[Chinese Mainland] Shaanxi's First Prefabricated Wastewater Treatment Plant Completed and Put into Operation: Construction Period of Xixian New Area No. 10 Reclaimed Water Plant Compressed to 6-8 Months

Located in Qinhan New Town, Xixian New Area, the Xixian New Area No. 10 Reclaimed Water Plant is Shaanxi's first prefabricated sewage treatment plant, treating 2万 tons of sewage per day on only 19 mu of land. The assembly rate of core structures reaches 85%, the construction period is compressed from the conventional 18 months to 6–8 months, building material usage is reduced by 86%, carbon emissions are lowered by 75%, and total investment is saved by more than 20%.

I. A Sewage Plant That "Doesn't Look Like a Sewage Plant"

Walking into the plant area, one sees no towering cooling towers, hears no roar from aeration tanks, and smells no distinctive odor typical of traditional sewage treatment plants. On the level green space, the plant buildings lie quietly on the ground—this is the first impression described by staff of the Xixian New Area No. 10 Reclaimed Water Plant.

This "unlikeness" is precisely the design intent. Traditional sewage treatment plants occupy large areas, have long construction periods, and consume high energy, and the NIMBY effect caused by noise and odor often deadlocks site selection. In urban new areas where land resources are scarce, the contradiction is particularly acute: on one hand, treatment capacity must be added; on the other, there is no land to spare and no time to wait. Prefabricated construction offers a path that responds to both constraints simultaneously.

The project is operated by Shaanxi Construction Engineering Qinhan Water Affairs Environmental Protection Co., Ltd. The Reclaimed Water Plant can treat 2万 tons of domestic and industrial sewage daily, which after multiple treatment stages is converted into clear reclaimed water for uses such as greening and heating.

II. Prefabricated Construction: Compressing the Construction Period from 18 Months to 6–8 Months

The core change of a prefabricated sewage plant is moving a large amount of on-site wet work into the factory. The project adopts a "factory-prefabricated modules + on-site assembly" approach, with main construction and internal equipment installation completed simultaneously in the factory, greatly reducing on-site work.

Public data provides the quantified effects of this model:

• Assembly rate 85%—the assembly proportion of the plant's core structures, a key indicator determining the construction period and on-site pollution levels.
• Construction period compressed to 6–8 months—the conventional construction period is 18 months, a reduction of more than half, which is particularly critical for projects that must be operational before peak water demand or assessment deadlines.
• Building material usage reduced by 86%—mold reuse and precise cutting in factory production significantly reduce material waste.
• Carbon emissions lowered by 75%—stemming both from material savings and from reduced on-site machinery and transportation operations.
• Total investment saved by more than 20%—the reduction in financial costs and on-site management costs brought by the shortened construction period, together with the cost advantages of factory-scale production, creates room for savings.

In addition, on-site dust, noise, and construction waste are greatly reduced. For projects adjacent to residential areas or built-up urban districts, this is often more persuasive than investment savings—it directly lowers the social resistance to project implementation.

III. Process Level: Eliminating the Secondary Clarifier, Using Aeration Off-Gas Instead of Plug-Flow

Prefabrication is not only a change in construction method; it also forces a simplification of the process flow. The project adopts a prefabricated biological reaction tank, streamlining the secondary clarifier step of traditional processes and achieving efficient synergy between biological degradation and sludge-water separation within limited space.

Even more ingenious is energy reuse: the Reclaimed Water Plant relies on aeration device off-gas to replace traditional mixing and plug-flow equipment. The aeration system must supply air continuously anyway; using its off-gas for mixing and plug-flow means applying one unit of energy in two places, greatly simplifying equipment count while reducing O&M costs. Achieving a treatment capacity of 2万 tons/day on 19 mu of land—the cumulative contribution of such details cannot be underestimated.

The result is that overall operational energy consumption is greatly reduced compared with traditional sewage treatment plants. For operators, energy and O&M account for a far higher proportion of the full life-cycle cost of a sewage treatment plant than construction cost; savings at the construction stage are one-time, while savings at the operational stage last more than twenty years.

IV. Why Prefabrication Deserves Attention Today

Prefabricated buildings have been promoted in the housing construction sector for many years, but in the sewage treatment field they are still a new thing, because the requirements of sewage plant structures for seepage prevention, corrosion resistance, and structural integrity are far higher than those of ordinary buildings—once a tank leaks, the consequences are difficult to remedy. The practice of the Xixian New Area No. 10 Reclaimed Water Plant shows that these technical obstacles can already be overcome at the process and material levels.

From the demand side, three trends are opening up space for prefabricated sewage plants:

• Incremental Demand from New Urban Districts — New districts introduce population and industries rapidly, so treatment capacity must keep pace or even stay ahead, yet both land and construction schedules are tight.
• Upgrading and Expansion of Existing Plants — A large number of old plants face the dual pressure of upgrading and expansion, while land acquisition is nearly impossible; prefabricated construction enables in-situ renovation within limited land.
• Carbon Reduction Constraints Entering Infrastructure — Embodied carbon from building material production and construction phases is beginning to be included in assessments, and the carbon reduction advantages of prefabricated construction now have a quantifiable basis.

Shaanxi itself is a typical sample of this demand: the province's per capita water resources are only half of the national average, with uneven temporal and spatial distribution and prominent supply-demand conflicts. During the "14th Five-Year Plan" period, the province's average annual growth rate of unconventional water utilization reached 21.5%, and water consumption per 10,000 yuan of GDP decreased by 17.15% compared with the "13th Five-Year Plan" period. Against this backdrop, local construction enterprises are also transforming from single construction contractors into full-chain service providers of "investment-construction-operation," combining construction innovations such as prefabrication with water ecological governance capabilities.

V. Three Insights for the Industry

• Evaluate construction schedule as a resource — For projects with tight schedules, the half-year saved is often more valuable than the investment saved; when comparing options, the schedule should be converted into financial and compliance benefits.
• Prefabrication rate does not equal full prefabrication — The standardization of interfaces for equipment, pipelines, and instruments is the key to on-site assembly efficiency; modular coordination at the design stage deserves more investment than the prefabrication ratio.
• Bring operations forward to the design stage — Improvements such as using aeration exhaust gas to replace push-flow can only be achieved when process design and equipment selection are considered together; operators should intervene at the scheme stage.

From "how to build" to "where to build and how to integrate into the city," prefabricated wastewater treatment plants are providing new answers. When treatment capacity no longer necessarily means large land occupation and long construction periods, the layout logic of urban water environment infrastructure will also be rewritten.

TIANYI TECH Co., Ltd. (TIANYI LIMITED) has long been deeply engaged in the fields of wastewater treatment and reclaimed water reuse. Centering on three major directions — low-carbon processes, resource recovery, and smart operations — it provides full-chain services from scheme design, equipment manufacturing, engineering construction to operation management for municipal wastewater treatment plants, industrial parks, and various water-using entities. With the goal of "stable compliance, energy saving and consumption reduction, and resource circulation," the company continues to help customers reduce operating costs and enhance system resilience in the green and low-carbon transition.

Source: Shaanxi Provincial People's Government Portal "New Ideas Bring New Opportunities" (2026年10月8日) and related public reports.