Reviewing factors affecting the effectiveness of decentralised domestic wastewater treatment systems for phosphorus and pathogen removal

Environmental pollution and risks to human health can result from diffuse sources of pollution originating from decentralised wastewater treatment systems (DWTS). In particular phosphorus pollution can lead to eutrophication and the downgrading of the quality of water bodies, for example, under the Water Framework Directive (WFD) in the EU, and pathogen pollution can result in increased risks of human exposure to pathogens and impacts on industries such as shellfish growing and tourism. The study reported in this paper reviews the effectiveness of various DWTS in removing phosphorus and pathogens from onsite systems. It was found that DWTS are typically not designed to specifically treat these pollutants and the most common type of DWTS, septic tanks, provide only basic treatment. Additional treatment such as filtration-based or wetland systems must be used to achieve desired levels of treatments. The performance of these systems is affected by site specific conditions, such as input load and sources, and climatic conditions and as such operational characteristics and treatment measures must be designed to take account of these factors

Constructed wetlands: Treatment of concentrated storm water runoff (part A)

The aim of this research was to assess the treatment efficiencies for gully pot liquor of experimental vertical- flow constructed wetland filters containing Phragmites australis (Cav.) Trin. ex Steud. (common reed) and filter media of different adsorption capacities. Six out of 12 filters received inflow water spiked with metals. For 2 years, hydrated nickel and copper nitrate were added to sieved gully pot liquor to simulate contaminated primary treated storm runoff. For those six constructed wetland filters receiving heavy metals, an obvious breakthrough of dissolved nickel was recorded after road salting during the first winter. However, a breakthrough of nickel was not observed, since the inflow pH was raised to eight after the first year of operation. High pH facilitated the formation of particulate metal compounds such as nickel hydroxide. During the second year, reduction efficiencies of heavy metal, 5-days at 20°C N-Allylthiourea biochemical oxygen demand (BOD) and suspended solids (SS) improved considerably. Concentrations of BOD were frequently �20 mg/L. However, concentrations for SS were frequently �30 mg/L. These are the two international thresholds for secondary wastewater treatment. The BOD removal increased over time due to biomass maturation, and the increase of pH. An analysis of the findings with case-based reasoning can be found in the corresponding follow-up paper (Part B)

Novel membrane bioreactors and constructed wetlands for treatment of pre-processed animal rendering plant wastewater in Scotland

The performance of a novel industrial membrane bioreactor (MBR) comprising denitrification, nitrification and ultrafiltration for the secondary treatment of primary treated animal rendering wastewater has been compared with an experimental, low-cost and novel vertical-flow constructed treatment wetland planted with Typha latifolia L. The process wastewater followed pre-treatment by dissolved air flotation (DAF). The DAF effluent gave highly variable chemical oxygen demand (COD) and ammonia of 5200 (± 2050) and 490 (± 270) mg/l, respectively. The MBR effluent for COD and ammonia was 45 and 63 mg/l, respectively. The treatment performance of the constructed wetland for COD, ammonia and suspended solids was 167, 63 and 15 mg/l, respectively

Využitie filtračných materiálov na odstraňovanie amoniaku z vody

Ammonia nitrogen is the primary product of the decomposition of plant and animal organic nitrogenous materials. Ammonium salts are part of some nitrogen fertilizers and are getting into ground and surface waters from agricultural areas. Secondary ammonium compounds can be formed directly in waters by reducing nitrates. This article is focused just on removing ammonia from drinking water, while the current research emphasizes the use of natural materials, especially for the removal of inorganic contaminants from water. The aim of this work consists in verifying the possibility of using natural filter materials - zeolites in ammonia removal and other filter materials, verify sorption (ion exchange) properties and efficiency of available types of materials under laboratory conditions.Amoniak je primárnym produktom rozkladu rastlinných a živočíšnych organických dusíkatých látok. Amónne soli sú súčasťou niektorých dusíkatých hnojív a z poľnohospodárskej plochy sa dostávajú do podzemných a povrchových vôd. Sekundárne amóniové zlúčeniny môžu byť vytvorené priamo vo vodách redukciou dusičnanov. Tento článok je zameraný práve na odstránenie amoniaku z pitnej vody, pričom súčasný výskum kladie dôraz na použitie prírodných materiálov, najmä pre odstránenie anorganických kontaminantov z vody. Cieľom tejto práce bolo overiť možnosti použitia prírodných filtračných materiálov - zeolitov a iných filtračných materiálov pri odstraňovaní amoniaku z vody, overiť sorpčné (ionovýmenné) vlastnosti a účinnosť dostupných typov materiálov v laboratórnych podmienkach

Phosphorus retention capacity in red ferralitic soil

In this study the main physical-chemical characteristics of red ferralitic soil to use as substrate in subsurface wetlands was determined. The P-removal was evaluated in a short-term isotherm batch experiment and in a column percolation experiment. The acid characteristic and high content of iron minerals in the red ferralitic soil facilitated the phosphorus removal. Also the sorption isotherms at two different temperatures were obtained. The results showed that the sorption capacity increases with an increase in solution temperature from 25 to 35 degrees C. The experimental data were fitted to Langmuir and Freundlich models, having a better fit to the Freundlich isotherms. The maximum P-sorption capacities estimated using the Langmuir isotherm were 0.96 and 1.13 g/kg at 25 and 35 degrees C respectively. Moreover a column experiment was carried out at two different flows. Sequential extractions of the phosphorus-saturated soil indicated that phosphorus is mainly bound with iron or aluminum minerals. The results have demonstrated a good potential for red ferralitic soil for phosphorus removal from urban wastewater

Practical measures for reducing phosphorus and faecal microbial loads from onsite wastewater treatment system discharges to the environment:a review

Onsite wastewater treatment systems (OWTS), the majority of which are septic tanks, are a contributing factor to phosphorus and faecal microbial loads. OWTS contribute to waterbodies failing to meet Water Framework Directive (WFD) objectives and as such, measures to improve the quality of OWTS discharges are required. Literature has been reviewed for a range of measures designed to reduce phosphorus and pathogen concentrations in effluent from OWTS. A feasibility assessment focussed on their application, effectiveness, efficiency, cost and ease of adaptation. A wide range of measures have been identified that could potentially improve water quality. Results show no one solution could be applied to reduce phosphorus and pathogen loadings to the water environment. The literature suggests that OWTS need to be designed to the local flow and load characteristics of the effluents streams,as well as site specific conditions. With that in mind, measures such as awareness raising, site planning, and maintenance are likely to contribute to reduction of impact of OWTS on the environment. The level of load reduction possible from measures such as awareness raising is difficult to quantify, but it is low-cost and relatively easy to implement. Those most effective for phosphorus and pathogen removal are post-tank measures that maximise physical removal, through adsorption and filtering, and maintain good conditions for biological breakdown of solids and predation of pathogens

Исследование очистки сточных вод от фосфатов материалами, полученными из природного сырья и отходов

Ограничение поступления соединений фосфора в водные объекты имеет важное значение для регулирования антропогенной эвтрофикации. Избыточное поступление фосфора приводит к изменению их трофического статуса. Увеличение трофности ведет к «цветению» и снижению качества воды. В работе проведено сравнение и выбор доступных материалов для удаления фосфатов из сточных вод на очистных сооружениях. Были отобраны доступные и недорогие материалы, содержащие Al, Fe, Ca и Mg. Испытан ряд материалов различного происхождения: природное сырье, отходы производства и промышленный сорбент. Установлены зависимости степени очистки по фосфатам от удельного расхода материалов. Среди испытанных материалов наиболее эффективными являются отработанный катализатор крекинга углеводородов нефти (ОКК), шлам водоподготовки (ШВП), электросталеплавильный шлак (ЭСПШ), доломит, термообработанный при 700°С и Polonite. Установлены значения предельной емкости по фосфатам для ОКК, ШВП, ЭСПШ и доломита термообработанного, которые соответственно равны: 21,2, 13,6, 35,3, и 70,8 мг РО4 3–/г. Меньшей степенью очистки от фосфатов характеризуются необработанное природное сырье (мел, глина, доломит, трепел) и осадки электрокоагуляционной очистки сточных вод. Результаты исследований, полученные в лабораторных условиях, подтверждены на сточных водах очистных сооружений канализации

Studi Penurunan Parameter Bod, Cod Dan Bod/cod Menggunakan Gabungan Vertical Roughing Filter Dan Horizontal Roughing Filter Pada Limbah Cair Domestik Artificial

Domestic wastewater treatment is necessary given the high levels of pollutants such as BOD and COD content. In Indonesia there have been domestic wastewater treatment technology but the application is not yet efficient enough, India and African implement a technology that is roughing filter water treatment using filtration mechanism. This study aims to determine the reduction in BOD, COD and BOD / COD using a combination of vertical roughing filters (VRF) and horizontal roughing filter (HRF) in domestic wastewater. This study uses VRF and HRF series of three variations of flow of 277.7 ml/h, 138.8 ml/h and 92.5 ml/h, three variations of the filter media size, coarse with diametres Ɵ20mm, Ɵ15mm, Ɵ10mm , medium size Ɵ15mm, Ɵ10mm, Ɵ6mm and fine size Ɵ10mm, Ɵ 6mm, Ɵ3mm and two variations of types filter media are gravel and charcoal. From research result obtained a removal parameters of BOD and COD optimum flow variation are 277.7 ml/h for the BOD by 90% eficiency and the variation of flow 138.8 ml/h for removals parameters COD by eficiency 99 %. Variations of filter media types for the removal parameters BOD and COD is gravel, while the optimum filter media size for the parameters BOD is coarse and optimum filter media size for COD is medium