scholarly journals Energy recovery in wastewater treatment systems through hydraulic micro-machinery. Case study

2020 ◽  
Vol 1 (1) ◽  
pp. 15
Author(s):  
Rosa Llácer-Iglesias ◽  
Jose M. Pérez ◽  
Jose Ricardo Satorre-Aznar ◽  
P. Amparo López-Jiménez ◽  
Modesto Pérez-Sánchez

<p class="JAREAbstract">The wastewater treatment plants (WWTP) treat the water from domestic and industrial use so that its discharge, once it passes through them, is harmless to the environment. However, large amounts of energy are necessary to carry out this process. Therefore, energy and process optimization are a key issue within these type of plant. One of the possibilities within the WWTPs is the recovery of hydraulic energy. This paper presents alternatives for the recovery of hydraulic energy, through the use of hydraulic micro-machinery such as PATs or hydrostatic pressure wheels. This type of machinery is capable of recovering a part of that energy that until now it was not possible to recover, in a more economical way and assuming an improvement for plants that have the possibility of installing it. In the here described case study, savings of over 4% were achieved with periods of return on investment of less than 5 years.</p>

1999 ◽  
Vol 40 (11-12) ◽  
pp. 223-229 ◽  
Author(s):  
Frédéric Clauss ◽  
Christel Balavoine ◽  
Delphine Hélaine ◽  
Gaëtan Martin

Forest industry wastewaters are difficult to clean: hydraulic and organic load variations, filamentous bulking or pin-point flocs negatively impact depollution processes. The addition of a fine, mineral, talc-based powder, Aquatal, into the aeration tanks of wastewater treatment plants connected to pulp and paper factories has been successfully tested since end of '97. The first case-study presents full results obtained over a period of 18 months in a 20,000 p.e. plant connected to a paper factory. The mineral powder was regularly added to control sludge volume index, thereby ensuring low suspended solids concentration in the outfluent. Plant operators could easily adapt biomass concentration to match organic load variation, thereby maintaining pollution micro-organisms ratio constant. In a second case study, a trouble-shooting strategy was implemented to counteract filamentous bulking. A one-off, large dosage enabled the plant operator to deal effectively with poor settleability sludge and rapidly control sludge blanket expansion. In both cases, the main common characteristics observed were an increase in floc aggregation and the production of heavier and well-structured flocs. The sludge settling velocity increased and an efficient solid/liquid separation was obtained. After a few days, the mineral particles of Aquatal were progressively integrated into the sludge floc structure. When the mineral powder was added to the activated sludge in the aeration basin, chemical interactions frequently encountered with other wastewater treatment additives did not pose a problem. Moreover, with this mineral additive, the biological excess sludge displayed good thickening properties and dewatering was improved. Despite the addition of the insoluble mineral particles, the amount of wet sludge expelled did not increase. Aquatal offers a rapid solution to floc settleability problems which so frequently arise when physical or biological disorders appear in forest industry wastewater treatment plants.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Cui Wang ◽  
Zhouhua Guo ◽  
Qingsheng Li ◽  
Jing Fang

AbstractIn order to protect the offshore environment and strengthen the comprehensive rectification of sewage outfalls, an evaluation method of regional sewage outfalls by combining the marine numerical simulation and comprehensive evaluation technology was constructed, considering the marine environmental capacity and the ecological impact of sewage discharge from outfalls on the marine eco-environment sensitive areas. Then the layout rationality of each outfall was evaluated and the discharge scale was optimized with a case study of existing sewage outfalls in Xiamen. The results show that, the comprehensive evaluation score of Yundang outfall was 3 points in 2025, evaluated as the outfall with irrational layout. In 2035, the comprehensive evaluation scores of Fenglin and Dalipu outfalls were 3 and 2 points respectively, evaluated as the outfall with irrational discharge scale. It is suggested to control the scale of expansion or increase the reclaimed water reuse rate in Jimei and Gaoqi Wastewater Treatment Plants. This method has enriched the evaluation system for layout optimization of sewage outfalls, providing scientific supports for comprehensive improvement of sewage outfalls and marine environmental management.


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