High-Concentration Integrated Anaerobic-Aerobic System for Slaughterhouse Waste

The High-Concentration Integrated Anaerobic-Aerobic System for Slaughterhouse Waste is a next-generation, compact wastewater treatment unit specifically developed for the slaughtering and meat processing industry. Slaughterhouse wastewater is characterized by "three highs and one low": high organic concentration (COD), high suspended solids (SS), high fats/oils, and a low carbon-to‑nitrogen ratio. Traditional single-stage processes struggle to achieve consistent compliance.

This system deeply integrates high-efficiency anaerobic digestion with mature aerobic contact oxidation. Through structural optimization and enhanced microbial cultivation, it is specifically designed to remove proteins, fats, blood, and suspended solids. The modular, integrated design offers a small footprint, strong shock-load resistance, low operating costs, and stable effluent quality.

The core process is based on anaerobic‑anoxic‑aerobic biochemical synergy, precisely controlling the environment for different microbial populations to achieve high removal efficiencies.

The front end uses an enhanced upflow anaerobic sludge blanket or hydrolysis/acidification reactor. Under high‑load shock, anaerobic microorganisms break down large‑molecule, long‑chain fats and proteins into volatile fatty acids. This not only significantly reduces the load on the downstream aerobic stage, but also converts refractory organic nitrogen into ammonia, preparing it for subsequent nitrogen removal.

The biological contact oxidation tank is filled with high‑specific‑surface area media. Under aeration, aerobic bacteria thoroughly oxidize organics, while nitrifying bacteria convert ammonia to nitrate. Thanks to the anaerobic pretreatment, sludge bulking is highly unlikely, ensuring stable operation.

An efficient mixed‑liquor recycle pump returns nitrate from the aerobic stage to the front anoxic zone. Using organic carbon in the raw wastewater as an electron donor, denitrifying bacteria reduce nitrate to nitrogen gas, achieving high total nitrogen removal and preventing eutrophication.

Slaughterhouse discharge is characterized by time‑concentrated peaks and wide fluctuations. Our system is designed for a volumetric loading rate of 1.5–4.5 kg COD/(m³·d). The buffering capacity of anaerobic biomass withstands pH and concentration shocks without system collapse – ideal for the irregular flow patterns of small to medium‑sized slaughterhouses.

Conventional concrete tanks (equalization, primary settling, anaerobic, aerobic, secondary settling) are integrated into one skid‑mounted or buried unit. Land footprint is reduced by 30–50% compared to traditional processes. Buried units allow surface greening or parking, avoiding occupation of production space.

The front‑end anaerobic stage requires no aeration, substantially cutting electricity bills. For larger installations, enclosed anaerobic reactors can be equipped with biogas collection – the biogas can heat boilers or generate electricity, achieving waste‑to‑energy resource recovery.

Multi‑stage sedimentation together with stable biofilm eliminates sludge bulking issues. A PLC‑based automatic control system continuously monitors DO, pH, and water level, enabling unattended operation – only periodic inspection is required.

• Livestock slaughtering: swine, cattle, sheep, poultry (chicken, duck, etc.)
• Meat processing: sausages, ham, cooked products
• Similar food industry wastewaters containing oils, fats, and proteins

Influent → Mechanical screen (hair/grit removal) → Grease trap / grit chamber → Equalization tank → DAF unit → Integrated unit (Anaerobic + Aerobic + Clarifier) → Disinfection / Filtration → Discharge

To address the two persistent  points of slaughterhouse wastewater – odor generation and sludge bulking – our system optimizes the anaerobic‑to‑aerobic ratio and aeration pattern to fundamentally inhibit filamentous bacterial growth, ensuring excellent sludge settleability. The fully enclosed anaerobic tank design effectively controls odor emission, improving the plant’s environmental hygiene.

From high‑strength blackwater to clear, compliant effluent – this system provides the most economical and stable all‑in‑one solution.