Water Conservation, Reuse, and Recycling Proceedings of an Iranian-American Workshop (2005) / Chapter Skim
Currently Skimming:
Pages 54-66
The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.
From page 54... ...
54 Small and Decentralized Systems for Wastewater Treatment and Reuse Kara L Nelson INTRODUCTION It is estimated that the wastewater generated by almost half of the population of the United States is treated by small or decentralized systems.
|
From page 55... ...
SMALL AND DECENTRALIZED SYSTEMS FOR WASTEWATER TREATMENT AND REUSE 55 businesses, and recreational facilities rely on onsite wastewater systems, which serve approximately 60 million people (USEPA, 2002) (Table 1)
|
From page 56... ...
56 WATER CONSERVATION, REUSE, AND RECYCLING Wastewater from most urban areas is collected and treated in centralized plants. About 10 percent of the U.S.
|
From page 57... ...
SMALL AND DECENTRALIZED SYSTEMS FOR WASTEWATER TREATMENT AND REUSE 57 the potential to achieve large savings in transport of both the untreated and treated wastewater. Furthermore, by treating the wastewater in smaller quantities, the necessary level of treatment can be coordinated with the reuse application.
|
From page 58... ...
58 WATER CONSERVATION, REUSE, AND RECYCLING pared to combined wastewater, it does not require as much treatment before disposal or reuse. Subsurface disposal of greywater may be possible without any treatment.
|
From page 59... ...
SMALL AND DECENTRALIZED SYSTEMS FOR WASTEWATER TREATMENT AND REUSE 59 be lower cost if the wastewater treatment plant is located at a similar or higher elevation than the households. Any of the alternatives may provide complete sewerage for a community or may be used in combination with conventional gravity sewers, as appropriate.
|
From page 60... ...
60 WATER CONSERVATION, REUSE, AND RECYCLING variable. At the other end of the spectrum are highly mechanized technologies that use pumps to distribute the wastewater, and use mechanical equipment to provide mixing, aeration, filtration, or other augmentation.
|
From page 61... ...
SMALL AND DECENTRALIZED SYSTEMS FOR WASTEWATER TREATMENT AND REUSE 61 In many areas of the United States, the soil type and groundwater hydrology are not amenable to a conventional SAS. In some cases, adequate disposal can be achieved by providing additional treatment of the wastewater before it is discharged to the SAS.
|
From page 62... ...
62 WATER CONSERVATION, REUSE, AND RECYCLING Small and Decentralized Systems: Wastewater Treatment Many of the same technologies that are used for treating the wastewater for large flows are also used for small communities in the United States. For example, extended aeration, oxidation ditches, and sequencing batch reactors are commonly used in small communities; all are aerobic, suspended growth biological processes and are similar to the activated sludge process.
|
From page 63... ...
SMALL AND DECENTRALIZED SYSTEMS FOR WASTEWATER TREATMENT AND REUSE 63 wastewater stabilization ponds are highlighted in the following section. More information on each of these types of natural treatment systems can be found in WEF (2001)
|
From page 64... ...
64 WATER CONSERVATION, REUSE, AND RECYCLING The main advantages of WSPs are as follows: • provide excellent pathogen removal or inactivation, • produce effluent well-suited to irrigation (no disinfection necessary) , • have low construction, operation, and maintenance costs, • can be gravity fed with no moving parts, and • require minimal technical training and skills to operate and maintain low sludge production.
|
From page 65... ...
SMALL AND DECENTRALIZED SYSTEMS FOR WASTEWATER TREATMENT AND REUSE 65 small, with surface area less than 10 acres; however, there are approximately 80 systems with surface areas between 10 and 100 acres, and 13 systems with an area greater than 100 acres (Figure 2)
|
From page 66... ...
66 WATER CONSERVATION, REUSE, AND RECYCLING REFERENCES California State Water Resources Control Board. Groundwater Resources Information Database.
|
Key Terms
This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More
information on Chapter Skim is available.