The Comparison of parasite eggs and protozoan cysts of urban raw wastewater and efficiency of various wastewater treatment systems to remove them

One of the most important quality characteristics associated with wastewater reuse in agriculture is the microbial quality. This study aimed to determine the efficiencies of Ghasreshirin (constructed wetland), Islamabadgharb and Gilangharb wastewater treatment plants (stabilization ponds), Sarpolezahab and Paveh (extended aeration activated sludge) and Kermanshah (conventional activated sludge) in the removal of protozoan cysts and parasitic eggs. This study was carried out during six months and samples were collected at weekly intervals from influent and effluent of the wastewater plants. In order to determine the concentration of ova, 288 samples were analyzed by Mc Master Slide according to Bailenger method. No parasite eggs or protozoan cysts were detected in the effluents of the constructed wetland or stabilization ponds systems. The extended aeration activated sludge system of Sarpolezahab removed 99-100% of parasite eggs and ≥99% of protozoan cysts. The respective values for extended aeration activated sludge system of Paveh were 97.5-100% and ≥99%. However, the conventional activated sludge of Kermanshah removed 97-99% and 99-100% of parasite eggs and protozoan cysts, respectively. According to the results, removal efficiency for cysts and parasite eggs in natural systems (constructed wetland and stabilization ponds) is better than mechanical systems (extended aeration activated sludge and conventional activated sludge). The effluent quality of all systems in terms of nematode eggs is consisted to Engelberg index (nematode eggs count: 1 ≥ counts per liter)

Standardization of activated sludge for biodegradation tests

Activated sludges are an inoculum source commonly used in biodegradation studies, as wastewater treatment facilities constitute an entry point to the environment for many chemicals. In this paper, the main issues relating to the use of activated sludge in biodegradability tests are presented. Special attention is also devoted to discussing the factors affecting both the activity of the microbial communities and the test results. After a short survey of the state of the art of microbiology of activated sludge, the paper focuses on the methods used to reduce the variations in the diversity, quality and quantity of these communities. Finally, use of surrogates as reference materials in biodegradability tests is discussed

Fate and occurrence of alkylphenolic compounds in sewage sludges determined by liquid chromatography tandem mass spectrometry

This is the author's accepted manuscript. The final published article is available from the link below. Copyright @ 2009 Taylor & Francis.An analytical method has been developed and applied to determine the concentrations of the nonionic alkylphenol polyethoxylate surfactants and their metabolites, alkylphenoxy carboxylates and alkyphenols, in sewage sludges. The compounds were extracted with methanol/acetone (1:1 v/v) from sludge, and concentrated extracts were cleaned by silica solid‐phase extraction prior to determination by liquid chromatography tandem mass spectrometry. The recoveries, determined by spiking sewage sludge at two concentrations, ranged from 51% to 89% with method detection limits from 6 µg kg−1 to 60 µg kg−1. The methodology was subsequently applied to sludge samples obtained from a carbonaceous activated sludge plant, a nitrifying/denitrifying activated sludge plant and a nitrifying/denitrifying activated sludge plant with phosphorus removal. Concentrations of nonylphenolic compounds were two to three times higher than their octyl analogues. Long‐chain nonylphenol polyethoxylates (NP3–12EO) ranged from 16 µg kg−1 to 11754 µg kg−1. The estrogenic metabolite nonylphenol was present at concentrations ranging from 33 µg kg−1 to 6696 µg kg−1.Public Utilities Board of Singapore, Thames Water and Yorkshire Water

BIOSORPTION OF TECHNICAL DIRECT DYES BY ACTIVATED SLUDGE

This study aimed to determine the effect of adsorbent mass, adsorption time and concentration of dye on adsorption efficiency of activated sludge toward technical direct dyes and to know the effect of the adsorption process of the COD (Chemical Oxygen Demand) value in technical direct dyes solution. The subject of this study was activated sludge. The object of this study was the activated sludge adsorption efficiency on technical direct dyes. Adsorption process was done by conditioning the variation of the mass of adsorbent, adsorption time and concentration of technical direct dyes. Technical direct dyes solution before and after adsorption were quantitatively analyzed with a COD reactor. Technical direct black dyes solution after adsorption were analyzed quantitatively by UV-Vis spectrophotometer. Adsorption efficiency expressed in terms of concentration of adsorbed dyes divided by the initial concentration of dye solution and multiplied by 100%. The results showed that: the greater the mass of adsorbent, the higher the adsorption efficiency of activated sludge to technical direct dyes, the longer the time given to the process of adsorption, the higher the adsorption efficiency of activated sludge to technical direct dyes, adsorption efficiency decreases with increasing concentration of technical direct dyes, chemical Oxygen Demand (COD) value technical direct were decrease after adsorption process by activated sludge

PROSES PENGOLAHAN LIMBAH CAIR DOMESTIK SECARA ANAEROB

The pollution occurred to rivers in many towns is considered as the impact of domestic sewage disposal. Domestic sewage contains organic matters that it can be used as products instead of treated substances. The sewage can be treated biologically by using anaerobic activated sludge system. This research purposes on determining the type of activated sludge, treatment time needed, and biogas generated from anaerobic digestion. The domestic sewage was taken from the sewer in Wonodri Street, Semarang. Activated sludge from the sewer and tofu production sewage were used as the source of microorganisms. COD analysis was used as a parameter of sewage treatment. The results of this research are the decrease of COD value during 30 days is 37,3% and the biogas generated is 2,25 L. The best result of sewage treatment by using tofu activated sludge is obtained when 10 L of sewage is treated. The decrease of COD value is influenced by retention time, the volume of sewage treated, and the type of activated sludge. The time needed in order to treat the sewage to meet the water standard is 84 days

Pengaruh Waktu Fermentasi Terhadap Produksi Biogas Menggunakan Digester Dua Tahap Pada Berbagai Konsentrasi Palm Oil-Mill Effluent Dan Lumpur Aktif

The production of biogas from palm oil-mill effluent (POME) and activated sludge derived from fresh cow feces through a few stages of the reaction at a single digester inhibited the reaction of anaerobic fermentation. The development of the biogas production process using two stages digester can optimize the anaerobic fermentation reactions. The aims of this research was to know the fermentation time effect toward biogas production in two stage digester. The study was done in three stages, that are subtrate analysis, biogas production by using two stages digester, and data analysis. The study was done in three combinations of feedstock which were POME concentrations of 90, 80, and 70% and activated sludge concentrations of 10, 20, and 30%. A mixture of POME and activated sludge at 0.35 L/day for 40 days were fed into two stages digester. Combination POME of 90% and activated sludge of 10% was denoted 90LC:10LA, combination POME of 80% and activated sludge of 20% was denoted 80LC:20LA, and combination POME of 70% and activated sludge of 30% was denoted 70LC:30LA. The result showed the fermentation time gave significant effect toward biogás production in the second stage digester. All combinations showed the upward trend in the volume of biogás during fermentation. Combination 80LC:20LA showed the highest volume increases from 1st digester to 2nd digester, that was 121,29%. Fermentation time in 2nd digester for all combinations (90LC:10LA, 80LC:20LA, and 70LC:30LA) gave significant effects toward pH where pH increased for 40 days the fermentation time. The highest volume of biogas was reached when POME and activated sludge in combination 90LC:10LA. It was 11.35 L

Operation of an activated sludge plant for fellmongery wastewater treatment : a thesis submitted in partial fulfilment of the requirements of the degree of Master of Technology in Environmental Engineering at Massey University, Palmerston North, New Zealand

Activated sludge is one of the most common wastewater-treatment processes used to reduce pollutant loads on the receiving environment. For efficient operation, there must be an effective process control and operation strategy in place to ensure that process problems are avoided. This research is a case study into the process control and operation of an activated sludge plant used for fellmongery wastewater treatment. Analysis of the pretreated fellmongery wastewater showed that it is characterised by high total and volatile suspended solids concentrations, and high organic nitrogen concentrations. The plant was experiencing frequent problems that were attributed to the high influent suspended solids load coupled with ineffective solids management. Operation of bench-scale simulations showed that solids retention time (SRT) control at 5 or 10 days will produce acceptable effluent suspended solids concentrations and soluble chemical oxygen demand (COD) removal. Soluble COD removal for both 5 and 10 days was high at 85 and 80 % respectively at a hydraulic retention time of 6.4 days. Effluent suspended solids concentrations were 100 and 157 g/m 3 respectively. A steady state control model was developed based on, mass balances of biochemical oxygen demand (BOD) and volatile suspended solids (VSS), process performance equations, and the solids retention time (SRT). The model used three control points, the clarifier underflow pump, the clarifier influent pump and the waste sludge pump. The model was incorporated into an off-line Activated Sludge Operation Program (ASOP) to provide a user-friendly interface between the plant and operator. The main output from ASOP includes values for the three control points and suggestions to help avoid problems. A process control and operation strategy was developed using ASOP, the knowledge gained in this research, and an operation manual developed from accepted operation practises

An evaluation of metal removal during wastewater treatment: The potential to achieve more stringent final effluent standards

This is the author's accepted manuscript. The final published article is available from the link below. Copyright @ 2011 Taylor & Francis.Metals are of particular importance in relation to water quality, and concern regarding the impact of these contaminants on biodiversity is being encapsulated within the latest water-related legislation such as the Water Framework Directive in Europe and criteria revisions to the Clean Water Act in the United States. This review undertakes an evaluation of the potential of 2-stage wastewater treatment consisting of primary sedimentation and biological treatment in the form of activated sludge processes, to meet more stringent discharge consents that are likely to be introduced as a consequence. The legislation, sources of metals, and mechanisms responsible for their removal are discussed, to elucidate possible pathways by which the performance of conventional processes may be optimized or enhanced. Improvements in effluent quality, achievable by reducing concentrations of suspended solids or biochemical oxygen demand, may also reduce metal concentrations although meeting possible requirements for the removal of copper my be challenging

Vrishabhavathi Valley Wastewater Treatment Plant System Upgrade

Sixteen activated sludge tanks, eight secondary clarifiers, and four return pump stations were designed for the Vrishabhavathi Wastewater Treatment plant in Bangalore India. The design included tank dimensions, mechanical equipment associated with each component, pipe sizes for the piping system, and a cost estimate with a construction schedule. The activate sludge tanks were designed to be made of reinforced concrete with a mechanical air diffuser system installed for oxidation purposes. The secondary clarifiers were designed using reinforced concrete and a mechanical sweeping mechanism to scrape up the sludge as it settles to the bottom of the tank. Return pump stations were designed to transport the sludge into recirculation pipes or to a waste activated sludge stream. The treated water from the expanded facility will be discharged back into the river or transported to a tertiary treatment facility on site. The effluent will act as a source of non-potable water for local urban and agricultural use. Construction of the proposed facility will not interfere with the operation of the existing plant. This expansion to the existing facility will provide the city of Bangalore with an additional 71.33 million gallons per day of fresh, not-potable water