Containerized MBR System Treats Slaughterhouse Wastewater

A mid-sized poultry slaughterhouse in eastern China processes approximately 15,000 chickens per day, generating 120 cubic meters of wastewater daily with characteristically high concentrations of blood, fats, proteins, and biodegradable organic matter. The raw effluent exhibited COD levels averaging 2,800 mg/L, BOD5 around 1,500 mg/L, ammonia nitrogen at 120 mg/L, and oil and grease exceeding 200 mg/L. These parameters far exceeded the discharge limits set by the local environmental protection bureau, which required the facility to achieve COD below 80 mg/L, BOD5 below 30 mg/L, ammonia nitrogen below 15 mg/L, and oil and grease below 10 mg/L before discharging into the municipal sewer network.

The slaughterhouse had been operating with a basic screening and settling system that was clearly inadequate for the pollutant load. Regulatory pressure was mounting, and the facility faced the risk of production suspension if compliance was not achieved within a specified timeframe. The plant manager needed a treatment solution that could be deployed rapidly, operated with minimal specialized staffing, and fit within a constrained budget. After evaluating proposals from several integrated wastewater treatment equipment manufacturers, the slaughterhouse selected Zhongqiao Enlightenment to design, manufacture, and commission a complete treatment system.

Zhongqiao Enlightenment proposed a two-stage treatment approach combining a dissolved air flotation (DAF) pretreatment unit with a containerized MBR integrated wastewater treatment system. The DAF unit was specified to remove the bulk of fats, oils, grease, and suspended proteinaceous solids before the effluent entered the biological treatment stage. This pretreatment step was critical because the high oil and grease content in slaughterhouse wastewater can rapidly foul MBR membranes, reducing flux and increasing chemical cleaning frequency. By removing over 85 percent of oil and grease upstream, the DAF system protected the membrane bioreactor and ensured stable long-term operation.

The biological treatment stage was configured as a containerized MBR system housed in a standard 40-foot shipping container. Inside the container, the treatment train included an anoxic zone for denitrification, an oxic zone for carbonaceous removal and nitrification, and a membrane filtration tank equipped with submerged hollow-fiber PVDF membrane modules with a pore size of 0.04 microns. The containerized design provided several advantages for this project: rapid deployment without civil construction, mobility for potential future relocation, and a controlled environment for the electrical and control panels that protected them from the humid and corrosive atmosphere typical of slaughterhouse facilities.

The DAF pretreatment unit was delivered as a skid-mounted system measuring 4 meters by 2 meters, installed adjacent to the containerized MBR unit on a level concrete pad. The entire treatment system was installed and commissioned within 25 days of equipment delivery. Zhongqiao Enlightenment's engineering team handled all mechanical and electrical connections, performed the initial startup and process acclimation, and provided operator training over a five-day commissioning period. The slaughterhouse did not need to halt production at any point during installation, as the new system was constructed alongside the existing drainage network and switched over during a scheduled weekend maintenance window.

Following the acclimation period, the combined DAF and MBR system achieved consistent compliance with all discharge parameters. The DAF unit reduced influent COD from 2,800 mg/L to approximately 900 mg/L, removed 88 percent of oil and grease, and eliminated over 80 percent of suspended solids. The MBR system then further treated the DAF effluent, producing final permeate with COD averaging 45 mg/L, BOD5 below 15 mg/L, ammonia nitrogen at 3 mg/L, and turbidity below 0.5 NTU. Oil and grease in the final effluent were consistently below detection limits. The membrane system operated at a stable flux of 14 liters per square meter per hour with chemical cleaning intervals of approximately 60 days, confirming that the DAF pretreatment effectively protected the membranes from fouling.

The PLC-based control system provided by Zhongqiao Enlightenment enabled fully automated operation of the entire treatment train. The DAF unit's recirculation pump speed was automatically adjusted based on real-time effluent turbidity measurements, optimizing chemical dosing and energy consumption. The MBR system's aeration blowers were controlled by variable-frequency drives responding to dissolved oxygen readings, reducing power consumption during low-load periods. All operational data was logged and accessible via a cloud-based dashboard, allowing the plant manager to monitor system performance remotely from a smartphone. Automatic SMS alerts were configured for any parameter excursions, ensuring rapid response to potential issues.

The slaughterhouse plant manager shared his experience: “Choosing Zhongqiao Enlightenment as our integrated wastewater treatment equipment manufacturer was the right decision. The combination of DAF pretreatment and containerized MBR solved our high-strength slaughterhouse wastewater problem completely. We have passed every regulatory inspection since commissioning, and the automated operation means our staff only needs to spend about 30 minutes per day on routine checks. The containerized design also means we can potentially relocate the system if we move to a new facility in the future, which protects our investment.”

The operating costs of the combined system have proven highly competitive. The DAF unit consumes approximately 2.5 kW of power and requires 8 to 10 kg per day of polyaluminum chloride coagulant and 2 kg per day of polyacrylamide flocculant. The MBR system's total power consumption averages 18 kW including aeration, permeate pumping, and membrane scouring. Chemical cleaning of the membranes is performed every 60 days using approximately 40 liters of sodium hypochlorite solution per cycle. The total operating cost, including chemicals, electricity, and sludge disposal, amounts to roughly 0.85 USD per cubic meter of wastewater treated, which is well below the industry average for slaughterhouse wastewater treatment and significantly lower than the sewer discharge surcharges the facility would have faced without adequate treatment.

Zhongqiao Enlightenment provides ongoing after-sales support including quarterly preventive maintenance visits, annual membrane integrity testing, and 24-hour remote technical assistance. The company's service network covers all of China and supports international clients through regional service partners. This project demonstrates how the strategic combination of DAF pretreatment and MBR technology, delivered by an experienced integrated wastewater treatment equipment manufacturer, can solve challenging industrial wastewater treatment problems efficiently and cost-effectively within tight project timelines.