Investigation and assessment of sludge pre-treatment processes

2004 ◽  
Vol 49 (10) ◽  
pp. 97-104 ◽  
Author(s):  
J.A. Müller ◽  
A. Winter ◽  
G. Strünkmann

The pre-treatment of sludges by disintegration will result in a number of changes in sludge properties. Floc destruction as well as cell disintegration will occur. This leads to an increase of soluble substances and fine particles. Furthermore, biochemical reactions may appear during or immediately after disintegration. The influence of disintegration of excess sludge on anaerobic digestion was studied in full scale. A stirred ball mill, an ultrasound disintegrator, a lysate centrifuge and ozone treatment were used. The results of the degradation process were compared to a reference system without pre-treatment. An enhancement of the degree of degradation of 7.4% to 20% was observed. The pollution of sludge water as well as the dewatering properties of the digested sludge were investigated. COD and ammonia in the sludge water were increased and a higher polymer demand was observed while the solid content after dewatering stayed almost unchanged. Based on these results the cost effectiveness has been assessed taking into account different conditions (size of WWTP, cost for disposal, etc.). Capital and energy costs are the main factors while the decrease in disposal costs due to the reduced amount of sludge is the main profit factor.

2001 ◽  
Vol 44 (10) ◽  
pp. 121-128 ◽  
Author(s):  
J.A. Müller

Pre-treatment processes have been developed in order to improve subsequent sludge treatment and disposal. Disintegration of sludge solids in the aqueous phase changes the sludge structure and solubilizes organic matter. This paper provides an overview of the applications of wet disintegration in wastewater and sludge treatment. Applied disintegration techniques such as mechanical, thermal, chemical and biological methods are briefly described. The methods are compared regarding energy consumption, operational reliability and stage of development for application on wastewater treatment plants. Mechanical and thermal methods appear to be most suitable at this stage. The effects of pre-treatment on subsequent sludge treatment processes and the wastewater treatment are described. The performance of various methods is assessed. For the improvement of stabilization, mechanical and ozone treatment as well as thermal treatment perform best. Dewatering can be enhanced by thermal and freeze/thaw treatment. All methods show positive effects in the reduction of the number of pathogens. Pre-treatment leads to secondary effects like the generation of recalcitrant compounds and odor, which is mainly a problem of thermal and ozone treatment. The evaluation of capital and operational costs is difficult, because of the lack of full-scale experience. Especially thermal, freeze/thaw and biological treatments can be realized at low costs if the conditions are appropriate. Nevertheless, the economic efficiency has to be investigated critically for each individual application.


2008 ◽  
Vol 58 (4) ◽  
pp. 919-923 ◽  
Author(s):  
X. J. Wang ◽  
S. L. Chen ◽  
X. Y. Gu ◽  
K. Y. Wang ◽  
Y. Z. Qian

The combination of chemical and biological treatment processes is a promising technique to reduce refractory organics from wastewater. Ozonation can achieve high color removal, enhance biodegradability, and reduce the chemical oxygen demand (COD). The biological technique can further decrease COD of wastewater after ozonation as a pre-treatment. In this study the ozonizing-biological aerated filter processes were used to treat textile washing wastewater for reuse after conventional treatment. The result showed that when the influent qualities were COD about 80 mg/L, color 16 degree and turbidity about 8 NTU, using the combination processes with the dosages of ozone at 30–45 mg/L with the hydraulic retention time (HRT) of biological aerated filter (BAF) at 3–4 hours respectively, gave effluent qualities of COD less than 30 mg/L, color 2 degree and turbidity less than 1NTU. The cost of treatment was less than one yuan/t wastewater, and these processes could enable high quality washing water reuse in textile industry.


1995 ◽  
Vol 32 (12) ◽  
pp. 91-97 ◽  
Author(s):  
P. Y. Yang ◽  
M. Kuroshima

In order to develop a simple operation for an anaerobic treatment process for highly concentrated pig wastewater for small producers, a three-stage anaerobic treatment process was investigated. The system provided a series of mixing, homogenization, biological reaction and final stabilization of concentrated pig waste (total solid content of 8–10%). The process provided a stable operational performance, simple operational procedure and well stabilized sludge effluent. It was also found that the system is economically feasible in Hawaii. Compared to the other treatment processes for highly concentrated pig waste, this process is considered as an appropriate alternative for the application of the small producers in land limited and tropical conditions. Also, the present treatment system can be easily developed into a prefabricated package plant which can minimize the on-site labor and building costs.


Polymers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 628
Author(s):  
Kazuma Kurihara ◽  
Ryohei Hokari ◽  
Naoki Takada

We investigated the enhancement of the capillary effect in a plastic capillary tube using only a nanostructured surface. Since plastic is a hydrophobic material, the capillary effect does not emerge without an additional coating or plasma treatment process. Therefore, capillary effect enhancement by the nanostructure fabrication method is expected to reduce the cost and minimise the contamination produced in the human body. By combining a hydrophilic nylon resin and a nanostructure at the tip of the plastic pipette, we could confirm that the capillary effect was produced solely by the tube fabrication process. The produced capillary effect increased linearly with increasing nanostructure height when a standard solution with a surface tension of 70 mN·m−1 was used. Thus, we can conclude that including the plastic part with nanostructure can be useful for biomedical applications. In addition, we suggest that the proposed method is highly effective in controlling the wetting properties of plastic surfaces, compared to the typical coating or plasma treatment processes.


2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Anita Ejiro Nwaefuna ◽  
Karl Rumbold ◽  
Teun Boekhout ◽  
Nerve Zhou

AbstractBioethanol from abundant and inexpensive agricultural and industrial wastes possesses the potential to reduce greenhouse gas emissions. Bioethanol as renewable fuel addresses elevated production costs, as well as food security concerns. Although technical advancements in simultaneous saccharification and fermentation have reduced the cost of production, one major drawback of this technology is that the pre-treatment process creates environmental stressors inhibitory to fermentative yeasts subsequently reducing bioethanol productivity. Robust fermentative yeasts with extreme stress tolerance remain limited. This review presents the potential of dung beetles from pristine and unexplored environments as an attractive source of extremophilic bioethanolic yeasts. Dung beetles survive on a recalcitrant lignocellulose-rich diet suggesting the presence of symbiotic yeasts with a cellulolytic potential. Dung beetles inhabiting extreme stress environments have the potential to harbour yeasts with the ability to withstand inhibitory environmental stresses typically associated with bioethanol production. The review further discusses established methods used to isolate bioethanolic yeasts, from dung beetles.


2020 ◽  
pp. 0734242X2097409
Author(s):  
Federica Ruggero ◽  
Alexandra E. Porter ◽  
Nikolaos Voulvoulis ◽  
Emiliano Carretti ◽  
Tommaso Lotti ◽  
...  

The present study develops a multi-step methodology for identification and quantification of microplastics and micro-bioplastics (together called in the current work micro-(bio)plastics) in sludge. In previous studies, different methods for the extraction of microplastics were devised for traditional plastics, while the current research tested the methodology on starch-based micro-bioplastics of 0.1–2 mm size. Compostable bioplastics are expected to enter the anaerobic or aerobic biological treatments that lead to end-products applicable in agriculture; some critical conditions of treatments (e.g. low temperature and moisture) can slow down the degradation process and be responsible for the presence of microplastics in the end-product. The methodology consists of an initial oxidation step, with hydrogen peroxide 35% concentrated to clear the sludge and remove the organic fraction, followed by a combination of flotation with sodium chloride and observation of the residues under a fluorescence microscope using a green filter. The workflow revealed an efficacy of removal from 94% to 100% and from 92% to 96% for plastic fragments, 0.5–2 mm and 0.1–0.5 mm size, respectively. The methodology was then applied to samples of food waste pulp harvested after a shredding pre-treatment in an anaerobic digestion (AD) plant in Italy, where polyethylene, starch-based Mater-Bi® and cellophane microplastics were recovered in amounts of 9 ± 1.3/10 g <2 mm and 4.8 ± 1.2/10 g ⩾2 mm. The study highlights the need to lower the threshold size for the quantification of plastics in organic fertilizers, which is currently set by legislations at 2 mm, by improving the background knowledge about the fate of the micro-(bio)plastics in biological treatments for the organic waste.


2006 ◽  
Vol 54 (5) ◽  
pp. 33-41 ◽  
Author(s):  
D. Dursun ◽  
M. Turkmen ◽  
M. Abu-Orf ◽  
S.K. Dentel

The effect of enzyme pre-treatment on dewaterability of anaerobically digested sludge was investigated at both laboratory and pilot scale. Our results revealed a significant increase in cake solid content (27% cake solids compared to 18% without enzyme pre-treatment), using an enzyme dose of only 20 mg/L. In order to assess practical application, enzyme pre-treatment was applied at the Wilmington, Delaware (US) wastewater treatment plant, using a pilot-scale centrifuge. However, the efficiency reached in laboratory scale could not be obtained in pilot scale, where the final cake solids content did not exceed 20%. Centrifuge and belt filter press (simulated by Crown Press™) dewatering were compared in terms of the process efficiencies in the absence and presence of enzyme pre-treatment. Possible factors that might cause the differences were tested by experimental and statistical comparisons. Results indicated that the higher shear applied in centrifugation is responsible for the lack of improved cake solids. The network strength of sludge determined by rheological measurements revealed that enzymatic treatment weakens the gel structure of the sludge floc through the hydrolysis of extracellular polymeric substances; this allows improved dewatering by filtration processes, but leads to floc deterioration when subjected to high shear during centrifugation.


Author(s):  
Mohamed Fazil Mohamed Firdhous ◽  
B. H. Sudantha ◽  
Naseer Ali Hussien

Vehicular traffic has increased across all over the world especially in urban areas due to many reasons including the reduction in the cost of vehicles, degradation of the quality of public transport services and increased wealth of people. The traffic congestion created by these vehicles causes many problems. Increased environment pollution is one of the most serious negative effects of traffic congestion. Noxious gases and fine particles emitted by vehicles affect people in different ways depending on their age and present health conditions. Professionals and policy makers have devised schemes for better managing traffic in congested areas. These schemes suffer from many shortcomings including the inability to adapt to dynamic changes of traffic patterns. With the development of technology, new applications like Google maps help drivers to select less congested routes. But, the identification of the best route takes only the present traffic condition on different road segments presently. In this paper the authors propose a system that helps drivers select routes based on the present and expected environment pollution levels at critical points in a given area.


Author(s):  
Gabrielle Nunes da Silva ◽  
Letícia Delduque Alves ◽  
Isabella Escobar dos Santos ◽  
Daniele Maia Bila ◽  
Alfredo Akira Ohnuma Júnior ◽  
...  

This study evaluates the rainwater harvesting system to determine the chemical quality of the water and allocate it for use. Samples were collected in the city of Rio de Janeiro at the points of Direct Precipitation (DP), First Flush (FF) and Reservoir (RR). The methodology involved carrying out an analysis of Ca, Cd, Cu, Na, Ni, Fe, K, Mg, Pb, Zn, conductivity, turbidity, pH and chloride. The R language was used for the principal component analysis, Pearson coefficient correlation, hierarchical cluster analysis, Tukey test and boxplot. The results show that when there is no interference from the catchment surface (DP), the rainwater has a low concentration of metals, although the first millimeters of rain have a concentration above what is permissible in the guidelines issued by the Ministry of Health (Ordinance n° 05/2017). The disposal system (FF) reduced the concentration of pollutants in the RR, but not enough to comply with legislation. It was noted that Ca, K and Na are the main metals found in rainwater. During the dry period, there were significant correlations between the physico-chemical and meteorological parameters. The high concentration of metals in the wet period suggests that rain assists the cleaning of the atmosphere and that most metals are present in the form of aerosols or fine particles suspended in the air. The findings reveal significant indications of acid rain and pre-treatment is recommended to ensure rainwater can be used safely for more mundane purposes.


2018 ◽  
Vol 2 (2) ◽  
Author(s):  
Jose Baeza Noci

INTRODUCTION: The use of ozone, intra or periarticular, for knee and hip joint osteoarthritis (KO / HO) is clearly justified by its anti-inflammatory and antioxidants properties, that should diminish the arthritic episodes of this disease [1]. Several papers have proved the safety and efficacy of this treatment for KO [2-12], comparable to other classical treatments (steroids or hyaluronic acid (HA)) [13-14]. However, there is no paper about HO yet. STUDY DESIGN: This work is based on two open prospective studies started in February 2002 and stopped in February 2010, one group for each joint. Recruitment criteria for both groups were: - Kellgren& Lawrence KO classification: any - One/bilateral - No previous joint trauma - No rheumatic disorder - No previous surgery (but arthroscopic meniscectomy) - NSAIDs for at least two months - Promise to abandon any anti-inflammatory drugs during ozone treatment - Informed consent Clinical evaluation for KO was done using WOMAC questionnaire, pre-treatment and 1, 3, 6, 12 months after treatment. In case of HO, we used VAS for evaluation instead. CLINICAL DATA: All patients have, at least, 12 months follow-up. For KO, we have complied 199 patients (225 knees). There are two missing cases, not compiled, due to death at the 1 year revision. Age of sample ranged from 51 to 89 during the treatment. WOMAC pre-treatment was: -Pain 13.3 -Stiffness 5.6 -Function 46.2 Other data compiled, were: age, gender, BMI, Kellgren & Lawrence radiological scale (I to IV) and relapses (time free of symptoms). For HO, we have compiled 126 patients (133 hips). There are no missing cases at one year follow-up. Age ranged from 49 to 83. EVA pre-treatment was 7,33. Other data compiled, were: age, gender, BMI, use of imaging, Kellgren & Lawrence radiological scale (I to IV) and relapses (time free of symptoms). OZONE TECHNIQUE: All patients got one intarticular injection of ozone, once a week; in case of associated tendinitis or bursitis, a second or third injection was done together the intrarticular one. Injections were performed under strict asepsy. For the knee, we used a 27G x 30 mm needle with a syliconized syringe and a supero-lateral approach and. Ozone dose for intraticular injection was 15 mL at 20 mcg/mL.[15-16] Paratendon injection was performed with 5 mL at 20 mcg/mL. We always did a minimun of three intrarticular injections. Patients that did not improve were classified as failure. For the rest of the patients, the average number of injections was 4,8 (range 3 to 7). For the hip, we used a 25G x 90 mm needle with a syliconized syringe and a lateral approach. Ozone dose for intraticular injection was 5-10 mL at 20 mcg/mL.[15-16] Paratendon injection was performed with 5 mL at 20 mcg/mL. 45 patients were injected with imaging guide due to severe obesity. In these patients we used a 22G x 205 mm needle. We always did a minimun of three intrarticular injections. Patients that did not improve were classified as failure. For the rest of the patients, the average number of injections was 5 (range 3 to 10). RESULTS: From 225 knees, 44 (19.5% - the “bad result” group) did almost not improve at all; other rescue treatments were offered. The rest (80.5%) achieved a significant improvement, increasing WOMAC index over 25% of their basal level. The clinical improvement was obtained during the treatment or the first three months after treatment. WOMAC global improvement was 48%, including both groups. Relapses over the “good result” group have been of 8% at 1 year revision, and are statistically related just with Kellgren & Lawrence classification. We registered no side effect that needed further treatment. From 133 hips, 80% improved at least 2 points in VAS and 73% improved at least 3 points. The one month follow-up VAS score was 3,3 (improvement of 55%). From the patients that improved, 25% had a relapse at 1 year visit, and are statistically related just with Kellgren & Lawrence classification. The use of imaging support did not improved the results. We registered no side effect that needed further treatment. DISCUSSION: Results for KO are similar to Moretti's paper [12] and similar to the ones published for HA papers [15]. These last papers are almost always referred to 6 month follow-up. Comparing our results with HA papers at one year follow-up, they are clearly better. Longer term results for HA are even worse. This study has flaws due to its design, but similar design has been used for reporting results about drugs, HA or surgery, so comparison can be done. For HO, the results are even better that the one published for steroids or HA injections [17-18]. We agree with the publication about the use of imaging [19]. CONCLUSION: Ozone treatment in KO improves clinical outcomes over 25% of its base level in more than 80% of the patients. Relapse rate is 8% and is related with advanced osteoarthritis (Kellgren & LAwrence grades III-IV); minimal time free of symptoms is almost one year. The similarity with Moretti's results in a double blind clinical trial strength the indication for ozone in patients with KO. No paper has been published yet about HA, but comparing the results with steroids or HA injections, this treatment option is promising.


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