Biosolids

                                                                          ABSTRACT                                                                                                                                                          

Biosolids are the nutrient-rich organic materials resulting
from the treatment of domestic sewage at a wastewater treatment facility.
Through biosolids management, solid residue from wastewater treatment is
processed to reduce or eliminate pathogens and minimize odors, forming a safe, beneficial
agricultural product. Farmers and gardeners have been recycling biosolids for
ages. Biosolids can be applied as fertilizer to improve and maintain productive
soils and stimulate plant growth. They also are used to fertilize gardens and
parks and reclaim mining sites. Biosolids are carefully monitored and must be
used in accordance with regulatory requirements. The term sludge is
generally used before applicable beneficial recycling criteria have been
achieved which normally occurs at the outlet of the stabilization process. The
term "sludge" should be used in tandem with a specific process
descriptor (e.g., primary sludge, waste activated sludge, secondary sludge,
etc.) The term biosolids is generally used after applicable beneficial
recycling criteria have been achieved, i.e., at the outlet of the stabilization
process. Common stabilization processes include the following: aerobic
digestion, autothermal thermophilic aerobic digestion (ATAD), anaerobic digestion,
composting, alkaline stabilization, thermal drying, including flash, rotary,
fluid bed, paddle, hollow-flight, disc, and infrared dryers, thermophilic
pozzolanic fixation, acid oxidation/disinfection, and heat treatment/acid
digestion. If the solids meet the regulatory requirements for land application
and are recycled, they are biosolids. Sewage sludge is not generated until
domestic sewage is treated in a treatment plant, and biosolids are not produced
until the sewage sludge meets the land application Part 503 requirements. For
these reasons, the treatment of biosolids cannot occur before the domestic sewage
reaches the wastewater treatment plant. Once the wastewater reaches the plant,
domestic sewage goes through physical, chemical, and biological processes that
clean the domestic sewage and remove the solids. If necessary, some of the
solids are then treated with lime to raise the pH level to eliminate
objectionable odors. Pathogen reduction (reduction of disease-causing
organisms, such as bacteria, viruses, and parasites) and reduction of other
organisms capable of transporting disease for the solids usually occurs in a
different process (e.g., a digester). After treatment and processing, biosolids
can be recycled and applied as fertilizer to improve and maintain productive
soils and stimulate plant growth. By treating sewage sludge, we create
biosolids that can be used as valuable fertilizer instead of taking up space in
a landfill or other disposal facility. In addition, an epidemiological study of
the health of farm families using biosolids showed that the use of biosolids
was safe.(Abbaszadegan,etal. 2003) 

 CONTENTS

ABSTRACT

SECTION ONE                                                                

INTRODUCTION………………………………………………………………………...3                                                                
BIOSOLIDS
............................................................................................................................2                                 BIOSOLIDS
TREATMENT
.............................................................................................................2              BIOSOLIDS CLASSIFICATION
.........................................................................................................3
MANAGEMENT OF LAND-APPLIED BIOSOLIDS ……………………..…………...5                                                                             RISK
ASSESSMENT AND RISK MANAGEMENT……………………………………6

SECTION TWO

CHEMICALS……………………………………………………………………………..7

INTRODUCTION…………………………………………………………….…..7

REGULATED CHEMICALS…………………………………………………….7

ORGANIC CHEMICALS…………………………………………………….…..9

SUMMARY………………………………………………………………….…..12

 

SECTION THREE

 

PATHOGENS……………………………………………………………………………12

INTRODUCTION……………………………………………………………….12

HUMAN PATHOGENS OF CONCERN………………………...……………..13

OTHER INFECTIOUS DISEASE CONCERNS………………………………..15

SUMMARY……………………………………………………………………...18

 

SECTION THREE

 

RADIOACTIVE CONTAMINANTS…...………………………………………………18

INTRODUCTION……………………………………………………………….18

SURVEY………………………………………………………………………...19

DOSE RESPONSE………………………………………………………………19

SUMMARY……………………………………………………………………...20

 

SECTION FOUR

 

4. HEALTH & ENVIRONMENTAL EFFECTS
........................................................................................6

4.1 NUTRIENT MANAGEMENT AND IMPACTS ON WATER QUALITY
............................................................7

4.2 TRACE METALS
.......................................................................................................................7

4.3
PATHOGENS..........................................................................................................................8

4.4 TRACE ORGANIC
CHEMICALS.....................................................................................................
10

4.5 BIOAEROSOLS .......................................................................................................................
11

4.6 ODOUR
...............................................................................................................................
11

4.7 ECOLOGICAL EFFECTS AND IMPACTS ON
BIODIVERSITY.....................................................................
12

 

SECTION FIVE

 

EPIDEMIOLOGY OF HUMAN HEALTH RISK………………………………………20

INTRODUCTION……………………………………………………………….20

STUDIES………………………………………………………………………...20

OBSERVED HEALTH OUTCOMES…………………………………………..22

ASSESSMENT OF CAUSALITY………………………………………………23

OTHER VIEWPOINTS/STUDIES..…………………………………………….23

SUMMARY……………………………………………………………………...24

 

SECTION SIX

 

CONCLUSIONS………………………………………………………………………...24

APPENDIX………………………………………………………………………………26

TABLES…………………………………………………………………………26

ATTACHMENTS………………………………………………………………..28

REFERENCES…………………………………………………………………………..31

OTHER RESOURCES…………………………………………………………………..34