Waste Water treatment by Multi Soil Layering Method 1
Background The use of soil for water treatment has a long history in the world. Conventional method Land treatment Sand filter Septic systems (EPA) Some limitations Low permeability > need large area > Risk of clogging Increase the permeability Soil has high purification function, but is highly depends on properties of each soil type. Regulation and enhancement of the purification functions Multi-Soil-Layering (MSL) Method 2
Multi-Soil-Layering (MSL) Method The MSL method consists of soil units arranged in a brick-like pattern surrounded by layers of zeolite or alternating particles of homogeneous sizes that allow a high hydraulic loading rate. Wastewater Soil mixture layer (10-3 cm sec -1 ) andisol : high soil aggregate formation, high phosphorus adsorption ability. sandy soil : large particle size and high permeability on-site soil: low cost iron : phosphorus adsorption, reducing agent charcoal : high porosity, hydrophobic adsorbent, habitat of microorganisms organic matter : food for microorganisms, electron donor for denitrification Treated water Permeable layer (10-1 cm sec -1 ) sandy soil: large particle size and high permeability zeolite : high NH 4 + adsorption ability, high CEC, high porosity Pumice : high porosity, low cost than zeolite charcoal : high porosity, hydrophobic adsorbent, habitat of microorganisms gravel 3
Conceptual diagram of Multi-Soil-Layering (MSL) Method Waste Water The soil mixture layers The permeable layers Treated Water 4
Treatment processes of MSL Method N 2 CO 2 Denitrification N 2, N 2 O CO 2, CH 4 Organic matters BOD COD Wastewater PO 4 3- NH 4 + Aerobic decomposition Anaerobic decomposition Soil mixture layer Metal iron O 2 PO 4 3- Fe Fe 2+ Fe(OH) 3 (Anaerobic) Organic material OH - CH 2 O + NO - 3 adsorption Charcoal Hydrophobicity NO 3 - H + (Aerobic) Zeolite NH 4 + adsorption Nitrification Fe(OH) 3 O 2 PO 3-4 adsorption Aeration Permeable layer 5
Characteristics of the MSL method 1. High purification ability 2. High removal efficiency of N and P 3. Stable high treatment performance against fluctuation of raw water 4. Low maintenance 5. Reuse of treated water and soil 6. Harmony with the landscape 6
Application of the MSL Method Sewage system, community plant Treated water from wastewater treatment plant Domestic wastewater Toilet Restaurant MSL method N P remove N, P, BOD, COD, etc P Polluted environmental water COD Treated Water 7
Application case Park Small scale community 8
Loading rate Performance of the MSL Method BOD T-N T-P removal The standard is L m -2 day -1. BOD removal only It can be increased up to 4000 L m -2 day -1 Experimental results (in Shimane University) type of water (loading rate) BOD T-P T-N Ⅰ Ⅱ Ⅲ river, lake, raw water (mg/l) 25 2.7 12 treated water from wastewater treatment plant treated water (mg/l) 5 1.7 4-3 (200-5000 L M day -1 removal rate(%) 77 44 52 ) domestic and toilet raw water (mg/l) 190 6.5 58 wastewater treated water (mg/l) 16 1.7 30 (200-2000 L M -3 day -1 ) removal rate(%) 91 75 48 livestock wastewater raw water (mg/l) 1400 40 240 high polluted water treated water (mg/l) 47 5.4 92 (30-300 L M -3 day -1 ) removal rate(%) 96 88 61 9
Results of practical use type of water (loading rate) BOD T-P T-N [park] raw water (mg/l) 5.4 4.46 39.4 a public latrine treated water (mg/l) 0.7 0.04 15.5 ( L M -3 day -1 ) removal rate(%) 81.7 99.1 60.7 [estate,office] raw water (mg/l) 44.1 4.72 45.8 a cooperative society office in Osaka treated water (mg/l) 8.5 1.35 13.2 (30 L M -3 day -1 ) removal rate(%) 80.7 71.4 71.2 [house] raw water (mg/l) 53.2 7.82 64.8 advanced treatment of domestic wastewater treated water (mg/l) 4.8 0.81 5.1 ( L M -3 day -1 ) removal rate(%) 90.9 89.6 92.1 [river] raw water (mg/l) 15.7 - - direct river treatment system in Kumazoe River treated water (mg/l) 1.6 - - (4000 L M -3 day -1 ) removal rate(%) 90 - - 10
Domestic wastewater treatment Toilet Gray Water Waste water inflow 0 450 0 B1 B2 Treated water outflow Masa soil Plastic net Gravel 40mm Porous pipe VU75mm septic tank Ceramic cups for collection of soil solution 600 mm Drainage pipe Aeration pipe Cross Section 150 50 50 50 50 50 50 50 25 00 2 000mm 1200 mm A 0 Soil, Jutepellet, Iron Mixture Jute net Zeolite 1-3mm Plastic net Gravel 40mm Vinyl sheet 0 Air Aeration Air 1200 1750 Plan of treatment quantity:1m 3 /day 90 0 Actual loading rate: ~250L/m 2 /day 400 0 85 0 350 0mm 11
( mg/l ) ( % ) Evaluation of system performance during the 10years operation 40 30 20 10 0 4 3 2 1 0 50 40 30 20 10 0 BOD removal percentage 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 T-P removal percentage 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 T-N removal percentage 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 80 60 40 20 0 80 60 40 20 0 80 60 40 20 0 Change of BOD,T-P,T-N concentration and removal percentage of treated water 12
Application case: Treatment of Polluted River Water by the MSL Method 13
Kumazoe River purification project Onga River Enlarged view Purification facilities Onga River Kumazoe River purification facilities location of Kumazoe River and situation of the watershed 14
Kumazoe River basin Iizuka Station 15
The general situation of Kumazoe River The catchment area 2.5km 2 ( the urban area: about 80%) Length of river channel 1.2km River flow average of winter: 7000m 3 day - 1 average of summer: 28000 m 3 day - 1 Quality of the river water average BOD concentration of winter 55mg L - 1 average BOD concentration of summer 9 mg L - 1 16
The contents of the project The design parameters of the MSL method Targeted quantity of the river water: 7000m 3 day -1 (the target is mean river flow of winter) Targeted quality of the river water: BOD 15.7 mg L -1 (on the average) BOD 50 mg L -1 (on the maximum) Targeted quality of the treated water: less than BOD 1.6mg L -1 (BOD removal rate: 90%) The scale of the MSL method Site area: the MSL method 1750m 2 total 6 series: 5 series of 6 series are always alternate operations. : pre-treatment system for SS removal (a contact oxidation system) The construction details of the MSL method The construction period: September,2002 ~ March,2005 (start: April,2005~) The cost of construction: 7.7 hundred million yen 110 thousand yen per 1m 3 day -1 of the water quantity 17
A plan for Kumazoe River purification project 20m 15m 15m 15m 15m 15m 9m MSL Method MSL Method Onga River Kumazoe River Pre-treatment System Sluice Administration building 18
Kumazoe River purification facilities (the MSL method) 19
Onga River The demonstration experiment of pilot scale on the site for Kumazoe River purification project MSL method Permeable layer Soil mixture layer Pre-treatment system MSL method Water-intake discharge The scale of the system Kumazoe River Water quantity for treatment 144m 3 day -1 (4m 3 m -2 day -1 ) (Loading rate) Pre-treatment system 72m 3 day -1 2 The MSL method 48m 3 day -1 3 Water-intake Pre-treatment system MSL method discharge 20
BOD( mgl -1 ) A performance of demonstration experiment 120 80 60 river water treated water(msl1) treated water(msl2) treated water(msl3) 40 20 0 12 1 2 3 4 5 6 7 8 9 10 11 2,000 2,001 MONTH source: survey by Ministry of Land, Infrastructure and Transport Seasonal change of BOD concentration in the demonstration experiment 21
120 May 18,2001 BOD(mgL -1 ) 80 60 river water treated water(msl1) treated water(msl2) treated water(msl3) 40 20 0 4:00 6:00 8:00 10:00 12:00 14:00 16:00 18:00 20:00 22:00 0:00 2:00 4:00 TIME source: survey by Ministry of Land, Infrastructure and Transport Dairy change of BOD concentration in the demonstration experiment 22
The comparison of performance and cost MSL system contact oxidation contact oxidation system advanced contact system by gravel by gravel and various oxidation system by with aeration types of plastic modules gravel with aeration with aeration BOD of influent water ( mgl - 1 ) 55 55 55 55 BOD of effluent water ( mgl - 1 ) 5 14 10 10 site area (m 2 ) 2,300 2,400 1,200 1,000 construction cost ( million yen ) 440 512 1,031 440 maintenance cost ( thousand yen ) 6,000 6,600 18,000 6,000 Source: The above construction cost are used as an example, and so are difficult to the real cost. 23
The construction processes of the MSL method In making of the soil mixture layers, a nonwoven fabric was laid in the plastic cage and the mixed soil was filled up in it. These blocks were laid like left picture. The void spaces (permeable layers) between each block and block sides were filled with pumice. The inlet pipe was installed at the top of the system. Soil is covered on the surface of the system. 24
reference data 25
Structure of Multi Soil Layering Method Wastewater inflow 0 0 B1 B2 Treated water outflow A 2500 Air 4000 Air 0 900 850 2000 mm 0 1200 1750 3500 mm Aeration Perspective figure 26
Masa soil Plastic net Gravel 40mm Porous pipe VU75mm 600 mm Ceramic cups for collection of soil solution Drainage pipe Aeration pipe Cross Section 150 50 50 50 50 50 50 50 1200 mm Soil, Jutepellet, Iron Mixture Jute net Zeolite 1-3mm Plastic net Gravel 40mm Vinyl sheet 27
Evaluation of system performance during the 10years operation 200 (mgl -1 ) (mgl -1 ) 5 180 left axis inflow (L) WW BOD 4.5 160 WW T-N TW BOD 4 140 120 right axis TW T-N WW PO 4 -P TW PO 4 -P 3.5 3 2.5 80 2 60 1.5 40 1 20 0.5 0 10:00 14:00 18:00 19:00 20:00 21:00 22:00 23:00 0:00 6:00 7:00 8:00 0 Daily fluctuation of waste and treated water(1991/2/13-14) 28
Evaluation of system performance during the 10years operation 200 180 160 (mg/l -1 ) left axis right axis (mg/l -1 ) WW BOD WW T-N TW BOD TW T-N WW PO 4 -P TW PO 4 -P 14 12 140 10 120 8 80 6 60 4 40 20 2 0 7:00 8:00 9:00 10:00 13:00 16:00 19:00 20:00 21:00 22:00 0 Daily fluctuation of waste and treated water(1999/12/22) 29
MSL structure and type of water treatment Heavily polluted water Low loading rate Toilet, Restaurant ww treatment High treatment efficiency Moderately polluted water High loading rate Advanced treatment of sewage or domestic ww Thick ness Soil unit Width Unit size is decided depending on the degree of treatment needed. High loading rate (less clogging) Less polluted water High loading rate Direct treatment of polluted river water 30
Prevention mechanisms of clogging and shortcut in the MSL method Lack of uniformity (a) Shortcut (b) Clogging Clogging (c) Prevention effect by MSL method Improvement of contact efficiency and filtration function Improvement of PO 4 -P,COD,SS removal (1)Water flow in soil (2)Water flow in the MSL method (3)Difference of water flows by various materials 31