Technical Review of the Doppstadt DSP 205 Screw Press: Strengths and Weaknesses in Waste Processing Applications
The Doppstadt DSP 205 Screw Press represents an advanced piece of environmental technology from the well-established Doppstadt Group, which is known for its robust range of waste processing equipment including grinders, shredders, and screens. The DSP 205 Screw Press is designed to handle solid-liquid separation in waste processing, specifically aimed at applications requiring clean separation for biogas production. The equipment leverages screw press technology to facilitate clean organic matter separation from materials like food waste, green waste, and kitchen waste—especially those containing plastic contamination.
The reviewer has assumed that particle size reduction will be carried out before the mixed waste material enters the screw press.
Technical Specifications
The Doppstadt DSP 205 Screw Press is engineered with several distinctive features:
- Dimensions and Weight: The unit has a length of 9,606 mm, width of 2,257 mm, and height of 3,652 mm, with a weight of 15,000 kg.
- Processing Capacity: Capable of processing an average of 8 to 12 tons per hour (t/h), with peaks up to 20 t/h, the DSP 205 has a high throughput suitable for large-scale operations.
- Screw and Press Design: The screw press includes a 500 mm diameter pressing screw and twin counter-conveying mixing screws, providing a consistent feed and effective opening of packaging materials without shredding them into smaller, problematic particles.
- Motor and Drive: The screw press is powered by a frequency-controlled three-phase motor with 45 kW of power and a drive torque between 18 and 26 kNm, optimized for continuous operation with minimal energy consumption.
Operational Strengths
1. Effective Solid-Liquid Separation
The DSP 205’s solid-liquid separation is a key feature, delivering a liquid phase (filtrate) with a high biogas potential, which is valuable in anaerobic digestion processes. The filtrate obtained contains more than 20% dry matter, making it highly suitable for biogas production without the need for additional water input, which minimizes energy consumption.
2. Low Plastic Contamination in Filtrate
A crucial advantage of the DSP 205 is its low plastic contamination in the liquid output. Test results indicate plastic content as low as 0.34 wt% in the filtrate, a result achieved through controlled material handling within the machine. The lack of pre-shredding eliminates the excessive reduction of plastic packaging, thereby preventing microplastic formation. This addresses environmental concerns over microplastics in waste streams, positioning the DSP 205 as a relatively environmentally friendly option among traditional waste processing machines.
3. Robust Against Foreign Objects
The DSP 205 is equipped to handle foreign bodies up to 80 mm in diameter without failure or jamming, thanks to the reverse function of the pressing screw and its hydraulic-driven pressing cone. This allows for uninterrupted processing of mixed waste, including hard-to-process kitchen and market waste with high plastic content, without frequent maintenance stops.
4. Low-Energy Operation and Reduced Maintenance
The screw press has been optimized for low energy consumption due to its co-rotating pressing cone, which reduces material friction during processing. The machine is also designed for one-man operation, equipped with a multifunction display and remote-control options, enhancing operational efficiency. Additionally, central lubrication and modular screen baskets allow for easy maintenance and configuration adjustments.
Challenges and Environmental Considerations
1. Presence of Microplastics in Processed Materials
While the DSP 205 minimizes plastic contamination in the filtrate, particle size reduction during processing before and within the screw press still raises concerns around microplastic formation. Similar to grinders and shredders, screw presses that handle packaging may release small plastic fragments that could potentially escape into the environment. Scientific studies highlight that even with careful processing, equipment that disintegrates plastic-containing materials can inadvertently contribute to microplastic pollution. Given these findings, a focus on depackaging and separation technologies that avoid particle reduction may offer better environmental outcomes, especially when plastic contamination is prevalent.
2. Limited Applicability with Certain Feedstocks
The DSP 205 is ideally suited for organic waste and mixed biowaste, but challenges arise when processing waste with varied moisture content or materials highly resistant to compression. Although its adjustable press basket allows for different feedstock handling, feedstocks with highly variable physical properties may result in inconsistent separation efficiency.
Case Studies and Real-World Applications
- Biogas Plant in Germany A biogas plant in Germany using the DSP 205 Screw Press processed high-plastic-content kitchen and green waste. The plant reported a significant reduction in pre-treatment requirements, thanks to the DSP 205’s ability to handle unshredded feedstock. Operators noted that the filtrate’s biogas yield was consistent, and the solid retentate was usable as a resource for refuse-derived fuel (RDF), thus improving the plant’s overall resource recovery rates.
- Market Waste Processing Facility In another case, a waste processing facility handling market waste found the DSP 205 advantageous due to its tolerance for foreign bodies and packaging materials. The machine’s ability to reverse and dislodge large objects improved uptime, reducing the facility’s maintenance burden and waste disposal costs. The facility appreciated the DSP 205’s filtration system, which maintained low plastic contamination in the filtrate, aligning with their environmental compliance goals.
Alternative Approaches to Shredding and Particle Reduction
Increasingly, depackaging systems that use gentler separation techniques are favored over traditional shredding. These systems avoid the downsides of particle size reduction, particularly regarding plastic contamination in organic streams. Doppstadt’s own line includes alternative machinery aimed at minimizing mechanical particle reduction, which can help facilities aiming to adhere to environmentally friendly processing standards by reducing microplastic risks.
Conclusion
The Doppstadt DSP 205 Screw Press is a robust and effective solution for facilities focused on biowaste processing and biogas production, offering unique strengths in solid-liquid separation and contamination control. With its ability to process high-plastic-content waste without extensive shredding, it addresses some of the pressing environmental concerns about microplastics. However, as environmental awareness grows, the push toward depackaging technologies that minimize particle reduction may shape future standards in waste processing equipment.
While the DSP 205 remains a high-performing option within its category, facilities should evaluate their waste composition and environmental compliance goals, when selecting equipment. Doppstadt’s responsive design and commitment to innovation suggest that the DSP 205 and similar models will continue to evolve to meet these changing requirements in sustainable waste management.
Environmental technology company specializing in recycling solutions
Industry Sector: Environmental Technology
Business Location: North Rhine-Westphalia Germany
Address:
Doppstadt
Steinbrink 13
D-42555 Velbert
Germany
T:
F: +49 (0) 20 52 88 9 – 144
info@doppstadt.de
www.doppstadt.com
Phone: +49 (0) 20 52 88 9 – 0
Website:
Doppstadt: https://www.doppstadt.de/
Opening Hours:
8am to 5pm weekdays
