New concept modular wastewater treatment plant is adopted to solve the difficulties of rural domestic sewage

As for the treatment of rural sewage, the Onyx believes that it is necessary to "refine the agricultural water and adapt to the local water conditions with the main and complement linked", and that the rural water environment treatment shall adopt "the treatment planning focused on gethering, supplemented by dispersion"; The process selection is mainly based on the mature AO   technical innovation-based unmanned duty, supplemented by MBR that is difficult to operate and manage, biological contact oxidation, etc"; The EPC project is implemented with the standardized, modular and integrated treatment units in combination, supplemented by traditional civil buildings/structures". In 2017, a full-cover PPP project for domestic sewage treatment was launched in the urban area of Xianfeng County, Hubei Province, covering 8 townships, including Xiaocun Township, Tangya Town, Dingzhai Township, Huolongping Township, Yangdong Town, Zhongbao Town, Jindong Township and Daluba Town.  Beijing Onyx Environmental Technology Co., Ltd. was responsible for the process design, equipment supply, and installation, and biochemical debugging of the project plant area, and transferred it to BOT Party with qualifiedeffluent wate.


"There is a long way to go! The decentralized wastewater treatment in China has only started for less than 10 years, while Japan has treated for nearly 50 years. Therefore, the Chinese decentralized wastewater treatment still has a long way to go."In September 2018,  Cai Xiaoyong, the founder of Onyx, once said after he visited Japan, "Chinese enterprises should increase investment in technology as soon as possible to clarify problems, understand procees, realize real products standardization through technical innovation, and provide better support for the market through large scale production and refined services."


Sewage treatment is a relatively complex system. To build an ecosystem to ensure the effective degradation of pollutants by microorganisms, different enterprises may have different processes. Cai Xiaoyong believes that environmental protection enterprises shall take full account of the specific features such as large fluctuation of rural sewage flow, unstable water quality, relatively short flow path, and relatively shallow water depths to carry out some detailed designs. Although these detailed designs require a lot of investment by enterprises, however, only in this way can real standardization, normalization and refinement be achieved in the true sense.

At the beginning of the project, what Onyx considered most is to adopt technologies that can resist water quality and quantity impacts based on the water quality characteristics of rural sewage.The SATBR self-aerated three-phase biofilm reactor fluidized bed technology is adopted to realize the fluidized bed mud film process and self-aerated dissolved oxygen regulation, with strong anti-shock load capability.


During the construction, the SATBR modular integrated waterworks mode is adopted. The enamel modular design and splicing technology make it replace the traditional structures. The main structure of the process adopts modular and integrated forms, which can adapt to the site requirements more flexibly. The installation is fast, thus shortening the construction cycle and can be reused. At the same time, the equipment is simple and easy to maintain. However, the following difficulties were encountered when the equipment was installed and got into the single machine and the whole plant linkage commissioning:

The actual incoming water amount is much lower than the designed value;

The incoming water quality load (especially COD or BOD5) is much lower than the designed incoming water quality.

In fact, the above problems are common and difficult to be avoided in village projects. In view of this, Onyx actively optimizes its own process technology to adapt to the current situation, upgrades the control program on the original central control system, increases linkage control mode on small water quantity of whole plant, so as to realize automatic operation of the system; In some water plants with low influent water quality load, the activated sludge shall be cultivated by adding carbon source during commissioning, and then the dissolved oxygen control, return ratio of nitrated liquid, sludge return ratio and other parameters of each area shall be optimized according to the influent water quality, so as to realize the optimal utilization of carbon source and finally meet Class A discharge standard in GB18918-2002.

In terms of operations, Onyx believes that operations are a huge test for the decentralized wastewater treatment. If the wastewater treatment facilities are not made to function effectively in ongoing operation, the impact on the environment and on the ecology must be catastrophic. When developing the decentralized wastewater treatment markets, domestic firms may propose the concept of "maintenance free" for competitive purposes. However, Cai Xiaoyong pointed out that such statements would mislead the decision makers of government departments, because in practical terms, no business or project can actually achieve maintenance free.

On the basis of ensuring the water output requirements, Onyx believes that it has achieved low comprehensive operating cost, low requirements for operating personnel, simple operation and maintenance of the water plant, and can realize unattended to the maximum extent.At the same time, taking into account the contiguous governance, the Internet of Things interface has been reserved in each project. By choosing one of the wastewater treatment plants as the central plant for monitoring, cloud control operation and real-time monitoring can be achieved. Under the premise of ensuring stable operation of the project, efforts are made to save the operation and maintenance personnel and maintenance costs.


Post time: Feb-16-2022