1.Project Overview

Environmental Overview: This project is located in Lüliang City, Shanxi Province. The area features a loess plateau topography, with terrain predominantly consisting of loess hills and significant elevation variations.

Project Overview: The extraction of deep coalbed methane generates substantial fracturing’返排液’ (fracturing effluent) and production water. These wastewater streams exhibit complex water quality characteristics, including high polymeric content, elevated mineral oil concentrations, significant suspended solids, and high salinity levels, with overall high COD, salt content, and hardness values that restrict discharge pathways. To reduce comprehensive wastewater discharge and protect surrounding aquatic ecosystems, effective treatment and reuse of fracturing返排液 and production water serve as critical measures for achieving water conservation, emission reduction, and environmental protection.

This procurement involves two sets of deep coal seam fracturing return fluid and produced water treatment equipment with a capacity of 1200m³/d each.

2.Project Scope and Technical Requirements

2.1 Project Scope and Construction Boundary

The scope of this project includes completing the preparation of water treatment process technology packages, collaborating with design units to finalize engineering designs; delivering equipment supply, providing on-site guidance for equipment system installation, overseeing system commissioning, and managing trial operation prior to production launch.

(1) Preparation of water treatment process technology packages and collaboration with design units to complete engineering design: Develop process technology packages to provide necessary data and materials for engineering design; Assist design units in completing preliminary design and construction drawing design for water treatment plants, and provide review comments on relevant designs.

(2) Equipment supply: The seller’s scope of work includes the design, manufacturing, testing, packaging, transportation, unloading, and hoisting and positioning of all equipment within the supply scope.

(3) On-site guidance for equipment system installation: The seller shall dispatch technically proficient, highly skilled, and diligent technicians to provide on-site technical guidance during equipment installation, commissioning, and operation.

(4) System debugging: The seller is responsible for single-machine debugging and joint debugging of the system (including personnel allocation during debugging).

The seller shall provide equipment preparation, tool allocation, and third-party water quality monitoring performance evaluation services. The seller is responsible for compiling trial operation manuals and operational manuals required during production processes. Additionally, the seller shall conduct training for daily maintenance personnel, including theoretical instruction, practical training, and laboratory training on water quality testing, to ensure trainees are competent in maintenance operations.

(5) Others:

1. The seller shall provide spare parts and specialized tools for two years;
2. The Seller guarantees that the provided equipment features advanced design concepts, mature technical applications, is brand-new, cutting-edge, complete, and safe and reliable.
3. The seller shall provide a detailed equipment supply list;
4. The seller shall ensure the completeness of the supply scope, meet the buyer’s requirements for installation, commissioning, operation, and equipment performance, and provide technical services and support related to equipment commissioning and operation.
5. The materials provided by the buyer represent the minimum requirements for the equipment. The seller shall specify deviations from the buyer’s requirements in the form of a deviation table based on their own products, provided that these deviations must exceed the buyer’s specified requirements.

(6) Equipment delivery boundary line

1. The seller is responsible for the complete supply of equipment, including the delivery and installation of the equipment itself and installation accessories.
2. At the junction between the external water inlet main pipeline and the water treatment equipment inlet interface, as well as at the connection point between the water treatment equipment outlet and the integrated tank interface. The seller shall provide flanges and anchor bolts at the interface boundary areas. The flanges shall comply with HG20592 (Series A) standards, with pressure ratings of PN16 and RF. Gaskets in the complete equipment shall meet HG/T20606-2009 specifications using polytetrafluoroethylene plates. Fasteners shall adhere to HG/T20613-2009 standards.
3. The seller shall be responsible for supplying equipment operation and maintenance platforms, ladders, guardrails, etc.

(7) Electrical supply boundary line

1. The interface shall be demarcated by the terminal block at the lower end of the distribution cabinet. The main distribution cabinet shall be uniformly installed in the low-voltage distribution room, with both the main distribution cabinet and main power supply being the responsibility of the buyer.
2. External power cables and control cables shall be connected by the supplier to the electrical control boxes of each equipment unit, while the cables within the equipment bay shall be supplied by the seller.
3. The equipment supplier’s contract scope does not include the central control system.

The reuse process must address the hardness issues of raw water by selecting appropriate treatment technologies to effectively remove calcium and magnesium ions, ensuring hardness levels meet the water quality requirements for fracturing fluid preparation. Additionally, comprehensive removal of other contaminants should be implemented to facilitate safe wastewater reuse. Hardness removal typically employs three major treatment methods: ion exchange, chemical hardening, and membrane-based hardening. Each approach has distinct characteristics and applicable scenarios. Ion exchange and membrane technologies are generally suitable for water with favorable quality and relatively low pollution levels, as excessive hardness and organic contaminants often lead to operational challenges due to frequent fouling and clogging. Chemical hardening, while offering broad applicability and operational flexibility, generates sludge residues. When high hardness removal rates or low discharge hardness control values are required, multi-stage serial operation becomes necessary, increasing operational complexity. The effectiveness of chemical hardening is significantly influenced by polymer content and properties in raw water. High molecular weight polymers with long chains and high viscosity exhibit strong dispersing capabilities, acting as anti-flocculants that interfere with effective flocculation and colloid separation, thereby reducing solid-liquid separation efficiency. To address these issues, this solution incorporates an electrochemical gel-breaking unit. Through synergistic effects of micro-electric fields, strong oxidizing free radicals, and catalytic media, this unit effectively disrupts polymer structures and reduces negative impacts on stable operation of hardening treatment systems.

Based on the above analysis, considering the specific characteristics of raw water quality, reuse water treatment requirements, as well as the advantages, disadvantages, and applicability of various treatment processes, and drawing on engineering experience from previous similar projects, we have adopted a process route primarily combining electrochemical desorption and multi-stage chemical hardness removal. This approach leverages the unique features and strengths of each treatment unit to ensure effective raw water treatment and safe, stable reuse.

According to the master plan, the treated water from this scheme and Yellow River water form the fracturing water source. When changes in the water quality of the Yellow River inflow affect the water quality of the produced water from this scheme, the process

3.Process Flow