4200L/d Shipboard Sewage Treatment Plant

4200L/d Shipboard Sewage Treatment Plant

Product Introduction:

The DY-60 is designed to operate reliably under demanding marine conditions, with an ambient temperature range of 0 to 55 degrees Celsius and relative humidity not exceeding 90 percent. The system meets the norms and rules of China Classification Society, ensuring full compliance with classification requirements. All measurements and units conform to ISO standards, providing clarity for international operators and surveyors. The nameplate is fabricated from chromated stainless steel material, featuring bilingual identification in both Chinese and English for easy reference. The paint color is either according to the manufacturer's standard finish or as specified by the shipowner at the time of ordering.

Technical Parameters and Effluent Quality：

The DY-60 model sewage treatment plant is rated at approximately 3.6 kilowatts of installed power and offers a daily treatment capacity of 4,200 liters, making it suitable for vessels with crews ranging from approximately forty to sixty persons. The treated effluent quality consistently meets or exceeds all mandatory discharge standards. Total suspended solids are maintained at no more than 35 milligrams per liter. Biochemical oxygen demand over five days remains below 25 milligrams per liter. Chemical oxygen demand does not exceed 125 milligrams per liter. The most probable number of thermotolerant coliforms is limited to no more than 100 per 100 milliliters. The pH value of the treated effluent falls between 6.0 and 8.5, while residual chlorine is kept below 0.5 milligrams per liter, ensuring environmentally safe discharge.

Control System and Electrical Specifications：

The DY-60 offers both automatic and manual control modes, providing operational flexibility for normal unattended running as well as maintenance and troubleshooting situations. The main power supply is AC 415 volts at 50 hertz. All electrical motors are rated to IP44 protection class, and the electrical control box is also rated IP44, providing adequate protection against solid objects and water ingress typical of marine engine room environments. The insulation class of all motors is Class F, ensuring reliable performance under elevated temperature conditions.

Structural Design and Physical Dimensions：

The entire unit adopts a robust frame structure with all components installed on a common base, which is then connected to the ship's foundation through bolts, facilitating straightforward installation and alignment. The treatment device is primarily composed of the main tank body, air pump, crushing pump, ultraviolet sterilizer, membrane bioreactor, electric control box, valves, and associated piping. The main body is internally divided by partition plates into three distinct chambers, namely the first contact oxidation tank, the second contact oxidation tank, and the membrane bioreactor tank, allowing sequential treatment of the sewage through different stages.

Outline Drawing:

System Schematic Diagram:

Technical Specifications:

Main Components and Specifications：

The complete system includes a comprehensive set of equipment. The main tank body is constructed from carbon steel with an anti-corrosion coating, providing excellent durability in the aggressive marine environment. The crushing pump, model 0.5CWF-10, delivers a flow rate of 5 cubic meters per hour with a head of 10 meters, powered by a 1.1-kilowatt motor. The blower, model 2HD220, provides an air flow rate of 85 cubic meters per hour at 24 kilopascals pressure, driven by a 0.7-kilowatt motor, ensuring adequate aeration for the biological oxidation process. The ultraviolet sterilizer operates at 25 watts, effectively disinfecting the treated effluent without chemical addition. The plunger pump, model DZ-500, serves as the discharge pump with a flow rate of 0.5 cubic meters per hour against a pressure head of 30 meters, powered by a 0.25-kilowatt motor. The membrane bioreactor includes both external and internal membrane modules integrated into the system design. The control box is powered from the vessel's 415-volt, 50-hertz supply. Liquid level float switches, three in number, monitor the water levels within the system and control the various operating sequences automatically.

Functional Operation:

During normal operation, incoming sewage first enters the first contact oxidation tank where aerobic microorganisms begin breaking down organic pollutants. The partially treated sewage then flows into the second contact oxidation tank for further biological degradation. The mixed liquor then passes into the membrane bioreactor tank where the membrane modules perform solid-liquid separation, retaining biomass and suspended solids while allowing purified water to pass through. The permeate from the membrane bioreactor is then subjected to ultraviolet disinfection, which eliminates any remaining pathogenic microorganisms. The final treated effluent is discharged overboard by the plunger pump, with the entire process monitored and controlled by the automatic control system based on signals from the liquid level float switches.

Conclusion:

The DY-60 Marine Sewage Treatment Plant represents a fully certified, reliable, and operationally flexible solution for shipboard sewage treatment with a capacity of 4,200 liters per day. By combining contact oxidation biological treatment with membrane bioreactor technology and ultraviolet disinfection, the system delivers effluent quality that not only meets but often exceeds the strict requirements of IMO Resolution MEPC.227(64) and MARPOL Annex IV. With robust construction, comprehensive certification, and complete documentation, the DY-60 provides shipowners and operators with confidence in environmental compliance and reliable performance throughout the vessel's service life.