| Item | Content |
|---|---|
| Location | Huayuan County, Xiangxi Tujia & Miao Autonomous Prefecture, Hunan (9 towns and 3 townships; county seat in Huayuan Town) |
| Capacity | Food waste 20 t/d (pretreatment + oil-water separation + deodorization, incl. in-plant utilities) |
| Population base | Permanent population 236,200 at end-2024; urbanization rate 46.65% (urban ~110,000); registered population 304,100 |
| Waste base | 2024 municipal solid waste collection 44,200 t (~121 t/d); harmless treatment rate 100% |
| Industrial profile | Tertiary industry 63.4%, led by cultural tourism (Biancheng Chadong, Shibadong scenic areas); high restaurant density |
At a food-waste generation intensity of ~0.1 kg/(cap·d), the urban population of 110,000 yields a theoretical generation of ~11 t/d. With three uplift factors, the countywide collectible volume rises markedly:
The estimated countywide collectible volume is ~12–16 t/d. At a typical county collection rate of 70–80%, stable collection after ramp-up is ~10–13 t/d, peaking above 15 t/d (Spring Festival return, tourist season).
| Item | Design condition |
|---|---|
| 1. Design capacity | Food waste 20 t/d; pretreatment on a single shift (8 h); design hourly throughput 2.5 t/h |
| 2. Organic solid (residue) | Dewatered and pressed, sent to farming workshop (black soldier fly) or sold off-site (TBC) |
| 3. Inorganics | Dewatered and hauled away to an incinerator or landfill |
| 4. Grease | Industrial crude grease extracted by three-phase separation, sold as biodiesel feedstock |
| 5. Wastewater | Collected in a wastewater holding tank and hauled away (this proposal excludes a wastewater station; treatment section quoted separately if needed) |
| 6. Odor | Central negative-pressure collection; treated by the deodorization system to Grade II of GB14554-93 (Emission Standard for Odor Pollutants) before discharge |
| 7. Work schedule | Pretreatment and oil-water separation on one shift (8 h/shift); farming section runs 24 h continuously when attached |
Food-waste collection trucks enter the plant, pass the truck scale, and proceed to the pretreatment workshop discharge hall; after the automatic odor-proof door, waste is tipped into the Hydraulic Pulping & Sorting Machine for receiving and conveying. The machine simultaneously breaks organics without damaging inorganics, automatically sorts foreign matter, and buffers flow. At its bottom, a buffer shaftless dewatering screw feeds inorganics into the dewatering machine; after dewatering and spinning dry, they go into a foreign-matter bin for haul-away.
The pulping machine pumps slurry into a holding tank; filtrate from the shaftless screw and dewatering machine drains into the holding tank. The material is mixed evenly by a pusher agitator and pumped to a fine sorting machine, which separates organics larger than 5 mm; these go through a press for dewatering and are sent to the farming workshop. Fine organic solids, oil phase and water phase flow into a heating tank for heated homogenization (direct steam 60–80℃), preparing feed for three-phase separation.
Heated material passes through a hydrocyclone desander and a slurry stabilizer/settler, then enters a horizontal three-phase separator, splitting into oil, water and residue: the oil phase flows by gravity into an oil-water separation tank, and clean oil is pumped to an oil tank for sale; the water phase goes to a wastewater holding tank for haul-away (hot water reused as backwash); the solid phase is conveyed by an organic-matter screw to the farming workshop. Plant-wide exhaust is treated centrally under negative pressure and discharged up to standard.
Collection trucks are weighed on the truck scale and proceed to the discharge bay. Managed by computer, the system automatically records vehicle number, type, time, gross mass, payload and daily totals, forming plant-wide automatic metering data that provides the raw ledger for government metered charging and subsidy settlement (essential for county projects).
(1) Discharge chute (pulping & sorting machine): installed inside the odor-proof hood of the discharge room; trucks tip directly in a sealed, odor-proof manner. Main body in stainless steel; the bottom buffer shaftless dewatering screw can run forward/reverse to clear jams. Top has an electric cover + deodorization suction; with the cover closed, a slight negative pressure prevents odor escape. All screws are VFD-controlled.
(2) Screw conveying system: shaftless screw conveyors greatly reduce jamming and wrapping; an opening at the low point collects leachate to keep feed moisture stable.
(3) Leachate conveying system: leachate collected through the screen plate, dewatering screw and dewatering machine drains into the holding tank (with agitator and slurry pump), pumped in short timed doses once set level is reached. Fully sealed, short residence time, no anaerobic reaction and no odor; intermittent dosing keeps downstream moisture stable.
(4) Integrated sorting system: comprises the pulping & sorting machine, dewatering machine, fine sorting machine, press, heating tank, hydrocyclone desander and residue screw. Direct steam heating at 60–80℃ with automatic temperature, pressure and time control. Integrated sorting fully inactivates pathogens; liquefies animal fat for high grease recovery; separates organic and inorganic matter thoroughly; and releases molecular water more easily, improving dewatering efficiency.
Comprises the horizontal three-phase separator and ancillary tanks. Heated-tank material is delivered by progressing-cavity pump to the three-phase separator (VFD + outlet flowmeter for stable feed), and split into oil, water and residue: the oil phase flows into an oil-water separation tank for full separation, and clean oil is pumped to an oil tank as biodiesel feedstock (industrial crude grease); the water phase is held in a wastewater tank and hauled away; solids go to the farming system or are sold.
Uses a SCADA monitoring and data-acquisition system with three control levels — local push-button box, control-room centralized monitoring, and computer-center centralized supervision — in manual/auto modes, with local operation having priority. A graphical interface displays the whole process; faults are auto-detected, alarmed and logged. Daily/monthly reports and equipment running records are auto-generated; historical data is kept over 1 year and retrievable by measurement point. One PLC control set (DI ~200 / DO ~120 / AI ~48 points, subject to technical confirmation).
Calculated at 400 m³/h per ton of daily throughput, the 20 t/d line is fitted with an 8,000 m³/h deodorization system using the combined process of "dynamic-wave cyclonic scrubber + magnetic photo-oxidation unit": workshop exhaust goes through collection ducts into two-stage dynamic-wave cyclonic water scrubbing, then through a magnetic photo-oxidation unit (UV + TiO₂ producing ozone and ·OH hydroxyl radicals) that oxidizes odor molecules, and is discharged at height via induced-draft fan and stack. Design target: Grade II of GB14554-93.
| No. | Name | Spec | Qty | Est. (10k RMB) |
|---|---|---|---|---|
| 1 | Dynamic-wave cyclonic scrubber | 8,000 CMH (model TBC) | 2 | 8.4 |
| 2 | Magnetic photo-oxidation unit | 8,000 CMH, SUS304 | 1 | 5.6 |
| 3 | Centrifugal induced-draft fan | 8,000 CMH, total pressure ~2,000 Pa | 1 | 2.2 |
| 4 | Stack | D450, incl. support and sampling platform | 1 | 1.8 |
| 5 | Ducting, electrical & installation | Per project layout | 1 | 2.6 |
| Deodorization subtotal (separate) | 20.6 | |||
| No. | Name | Model / Spec | Qty | Power (kW) | Total (10k RMB) |
|---|---|---|---|---|---|
| 1 | Hydraulic pulping & sorting machine | ZSGJ-2 | 1 | 45 | 19.8 |
| 2 | Dewatering screw conveyor | Ø400×10000 | 1 | 7.5 | 7.6 |
| 3 | Dewatering machine | ZJFX-350 | 1 | 22 | 9.8 |
| 4 | Pulping-machine slurry pump | ZJB-5 | 1 | 7.5 | 1.2 |
| 5 | Pusher agitator | ZTJ-350 | 1 | 4 | 2.2 |
| 6 | Holding-tank slurry pump | ZJB-3 | 1 | 3 | 1.2 |
| 7 | Fine sorting machine | ZSK-1 | 1 | 0.37+0.37 | 6.2 |
| 8 | Heating tank | 4 m³ | 2 | 3×2 | 10.8 |
| 9 | Heating-tank slurry pump | ZJB-5 | 2 | 7.5×2 | 2.4 |
| 10 | Hydrocyclone desander | XLCS-1 | 1 | 5.5 | 5.8 |
| 11 | Press (Squeezer) | ZNJ-250 | 1 | 7.5 | 12.8 |
| 12 | Organic-matter screw | Ø219×6000 | 1 | 2.2 | 3.6 |
| 13 | Slurry stabilizer/settler | — | 1 | — | 2.6 |
| 14 | Three-phase separator | WLL-350 | 1 | 30+11+0.75 | 22.8 |
| 15 | Oil-water separation tank | 2 m³ | 1 | — | 2.6 |
| 16 | Oil transfer pump | KCB-83 | 1 | 1.5 | 1.2 |
| 17 | Oil tank | 15 m³ | 1 | — | 7.8 |
| 18 | Filling pump | KCB-135 | 1 | 2.2 | 1.5 |
| 19 | Wastewater holding tank | 20 m³ | 1 | — | 7.2 |
| 20 | Water pump | — | 1 | 5.5 | 1.2 |
| 21 | Electrical control box | 1 set | 1 | — | 4.8 |
| 22 | PLC control system | 1 set | 1 | — | 21.8 |
| 23 | Air compressor | — | 1 | 1.5 | 0.9 |
| 24 | Air receiver tank | — | 1 | — | 0.6 |
| 25 | Cables, wires, trays & conduit | — | 1 lot | — | 5.5 |
| 26 | Platforms, ladders & railings | — | 1 lot | — | 6.2 |
| 27 | Level/temperature sensors & instruments | — | 1 lot | — | 5.0 |
| 28 | Insulation | — | 1 lot | — | 3.4 |
| 29 | Valves | — | 1 lot | — | 5.6 |
| 30 | Pipes | — | 1 lot | — | 6.8 |
| 31 | Biomass boiler (steam source) | LSH0.3-0.7 | 1 set | 4 | 4.2 |
| 32 | Pure-water unit | 0.5 T/h | 1 set | — | 1.2 |
| 33 | Odor-proof hood | — | 1 | — | 6.8 |
| 34 | Odor-proof door | — | 1 | — | 2.1 |
| 35 | Installation & commissioning | — | 1 item | — | 9.8 |
| 36 | Truck scale | 20 T | 1 | — | 7.5 |
| 37 | Inorganic residue truck | 3 T | 1 | — | 5.8 |
| 38 | Organic-material feeder cart | 0.3 T | 2 | — | 3.0 |
| 39 | Overhead crane | 3 T | 1 | — | 3.2 |
| 40 | Wheel washer | — | 1 | — | 0.6 |
| 41 | Lighting | — | 1 lot | — | 0.8 |
| 42 | CCTV system | — | 1 set | — | 3.2 |
| Equipment List subtotal (tax incl., freight excl.; incl. installation, commissioning and 3-day training) | 239.1 | ||||
| Tier | Content | Amount (10k RMB) |
|---|---|---|
| Mandatory | Pulping & sorting machine, dewatering screw, dewatering machine, slurry pumps/pusher, fine sorting machine, heating tanks & pumps, hydrocyclone desander, press, organic-matter screw, slurry stabilizer, three-phase separator, oil-water separation tank, oil transfer pump, oil tank, filling pump, wastewater holding tank, water pump, control box, installation & commissioning | 144.9 |
| Optional | PLC auto-control 21.8 ＋ negative-pressure deodorization 20.6 ＋ biomass boiler (steam source) 4.2 | 46.6 |
| Owner-supplied | Pipes 6.8, valves 5.6, cables/trays/conduit 5.5, platforms/ladders/railings 6.2, instruments 5.0, insulation 3.4, air compressor 0.9, air receiver 0.6, odor-proof hood 6.8, odor-proof door 2.1, truck scale 7.5, residue truck 5.8, feeder cart 3.0, crane 3.2, CCTV 3.2, wheel washer 0.6, lighting 0.8, pure-water unit 1.2 (owner procures; we provide the specification list and technical requirements) | 68.2 |
| Equipment total (mandatory + optional + owner-supplied, incl. deodorization & installation, tax incl., freight excl.) | 259.7 | |
| No. | Investment item | Content | Est. (10k RMB) |
|---|---|---|---|
| 1 | Equipment (mandatory+optional+owner-supplied) | Pretreatment main line, oil-water separation, PLC auto-control, negative-pressure deodorization, boiler, in-plant utilities and installation | 259.7 |
| 2 | Building & civil works | Pretreatment workshop 400–500 m² (new or retrofit), hardened floor, equipment foundations | 60 – 120 |
| 3 | Collection vehicles | 2 food-waste trucks (5-t class, incl. on-board bins) (excluded if the government runs unified collection) | 40 – 60 |
| 4 | Design, EIA & acceptance | Process design, EIA/pollutant permit, environmental acceptance, contingencies | 15 – 25 |
| Total project investment reference range | ~375 – 465 (midpoint ~420) | ||
| Parameter | Value | Note |
|---|---|---|
| Oil content | 8% (main basis) | Xiangxi cuisine is heavy-oil/spicy, a medium-high oil region; reference: Hunan-Hubei 8%, Sichuan-Chongqing 8–12%, Jiangsu-Zhejiang ~2% |
| Grease extraction rate | 80% | This configuration's three-phase separator (10 mm feed) plus upstream homogenization outperforms conventional units |
| Industrial crude grease price | 4,000 RMB/t | Biodiesel feedstock; price floats with oil prices; check current market before signing |
| Food-waste treatment fee | 180 RMB/t (range 150–220) | Subject to local Huayuan policy; this proposal does not guarantee a specific subsidy |
| Annual operating days | 330 days | Reserved for maintenance and holidays |
| Organic solid output | ~3 t/d (15% of feed) | Sent to black soldier fly farming or sold (conservatively 150 RMB/t) |
| Revenue item | Calculation | Annual amount (10k RMB) |
|---|---|---|
| Industrial crude grease sale | 20 t/d × 8% × 80% = 1.28 t/d × 4,000 RMB × 330 days | 169.0 |
| Food-waste treatment fee | 20 t/d × 180 RMB × 330 days | 118.8 |
| Organic solid sale | 3 t/d × 150 RMB × 330 days (self-run BSF yields more, separate) | 14.9 |
| Total annual revenue | 302.7 | |
| Expense item | Calculation | Annual amount (10k RMB) |
|---|---|---|
| Labor | 6 people × 55,000 RMB (duty, operation, maintenance, management) | 33.0 |
| Electricity | 80 kW × 8 h × 0.8 RMB × 330 days | 16.9 |
| Steam / biomass fuel | Boiler fuel and maintenance | 10.0 |
| Water & chemicals | Rinse water, deodorization circulating water, disinfectants | 5.0 |
| Maintenance & spares | 3% of equipment investment | 7.8 |
| Management & other | Office, testing, insurance, finance | 8.0 |
| Total annual expense | 80.7 | |
| Oil content | Reference region | Daily grease output | Annual grease revenue | Annual net | Payback · equipment basis (2.597M) | Payback · total basis (4.2M) |
|---|---|---|---|---|---|---|
| 5% | Light-oil diet regions (Jiangsu-Zhejiang ref.) | 0.80 t | 105.6 | 158.6 | 1.6 yr | 2.6 yr |
| 8% (this proposal) | Hunan-Hubei medium-high oil (Huayuan) | 1.28 t | 169.0 | 222.0 | 1.2 yr | 1.9 yr |
| 12% | Sichuan-Chongqing high-oil region | 1.92 t | 253.4 | 306.4 | 0.8 yr | 1.4 yr |
| No. | Item to confirm | Impact |
|---|---|---|
| 1 | Residue destination: BSF farming / sale / landfill-incineration | Whether to include feeder cart; organic-matter screw routing (we can supply a BSF farming solution) |
| 2 | Wastewater: self-hauled / treatment section required | This proposal excludes a wastewater station; add if needed |
| 3 | Collection model: government delivers to plant / project company contracts collection | Collection cost and vehicle investment ownership |
| 4 | Steam source: self-built boiler / existing plant steam | Boiler 4.2M can be added/removed |
| 5 | Transformer capacity / building size (new or retrofit) / overhead crane availability | Power distribution, civil works and crane configuration |
| 6 | Shift: one 8-h shift / two 16-h shifts | Equipment hourly-throughput selection |
| 7 | Local treatment-fee policy and collection-rate plan | Revenue estimate and decision basis |
| 8 | Whether to add a BSF farming section (we can provide the technical solution) | Determines residue conveying and farming-workshop interface |