Review of the status qua ultrasonic treatment sludge

Abstract： The use of ultrasound technology for anaerobic digestion of sludge pre-treatment has been highly favored by scholars. This article will focus on the current status of research ultrasonic treatment sludge. Introduction of ultrasonic treatment sludge factors and other processing techniques combined ultrasonic treatment sludge.

Keywords： sanitation； factors； other treatment technologies

Introduction

Emissions sludge has always been a research hotspot. Use of ultrasonic pretreatment on anaerobic digestion of the sludge， can achieve reduction and resource needs[1][[1] Yu Qiang， Liu Hui. Treatment and disposal of urban sewage sludge Status Summary Industrial Technical and Vocational Education. Volume 11， No. 2 .2013 .1 June 1-3]. Ultrasonic sludge handling mechanism has been studied almost all scholars mature. This paper will draw on some relatively sound data to discuss.

Mechanism of ultrasonic treatment sludge from among the factors that affect the treatment effect can be seen there are many， the main factors[2][[2] Zhang Ningning， Sheng-Ju， Cheng Yan. Discusses factors ultrasonic treatment sludge. Energy environmental protection. Volume 21， No. 1 .6 .2007 February 1-9]： ultrasound parameters and duration of action（ frequency and power， sound intensity， sound energy density， action time）， affect the design of the transducer of the reactor， sludge own factors（water content of sludge， temperature， PH value and such others）. Simple ultrasonic treatment sludge has been able to achieve good results， and anaerobic digestion of municipal sludge treatment technologies have other pretreatment， such as： thermal hydrolysis pretreatment， alkali pretreatment， ozone oxidation pretreatment， previous studies showed that the use of processing techniques and other joint pretreated greater efficiency can be obtained.

1 Mechanism of ultrasonic treatment sludge

Sludge "reduction"， "resource" is a sludge that microbial fermentation process for converting biomass into methane， carbon dioxide， methane and other components， and factors restricting this technology has two， one bottleneck is the fermentation time， People in order to break through this bottleneck in the study of the various possible methods （physical， chemical， biological， etc.）， we found that the advantages of ultrasonic technology[3][[3] Yangshun Sheng， high Xiaoyong forecast ultrasonic technology application status and prospects in the sludge treatment and utilization of the Sichuan Environmental .2006. Vol 25 1 .61 ～ 64]. Most of the sludge organic matter present in the microbial cells， Microbial cell wall is a stable semi-rigid structure， difficult to biodegradation， resulting in anaerobic sludge digestion process take a longer residence time. Select a certain frequency and amplitude of ultrasonic， using its generated in the liquid "hole" （cavitation）， the formation of extreme physical and mechanical conditions， local temperature up to 5000K， 5 × 104KPa pressure， and shear forces. This is the hole， "implosion" （implosion） produces the so-called "hot spots" （hotspot）， the microbial cell wall breaking， cytoplasm and enzymes to release enzymes microbial cells lose make the rest has not been broken in the sludge tank fermentation environment adaptability， rapidly become anaerobic microbial nutrient is consumed， thereby enhancing the biological system degradation efficiency； which was released as a supplementary carbon source from the cytoplasm into the anaerobic biological systems， not only to improve the effect of nitrogen and phosphorus removal， and provide more carbon for the rear section of the aerobic process， making digestion and denitrification simultaneously improve COD removal capacity of the entire biological system， thus shortening the duration of anaerobic digestion. In addition the whole process of conventional ultrasonic process converts biodegradable material easily degradable substances， improves biodegradation rates and reduces the amount of excess sludge.