Sulfate disinfection, stabilisation and heavy metal removal from sewage sludge – process description and preliminary results

2002 ◽  
Vol 45 (10) ◽  
pp. 287-292 ◽  
Author(s):  
D. Lowrie ◽  
J. Hobson ◽  
D.C. Stuckey

A new, closed loop process for the disinfection, stabilisation and removal of heavy metal from sewage sludge (consisting of a sludge/sulfuric acid reactor, hybrid H2S generator and H2S bioscrubber) is described. Preliminary results for total solids (TS), volatile suspended solids (VSS), chemical oxygen demand (COD), acetate and propionate destruction in the hybrid H2S generator have shown that digestion efficiency is not compromised in a hybrid reactor generating H2S compared to a methanogenic reactor. 70% of the electron flow in the hybrid H2S generator was diverted to methane at a COD:SO4 ratio of 5.45:1. Enough H2SO4 could be generated from the H2S emitted at this ratio to effect sufficient metal solubilisation and pathogen removal from primary sludge.

2020 ◽  
Vol 242 ◽  
pp. 116822 ◽  
Author(s):  
Degang Ma ◽  
Meizhong Su ◽  
Jingjing Qian ◽  
Qian Wang ◽  
Fanyi Meng ◽  
...  

2008 ◽  
Vol 28 (12) ◽  
pp. 2709-2722 ◽  
Author(s):  
H. Mattenberger ◽  
G. Fraissler ◽  
T. Brunner ◽  
P. Herk ◽  
L. Hermann ◽  
...  

2021 ◽  
Author(s):  
Jun Nie

Removal of heavy metal contaminants from sewage sludge is a necessity before it is used as an agricultural fertilizer (biosolid), due to environmental concerns and municipal, provincial and federal regulations. The bioleaching method is recommended as an economical and effective process for the removal of heavy metals from the Ashbridges Bay Treatment Plant (ABTP) sludge, some of them with concentrations exceeding the recommended level by the Ontario Ministry of Agriculture, Food, and Rural Affairs guidelines. The Gram-negative thiobacilli is a group of organisms with physiological and morphological similarity and grows by oxidizing ferrous ion and reduced sulphur compounds. One species of thiobacillus, T. ferrooxidan , was recommended as an effective bacterium for the heavy metal removal from sewage sludge. This research involved the incubation of adapted sludge using fresh raw digested sludge and activated sludge of ABTP. Using adapted sludge for the bioleaching process, the method was tested in a continuously stirred tank reactor (CSTR) in combination with a series of jar tests. Results showed that the metal removal efficiency increases with decreasing pH, and the solids content does not affect the removal efficiency of cupper and zinc very much during short term jar test. The results from the long-term (20-day) CSTR test demonstrated that the high T ferrooxians-contained adapted sludge could remove copper from the sewage sludge of ABTP very effectively, by as much as 79.2%. In comparison, the simultaneous removal efficiency of zinc and cadmium were also studied for the same process and, they are 82.0% and 83.9% respectively. The TSS degradation constant rate during the 20 days' bioleaching was found to be 0.0522 day -1. It is concluded that Ontario should continue to apply sludge to agricultural land, as sludge is an economic alternative, promotes recycling of resources, and is a valuable fertilizer. However, the toxic metals in sludge should be removed from sewage sludge using the bioleaching process to recommended level before it is disposed as a fertilizer for land application.


2000 ◽  
Vol 34 (8) ◽  
pp. 1572-1575 ◽  
Author(s):  
Shiro Yoshizaki ◽  
Tahei Tomida

2016 ◽  
Vol 6 (1) ◽  
pp. 115-120 ◽  
Author(s):  
Khalid Muzamil Gani ◽  
Muntjeer Ali ◽  
Ankur Rajpal ◽  
Hitesh Jaiswal ◽  
Absar Ahmad Kazmi

Moving bed biofilm reactor based sewage treatment plants (STPs) have been installed in northern India over the last decade. As such, there are no performance evaluation studies of this technology in the region. Evaluation of four such STPs was carried out in terms of removal efficiencies of physico-chemical parameters, microbiological parameters and heavy metals. Results showed that the average chemical oxygen demand, biological oxygen demand, total suspended solids, total nitrogen and total phosphorus removal of all STPs ranged from 74 to 91%, 81 to 95%, 79 to 93%, 44 to 80% and 58 to 85%, respectively. Total and thermotolerant (faecal) coliform in the influent and effluent of STPs ranged from 1.5 × 104 to 9.3 × 107 most probable number (MPN)/100 mL and 0 MPN/mL to 2,400 MPN/mL, respectively. Heavy metal concentration (nickel, zinc, cadmium, iron, lead, chromium, and copper) in effluent samples of all the STPs was below Indian discharge limits except lead. Integrated efficiency (IE) of the STPs was also evaluated and the results showed that the actual IE of all STPs was 0–10% larger than standard IE, indicating the suitability of the technology in the region.


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