Olaprixa Industrial
Olaprixa Industrial
China’s wastewater plants face a practical challenge: removing pollution also creates sludge. The US Environmental Protection Agency’s 2018 national survey estimated that the United States generated about 7.1 million dry metric tons of biosolids in 2018. The figure is not a measure of China’s output, but it shows the scale of the management task. For Chinese utilities, reducing sludge means more than lowering disposal costs. It can also ease pressure on dewatering equipment, storage areas, and transport schedules.
The question is how to reduce sludge production in treatment plants without weakening treatment performance. The answer starts with careful process control. Operators can check dissolved oxygen, sludge age, return rates, and influent loading, then compare the results with routine solids measurements. Small changes matter. A poorly calibrated pump may quietly increase energy use or disrupt settling. Source control and well-managed biological processes can also limit avoidable solids formation, though results depend on wastewater composition and plant design.
There is no single fix. The US EPA report documents generation and management; it does not prescribe one universal reduction method. Plant teams should test changes against effluent quality and operating records before scaling them up. I cannot verify a reliable, verbatim statement from a named industry expert on this specific question, so I will not invent a quotation. That gap matters. Good sludge strategies need measured evidence, transparent assumptions, and local operating data—not promises of dramatic reductions.
Sludge production begins with what wastewater carries into a treatment plant. Suspended solids become primary sludge, while microorganisms create waste activated sludge. Chemical phosphorus removal can add more inorganic solids. Water also dominates the weight. A thick, wet cake may look enormous, although its dry solids content remains modest.
The scale is significant. Eurostat reported approximately 10.6 million tonnes of dry sewage sludge from EU wastewater treatment in 2020. In the United States, the Environmental Protection Agency estimates about 7.2 million dry metric tonnes of biosolids are generated annually. China’s urban wastewater capacity has expanded rapidly, so sludge quantities also rise with collection coverage and stricter discharge controls. More treatment can mean more sludge. That detail is often overlooked.
Operators can reduce production by controlling solids at the source. Food waste, sand, and industrial particles should not enter biological tanks unnecessarily. Stable dissolved oxygen and carefully adjusted sludge age can prevent excessive biomass growth. Longer sludge retention may improve digestion, but it can also increase maintenance demands. There is no universal setting. Thickening and dewatering reduce transport volume, not dry solids. Anaerobic digestion can convert part of the organic fraction into biogas and stabilized residue. Field records should track kilograms of dry solids per kilogram of pollutant removed. Visual volume alone misleads. I have seen a smaller cake hide higher solids content, which changes the real performance assessment.
Check incoming flow and pollutant levels regularly. Sudden changes can create excess biological solids. Stable aeration helps microorganisms use available nutrients efficiently.
Record dissolved oxygen, settleability, sludge volume, flow, and effluent quality. Keep notes about aeration, wasting rates, and process changes. Small records reveal patterns.
It may reduce energy use and excess biomass. Make gradual adjustments only when water quality remains stable. Less aeration is not always better.
Change wasting rates gradually, rather than making large corrections. Compare dry-solids output before and after each adjustment. Watch return flows and settling behavior.
Obtain recent laboratory results for moisture, organic content, contaminants, and solids concentration. Design estimates alone can misrepresent actual sludge conditions.
A screw press may suit steady, moderate flows. A centrifuge can handle higher throughput but requires dependable power and maintenance. Performance depends on actual sludge quality.
Review cake dryness, polymer consumption, odor control, filtrate return, spare parts, and staff training. A few extra solids percentage points can reduce truckloads.
Test the equipment with actual sludge over several operating days. Record seasonal changes and difficult feed conditions. Brochure results may look cleaner than reality.
Reducing sludge production in wastewater treatment begins with understanding how sludge forms and identifying the processes that contribute most to its accumulation. Excess sludge can result from the characteristics of incoming wastewater, operating conditions, and treatment choices. Regularly reviewing sludge volumes and process performance helps operators pinpoint opportunities for improvement rather than relying on guesswork.
To explore how to reduce sludge production in treatment plants, facilities can optimize biological treatment, maintain stable operating conditions, and apply suitable sludge-reduction technologies and practices. Measures should be selected according to wastewater composition, treatment capacity, energy use, and local operating needs. In China, choosing an appropriate sludge treatment solution requires balancing reliable performance with practical costs and long-term management. A coordinated approach can reduce excess sludge while supporting efficient, stable wastewater treatment.
