biofilm Optimization

● Technology: MBBR carriers with 800 m²/m³ surface area host nitrifying bacteria (e.g., Nitrosomonas, Nitrobacter) to convert NH₃-N → NO₂⁻ → NO₃⁻.

Efficiency Gains:

● Ammonia Removal: >95% at hydraulic retention time (HRT) of 4 hours.

● Compact Design: 50% smaller footprint vs. activated sludge.

Integrated Recirculating Aquaculture Systems (RAS)

● Technology: Combines MBBR, drum filters, and UV disinfection for closed-loop water reuse.

Key Components:

● Drum Filter: Removes 90% suspended solids (TSS <10 mg/L).

● UV Sterilization: Inactivates 99.9% pathogens without chemical residues.

Smart DO Management

● Technology: IoT sensors + AI algorithms adjust aeration in real time, maintaining DO at 5-7 mg/L.

● Energy Savings: 25% reduction in aeration costs compared to fixed-speed blowers.

Addressing Emerging Challenges

Antibiotic Degradation via AOP

● Technology: UV/H₂O₂ breaks down oxytetracycline and enrofloxacin into non-toxic fragments.

Efficiency Gains:

● Case Study: A shrimp farm in Thailand reduced oxytetracycline from 500 µg/L to <1 µg/L, eliminating resistance gene risks.

Sludge-to-Feed Conversion

● Technology: Dehydrated sludge (moisture <15%) is processed into protein-rich feed supplements.

● Efficiency: 1 ton sludge → 300 kg feed (35% protein content).

Case Studies

High-Density Shrimp Farm in Vietnam

1

Challenge

NH₃-N 8 mg/L, NO₂⁻ 5 mg/L, and recurrent disease outbreaks.
2

Solution

MBBR + RAS: Installed 200 m³ MBBR reactors with 800 m²/m³ carriers.

AI-Driven Aeration: Maintained DO at 6 mg/L.
3

Results

Parameter Before Upgrade After Upgrade

NH₃-N 8 mg/L 0.3 mg/L

NO₂⁻ 5 mg/L 0.1 mg/L

Shrimp Survival 65% 92%

ROI: 2.5 years via reduced feed costs and disease treatment.

Offshore Salmon Farm in Norway

1

Challenge

Space constraints and strict EU nitrate limits (NO₃⁻ <50 mg/L).
2

Solution

Compact MBBR Modules: Stackable units installed on floating platforms.

Denitrification Biofilters: Converted NO₃⁻ to N₂ gas.
3

Results

NO₃⁻: 120 → 35 mg/L

Space Saved: 70% compared to land-based systems.

Future Trends

AI-Powered Disease Prediction

Early warning systems for waterborne pathogens.
Green Feed Additives

Reduce nitrogen excretion by 30% through enzyme-enhanced feeds.

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Why the Industry Adopts These Solutions? Why the Industry Adopts These Solutions?

Proven Efficiency: MBBR achieves 95% ammonia removal in 4 hours.

Sustainability: RAS systems recycle 90% water, reducing coastal pollution.

Cost-Effectiveness: 25% lower operating costs vs. traditional methods.

INQUIRY NOW

Parameter	Before Upgrade	After Upgrade
NH₃-N	8 mg/L	0.3 mg/L
NO₂⁻	5 mg/L	0.1 mg/L
Shrimp Survival	65%	92%