Sewage Sludge Treatment by anaerobic digestion is well established, and the challenge now is how to improve Water Industry AD plant performance. The news is that the Global Biogas Expo is where the AD industry will be exhibiting more ways to raise sewage sludge energy and wastewater electricity/ power output than ever before.
In fact, our advice is that all water industry biogas plant professionals responsible for efficient biogas production at municipal wastewater treatment plants should be there.
Biogas Trade Show Press release follows:
A record number of representatives from the water industry are expected at UK AD & World Biogas Expo 2018 at the NEC in Birmingham (July 11th & 12th), the largest global trade show dedicated solely to anaerobic digestion and biogas.
Featuring the very latest in biogas technology, this highly focused Expo, now in its ninth year, presents the water industry with the perfect opportunity to achieve its goal of energy self-sufficiency – with products and systems to increase the generation of renewable energy.
Including the very latest in pumps, mixers, valves, tanks, flares instrumentation and much more, UK AD & World Biogas Expo 2018 is an international who’s who under one roof. It gives water companies and contractors a hands-on look at what would be best for new digesters and how existing sludge tanks can benefit from:
A boost in biogas yields
Reduced carbon emissions
Reduced energy costs
Improved health and safety
“UK AD & World Biogas Expo is firmly established as a must in the calendar for all those in biogas seeking cleaner and more efficient renewable energy”,
said Charlotte Morton, Chief Executive of the Anaerobic Digestion and Bioresources Association, who are organising the Expo in partnership with the World Biogas Association.
“But whilst we do of course continue to attract visitors from numerous sectors, it is very encouraging indeed to see such a healthy response from those in the water industry who want to get the very best from their biogas production and biosolids”.
The Expo is expected to attract over 3,000 attendees and more than 200 exhibitors from around the world. There will also be over 100 speakers, including key personnel from Ofwat and heads of bioresources from UK water companies.
Sewage Sludge Treatment – A Round-up of Wastewater Sludge Treatment Information Available Online
Sewage sludge refers to the residual, semi-solid material that is produced as a by-product during sewage treatment of industrial or municipal wastewater. The term septage is also referring to sludge from simple wastewater treatment but is connected to simple on-site sanitation systems, such as septic tanks. Anaerobic digestion wastewater treatment – via Sewage sludge – Wikipedia
Sewage Sludge Treatment
Sewage sludge treatment describes the processes used to manage and dispose of sewage sludge produced during sewage treatment. Sludge is mostly water with lesser amounts of solid material removed from liquid sewage. Primary sludge includes settleable solids removed during primary treatment in primary clarifiers. Secondary sludge separated in secondary clarifiers includes treated sewage sludge from secondary treatment bioreactors.
Sludge treatment is [historically] focused on reducing sludge weight and volume to reduce disposal costs, and on reducing potential health risks of disposal options. Water removal is the primary means of weight and volume reduction, while pathogen destruction is frequently accomplished through heating during thermophilic digestion, composting, or incineration.
The choice of a sludge treatment method depends on the volume of sludge generated, and comparison of treatment costs required for available disposal options. Air-drying and composting may be attractive to rural communities, while limited land availability may make aerobic digestion and mechanical dewatering preferable for cities, and economies of scale may encourage energy recovery alternatives in metropolitan areas.
Energy may be recovered from sludge through methane gas production during anaerobic digestion or through incineration of dried sludge, but energy yield is often insufficient to evaporate sludge water content or to power blowers, pumps, or centrifuges required for dewatering. Coarse primary solids and secondary sewage sludge may include toxic chemicals removed from liquid sewage by sorption onto solid particles in clarifier sludge. Reducing sludge volume may increase the concentration of some of these toxic chemicals in the sludge.
There is further information available on Wikipedia on biosolids, sewage sludge thickeners, Sidestream treatment technologies, and Phosphorus recovery, plus anaerobic digestion, and composting of sewage sludge.via Treatment of SS
Biosolids on the US EPA Website
Sewage sludge treatment standards help protect public health and the environment. Biosolids undergo treatment to make them safe for land application. via Biosolids | US EPA
Wastewater treatment – Sewage Sludge treatment and disposal
The residue that accumulates in sewage treatment plants is called sludge (or biosolids). Sewage sludge is the solid, semisolid, or slurry residual material that is produced as a by-product of wastewater treatment processes. This residue is commonly classified as primary and secondary sludge.Primary sludge is generated from chemical precipitation, sedimentation, and other primary processes, whereas secondary sludge is the activated waste biomass resulting from biological treatments.Some sewage plants also receive septage or septic tank solids from household on-site wastewater treatment systems. Quite often the sludges are combined together for further treatment and disposal. via Wastewater treatment
Digestion – Anaerobic Digestion in wastewater treatment
After thickening, the sludge is further treated to make it safer for the environment. The sludge is placed in oxygen-free tanks, called digesters, and heated to at least 95 degrees Fahrenheit for between 15 to 20 days. This stimulates the growth of anaerobic bacteria, which consume organic material in the sludge. Unlike the bacteria in the aeration tanks, these bacteria thrive in an oxygen-free or “anaerobic” environment.
The digestion process stabilises the thickened sludge by converting much of the material into water, carbon dioxide and methane gas. The black sludge that remains after digestion has the consistency of pea soup and has little odour. This is called digested sludge.
Methane gas is often used as an energy source at the City’s wastewater treatment plants. The gas may be used in engines to produce electricity or directly drive plant equipment.
Gas is also used in boilers to provide heat for digestion and plant-wide buildings. Currently, DEP and the New York Power Authority (NYPA) have jointly installed fuel cells at four of the City’s water pollution control plants; 26th Ward, Red Hook, Oakwood Beach and Hunts Point.
Fuel cells convert the methane gas and carbon dioxide into heat and electricity that is then used to operate the plants. This technology contributes to New York City’s efforts to enhance clean air operations at its facilities. There is a significant reduction in air emissions as a result of using fuel cells.
Digester sludge is pumped from sludge storage tanks to a dewatering facility. At some treatment plants, where there are no dewatering facilities on site, the sludge is transported for processing through a pipeline or by a sludge boat to a plant that has a dewatering facility. (See pictures of sludge vessels.) via WWT Process – New York City