Against the backdrop of increasingly close global environmental cooperation, Chinese environmental equipment manufacturing enterprises are accelerating their entry into the international market. The U.S. wheat washing wastewater containerized treatment project undertaken by Shandong Zhongqiao Enlightenment Environmental Protection Equipment Co., Ltd. is a representative cross-national environmental engineering practice. The successful delivery of this project fully demonstrates Zhongqiao Enlightenment's technical strength and project execution capability in the field of containerized integrated sewage treatment equipment.
The project is located in the wheat-producing region of the American Midwest. The client is a large grain processing enterprise whose main business includes wheat washing, screening, and primary processing. The wheat washing process generates a large volume of wastewater containing wheat husks, soil, fine sand, and organic suspended solids, with a daily wastewater volume of approximately 150 cubic meters. The raw wastewater has a COD concentration between 800 and 1,200 mg/L, suspended solids concentration exceeding 1,500 mg/L, and a slightly acidic pH (5.5-6.5), exhibiting typical characteristics of food processing wastewater. Due to the local environmental authority's strict discharge standards, effluent COD must be below 60 mg/L, suspended solids below 20 mg/L, and pH must be adjusted to within the range of 6.5-8.5. The client's existing treatment facilities could no longer meet the new discharge requirements, creating an urgent need for systematic upgrading and retrofitting.
Upon receiving the project inquiry, Zhongqiao Enlightenment quickly assembled a project team composed of process engineers, mechanical engineers, and electrical engineers, and conducted in-depth technical communication with the client at the earliest opportunity. Through detailed analysis of the wastewater quality test report provided by the client, combined with on-site conditions surveyed via remote video inspection, the project team completed the solution design within two weeks. Considering the client's limited site area and tight project schedule, the team ultimately determined a solution using containerized integrated sewage treatment equipment, integrating all treatment units within a standard shipping container for overall transportation and rapid deployment.
In terms of process route design, targeting the typical characteristics of wheat washing wastewater, the project team designed a combined treatment process of "pre-screening + coagulation dissolved air flotation + AO biochemical treatment + sedimentation and filtration + disinfection." The pretreatment section features a rotary mechanical screen (2 mm bar spacing) to intercept wheat husks and large particle impurities in the wastewater, followed by a pipe mixer dosing PAC and PAM coagulants, entering the YW dissolved air flotation machine for solid-liquid separation to remove the majority of suspended solids and some organic matter. The flotation effluent enters the AO biochemical treatment system, where denitrification occurs in the anoxic section and the activated sludge degrades remaining organic matter in the aerobic section, with the mixture recirculated to the anoxic section for nitrogen and phosphorus removal. After biochemical treatment, the effluent undergoes sludge-water separation in a sedimentation tank, then enters a sand filtration unit for advanced filtration, and finally achieves compliant discharge after UV disinfection. The entire process design balances treatment efficiency and operational stability, with all effluent indicators surpassing the client's discharge standard requirements.
During the equipment manufacturing phase, Zhongqiao Enlightenment fully leveraged the manufacturing advantages of its 40,000-square-meter production base, strictly producing and processing in accordance with the American ASME standard and the client's technical specifications. The container body adopts a Q345B structural steel frame, with exterior walls clad in 50 mm-thick rock wool insulation, and interior walls lined with 316L stainless steel plates for corrosion protection to adapt to the variable U.S. climate conditions. Internal equipment includes a screen machine, flotation machine, biochemical tank aeration system, chemical dosing system, sludge dewatering system, and PLC control cabinet. All equipment was installed and commissioned at the factory, followed by a 72-hour continuous full-load trial run. After all performance indicators met design requirements, the equipment was sealed and shipped.
Transportation and on-site installation were major challenges of this project. The equipment was shipped from a Chinese port to a U.S. West Coast port, with the entire sea voyage taking approximately three weeks. After arriving at the destination port, it was transported to the project site by flatbed trailer. Zhongqiao Enlightenment dispatched two engineers to the site in advance to guide the installation. After the equipment was hoisted into position, it only required connection of inlet/outlet water pipes, power cables, and chemical dosing pipelines before operation could commence. From equipment arrival to water commissioning took only five days, far shorter than the client's expected two-week installation period, for which the client expressed high satisfaction.
After the project was put into operation, Zhongqiao Enlightenment established a remote operation and maintenance monitoring platform, collecting real-time equipment operational data through IoT technology, including water quality parameters of each treatment unit, equipment operating status, and energy consumption data, enabling remote fault diagnosis and technical support. Meanwhile, the company prepared a detailed operation and maintenance manual for the client and conducted a three-day systematic training for the client's operation and maintenance personnel, ensuring the client's team could independently carry out daily operation and maintenance management.
Operational data shows that after the system achieved stable operation, the effluent COD was consistently below 40 mg/L, suspended solids below 15 mg/L, and pH controlled between 7.0 and 7.5, fully surpassing the discharge standard requirements. The energy consumption of the entire system is approximately 0.45 kWh per ton of water treated, with operating costs controlled within $1.2 per ton, demonstrating excellent economic performance. The client gave high praise to the equipment quality, engineering service, and technical support provided by Zhongqiao Enlightenment, and the two parties have already begun in-depth discussions on the subsequent Phase II expansion project.
The successful delivery of this U.S. wheat washing wastewater containerized treatment project is another important achievement of Zhongqiao Enlightenment's internationalization strategy. In the future, Zhongqiao Enlightenment will continue to provide global customers with one-stop sewage treatment solutions through high-quality products and professional services, enabling Chinese-made environmental equipment to deliver greater value on the international stage.
