Recently, the high-temperature water-source heat pump unit independently developed by OYRR has been successfully in operation for one year at a sewage treatment plant near Guangzhou South Station.

Recently, the high-temperature water-source heat pump unit independently developed by OYRR has been successfully in operation for one year at a sewage treatment plant near Guangzhou South Station. Its stable output of 90°C hot water provides an efficient heat source for sludge drying, not only resolving the energy-consumption issues of traditional heating methods but also advancing the sewage treatment process toward low-carbon transformation, becoming a benchmark case for environmental technology applications in the Guangdong-Hong Kong-Macao Greater Bay Area.

1. Full-process analysis of sewage treatment: sludge drying is the key to compliance

The complete sewage treatment process includes four core stages: pretreatment, biochemical treatment, advanced treatment, and sludge disposal, with sludge disposal directly determining the final removal of pollutants. After pretreatment through screens and grit chambers, sewage undergoes anaerobic and aerobic biochemical reactions to break down organic pollutants, then solid–liquid separation in sedimentation tanks produces sludge with about 80% moisture content.

If such sludge is landfilled or piled directly, it can cause secondary pollution; it must be dried to 10%–40% moisture to meet subsequent resource recovery or safe disposal requirements. Sludge drying requires a continuous and stable 90°C high-temperature hot water supply for thermal energy, and this stage accounts for 35%–50% of a sewage treatment plant’s total energy consumption, making it the core target for process optimization.

2.       Pain points of traditional heating modes: prominent cross-border compliance and globalization challenges

Before OYRR’s high-temperature water-source heat pump was applied, global sewage treatment plants mainly relied on three traditional heating technologies for sludge drying. Their pain points are more pronounced in international contexts, severely restricting cross-border project implementation and compliant operation:

1.         Coal/gas boiler heating: As a traditional mainstream solution, it faces multiple compliance and cost pressures in the international market. First, energy costs are heavily affected by global oil and gas price volatility—annual gas cost fluctuations of 30%–50% in regions like Europe and Southeast Asia; a 50 t/d facility can incur annual operating costs exceeding €300,000, making cross-border budget control difficult. Second, environmental compliance risks are very high: EU REACH and US EPA limits on SO2 and NOx are strict, some countries ban high-pollution boilers, and carbon border adjustment mechanisms (CBAM) can add 15%–25% to operating costs from combustion emissions. Third, safety and maintenance costs are high: cross-border equipment maintenance must meet local technical standards; labor and spare-part costs for descaling and pipeline maintenance are 2–3 times domestic levels, and explosion risks keep cross-border insurance premiums elevated.

2.         Direct electric heating: Under global energy constraints, its high energy consumption is exposed. With a coefficient of performance around 0.9, drying 1 ton of sludge requires 500–700 kWh; in high-electricity-price regions like Europe and Australia, operating costs are 3–4 times those of heat pump technology. Some countries impose tiered electricity prices or carbon quotas on high-consumption equipment. Electric heating elements are prone to fouling and failure; cross-border spare-part logistics can take 4–8 weeks, severely impacting process continuity and failing to meet international reliability standards.

3.         Solar-assisted heating: Constrained by regional climate and international project standards. High-latitude regions (e.g., Northern Europe, northern North America) have less than 6 hours of daylight in winter, reducing heating efficiency by over 70%. Tropical rainy regions (e.g., Southeast Asia, Amazon) have over 40% cloudy/rainy days, requiring backup heat sources and extra investment. International environmental projects typically demand >95% annual operational stability—solar intermittency cannot meet this, resulting in under 5% adoption in cross-border sewage projects.

These traditional technologies not only fail to adapt to different countries’ environmental regulations, energy structures, and operational standards, but also run counter to the global green investment trend under carbon-neutral consensus, becoming a core obstacle to international sewage treatment project implementation.

3.       OYRR heat pump technological breakthrough: 90°C high-temperature output + three core advantages

Addressing industry pain points, OYRR’s high-temperature water-source heat pump unit has achieved key technical breakthroughs. Its core principle uses refrigerant phase-change cycles to absorb low-grade heat (20°C–60°C) from sewage, compress and upgrade it to produce 90°C high-temperature hot water. The process “only extracts heat, not water”; the sewage returns to the treatment system after heat exchange, enabling energy recycling.

Compared with traditional methods, this technology demonstrates three core advantages:

1.         Extreme energy saving, resilient to global energy fluctuations: The unit achieves a COP ≥ 3.5—1 kWh electricity produces 3.5 kWh of heat—saving over 60% versus electric heating and reducing energy costs by 22%–30% versus gas boilers. Against global energy price volatility, it helps international clients lock long-term operating costs. After commissioning at the Guangzhou South Station sewage plant, annual electricity savings are projected to exceed RMB 1.8 million, with a payback period of 1.5–2 years, meeting cross-border project ROI requirements.

2.         Global compliance, aligned with international environmental standards: No fossil fuel combustion—no exhaust or solid waste emissions—reducing carbon emissions by over 700 tons per year, equivalent to saving 340 tons of standard coal. It fits EU CBAM, US LEED, ISO 14001, and other global standards. Using low-GWP refrigerant R515B (GWP ≈ 296), it meets the Kigali Amendment to the Montreal Protocol and can pass environmental access reviews in various countries.

3.         Stable adaptation, meeting cross-border operational needs: The unit uses a high-temperature screw compressor and electronic expansion valve to control hot water temperature within ±1°C, achieving >98% annual operational stability, suitable for high-latitude and rainy climates. The footprint is only 30% of a boiler system; modular design supports cross-border shipping and rapid installation with retrofit cycles as short as 15–20 days. It can use the plant’s own effluent as the heat source without extra heat-source piping, reducing cross-border infrastructure and logistics costs.

4.       Guangzhou South Station project implementation: setting a new industry application benchmark

The sewage treatment plant near Guangzhou South Station, an important environmental infrastructure in the Greater Bay Area, treats 50,000 tons of sewage per day and has urgent sludge-drying needs. After commissioning OYRR’s high-temperature water-source heat pump unit, it has operated stably for one continuous year, producing an average of 200 tons/day of 90°C hot water, reducing sludge moisture content from 80% to below 30% and improving treatment efficiency by 15% compared with gas boilers.

Field measurements show sludge drying unit energy consumption dropped to 330–400 kWh/ton of water, reducing annual carbon emissions by 745 tons. This not only solves environmental issues of traditional processes but also saves the plant over RMB 2.3 million in annual operating costs, becoming a domestic demonstration case for “energy saving and carbon reduction.” Its technical parameters and operational results have been certified by international third-party testing bodies, providing a replicable solution for similar global projects.