Prospects and problems of sludge pre-treatment processes

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.

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.


2002 ◽  
Vol 46 (10) ◽  
pp. 71-77 ◽  
Author(s):  
K.-H. Ahn ◽  
K.Y. Park ◽  
S.K. Maeng ◽  
J.H. Hwang ◽  
J.W. Lee ◽  
...  

An ozone treatment system was introduced as an alternative method for municipal sludge treatment and disposal. A pilot-scale facility was built to investigate the feasibility of the ozonation for sludge reduction and recycle. The system consists of three main parts; advanced wastewater treatment, sludge ozone treatment and belt press dewatering. Ozonation of wastewater sludge resulted in mass reduction by mineralization as well as volume reduction by improvement of dewatering characteristics. The supernatant of the ozonated sludge, consisting of solubilized organics and micro-particles, proved to be an effective carbon source for denitrification. A simple economic assessment reveals that the ozonation process can be more economical than incineration for sludge treatment and disposal at small- and medium-sized wastewater treatment plants.


RSC Advances ◽  
2014 ◽  
Vol 4 (92) ◽  
pp. 50644-50652 ◽  
Author(s):  
Xu Zhou ◽  
Guangming Jiang ◽  
Qilin Wang ◽  
Zhiguo Yuan

The production of excess sludge by biological wastewater treatment processes has been a serious issue for the operation of wastewater treatment plants (WWTP) on both the economic and environmental sides.


2000 ◽  
Vol 42 (12) ◽  
pp. 33-48 ◽  
Author(s):  
H. Ødegaard

Advanced compact wastewater treatment processes are being looked for by cities all over the world as effluent standards are becoming more stringent and land available for treatment plants more scarce. In this paper it is demonstrated that a very substantial portion of the pollutants in municipal wastewater appears as particulate and colloidal matter. Pre-coagulation, therefore, gives very efficient pre-treatment that results in considerable saving in the total space required by the plant, especially when combined with a biofilm process for the removal of the soluble matter. A new biofilm process for this purpose is described. The moving bed biofilm process is based on plastic carriers, that move in the reactor, on which biomass attach and grow. The carriers are kept withinthe reactor by a sieve arrangement and biomass that is sloughing off the carriers is separated before effluent discharge. In addition to combining the moving bed biofilm process with pre-coagulation, the paper discusses also the use of a high-rate moving bed process combined with coagulation directly after the biofilm reactor in order to enhance separability. This results in very compact treatment plants for secondary treatment and possibly phosphate removal.


2020 ◽  
Vol 21 (23) ◽  
pp. 9241
Author(s):  
Timothy Abbott ◽  
Gokce Kor-Bicakci ◽  
Mohammad S. Islam ◽  
Cigdem Eskicioglu

Antimicrobial compounds are used in a broad range of personal care, consumer and healthcare products and are frequently encountered in modern life. The use of these compounds is being reexamined as their safety, effectiveness and necessity are increasingly being questioned by regulators and consumers alike. Wastewater often contains significant amounts of these chemicals, much of which ends up being released into the environment as existing wastewater and sludge treatment processes are simply not designed to treat many of these contaminants. Furthermore, many biotic and abiotic processes during wastewater treatment can generate significant quantities of potentially toxic and persistent antimicrobial metabolites and byproducts, many of which may be even more concerning than their parent antimicrobials. This review article explores the occurrence and fate of two of the most common legacy antimicrobials, triclosan and triclocarban, their metabolites/byproducts during wastewater and sludge treatment and their potential impacts on the environment. This article also explores the fate and transformation of emerging alternative antimicrobials and addresses some of the growing concerns regarding these compounds. This is becoming increasingly important as consumers and regulators alike shift away from legacy antimicrobials to alternative chemicals which may have similar environmental and human health concerns.


1995 ◽  
Vol 31 (5-6) ◽  
pp. 97-104 ◽  
Author(s):  
K. L. Stadterman ◽  
A. M. Sninsky ◽  
J. L. Sykora ◽  
W. Jakubowskii

To determine the fate of Cryptosporidium parvum oocysts during wastewater treatment, a model of an activated sludge treatment plant was designed with a flow of 17 ml/min and a detention time of 6 hours. Samples of raw sewage were seeded with oocysts and primary and secondary effluents were analyzed for C. parvum using an immunofluorescent technique. To compare removal efficiencies of oocysts by various wastewater treatment processes, raw sewage, activated sludge, trickling filter and biodisc effluents were seeded with oocysts and settled for 2 hr and for the respective detention times. Sludge produced by a wastewater treatment plant and anaerobically digested at 37° C in a laboratory digester was also seeded with C. parvum oocysts. Oocyst inactivation was measured by excystation and direct counts. Removal of oocysts in primary and secondary sedimentation averaged 83.4% and 90.7% respectively. The total oocyst removal in sewage treatment averaged 98.6%. In comparison with other treatment processes, activated sludge had the maximum oocyst removal efficiency at 92%. The anaerobic digestion process inactivated 90% of the oocysts within four hours of exposure. 99.9% of the oocysts were eliminated by anaerobic digestion after 24 hours. This demonstrates that the activated sludge process and anaerobic digestion can be effective for the removal and inactivation of C. parvum oocysts.


2019 ◽  
Vol 1 (2) ◽  
pp. 1-14
Author(s):  
Mazurkiewicz Jakub ◽  
Damian Janczak ◽  
Dawid Wojcieszak ◽  
Sebastian Kujawiak ◽  
Przemysław Zakrzewski

Especially in non-urbanized areas there is a need to use various waste products, e.g. from agriculture, households, etc. New products that are created in a simple way should be able to be used many times without the use of complicated and expensive technology. This article presents the potential of biochar used in wastewater treatment processes and sludge management in small installations - for the maximum maintained number of users equal to 50. The possibilities of two substances used in sewage management processes, such as char and biochar will be presented. These substances, produced from pyrolysis, are stable carbon-rich compounds which have various beneficial applications like soil conditioning, remediation and wastewater treatment. In particular, biochar originating from wastewater sludge pyrolysis, possible to be generated at the place of formation, was taken into account. In addition, ways to increase the reliability of the treatment plant with biochar based filters are described.


2015 ◽  
Vol 768 ◽  
pp. 506-514
Author(s):  
Chang Xiu Gong ◽  
Jian Guo Jiang

We focused on the effects of ultrasound and Fenton reagent in ultrasonic coupling Fenton oxidation (U+F) pre-treatment processes on the disintegration of wastewater treatment plant sludge. The results demonstrated that U+F treatment could significantly increase SCOD, TOC, total N, proteins, total P and PO43- concentrations in sludge supernatant. This method was more effective than ultrasonic (U) or Fenton oxidation (F) treatment alone. U+F treatment increased the SCOD by 2.1-and 1.4-fold compared with U and F alone, respectively. U+F treatment increased the total N and P by 1.7-and 2.2-fold, respectively, compared with F alone. This demonstrated that U+F treatment induces disintegration of sludge and release of organic carbon, nitrogen and phosphorus better.


2020 ◽  
Vol 5 (3) ◽  
pp. 179-184
Author(s):  
Marianna Havryshko ◽  
◽  
Olena Popovych ◽  
Halyna Yaremko ◽  
◽  
...  

At the present stage of development, the entire world industry has faced the problem of rational use of renewable natural resources, in particular the most efficient ways of wastewater treatment and the use of accumulated waste in the production process as a secondary raw material. In particular, the alcohol industry, as one of the components of food, medical, chemical and various industries,leads to the formation of huge amounts of waste, including wastewater. The food industry, like any other industry, has a negative impact on the environment. Water bodies are the most affected by the food industry. Almost the first place in terms of water consumption per unit of production is the production of alcohol. Consumption of large amounts of water leads to the formation of wastewater, which is highly polluted and adversely affects the environment. Due to the high chemical and biological consumption of oxygen, specific color and odor, suspended solids, low pH value, the purification of such waste in the filtration fields and discharge into water bodies is not possible. The purpose of our work is: 1) conducting the analysis of the alcohol industry potential in Ukraine in recent years, and methods of waste disposal as a potential source for the development of bioenergy. 2) environmental aspects of the alcohol industry modernization at present stage of development and implementation of modern wastewater treatment technologies.


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