Protection of biomass from snail overgrazing in a trickling filter using sponge media as a biomass carrier: down-flow hanging sponge system

2015 ◽  
Vol 71 (4) ◽  
pp. 518-523 ◽  
Author(s):  
Takashi Onodera ◽  
Kazuaki Syutsubo ◽  
Wilasinee Yoochatchaval ◽  
Haruhiko Sumino ◽  
Motoyuki Mizuochi ◽  
...  
Keyword(s):  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Pilot Scale ◽  
Municipal Sewage ◽  
Process Performance ◽  
Trickling Filter ◽  
Average Value ◽  
Chemical Treatments ◽  
Sponge Media

This study investigated down-flow hanging sponge (DHS) technology as a promising trickling filter (TF) using sponge media as a biomass carrier with an emphasis on protection of the biomass against macrofauna overgrazing. A pilot-scale DHS reactor fed with low-strength municipal sewage was operated under ambient temperature conditions for 1 year at a sewage treatment plant in Bangkok, Thailand. The results showed that snails (macrofauna) were present on the surface of the sponge media, but could not enter into it, because the sponge media with smaller pores physically protected the biomass from the snails. As a result, the sponge media maintained a dense biomass, with an average value of 22.3 gVSS/L sponge (58.1 gTSS/L sponge) on day 370. The snails could graze biomass on the surface of the sponge media. The DHS reactor process performance was also successful. The DHS reactor requires neither chemical treatments nor specific operations such as flooding for snail control. Overall, the results of this study indicate that the DHS reactor is able to protect biomass from snail overgrazing.

The Possible Utilization of Waste Sludge as an Adsorbent for Removal of Organic Vapor

1986 ◽  
Vol 18 (7-8) ◽  
pp. 413-420 ◽  
Author(s):  
P. C. Chiang ◽  
J. H. You
Keyword(s):  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Municipal Sewage ◽  
Methyl Ethyl ◽  
Organic Vapor ◽  
Waste Sludge ◽  
Catalyst Temperature ◽  
Major Factors ◽  
Municipal Sewage Treatment Plant

In this investigation it was found that the waste sludge obtained from a municipal sewage treatment plant could be reclaimed as an adsorbent for removal of organic vapours, i.e. toluene, methyl-ethyl-ketone and 1-1-2-trichloroethylene, through use of a pyrolysis technique. In order to find the optimum manufacturing process, several tests were performed under various conditions in which the addition of a catalyst, temperature control, and residence time in the furnace, were considered as the three major factors. Both the reclaimed adsorbent and commercially available activated carbon were evaluated to determine their adsorption capacity at various influent concentrations of organic vapours.

scholarly journals The effect of purified sewage discharge from a sewage treatment plant on the physicochemical state of water in the receiver

2016 ◽  
Vol 48 (3) ◽  
pp. 267-284
Author(s):  
Włodzimierz Kanownik ◽  
Agnieszka Policht-Latawiec ◽  
Magdalena Wiśnios
Keyword(s):  
Water Saturation ◽  
Stream Water ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Fold Increase ◽  
Municipal Sewage ◽  
Stream Water Quality ◽  
Sewage Discharge ◽  
Physicochemical State

Abstract The paper presents changes in the contents of physicochemical indices of the Sudół stream water caused by a discharge of purified municipal sewage from a small mechanical-biological treatment plant with throughput of 300 m3·d−1 and a population equivalent (p.e.) – 1,250 people. The discharge of purified sewage caused a worsening of the stream water quality. Most of the studied indices values increased in water below the treatment plant. Almost a 100-fold increase in ammonium nitrogen, 17-fold increase in phosphate concentrations and 12-fold raise in BOD5 concentrations were registered. Due to high values of these indices, the water physicochemical state was below good. Statistical analysis revealed a considerable effect of the purified sewage discharge on the stream water physicochemical state. A statistically significant increase in 10 indices values (BOD5, COD-Mn, EC, TDS, Cl−, Na+, K+, PO43−, N-NH4+ and N-NO2) as well as significant decline in the degree of water saturation with oxygen were noted below the sewage treatment plant. On the other hand, no statistically significant differences between the water indices values were registered between the measurement points localised 150 and 1,000 m below the purified sewage discharge. It evidences a slow process of the stream water self-purification caused by an excessive loading with pollutants originating from the purified sewage discharge.

Assessment of Environmental Quality of Soil Fertilized Grapefruit Trees with Municipal Sewage Sludge

2013 ◽  
Vol 671-674 ◽  
pp. 2736-2741
Author(s):  
Yin An Ming ◽  
Tao Tao
Keyword(s):  
Sewage Sludge ◽  
Environmental Quality ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Land Application ◽  
Municipal Sewage ◽  
Municipal Sewage Sludge ◽  
Limiting Factor

To reuse municipal sewage sludge safely, experiment was carried out on grapefruit trees fertilized with composted sludge from Shiweitou Sewage Treatment Plant in Xiamen City of China, and a method was introduced of how to assess the environmental quality of grapefruit trees soil fertilized with sludge by Set Pair Analysis (SPA) model. The results showed that the soil in the surface layer (0-15cm) and the deeper layer (15-30cm) was less clean, and the environment of soil was not polluted. Thus it was feasible to use sludge as fruit fertilizer. The maximum service life of sludge for continuous land application was estimated by taking Cd as the limiting factor, which would provide scientific guide and technical support for safe land application of sludge.

scholarly journals Is It Possible to Restore a Heavily Polluted, Shallow, Urban Lake?

2020 ◽  
Vol 10 (11) ◽  
pp. 3698
Author(s):  
Jolanta Grochowska ◽  
Renata Augustyniak ◽  
Michał Łopata ◽  
Renata Tandyrak
Keyword(s):  
Bottom Sediment ◽  
Sediment Resuspension ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Water Reservoir ◽  
Dry Weight ◽  
Municipal Sewage ◽  
Lake Basin ◽  
Phosphorus Inactivation

The research was carried out on Karczemne Lake, a water reservoir located in Kartuzy (northern Poland, Pomeranian Lake District). Monitoring of the water and bottom sediment of Karczemne Lake showed a very high level of contamination of the reservoir by a long-term inflow of untreated municipal sewage. The trophic status index of total phosphorus (TP) was unusually high at 101, and the TP content in the bottom sediments—31 mg g−1 (dry weight)—was the highest value recorded worldwide in a lake. Based on the monitoring results, to achieve constant improvement of the water quality, we recommend a completely new, safe and economically justified method of bottom sediment removal and management. A very important aspect of this method is the prevention of uncontrolled sewage discharge back into the lake basin. Removed sediment with interstitial water will be pumped through a pipeline and transported to a sewage treatment plant. In the sediment mining field in which the sludge will be removed, the first phase of phosphorus inactivation will be carried out to chemically precipitate pollutants distributed in the water column as a result of sediment resuspension. After the deepening of the entire lake basin, the method of phosphorus inactivation will be carried out on the entire surface of the lake as the next stage of restoration. A supporting activity will be biomanipulation. Before the restoration is started, the municipal sewerage system will be modernized.

Impact of cold and dilute sewage on pre-fermentation - a case study

2001 ◽  
Vol 43 (11) ◽  
pp. 109-117 ◽  
Author(s):  
D. Bixio ◽  
P. van Hauwermeiren ◽  
C. Thoeye ◽  
P. Ockier
Keyword(s):  
Phosphorus Removal ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
High Rate ◽  
Cold Weather ◽  
Biological Nutrient Removal ◽  
Municipal Sewage ◽  
Biological Phosphorus Removal ◽  
Primary Sludge

The municipal sewage treatment plant (STP) of the city of Ghent (Belgium) has to be retrofitted to a 43%-increase in the nitrogen treatment capacity and to phosphorus removal. Cold weather, dilute sewage and a critical COD over N ratio make the retrofit a challenge for full biological nutrient removal. The potential for fermentation of primary sludge to alter those critical feed sewage characteristics was experimentally evaluated. The idea was that the pinpoint introduction of fermentate could optimise the available reactors by achieving high-rate denitrification and enhanced biological phosphorus removal. The fermentation process was evaluated with a bench scale apparatus. At 20°C (heated process), the hydrolysis yield - expressed in terms of soluble COD - varied from 11% to 24% of the total sludge COD. The fermentation yield expressed in VFA COD varied from 8% to 13% of the total sludge COD. The efficiency of heated fermentation of primary sludge was lower during cold and wet weather, due to the different sewage characteristics, as a result of extended dilution periods and low temperature. The raw sewage, the primary effluent and the fermentate were fractionated according to the requirements for the IAWQ Activated Sludge Model No. 2d. The results clearly show that fermentation in the sewer played an important role and temperature was the driving parameter for the characteristics of the dissolved COD. Instead, the weather flow conditions were the driving parameter for the characteristics of the suspended COD. The results of the detailed fractionation were used as background for process evaluation. The final scenario choice for the retrofit depends on a cost-efficiency calculation.

Toxicity assays and their evaluation on organic polymer flocculants used for municipal sludge dewatering

1998 ◽  
Vol 38 (7) ◽  
pp. 207-215 ◽  
Author(s):  
H. Takigami ◽  
N. Taniguchi ◽  
Y. Shimizu ◽  
S. Matsui
Keyword(s):  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Algal Growth ◽  
Pilot Scale ◽  
Organic Polymer ◽  
Municipal Sludge ◽  
Sludge Dewatering ◽  
Algal Toxicity ◽  
Reproduction Tests

The toxicity of organic polymer flocculants used for the dewatering of municipal sludge was evaluated by using two different toxicity assays: the Closterium ehrenbergii algal toxicity test and the Bacillus subtilis rec-assay. The algal toxicity of the effluents from a pilot-scale sewage treatment plant was investigated with and without the addition of a flocculant (0, 0.05, 0.10 and 0.20 mg/L). No clear evidence on the toxicity caused by the flocculant was observed on both asexual and sexual reproduction tests of C. ehrenbergii. It was also found that the algal growth inhibition of various types of flocculants (i.e., cationic, anionic, amphoionic and non-ionic) was in the order of 1 to 20 mg/L, which was mainly due to a molecular weight (MW) fraction of greater than 100,000. The results of the B. subtilis rec-assay for these flocculants indicated that eight out of ten cationic flocculants caused the direct DNA damage with LC50 =0.1 to 10 mg/L. One of the genotoxic flocculants was also fractionated into their components by MW. The experimental results showed that the lethal effects were mainly contributed by the polymer fraction of MW greater than 100,000, although the genotoxicity was not detected in that fraction. Therefore, the detected genotoxicity of the flocculants could be caused by the combined effects of various components, such as polymers, oligomers, monomers and additives.

Thermochemical pretreatment in the anaerobic digestion of waste activated sludge

2002 ◽  
Vol 46 (10) ◽  
pp. 173-179 ◽  
Author(s):  
S. Tanaka ◽  
K. Kamiyama
Keyword(s):  
Anaerobic Digestion ◽  
Activated Sludge ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Municipal Sewage ◽  
Waste Activated Sludge ◽  
Anaerobic Digesters ◽  
Thermochemical Pretreatment ◽  
Methane Production Rate

Effects of a thermochemical pretreatment on the anaerobic digestion of waste activated sludge (WAS) was investigated by semicontinuously-fed digesters operated at 37¡C. WAS from a return sludge line of a municipal sewage treatment plant was pretreated by autoclaving at 130°C for 5 minutes after adding 0.3g NaOH/g VSS. Solids of WAS were thermochemically solubilized to one half and then 60% or more were in totality solubilized in anaerobic digesters fed with pretreated WAS at 2-8 days of hydraulic retention times (HRT), while only 16-36% were solubilized in digesters fed with raw WAS. The adverse effect of the set temperature (130°C) on the biodegradability of protein was not found. As a result, removal rates of COD in digestion was increased from 38% to 57% at 8 days HRT by the pretreatment. A specific methane production rate in the pretreated process was three times as high as the normal process. The thermochemical pretreatment was found to be very effective to enhance biodegradability as well as solubilization of WAS in anaerobic digestion.

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