[Chinese Mainland] EPC Contract Awarded at RMB 634 Million: Wuhan Erlangmiao Wastewater Treatment Plant to Upgrade 240,000 m³/d to Quasi-Class IV Standard, with 71,900 m² of Capping and Odor Control plus Concurrent Construction of a Reclaimed Water Utiliz

The winning bid result for the general contracting (EPC) of the upgrading and capping project of Wuhan Erlangmiao Wastewater Treatment Plant has been announced. The winning consortium consists of four units including Wuhan Water Engineering Construction Co., Ltd., with a winning bid amount of 63359.0751万 yuan (approximately 6.34亿 yuan). The project maintains a scale of 24万m³/d, with main indicators upgraded from Grade 1B to Quasi-Class IV, a total capping area of approximately 71876 square meters, and simultaneous construction of a reclaimed water utilization project within the plant area.

A major urban wastewater treatment plant that has been in operation for many years is being redefined. This renovation of Erlangmiao Wastewater Treatment Plant does not add treatment capacity, but rather elevates effluent quality, plant environment, and resource utilization simultaneously — this is also the typical form of existing wastewater plant renovation in the core areas of provincial capital cities: unchanged scale, upgraded standards, composite functions.

Based on the winning bid amount and treatment scale, the unit investment of this project is approximately 2640元/m³·d, which can serve as a reference coordinate for the cost level of "upgrading + capping" renovation of large wastewater plants in similar urban central areas.

Upgrading: From Grade 1B to Quasi-Class IV, with Other Indicators Following Grade 1A

The leap in effluent standards is the technical mainline of this project, involving three levels of requirements:

• Main indicators at Quasi-Class IV — The three main indicators of CODcr, NH3-N, TP in the effluent meet the Class IV water standards of the "Environmental Quality Standards for Surface Water" (GB 3838—2002), commonly known in the industry as "Quasi-Class IV";
• Other indicators at Grade 1A — Indicators not listed among the above three follow the Grade 1A standards of the "Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant" (GB 18918—2002);
• Starting point is Grade 1B — The current effluent follows Grade 1B standards, and this renovation represents a leap of two levels in main indicators.

From Grade 1B to Quasi-Class IV, the difficulty is concentrated in advanced removal of Total Phosphorus and Total Nitrogen. To stably achieve the indicator ranges corresponding to Class IV water on the basis of the original secondary treatment section, it is typically necessary to add advanced treatment units after biological treatment, and simultaneously address changes in operating costs brought about by carbon source dosing, chemical phosphorus removal agent consumption, and increased sludge production. This is why such renovations are not just "adding one more process stage," but a systematic restructuring.

Process: Magnetic Coagulation High-Efficiency Sedimentation Tank + Denitrification Deep-Bed Filter

To meet the new effluent requirements, the technical route determined for this project is clear and representative:

• New advanced treatment — Adopting the combination of "Magnetic Coagulation High-Efficiency Sedimentation Tank + (Denitrification) Deep-Bed Filter." Magnetic coagulation enhances floc settling by adding magnetic powder, saving footprint and achieving rapid separation, suitable for scenarios with limited space in existing plants; the deep-bed filter undertakes the functions of further removing Suspended Solids and denitrification;
• Upgrading and renovation of secondary treatment section — Renovating existing structures such as biological tanks, secondary clarifiers, blower rooms, and sludge pump rooms, and replacing old equipment including blowers in the blower room and mixers in biological tanks;
• New supporting buildings and units — Constructing new pretreatment rooms, sludge dewatering rooms, comprehensive equipment rooms, mechanical repair rooms, transformer and distribution rooms, comprehensive office buildings, and advanced treatment comprehensive tanks, with a total building area of approximately 12410 square meters.

It is worth noting that this "magnetic coagulation + deep-bed filter" combination has appeared with high frequency in urban wastewater plant upgrading projects in recent years. Its advantages lie in small footprint, rapid startup, and strong adaptability to influent load fluctuations, making it particularly friendly to old plant areas that cannot be expanded; the cost is increased equipment maintenance workload for the magnetic powder recovery system and filter backwashing. For wastewater plants located in urban built-up areas with no available land for expansion nearby, such processes are almost a mandatory choice.

Capping: Approximately 7.19万 Square Meters, Solving Odor Control and Landscaping Simultaneously

If upgrading addresses the problems in the water, capping addresses the problems of air and the surrounding environment. The project involves capping the upper part of existing biological tanks and secondary clarifiers, with a total capping area of approximately 71876 square meters, adopting two structural forms according to the nature of the structures:

• Portal steel structure capping — used for the upper part of the existing biological tank and secondary clarifier, can be constructed under conditions of no shutdown or minimal shutdown, adapting to the span of existing tanks;
• Concrete capping — used for new structures such as the pretreatment room, sludge dewatering workshop, and advanced treatment integrated tank, designed and constructed in sync with the main structure, offering better sealing performance and durability.

Capping itself is not the end point — the odor control system is what determines the effect. After capping, odorous gas needs to be collected and treated. Common routes include biological filters, chemical scrubbing, activated carbon adsorption, or combined processes. The design of intake air volume and retention time directly determines whether fugitive emissions at the plant boundary meet standards. For plants whose surroundings have already been urbanized, this step often matters more to residents' perception than water quality compliance.

Reclaimed Water: A Synchronized Item Written into the Tender Documents

Another easily overlooked aspect of this project is the synchronized construction of the plant's reclaimed water utilization works. Although public information has not disclosed the specific scale, bundling the reclaimed water works with the upgrading and reconstruction in the same general contracting package itself sends a clear signal:

• Priority for in-plant use — filter backwashing, chemical dilution, green area irrigation, road washing, and similar applications are the most economical and stable destinations for reclaimed water;
• Pipeline network reserved in advance — reserving reclaimed water interfaces and pipe positions during synchronized civil construction costs far less than later excavation;
• Effluent quality provides the basis — after meeting the main indicators of quasi-Class IV standards and undergoing moderate advanced treatment, it can meet the water quality requirements for most industrial cooling and municipal miscellaneous water uses.

This logic is consistent with the requirements of the Ecological Environment Code of the People's Republic of China, which encourages wastewater resource utilization and incorporates reclaimed water into the unified allocation of water resources. For a region like the middle reaches of the Yangtze River, where total water resources are relatively abundant but water environment capacity constraints continue to tighten, the value of reclaimed water lies more in substituting high-quality water sources than in simply increasing water volume.

What It Means for Us: TIANYI TECH's Assessment

TIANYI TECH has long served municipal and industrial park wastewater treatment and reclaimed water reuse clients. We have observed a clear trend: the renovation of large wastewater treatment plants in urban core areas has shifted from a single objective (effluent compliance) to multiple objectives (effluent, odor, noise, landscape, resource utilization), and owners' evaluation criteria for proposals have changed accordingly — no longer只看吨水投资，而是看综合改造后厂区的整体运行表现与周边接受度。

Based on this, we offer three suggestions to peers and owners: First, incorporate odor control and reclaimed water into the plan as early as possible rather than leaving them for Phase II, as the incremental cost is lowest when implemented in sync with civil works; Second, the selection of advanced treatment processes must match the actual fluctuations in influent water quality, with particular attention to combined sewer areas with a high proportion of industrial wastewater mixing, where a low influent carbon-to-nitrogen ratio will directly drive up chemical and carbon source costs; Third, pay attention to operational safety after capping, as ventilation, monitoring, and confined space management procedures for enclosed space operations must be established simultaneously to avoid introducing new safety hazards through the renovation.

It should be noted that public information has not yet disclosed the specific construction schedule milestones and the scale of the reclaimed water works for this project, and relevant figures are subject to subsequent disclosure by the tenderer. However, judging from the process list and investment intensity, this is already a fairly complete "modernization and renovation template for existing wastewater treatment plants."

About TIANYI LIMITED: TIANYI TECH is deeply engaged in the field of wastewater treatment and reclaimed water reuse, committed to providing efficient, low-carbon, and sustainable water treatment solutions for municipal and industrial clients.