scholarly journals Microbial Flocculants as an Alternative to Synthetic Polymers for Wastewater Treatment: A Review

Symmetry ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 556 ◽  
Author(s):  
Faouzi Ben Rebah ◽  
Wissem Mnif ◽  
Saifeldin M. Siddeeg

Microorganisms such as bacteria, fungi, and microalgae have been used to produce bioflocculants with various structures. These polymers are active substances that are biodegradable, environmentally harmless, and have flocculation characteristics. Most of the developed microbial bioflocculants displayed significant flocculating activity (FA > 70–90%) depending on the strain used and on the operating parameters. These biopolymers have been investigated and successfully used for wastewater depollution in the laboratory. In various cases, selected efficient microbial flocculants could reduce significantly suspended solids (SS), turbidity, chemical oxygen demand (COD), total nitrogen (Nt), dye, and heavy metals, with removal percentages exceeding 90% depending on the bioflocculating materials and on the wastewater characteristics. Moreover, bioflocculants showed acceptable results for sludge conditioning (accepted levels of dry solids, specific resistance to filtration, moisture, etc.) compared to chemicals. This paper explores various bioflocculants produced by numerous microbial strains. Their production procedures and flocculating performance will be included. Furthermore, their efficiency in the depollution of wastewater will be discussed.

2012 ◽  
Vol 7 (1) ◽  
Author(s):  
S. S. Fatima ◽  
S. Jamal Khan

In this study, the performance of wastewater treatment plant located at sector I-9 Islamabad, Pakistan, was evaluated. This full scale domestic wastewater treatment plant is based on conventional activated sludge process. The parameters which were monitored regularly included total suspended solids (TSS), mixed liquor suspended solids (MLSS), mixed liquor volatile suspended solids (MLVSS), biological oxygen demand (BOD), and chemical oxygen demand (COD). It was found that the biological degradation efficiency of the plant was below the desired levels in terms of COD and BOD. Also the plant operators were not maintaining consistent sludge retention time (SRT). Abrupt discharge of MLSS through the Surplus Activated sludge (SAS) pump was the main reason for the low MLSS in the aeration tank and consequently low treatment performance. In this study the SRT was optimized based on desired MLSS concentration between 3,000–3,500 mg/L and required performance in terms of BOD, COD and TSS. This study revealed that SRT is a very important operational parameter and its knowledge and correct implementation by the plant operators should be mandatory.


2020 ◽  
Vol 9 (6) ◽  
pp. e183963748
Author(s):  
Rafael Souza Leopoldino Nascimento ◽  
Ludymyla Marcelle Lima Silva ◽  
Lucas Periard ◽  
Anibal da Fonseca Santiago

The technology of microalgae photobioreactors and illuminated by LEDs has been widely studied for the treatment of wastewater. However, sunlight is a free resource and should be taken advantage of. But the question remains whether photobioreactors illuminated by natural (sunlight) light in combination with artificial light can have greater operational stability or greater performance when compared to systems illuminated only by artificial light. In this context, continuous flow photobioreactors illuminated by Light Emitting Diodes (LEDs) combined, or not, with sunlight were operated and had their performance evaluated. The variables analyzed were pH, OD, chemical oxygen demand (COD), chlorophyll - a and total suspended solids. The photobioreactors were effective for removing organic matter, with 75 ± 15% in the photobioreactor illuminated by LED and 65 ± 10% in the photobioreactor illuminated by sunlight and LED. The results showed that the use of combined lighting favors the production of dissolved oxygen and ensures greater operational stability in the removal of carbonaceous organic matter.


Author(s):  
Huiru Li ◽  
Shaohua Wu ◽  
Cheng Du ◽  
Yuanyuan Zhong ◽  
Chunping Yang

In recent years, close attention has been paid to microbial flocculants because of their advantages, including safety to humans, environmental friendliness, and acceptable removal performances. In this review, the preparation methods of microbial flocculants were first reviewed. Then, the performances of bioflocculants in the removal of suspended solids, heavy metals, and other organic pollutants from various types of wastewater were described and commented, and the removal mechanisms, including adsorption bridging, charge neutralization, chemical reactions, and charge neutrality, were also discussed. The future research needs on microbial flocculants were also proposed. This review would lead to a better understanding of current status, challenges, and corresponding strategies on microbial flocculants and bioflocculation in wastewater treatment.


Author(s):  
Mayowa Oladele Agunbiade ◽  
Carolina Pohl ◽  
Esta Van Heerden ◽  
Oluwaseun Oyekola ◽  
Anofi Ashafa

This study evaluated the potential of a biopolymeric flocculant produced by Terrabacter sp. isolated from Sterkfontein Dam, South Africa. Microbial flocculants aid the aggregation of suspended solutes in solutions, thus, suggesting its alternative application to inorganic and synthetic organic flocculants, which are associated with health-related problems. The 16S rDNA analysis revealed the bacteria to have 98% similarity to Terrabacter sp. MUSC78T and the sequence was deposited in the Genbank as Terrabacter sp. with accession number KF682157.1. A series of experimental parameters such as bioflocculant dosage, cations concentrations, pH, and application of the purified bioflocculant in wastewaters treatment were investigated. In the presence of glucose as a sole carbon source, Ca2+ as cation at pH 8, the optimal flocculating activity attained was 85%. Optimum bioflocculant dosage of 0.5 mg/mL was able to remove chemical oxygen demand (COD), biological oxygen demand (BOD), suspended solids (SS), nitrate, and turbidity in dairy wastewater. In addition, the tested bioflocculant exhibited higher flocculating efficiency as compared to polyaluminum chloride, polyethylenime, and alum. Inductible coupled plasma optical emission spectroscopy (ICP-OES) analyses confirmed significant removal of 77.7% Fe, 74.8% Al, 61.9% Mn, and 57.6% Zn as representatives of heavy metals from treated dairy wastewater. Fourier transform infrared spectroscopy (FTIR) indicated the presence of carboxyl, hydroxyl, and amino groups in the purified bioflocculant which could be responsible for flocculation. Findings from this study showed the prospect of the studied bioflocculant as an alternative candidate in wastewater treatment and remediating of heavy metals.


2012 ◽  
Vol 2012 ◽  
pp. 1-17 ◽  
Author(s):  
Inchio Lou ◽  
Yuchao Zhao

Sludge bulking is the most common solids settling problem in wastewater treatment plants, which is caused by the excessive growth of filamentous bacteria extending outside the flocs, resulting in decreasing the wastewater treatment efficiency and deteriorating the water quality in the effluent. Previous studies using molecular techniques have been widely used from the microbiological aspects, while the mechanisms have not yet been completely understood to form the deterministic cause-effect relationship. In this study, system identification techniques based on the analysis of the inputs and outputs of the activated sludge system are applied to the data-driven modeling. Principle component regression (PCR) and artificial neural network (ANN) were identified using the data from Chongqing wastewater treatment plant (CQWWTP), including temperature, pH, biochemical oxygen demand (BOD), chemical oxygen demand (COD), suspended solids (SSs), ammonia (NH4+), total nitrogen (TN), total phosphorus (TP), and mixed liquor suspended solids (MLSSs). The models were subsequently used to predict the sludge volume index (SVI), the indicator of the bulking occurrence. Comparison of the results obtained by both models is also presented. The results showed that ANN has better prediction power (R2=0.9) than PCR (R2=0.7) and thus provides a useful guide for practical sludge bulking control.


2001 ◽  
Vol 44 (11-12) ◽  
pp. 393-398 ◽  
Author(s):  
J.S. Begg ◽  
R.L. Lavigne ◽  
P.L.M. Veneman

Reed beds are an alternative technology wastewater treatment system that mimic the biogeochemical processes inherent in natural wetlands. The purpose of this project was to determine the effectiveness of a reed bed sludge treatment system (RBSTS) in southern New England after a six-year period of operation by examining the concentrations of selected metals in the reed bed sludge biomass and by determining the fate of solids and selected nutrients. Parameters assessed in both the reed bed influent and effluent: total suspended solids, biochemical oxygen demand, nitrate-nitrogen and total phosphorus. In addition, the following metals were studied in the reed bed influent, effluent and Phragmites plant tissue and the sludge core biomass: boron, cadmium, chromium, copper, iron, lead, manganese, molybdenum, nickel, and zinc. The removal efficiencies for sludge dewatering, total suspended solids and biochemical oxygen demand were all over 90%. Nitrate and total phosphorus removal rates were 90% and 80% respectively. Overall metals removal efficient was 87%. Copper was the only metal in the sludge biomass that exceeded the standards set by the Massachusetts Department of Environmental Protection for land disposal of sludge. The highest metal concentrations, for the most part, tended to be in the lower tier of the sludge profile. The exception was boron, which was more concentrated in the middle tier of the sludge profile. The data and results presented in this paper support the notion that reed bed sludge treatment systems and the use of reed beds provide an efficient and cost effective alternative for municipal sludge treatment.


Author(s):  
Tomáš Vítěz ◽  
Jana Ševčíková ◽  
Petra Oppeltová

This paper is focused on primary, secondary, and total efficiency evaluation of the wastewater treatment process for chosen small wastewater treatment plant (WWTP) located near the Moravian Karst. Eight wastewater samples were taken during one year in three sampling profiles of WWTP: biochemical oxygen demand (BOD), chemical oxygen demand (COD), suspended solids (SS), pH, ammonia nitrogen (N-NH4), nitrite nitrogen (N-NO2), nitrate nitrogen (N-NO3), inorganic nitrogen (Ninorg), total phosphorus (Ptotal). Treatment efficiency by reduction was calculated for all laboratory analyzed indicators and average values were determined for the whole period. Calculated treatment efficiency of indicators BOD, COD and suspended solids was compared with the permissible minimum treatment efficiency of discharged waste water by Government Regulation No. 61/2003 Coll., for the WWTP from 500 to 2 000 PE. Permissible minimum treatment efficiency is not legislatively determined for the primary and secondary level. The results of the work will be used especially to compare results with other similar works.Analyzed values ​​of parameters BOD, COD, suspended solids, N-NH4 at the outflow from wastewater treatment plant were compared with the permissible maximum values at the outflow of the WWTP which the municipality has an obligation to respect according to the decision issued by the District Environment Authority.


2019 ◽  
Vol 80 (8) ◽  
pp. 1524-1537
Author(s):  
Rana Muhammad Asif Kanwar ◽  
Zahid Mahmood Khan ◽  
Hafiz Umar Farid

Abstract The present research was conducted to assess the feasibility of biological treatment of a typical wastewater (WW) stream in Multan, Pakistan, using daily trends of WW characteristics and to design a wastewater treatment (WWT) system for that stream. The pH (5.8–6.2), temperature (24–30 °C), biological oxygen demand (BOD5: 128–265 mg/L), ultimate BOD (BODu: 227–438 mg/L), BOD/total Kjeldahl nitrogen (BOD5/TKN:5.9–11.2), BODu/BOD5 (1.6–2.0), carbonaceous BODu/nitrogenous BODu (CBODu/NBODu:1.6–2.8) of the WW was found to support the biological WWT. The inclusion of NBOD also indicated the need for nitrification-denitrification. The linear regression analysis of volatile suspended solids (VSS) with total suspended solids (TSS) indicated the high content of organic solids, which also made the WW suitable for biological treatment. The BOD/COD (chemical oxygen demand) <0.8 indicated the requirement for biomass acclimation. The major process units of the WWT system developed included a primary clarifier, cascade aeration, trickling filter, adsorption filter and chlorination contact tank. During the validation of design procedures, considerable removal of TSS (91%), TDS (46%), BOD5 (88%), COD (87%) was observed over the 15 week operational period of the secondary WWT system. The WWT system developed was appropriate as a sustainable WWT system that consumed less energy and had lower operational costs.


2005 ◽  
Vol 51 (11) ◽  
pp. 159-166
Author(s):  
E. Ubay-Cokgor ◽  
C.W. Randall ◽  
D. Orhon

In this paper, the performance of the Tyson Foods wastewater treatment plant with an average flow rate of 6500 m3/d was evaluated before and after upgrading of the treatment system for nitrogen removal. This study was also covered with an additional recommendation of BIOWINTM BNR program simulation after the modification period to achieve an additional nutrient removal. The results clearly show that the upgrading was very successful for improved nitrogen removal, with a 57% decrease on the total nitrogen discharge. There also were slight reductions in the discharged loads of biological oxygen demand, total suspended solids, ammonium and total phosphorus with denitrification, even though the effluent flow was higher during operation of the nitrogen removal configuration.


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