Recent progress in microalgal biomass production coupled with wastewater treatment for biofuel generation

Salama, El-Sayed,Kurade, Mayur B.,Abou-Shanab, Reda A.I.,El-Dalatony, Marwa M.,Yang, Il-Seung,Min, Booki,Jeon, Byong-Hun Elsevier 2017 RENEWABLE & SUSTAINABLE ENERGY REVIEWS Vol.79 No.-

<P><B>Abstract</B></P> <P>Microalgae are a potential source of sustainable biomass feedstock for biofuel generation, and can proliferate under versatile environmental conditions. Mass cultivation of microalgae is the most overpriced and technically challenging step in microalgal biofuel generation. Wastewater is an available source of the water plus nutrients necessary for algae cultivation. Microalgae provide a cost-effective and sustainable means of advanced (waste)water treatment with the simultaneous production of commercially valuable products. Microalgae show higher efficiency in nutrient removal than other microorganisms because the nutrients (ammonia, nitrate, phosphate, urea and trace elements) present in various wastewaters are essential for microalgal growth. Potential progress in the area of microalgal cultivation coupled with wastewater treatment in open and closed systems has led to an improvement in algal biomass production. However, significant efforts are still required for the development and optimization of a coupled system to simultaneously generate biomass and treat wastewater. In this review, the systematic description of the technologies required for the successful integration of wastewater treatment and cultivation of microalgae for biomass production toward biofuel generation was discussed. It deeply reviews the microalgae-mediated treatment of different wastewaters (including municipal, piggery/swine, industrial, and anaerobic wastewater), and highlight the wastewater characteristics suitable for microalgae cultivation. Various pretreatment methods (such as filtration, autoclaving, UV application, and dilution) needed for wastewater prior to its use for microalgae cultivation have been discussed. The selection of potential microalgae species that can grow in wastewater and generate a large amount of biomass has been considered. Discussion on microalgal cultivation systems (including raceways, photobioreactors, turf scrubbers, and hybrid systems) that use wastewater, evaluating the capital expenditures (CAPEX) and operational expenditures (OPEX) of each system was reported. In view of the limitations of recent studies, the future directions for integrated wastewater treatment and microalgae biomass production for industrial applications were suggested.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Challenges in using wastewater for microalgae cultivation and biomass production. </LI> <LI> Treatment of different wastewaters and reuse of the treated water. </LI> <LI> Recovery of valuable nutrients (N/P) and removal of organic pollutants. </LI> <LI> Application of wastewater in raceways, photobioreactors, turf scrubbers, and hybrid systems. </LI> <LI> Genetically engineered microalgae for efficient wastewater treatment. </LI> </UL> </P>

전기화학 계면반응에 기초한 DSA 전극을 사용한 고성능 폐수처리 시스템

나영수 ( Young Soo Na ),이만성 ( Man Sung Lee ),김경호 ( Kyoungho Kim ) 한국접착및계면학회 2018 접착 및 계면 Vol.19 No.3

도시의 산업화와 인구의 빠른 증가로 인해, 지구상에서 여전히 7억 8천만명이 물자원 사용에 어려움을 격고 있으며, 이에 따라 깨끗하고 저렴한 물자원 확보 방안에 대한 관심이 집중되고 있다. 그러나, 현존하는 폐수처리 시스템은 낮은 공정효율, 높은 운영비용, 그리고 넓은 부지 요구 등의 다양한 이슈에 직면하여 있는 실정이다. 따라서, 저렴하고 효율적인 폐수 처리 시스템의 개발이 시급히 요구된다. 이러한 노력의 일환으로 rutile type RuO₂를 기반으로 한 DSA전극을 이용한 전기 화학적 방법에 기초한 폐수 처리 시스템을 제안하였고, 이를 성공적으로 시연하였다. 우리의 폐수 처리 시스템은 생활폐수의 경우, 생화학적 산소 요구량 (BOD), 화학적 산소 요구량 (COD) 및 총 유기탄소 (TOC) 제거 효율이 52.0 %, 77.8 % 및 65.6 % 로 우수한 특성을 보였다. 또한 축산 폐수의 경우, BOD, COD, 총 질소(TN), 총 인 (TP)의 제거 효율이 각각 92.9 %, 75.6 %, 35.1 %, 100 %로 획기적인 감축 효과를 거두었습니다. 이 장치의 탁월한 제거 효율과 작은 크기를 고려할 때, rutile RuO2로 코팅된 DSA를 사용한 전기화학적 폐수 처리는 생활 및 축산 폐수의 처리를 위한 유망한 방안이 될 수 있음을 제안하고자 합니다. With the rapidly growing of the population and industrization of cities, the clean and affordable water resources have gained immense interest because of remaining about 780 million people still lack access to it. However, present wastewater treatment systems have been faced with various issues, such as low processing efficiency, high operational costs and the requirement of a large area for manufacturing. It is therefore urgently required to develop an inexpensive and efficient wastewater treatment system. As the one of these efforts, we suggested and successfully demonstrated the wastewater treatment system using and electrochemical method via a dimensionally stable anode (DSA) based on rutile type RuO₂. Our system achieved biochemical oxygen demand (BOD), chemical oxygen demand (COD), and total organic carbon (TOC) removal efficiently at the respective rates of 52.0%, 77.8%, and 65.6% from household wastewater. In addition, we were able to remove BOD, COD, total nitrogen (TN), and total phosphorus (TP) from animal husbandry wastewater at rates of 92.9%, 75.6%, 35.1%, and 100%, respectively, thereby achieving dramatic reductions. Considering the excellent removal efficiency and the small size of this device, electrochemical wastewater treatment using a DSA coated in rutile RuO2 presents a promising option for the treatment of both household and animal husbandry wastewater.

생태학적 수처리 시스템을 이용한 고농도 유기성 폐수처리

조재훈,김중곤,김준휘,윤성명,이정섭,김시욱 한국미생물학회 2001 미생물학회지 Vol.37 No.4

본 연구실에서 개발한 3단계 메탄발효시스템을 이용하여 음식폐기물을 소화하고 배출되는 고농도 유기성 폐수를 미생물막 반응조와 조류, 물벼룩을 이용한 생택학적 수처리 시스템으로 처리하였다. 미생물막 반응조에서 유출되는 폐수에 두 종의 조류를 처리하였을 때 Chlorella sp. 보다 Selenastrum capricornutum이 더 잘 성장하였고, 질소제거 효과도 높았다. 고농도의 $Mg^{2+}$과 $Ca^{2+}$을 주입하고 유출수의 질소와 인 농도 비율을 10 : 1이 되도록 인위적으로 인농도를 조절하였을 때에는 더욱 높은 질소 제거와 조류 성장을 나타내었다. 시험관에서 조류와 물벼룩 두 종의 개체 수 변화를 관찰했을 때, 초기 조류 개체수는 물벼룩 개체수의 증가에 따라 감소하다가 물벼룩의 개체수가 최대치에 이른 후 환경저항에 의해 감소하기 시작하는 시점부터 점차적으로 증가하는 양상을 나타냈다. 본 연구에서 제시하는 생태학적 수처리 시스템은 유기성 폐수내 질소 및 인 처리에 매우 효율적이며, 시스템내의 최종 섭식자인 물벼룩을 대량 사육함으로써 이를 어류의 사료로 쓸수 있는 가능성을 확인할 수 있었다. We have previously developed three stage methane fermentation system capable of digesting food wastes effectively and then releasing high organic wastewater as a final product. In this study, we tried to devise an ecological water treatment system, which can efficiently remove the nitrogen and phosphorus contained in the organic wastewater. The system was made of microbiological filters, algae, and waterfleas. Of two species of alga tested, Selenastrum capricornutum showed higher growth rate and more efficiently removed the nitrogen from the wastewater than by Chlorella sp. In addition, the highest growth rate and the nitrogen removal efficiency could be obtained when high concentrations of $Mg^{2+}\; and\; Ca^{2+}$ were added to the diluted wastewater and the molar ratio of nitrogen to phosphorus was adjusted to 10 : 1. In this study the population relationship between alga and water flea was also examined in a test tube. The initial number of algal cells decreased as the waterflea population increased. However, the number of algal cells gradually increased again when waterflea population decreased partly due to the environmental resistance. From these results, it was believed that the ecological water treatment system could be used for removing the nitrogen and phosphorus from organic wastewater very effectively. Moreover, the waterflea cultured by this system as a final predator could be used as a good foodstuff for fishes.

하,폐수 처리수의 수질개선을 위한 고율 생물막 공정연구

현길수 ( Kil Soo Hyun ),최정우 ( Jeung Woo Choi ),심창석 ( Chang Suk Sim ) 한국수처리학회 2004 한국수처리학회지 Vol.12 No.4

N/A The water bodys of river and reservoir have been contaminated from the effluent of the existing wastewater treatment plants mostly adopted activated sludge processes, which have treated a mixtured wastewater of domestic wastewater, night-soil, and leachate from the waste landfill site. This researches with biofilters were conducted to improve the effluents of water and wastewater treatment plants. The biofilters consist of the aerated filter with single-media layer for water treatment and anaerobic-aerobic filters for wastewater treatment. The experiments of pilot-scale plants were conducted at the field of water and wastewater treatment plants. Based on the results of this researches, COD removal of anaerobic granule biofilter was more than 90%, but COD removal decreased to less than 60% due to inhibition of ammonia when influent NH^(+)₄-N concentration was high level of 400mg/L above, which indicate the ratio of COD/NH^(+)₄-N of less than 5 was desirable to improve the quality of effluent. For the anaerobic-aerobic biofilter, on the other hand, at the influent loadings of 0.07-0.64 kgBOO/m3.d, 0.07-0.38 kgCOD/m³.d, 0.025-0.141 kgTN/m³.d, 0.004-0.026 kgTP/m³.d, the percentages of BOD, COD, T-N and T-P removals averaged from 70 to 90% with all effluent of less than 10 mgT-N/L and 1mgT-P/L. These results show the effluent of anaerobic-aerobic Biofilter will be reused as various purpose as if it will be introduced to the existing wastewater treatment system adopted activated sludge processes.

설명가능한 신경회로망을 이용한 하수처리시스템의 활성슬러지 공정 최적화

남의석 대한전기학회 2020 전기학회논문지 Vol.69 No.12

In this paper, we proposed DO(Dissolved Oxygen) neural network model and DO Control of activated sludge process in wastewater treatment system. Explainable neural network was utilized to decide water qualities which have a much influences in DO biological operation. These water qualities was to be inputs of DO neural network. Also, in regulations, effluent COD, T-N, T-P, pH, SS are hourly to transmitted in Korea Environment Corporation. If these data are exceed the standard, the penalty is given. So, these data are very exact and is controlled by operators critically. So, these data is to be inputs of DO neural network model. DO neural network model is to be utilized for optimal DO set-point which is controlled by blower. As one blower is connected to several aeration tanks, it is difficult to control DO in each aeration tank. Each aeration tank has 2-4 DO sensors which have different values. These are problems in automatic DO control. We also propose practical control solution by valve control logic and DO sensors calibration. The validity of the method is proved by applying to the DO neural network model of activated sludge process which was developed in previous research. The result show that the performance of the proposed model was improved in comparison of previous fuzzy model and conventional neural network models. Also, applicability is proved by field test of DO control in real activated sludge process in wastewater treatment system. In the future, it will be more effective in saving of blower power if this methodology is connected to control of blower valves.

생물학적 하수처리에 소요되는 적정 폭기량의 판단 시스템 설계

이진락,양일화,이해영 한국조명전기설비학회 2001 조명·전기설비학회논문지 Vol.15 No.6

본 논문에서는 생물학적 반응을 이용한 하수처리에서 미생물의 유기물 분해 반응에 필요한 적정 폭기량을 판단하는 기법을 제안한다. 적정 폭기량의 판단 시스템은 크게 세가지 부분으로 구성된다. 첫 번째는 주어진 운전데이터로부터 적정 폭기량을 판단하는 기능이며, 두 번째는 투입 폭기량을 판단된 적정 폭기량으로 변경했을 때의 처리 성능을 하수 처리 과정의 모델을 이용하여 계산하는 부분이고, 세 번째는 판단 결과를 보여주는 부분이다. 40일 동안의 하수처리장 운전데이터를 이용하여 제안된 판단 시스템의 성능을 확인하여 본 결과, 하수처리의 목적을 달성하면서도 폭기량을 10%이상 절감할 수 있음을 보였다 This paper presents a decision making technique of reasonable $O_2$quantity needed to resolve organic matter via microbe in wastewater treatment. Decision making system of inferring reasonable $O_2$quantity consists of three parts. The first part is to compute reasonable $O_2$quantity with given process data. The second part is to find output features of processed wastewater using process model when $O_2$quantity is changed to a value inferred from decision making system. The third part is to show the results of decision making system. In order to verify performance of proposed decision making system computer simulation was done with process data gathered during 40 days. Simulation result shows that $O_2$quantity can be reduced over 10% under the condition of satisfying the specifications for processed wastewater.

Treatment of real wastewater using co-culture of immobilized <i>Chlorella vulgaris</i> and suspended activated sludge

Mujtaba, Ghulam,Lee, Kisay Elsevier 2017 Water research Vol.120 No.-

<P><B>Abstract</B></P> <P>The use of algal-bacterial symbiotic association establishes a sustainable and cost-effective strategy in wastewater treatment. Using municipal wastewater, the removal performances of inorganic nutrients (nitrogen and phosphorus) and organic pollutants were investigated by the co-culture system having different inoculum ratios (R) of suspended activated sludge to alginate-immobilized microalgae <I>Chlorella vulgaris</I>. The co-culture reactors with lower R ratios obtained more removal of nitrogen than in pure culture of <I>C. vulgaris</I>. The reactor with R = 0.5 (sludge/microalgae) showed the highest performance representing 66% removal after 24 h and 95% removal after 84 h. Phosphorus was completely eliminated (100%) in the co-culture system with inoculum ratios of 0.5 and 1.0 after 24 h and in the pure <I>C. vulgaris</I> culture after 36 h. The COD level was greatly reduced in the activated sludge reactor, while, it was increasing in pure <I>C. vulgaris</I> culture after 24 h of incubation. However, COD was almost stabilized after 24 h in the reactors with high R ratios such as 2.0, 5.0, and 10 due to the higher concentration of activated sludge. The growth of <I>C. vulgaris</I> was promoted from 0.03 g/L/d to 0.05 g/L/d in the co-culture of low inoculum ratios such as R = 0.5, implying that there exist an optimum inoculum ratio in the co-culture system in order to achieve efficient removal of nutrients.</P> <P><B>Highlights</B></P> <P> <UL> <LI> This paper highlights the use of co-culture system in municipal wastewater treatment. </LI> <LI> Removal of nutrients was significantly increased in properly inoculated co-culture system. </LI> <LI> Release of organic matter from <I>Chlorella</I> biomass decreased the COD removal performance. </LI> </UL> </P>

물옥잠을 이용한 수중처리방법에 의한 농공단지 폐수처리에 관한 연구

윤춘경 ( Yoon Chun Gyeong ),김형중 ( Kim Hyung Joong ),류재현 ( Ryu Jae Hyeon ),여운식 ( Yo Woon Shik ) 한국농공학회 1997 韓國農工學會誌 : 전원과 자원 Vol.39 No.3

Floating aquatic plant system using water hyacinth was applied to examine feasibility as a wastewater treatment system for the industrial complex in rural area. The wastewater from the industrial complex does not likely contain toxic pollutants because the industries which generate wastewater with toxic compounds are not allowed to move in. Pilot plant was installed at Baeksuk Nongkong Danzi in Chunahn-City, Chunchungnam-Do, and field study was performed during summer and fall of 1996. Hydraulic loading rate was 0.19m³/m² ·day. The effluent concentration of DO was higher than influent, and it implies that 0.6m depth reactor was reaerated enough to increase DO level. The influent concentration of BOD varied significantly from less than 30 to 120mg/ ℓ during the study period, however, effluent concentrations were generally lower than the water quality standard and removal efficiency was up to 85 %. The influent concentration of COD also showed wide variation from less than 40 to 160mg/ ℓ, and effluent concentration was higher than water quality standard when influent concentration was over 100mg/ ℓ. The influent concentrations of T -Nand T - P were lower than water quality standard and no further treatment was required, and these compounds were also removed in the system. Although some improvement and refinement are still required, overall, the floating aquatic plant system was proved to be feasible to apply to treat wastewater from industrial complex in rural area.

Zero Emission Production for Conservation of Water Environment

FUJIE, Koichi 嶺南大學校 環境問題硏究所 1999 環境硏究 Vol.18 No.2

AbstractsThis paper aims to give basic information for the minimization of pollution load to environment by reducing wastewater discharge from production process and by selecting appropriate wastewater treatment processes based on characteristic evaluation of both treatment processes and that of wastewaters. Strategies and methodologies to analyze emissions from the production processes to reduce those by refining and/or replacing the unit process with the alternatives are introduced as well. It was stressed that taking materials and energy balances of the production process are the essential to clarify emissions quantitatively for the reduction of pollutants in the focused process. A procedure including biological degradability, activated carbon adsorption, chemical oxidation for mineralization and for improvement of biodegradability of pollutants, coagulation, and so on, was proposed to evaluate wastewaters for appropriate selection of treatment processes.

Prevention of Electrochemical Degradation in Bioelectrochemical System by Electrical Control

Taeyoung KIM 한국생물공학회 2021 한국생물공학회 학술대회 Vol.2021 No.4

The bioelectrochemical system is recognized for its potential as a useful future environmental-energy techno-logy in terms of sustainable wastewater treatment and green energy production^1,2). Though the bioelectrochemical technology has rapidly developed over the past 20 years, until now, the scale-up of the bioelectrochemical system to the level of industrial application in the real world has not been achieved. The problems in bioelectrochemical degradation such as voltage reversal phenomenon and power overshoot should be overcome in order to achieve a proven level of wastewater treatment efficiency and power generation³⁾. In this study, three multi-electrode-embedded microbial fuel cells (MFCs) were sequentially connected and operated in series and parallel modes, fed by effluent of an anaerobic digester continuously operated using swine wastewater. The MFCs connected in parallel showed the higher power density compared to the series mode. The bioelectrochemical degradations were prevented by MFCs connected in parallel and connected with power management system despite inevitable electrical malfunction conditions by imbalance organic loadings. These findings can lead to be closer real application of bioelectrochemical systems for sustainable wastewater treatment and bioenergy generation.