3.2.1 Solid Waste Treatment
Reduce solid waste and sludge from on site waste water treatment. Sludge is collected as the sediment of solids at the floor of waste water treatment systems and can be put to use. It is periodically collected to be processed off-site into pellets and used as either fertilizer or as fuel, i.e. for cogeneration plants. Cogeneration uses a source of energy such as pellets in a combined heat and engine power station to simultaneously generate both electricity and useful heat.
Septic tank effluent filters are located next to membrane bioreactors and pumps. They are designed to reduce suspended solids discharged in septic tank effluent by promoting natural sedimentation and excluding gas-lifted particles from entering the outlet pipe. Remote controlled scraper systems can push or pull the sludge to the discharge end of the basin.
Sludge from waste water treatment is periodically collected. Rotating, high-temperature dryers are used to kill all the unwanted elements in the sludge. The plant produces a small, hard granule that is approximately 60 percent organic matter. The pellets can be used as fuel or as fertilizer, containing several important nutrients such as nitrogen, calcium and sulfur. The nitrogen in the fertilizer is in an organic form, so it feeds plants slowly and minimizes the risk of nitrate pollution. The fertilizer is used for landscaping, gardening and large-scale agriculture, improving soil textures and moisture-holding capacity.
Maximum utilities savings are possible due to reduced sewage loads and reduced potable water demand.
Minimum waste disposal, associated infrastructure and fees and minimum dependency on municipal sewage treatment. Sediment scraper systems allow for no interruption in sedimentation process, have minimal power requirements, low hydraulic pressure and few moving parts. They are also simple to install and easy to maintain.
Suitable for use with most types of sludge containing 0.5 percent to 8.0 percent dry solids content; rectangular sedimentation tanks. Can replace faulty or worn out chain and flight systems. Ideal for basins shallower than 11 feet (3.35 meters) and for retrofits.
1.6.4 Biomass Energy
3.1.1 Waste Water Treatment