Extended Wastewater Treatment Research Articles

Dark fermentative hydrogen production: Potential of food waste as future energy needs

Globally, food waste (FW) is found to be one of the major constituents creating several hurdles in waste management. On the other hand, the energy crisis is increasing and the limited fossil fuel resources available are not sufficient for energy needed for emerging population. In this context, biohydrogen production approach through valorization of FW is emerging as one of the sustainable and eco-friendly options. The present review explores FW sources, characteristics, and dark fermentative production of hydrogen along with its efficiency. FW are highly biodegradable and rich in carbohydrates which can be efficiently utilized by anaerobic bacteria. Based on the composition of FW, several pretreatment methods can be adapted to improve the bioavailability of the organics. By-products of dark fermentation are organic acids that can be integrated with several secondary bioprocesses. The versatility of secondary products is ranging from energy generation to biochemicals production. Integrated approaches facilitate in enhanced energy harvesting along with extended wastewater treatment. The review also discusses various parameters like pH, temperature, hydraulic retention time and nutrient supplementation to enhance the process efficiency of biohydrogen production. The application of solid-state fermentation (SSF) in dark fermentation improves the process efficiency. Dark fermentation as the key process for valorization and additional energy generating process can make FW the most suitable substrate for circular economy and waste based biorefinery.

Trends in Biological Nutrient Removal for the Treatment of Low Strength Organic Wastewaters

Recently, the quickly growing population living in urban location has caused numerous conflicts related to increase in water demand and water pollution. In urban areas, the surface water bodies allow runoffs and storms and in addition act as wastewater drainage pathways. Mostly, the imperfect separation of rainwater and clean wastewater has made large quantities of wastewater discharged into the surface water, resulting in serious pollution. There are many treatment methods for the polluted water bodies such as coagulation, filtration, and ecological floating bed which are related to nutrient removal. The above listed methods are usually capable in reducing pollution load. Wastewaters generated from two sources such as point source (domestic and industries) and non-point source (agricultural and storm water runoff). Finally it reaches nearby water bodies and the abovementioned methods are to be frequently employed in a wastewater treatment plant to remove nutrients. Most of the pollutants in the vastly polluted water are in dissolved forms; hence, an appropriate treatment method relevant to the design and development of the integrated multistage reactor with extended wastewater treatment is reviewed in this paper. Evaluating the accumulation, precipitation, retention, and removal of phosphorus, along with removal of nitrogen, is discussed in brief.

Development and First Year Operation of Extended Wastewater Treatment Plant in Dobron

Development and First Year Operation of Extended Wastewater Treatment Plant in Dobron The aim of the investigation was characterizing and operation assessment of the wastewater treatment plant in Dobron taking into consideration its flow capacity, before (350 m3/d) and after development including building of the second technological pipe with the same flow capacity (350 m3/d), finished in September, 2009. Concise description of the applied wastewater treatment technology and results of investigations concerning flow rates of wastewater within last few years, are presented. Example results of wastewater composition analysis and reached treatment conversion are described. Analysis results of screenings, sand removed from sand traps and stabilized sludge are shown.

Increase of efficiency of an activated sludge plant in paper manufacturing industry by application of a fluidized bed system

In the past the paper mill Niefern GmbH had a yearly production of approximately 20 000 tons of high quality refined paper. For the purification of its wastewater in 1978 the paper mill put a mechanical/biological wastewater treatment plant into operation. Over years the conditions for the effluent concentration into the receiving water could be kept below requirements. In the course of the years the production was switched over more and more to recycling products. Therefore the hydraulic load of the wastewater treatment plant increased by 140 %, the organic load by 295 %. In order to keep the minimum requirements for the future the upgrading of the company's wastewater treatment plant became necessary. A conventional extension of the wastewater treatment plant was not possible because of the extremely restricted space. Therefore it was decided to employ a fluidized bed for the upgrading of the plant. In spring 1991 the extended wastewater treatment plant was put into operation. The company's experience within approximately 1 1/2 years showed that upgrading of water purification plants by additional use of fluidized bed systems in paper producing factories offers an ecological and convenient possibility for extension.

Phosphorus Agriculture Sewage for Agriculture

Land application of sewage sludge seems justifiable mostly because of its phosphorus content. Depending on the distribution of cattle manure the total Danish supply of phosphorus could be provided by manure and sludge. Or sludge phosphorus could substitute from 30—100% of all imported raw phosphates utilized domestically for agricultural purposes. Increased sludge phosphorus production would require extended waste water treatment. Due to increased costs of imported phosphorus such treatment may actually prove economically sound using well known technology. Furthermore it may reduce eutrofication of receiving waters. Recent research shows that Danish sludge need not contribute more Cadmium to soil than chemical fertilizers, if both are applied only accordingly to plant phosphorus demand. Consequently, increased sewage sludge application in agriculture should be deemed favourable compared with present extensive use of chemical fertilizers.