The Activated Sludge Advisor Prototype - ACS Publications - American

KnowledgePro (r), ASAP resides on an IBM PC/AT (or compatible); it incorporates a window-based user- interface, graphics ... 1990 American Chemical So...
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Chapter 10

The Activated Sludge Advisor Prototype 1

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Joseph Schmuller and Michael R. Morlino 1

Expert Systems Team, CDM Federal Programs Corporation, 13135 LeeJackson Memorial Highway, Fairfax, VA 22033 Camp Dresser and McKee, Inc., Dallas, TX 75231

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The Activated Sludge Advisor Prototype (ASAP) i s an Expert System designed to assist wastewater treatment operators at the Dallas Water U t i l i t i e s Central Wastewater Plant. As i t s name implies, ASAP's focus i s the activated sludge process, a biological method that uses microorganisms to speed up decomposition of wastes in wastewater. This process i s routinely susceptible to a large number of operational problems. Solving these problems is often d i f f i c u l t for novice operators, particularly if there are no experienced operators around to help. ASAP's knowledge base contains the heuristics and insights of an experienced operator. Written i n KnowledgePro ( r ) , ASAP resides on an IBM PC/AT (or compatible); it incorporates a window-based userinterface, graphics, and hypertext. Starting from a set of a half-dozen treatment plant symptoms, ASAP leads the user through sequences of questions resulting i n selection of one of 50 diagnoses.

Wastewater

Treatment

A wastewater t r e a t m e n t p l a n t i s a complex s t r u c t u r e w i t h a s i m p l e g o a l - - t o i n s u r e t h a t d i r t y w a t e r coming i n ( t h e i n f l u e n t ) w i l l be t u r n e d i n t o c l e a n w a t e r g o i n g out (the e f f l u e n t ) . The s t r u c t u r e encompasses a number o f i n s t r u m e n t s , p r o c e s s e s , and p e o p l e , a l l o f w h i c h a r e needed because o f t h e wide v a r i e t y o f s u b s t a n c e s w h i c h might contaminate the w a t e r . A t r e a t m e n t f a c i l i t y i s u s u a l l y c o n s i d e r e d t o have t h r e e major components -- c o l l e c t i o n , t r e a t m e n t , and d i s p o s a l . Wastewater i s c o l l e c t e d and brought t o t h e f a c i l i t y t h r o u g h a complex network o f p i p e s and pumps; t h e system w h i c h b r i n g s w a t e r from h o u s e h o l d s , commerce, and i n d u s t r y i s t y p i c a l l y s e p a r a t e from the system w h i c h b r i n g s storm r u n o f f water from s t r e e t s , l a n d , and r o o f s o f b u i l d i n g s . 0O97-6156790/0431-O139$06.00A) © 1990 American Chemical Society

Hushon; Expert Systems for Environmental Applications ACS Symposium Series; American Chemical Society: Washington, DC, 1990.

E X P E R T SYSTEMS FOR

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ENVIRONMENTAL APPLICATIONS

When the wastewater a r r i v e s a t the t r e a t m e n t p l a n t , i t moves through a s e r i e s o f p r o c e s s e s w h i c h remove the waste from the w a t e r and reduce i t s t h r e a t t o p u b l i c h e a l t h . Treatment a t the p l a n t c o n s i s t s o f p r e - t r e a t m e n t , p r i m a r y t r e a t m e n t , and secondary t r e a t m e n t . P r e - t r e a t m e n t p h y s i c a l l y s c r e e n s out l a r g e d e b r i s , and removes sand, g r a v e l , and o i l . P r i m a r y t r e a t m e n t removes s e t t l e d and f l o a t i n g materials. Secondary t r e a t m e n t i n v o l v e s b i o l o g i c a l , c h e m i c a l , and p h y s i c a l p r o c e s s e s w h i c h remove suspended and d i s s o l v e d s o l i d s ; secondary t r e a t m e n t a l s o k i l l s p a t h o g e n i c organisms.

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The A c t i v a t e d Sludge

Process

A c t i v a t e d sludge c o n s i s t s o f p a r t i c l e s produced i n wastewater by the growth o f organisms i n the presence o f d i s s o l v e d oxygen. The term " a c t i v a t e d " r e f l e c t s the h i g h d e n s i t y o f b a c t e r i a , f u n g i , and p r o t o z o a on the p a r t i c l e s . The a c t i v a t e d s l u d g e p r o c e s s i s a secondary treatment which uses these microorganisms to speed up the decomposition of wastes. When a c t i v a t e d s l u d g e i s added t o wastewater, the microorganisms f e e d and grow on waste p a r t i c l e s i n the wastewater, and groups o f them come t o g e t h e r t o form c l u s t e r s c a l l e d "floe." They use the wastes f o r food and as a source o f energy f o r t h e i r l i f e p r o c e s s e s and f o r the r e p r o d u c t i o n o f more organisms, w h i c h w i l l i n t u r n use more o f the waste f o r f o o d . A l s o , the a c t i v a t e d sludge forms a l a c y network, c a l l e d a " f l o e mass", t h a t e n t r a p s many m a t e r i a l s not used as f o o d . In a t r e a t m e n t p l a n t , the i n f l u e n t f l o w s c o n t i n u o u s l y i n t o an a e r a t i o n t a n k , where a i r i s i n j e c t e d t o mix the a c t i v a t e d sludge w i t h the wastewater and t o s u p p l y the oxygen needed f o r the microorganisms to decompose the waste. The m i x t u r e o f a c t i v a t e d sludge and wastewater i n the a e r a t i o n tank i s c a l l e d "mixed l i q u o r " . The mixed l i q u o r f l o w s from the a e r a t i o n tank t o a "secondary c l a r i f i e r " , a tank a d j a c e n t t o the a e r a t i o n t a n k , where the a c t i v a t e d s l u d g e i s s e t t l e d . Most o f the s e t t l e d sludge i s r e t u r n e d t o the a e r a t i o n tank t o m a i n t a i n a h i g h p o p u l a t i o n o f organisms t o break down the w a s t e s . As more a c t i v a t e d sludge i s produced than can be used i n the p r o c e s s , some o f the r e t u r n sludge i s d i s p o s e d o f (wasted). To keep t h i s p r o c e s s moving smoothly, a wastewater treatment o p e r a t o r has t o p e r f o r m a d e l i c a t e b a l a n c i n g a c t a c r o s s s e v e r a l f a c t o r s . One o f these f a c t o r s i s the f o o d - t o - o r g a n i s m s r a t i o , w h i c h i s m a i n t a i n e d by w a s t i n g . A n o t h e r i s the amount o f d i s s o l v e d oxygen (DO) i n the a e r a t i o n t a n k . I f DO i s too low, f i l a m e n t o u s b a c t e r i a c o u l d d e v e l o p , w h i c h would keep the sludge f l o e from s e t t l i n g i n the secondary c l a r i f i e r ; i f DO i s t o o h i g h , p i n p o i n t f l o e ( t i n y c l u s t e r s of organisms) w i l l develop and not be removed i n the secondary c l a r i f i e r . One f i n a l f a c t o r i s the need t o keep f l o w d i s t r i b u t e d e v e n l y among m u l t i p l e t r e a t m e n t u n i t s . In c o n t r o l l i n g the p r o c e s s , an e x p e r i e n c e d o p e r a t o r l o o k s f o r c e r t a i n s i g n s l i k e the c o l o r o f the sludge and the amount o f t u r b u l e n c e a t the s u r f a c e o f the mixed l i q u o r . An e x p e r i e n c e d o p e r a t o r might a l s o use h i s / h e r sense o f s m e l l . I n a d d i t i o n t o these p e r s o n a l o b s e r v a t i o n s , an o p e r a t o r must a l s o a n a l y z e samples o f wastewater t a k e n from d i f f e r e n t l o c a t i o n s throughout the p r o c e s s t o c o n f i r m h i s / h e r judgments. A f a i r amount o f e x p e r t i s e , t h e n , i s needed to m a i n t a i n smooth o p e r a t i o n o f an a c t i v a t e d s l u d g e p r o c e s s .

Hushon; Expert Systems for Environmental Applications ACS Symposium Series; American Chemical Society: Washington, DC, 1990.

10.

SCHMULLERANDMORLINO

The Activated Sludge Advisor Prototype

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ASAP The A c t i v a t e d Sludge A d v i s o r P r o t o t y p e (ASAP) was d e s i g n e d t o h e l p t h e D a l l a s C e n t r a l Wastewater P l a n t ' s n o v i c e o p e r a t o r s c o n t r o l t h e a c t i v a t e d sludge p r o c e s s . Our u l t i m a t e g o a l i s t o develop an e x p e r t system w h i c h d e a l s w i t h a l l a s p e c t s o f p l a n t f u n c t i o n i n g . The a c t i v a t e d sludge p r o c e s s was chosen as t h e f o c u s o f o u r i n i t i a l e f f o r t because (a) i t i s c r u c i a l t o t r e a t m e n t p l a n t f u n c t i o n i n g , (b) i t e n t a i l s a c o n s i d e r a b l e amount o f e x p e r t i s e , and (c) i t s c i r c u m s c r i b e d n a t u r e would p e r m i t development o f an e x p e r t system w i t h i n a r e a s o n a b l e time frame. ASAP was developed by CDM FPC's E x p e r t Systems team, through a c o n t r a c t h e l d by Camp D r e s s e r & McKee-Dallas w i t h t h e D a l l a s Water U t i l i t i e s . The domain e x p e r t , an employee o f Camp D r e s s e r & McKeeD a l l a s , has over 20 y e a r s * e x p e r i e n c e i n t h e wastewater f i e l d , and works c l o s e l y w i t h D a l l a s Water U t i l i t i e s . Development proceeded a c c o r d i n g t o well-known e x p e r t system development g u i d e l i n e s , f a c i l i t a t e d by t h e wastewater t r e a t m e n t e x p e r i e n c e o f one o f t h e knowledge e n g i n e e r s on t h e team. We e s t i m a t e t h a t h e r e x p e r i e n c e saved about 2 person-months i n the 12 person-month development e f f o r t . P r e l i m i n a r y knowledge was a c q u i r e d by r e a d i n g Water P o l l u t i o n C o n t r o l F e d e r a t i o n p u b l i c a t i o n s , and wastewater o p e r a t o r i n s t r u c t i o n manuals ( 1 ) , e n a b l i n g t h e knowledge e n g i n e e r s t o use wastewater t e r m i n o l o g y when i n t e r v i e w i n g the domain e x p e r t . B e f o r e i n t e r v i e w i n g t h i s e x p e r t , t h e knowledge e n g i n e e r s i n t e r v i e w e d a Camp D r e s s e r & McKee e n g i n e e r who has e x t e n s i v e e x p e r i e n c e i n t h e d e s i g n o f wastewater treatment p l a n t s . A l s o , p r i o r t o knowledge a c q u i s i t i o n , t h e development team t o u r e d a t r e a t m e n t f a c i l i t y i n V i r g i n i a , and t h e C e n t r a l Wastewater P l a n t i n D a l l a s . Two 3-day knowledge a c q u i s i t i o n s e s s i o n s were h e l d w i t h t h e domain e x p e r t . Three knowledge e n g i n e e r s were p r e s e n t a t t h e f i r s t s e s s i o n , two a t t h e second. A f t e r t h e f i r s t s e s s i o n , t h e knowledge e n g i n e e r s ' notes were c o m p i l e d and used as t h e b a s i s f o r c o n s t r u c t i n g a " d e c i s i o n diagram" ( a l s o c a l l e d a "knowledge t r e e " ) -- a p i c t u r e w h i c h i l l u s t r a t e s t h e sequence o f an e x p e r t ' s d e c i s i o n s i n g i v e n s i t u a t i o n s , and c a n be c o n v e r t e d i n t o a s e t o f p r o d u c t i o n r u l e s . I n the s i x weeks between s e s s i o n s , t h e domain e x p e r t was sent t h e d e c i s i o n diagram f o r comments and a d d i t i o n s , and c o d i n g was i n i t i a t e d . A t t h e second s e s s i o n , t h e d e c i s i o n diagram was used as t h e b a s i s f o r i n t e r v i e w i n g the expert. The d e c i s i o n diagram grew b o t h i n depth and i n b r e a d t h as a r e s u l t o f t h e second s e s s i o n . I n i t s f i n a l form, t h e diagram c a n take one o f s i x p a t h s , each o f w h i c h has s e v e r a l p o s s i b l e branches. Each p a t h s t a r t s w i t h a r e a d i l y o b s e r v a b l e symptom i n t h e a c t i v a t e d sludge p r o c e s s and u l t i m a t e l y d i v e r g e s i n t o s e v e r a l d i a g n o s e s , so t h a t ASAP can conclude w i t h any o f 50 d i a g n o s e s . Thus, a l t h o u g h ASAP wears t h e " p r o t o t y p e " l a b e l , t h e depth and b r e a d t h o f i t s knowledge base take i t beyond t h e l e v e l o f a p r o t o t y p e . The s p e c i f i c i t y o f some o f t h e parameter v a l u e s i n i t s knowledge base c o n f i n e s i t t o d e c i s i o n s f o r the C e n t r a l Wastewater P l a n t , b u t i t c o u l d be c u s t o m i z e d f o r o t h e r facilities. The a l m o s t - f i n i s h e d system was shown t o C e n t r a l Wastewater P l a n t o p e r a t o r s , so t h a t t h e knowledge e n g i n e e r s c o u l d i n c o r p o r a t e t a r g e t u s e r s * comments on t h e u s e r i n t e r f a c e , and t h e i r i m p r e s s i o n s about i n t e r a c t i n g w i t h t h e system. The f i n i s h e d system and t h e f i n a l

Hushon; Expert Systems for Environmental Applications ACS Symposium Series; American Chemical Society: Washington, DC, 1990.

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d e c i s i o n diagram were g i v e n t o another Camp D r e s s e r & McKee employee who has e x t e n s i v e wastewater e x p e r i e n c e . T h i s e x p e r t worked w i t h t h e system and checked i t s r u l e s ; he was n o t i n v o l v e d w i t h t h e development of ASAP i n any o t h e r way.

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ASAP

Implementation

ASAP was implemented i n KnowledgeGarden's PC-based e x p e r t system s h e l l c a l l e d KnowledgePro ( r ) , and i t works on a PC/AT o r e q u i v a l e n t machine. We s e l e c t e d t h i s s h e l l because o f i t s f l e x i b l e knowledge r e p r e s e n t a t i o n , i t s i n t e r f a c e t o g r a p h i c s packages, i t s use o f h y p e r t e x t , and i t s f a c i l i t i e s f o r e a s i l y d e v e l o p i n g a u s e r - f r i e n d l y i n t e r f a c e . Our v e r s i o n o f KnowledgePro was w r i t t e n i n Turbo P a s c a l , w h i c h can be used as an e x t e n s i o n language. O r i g i n a l l y , we thought we might have t o do some P a s c a l programming t o implement a r e c o r d k e e p i n g c a p a b i l i t y f o r ASAP ( i . e . , t o keep t r a c k o f t h e u s e r ' s o b s e r v a t i o n s , u s e r - s y s t e m i n t e r a c t i o n s , system recommendations, u s e r ' s a c t i o n s t a k e n , and consequences o f those a c t i o n s ) , b u t i t t u r n e d out t h a t KnowledgePro i t s e l f was e q u a l t o t h e t a s k . One drawback o f KnowledgePro (which d i d n o t a f f e c t t h i s p r o j e c t ) , i s t h a t i t does n o t c o n t a i n a b u i l t - i n f a c i l i t y f o r implementing certainty factors ( q u a n t i t a t i v e r e p r e s e n t a t i o n s o f how sure an e x p e r t i s o f h i s / h e r c o n c l u s i o n s ) ; CDM-FPC's E x p e r t Systems Team i s c u r r e n t l y d e v e l o p i n g a way t o do t h i s i n KnowledgePro f o r another p r o j e c t . Knowledge r e p r e s e n t a t i o n i n KnowledgePro i s b u i l t around t h e t o p i c , a s o f t w a r e s t r u c t u r e w h i c h has been c a l l e d t h e " u l t i m a t e l y f l e x i b l e knowledge r e p r e s e n t a t i o n scheme" ( 2 ) . KnowledgePro uses t o p i c s f o r s t o r i n g i n f o r m a t i o n , f o r o r g a n i z i n g s t r u c t u r e , and as t h e b a s i s f o r h y p e r t e x t ; t o p i c s can a l s o be used t o s e t up f r a m e - l i k e s t r u c t u r e s w h i c h can be used i n an o b j e c t - o r i e n t e d f a s h i o n . D e c i s i o n p o i n t s on the ASAP d e c i s i o n diagram were e a s i l y and i n t u i t i v e l y r e p r e s e n t e d as KnowledgePro t o p i c s , and o p t i o n s a t each d e c i s i o n p o i n t were e a s i l y r e p r e s e n t e d w i t h i n t h e t o p i c s . P r o d u c t i o n r u l e s ( t h e e x p e r t ' s " h e u r i s t i c s " ) were a l s o r e p r e s e n t e d w i t h i n t o p i c s , p r o v i d i n g o r g a n i z a t i o n t o t h e knowledge base. U n l i k e o t h e r e x p e r t system development t o o l s (such as 0PS5), a p r o d u c t i o n r u l e ' s l o c a t i o n ( w i t h r e s p e c t t o t o p i c s ) i s o f extreme importance i n KnowledgePro. ASAP i n c o r p o r a t e s h y p e r t e x t , a t e c h n i q u e w h i c h connects p i e c e s of t e x t i n a n o n - l i n e a r f a s h i o n . H y p e r t e x t a l l o w s t h e d e v e l o p e r t o l i n k a term o r a phrase t o i t s d e f i n i t i o n o r t o o t h e r c l a r i f y i n g i n f o r m a t i o n , so t h a t the a d d i t i o n a l i n f o r m a t i o n i s h i d d e n from v i e w when t h e term i s on the s c r e e n ; t h e u s e r , a t h i s / h e r o p t i o n , can b r i n g the a d d i t i o n a l i n f o r m a t i o n onto t h e s c r e e n . A term can be l i n k e d t o a d e s c r i p t i v e g r a p h i c , as w e l l as t o t e x t . The a d d i t i o n a l i n f o r m a t i o n can be s i m i l a r l y l i n k e d t o more i n f o r m a t i o n , and so on. ASAP i n c o r p o r a t e s a l l o f these t e c h n i q u e s , r e s u l t i n g i n a u s e r i n t e r f a c e w h i c h each u s e r , i n e f f e c t , t a i l o r s t o h i s / h e r own c a p a b i l i t i e s d u r i n g each s e s s i o n . That i s , each u s e r has a p o t e n t i a l l y different background and l e v e l o f e x p e r i e n c e , and w i l l know t h e d e f i n i t i o n s o f some terms and n o t o t h e r s . H y p e r t e x t p r o v i d e s an o p p o r t u n i t y f o r a u s e r t o l o o k up a d e f i n i t i o n w i t h o u t b r e a k i n g away from the system. The g e n e r a l development o f t h e u s e r i n t e r f a c e proceeded a l o n g w i t h t h e development o f t h e system. O r d i n a r i l y , w i t h any o f a number of o t h e r e x p e r t system s h e l l s , we w o u l d have f i r s t developed t h e knowledge base, t e s t e d i t , and then developed t h e u s e r i n t e r f a c e .

Hushon; Expert Systems for Environmental Applications ACS Symposium Series; American Chemical Society: Washington, DC, 1990.

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10.

SCHMULLERANDMORUNO

The Activated Sludge Advisor Prototype

KnowledgePro, however, e n a b l e s the d e v e l o p e r t o c o n s t r u c t a windowbased i n t e r f a c e v e r y e a s i l y and q u i c k l y . We b e l i e v e t h a t d e v e l o p i n g the u s e r i n t e r f a c e i n t h i s way ( i . e . , w h i l e i m p l e m e n t i n g the system as a whole) r e s u l t e d i n a time s a v i n g o f about 10Z. We a l s o f e e l t h a t i t r e p r e s e n t s a more n a t u r a l way t o d e v e l o p a system. A s e s s i o n w i t h ASAP b e g i n s w i t h the u s e r e n t e r i n g i d e n t i f i c a t i o n i n f o r m a t i o n and i n i t i a l comments about observed c o n d i t i o n s . The s e s s i o n proceeds w i t h ASAP q u e s t i o n i n g t h e u s e r , and t h e u s e r answering by c h o o s i n g one of s e v e r a l o p t i o n s , e x c e p t when ASAP d i r e c t s the u s e r t o e n t e r q u a n t i t a t i v e i n f o r m a t i o n . As shown i n F i g u r e 1, each q u e s t i o n appears i n a window, and a n s w e r i n g o p t i o n s appear on a menu w i t h i n the window. Terms l i n k e d t o t h e i r d e f i n i t i o n s v i a h y p e r t e x t are h i g h l i g h t e d , so t h a t t h e u s e r always knows w h i c h terms have f u r t h e r i n f o r m a t i o n a v a i l a b l e ; f u n c t i o n keys a l l o w t h e u s e r t o n a v i g a t e among these terms and d i s p l a y t h e i r d e f i n i t i o n s . Some o f the terms are l i n k e d t o t e x t , some t o g r a p h i c s . As F i g u r e 2 i l l u s t r a t e s , a t e x t - b a s e d d e f i n i t i o n or c l a r i f i c a t i o n , when brought t o the s c r e e n , appears i n a window w h i c h i s s m a l l e r t h a n a question-window, and p a r t i a l l y o v e r l a p s w i t h t h e window w h i c h l i n k s t o i t . G r a p h i c h y p e r t e x t dominates most o f the s c r e e n . ASAP's c o n c l u s i o n s a l s o appear i n windows. A s e s s i o n concludes w i t h the u s e r e n t e r i n g comments, a c t i o n s t a k e n , and consequences o f those a c t i o n s . The e n t i r e s e t o f q u e s t i o n s , responses, and comments i n a s e s s i o n i s t h e n w r i t t e n t o a file. Summing Up At p r e s e n t , wastewater o p e r a t o r t e s t s o f ASAP are p e n d i n g . Management s t a f f a t D a l l a s Water U t i l i t i e s have run t h r o u g h s e s s i o n s w i t h ASAP, and t h e i r r e a c t i o n has been v e r y p o s i t i v e . We e n v i s i o n s e v e r a l f u t u r e d i r e c t i o n s f o r our work w i t h ASAP. F i r s t , we t h i n k t h a t ASAP c o u l d be used as a t r a i n i n g t o o l as w e l l as a t r o u b l e s h o o t i n g t o o l . I n t h e s h o r t term, t h i s w i l l o c c u r as o p e r a t o r s become i n c r e a s i n g l y c o m f o r t a b l e w i t h ASAP, and e n t e r h y p o t h e t i c a l wastewater p l a n t s i t u a t i o n s , as w e l l as s i t u a t i o n s w h i c h they have observed. The o p e r a t o r s ' n o t i n g and remembering ASAP's responses w i l l e f f e c t a t r a n s f e r o f e x p e r t i s e from ASAP's knowledge base (and, u l t i m a t e l y , from our domain e x p e r t ) t o the o p e r a t o r s . I n the l o n g term, ASAP c o u l d serve as one component o f an I n t e l l i g e n t C o m p u t e r - A s s i s t e d I n s t r u c t i o n (ICAI) system. ICAI systems combine the knowledge o f a domain e x p e r t and the knowledge o f an e x p e r i e n c e d teacher, r e s u l t i n g i n a computerized t u t o r i n a p a r t i c u l a r f i e l d . A u s e r i n t e r a c t s w i t h an ICAI system i n much the same way t h a t he/she would i n t e r a c t w i t h a human t u t o r -- by a s k i n g q u e s t i o n s , s o l v i n g problems posed by the t u t o r (which are geared t o the u s e r ' s mastery of the f i e l d and l e a r n i n g r a t e ) , and h a v i n g h i s / h e r problem s o l u t i o n s e v a l u a t e d by the t u t o r . We a l s o t h i n k t h a t a l o g i c a l n e x t s t e p f o r ASAP i s t o expand the knowledge base t o d e a l w i t h t r e n d s i n the mass o f d a t a w h i c h i s c o n t i n u o u s l y b e i n g gathered a t the C e n t r a l Wastewater P l a n t . As KnowledgePro has database i n t e r f a c e f a c i l i t i e s , we f e e l t h a t t h i s c a p a b i l i t y c o u l d be implemented v e r y e a s i l y . F i n a l l y , we b e l i e v e t h a t ASAP w i l l serve as the c o r n e r s t o n e f o r r e a c h i n g our a f o r e m e n t i o n e d g o a l of a system w h i c h h e l p s o p e r a t o r s t o c o n t r o l and t r o u b l e s h o o t a l l phases o f wastewater p l a n t o p e r a t i o n ,

Hushon; Expert Systems for Environmental Applications ACS Symposium Series; American Chemical Society: Washington, DC, 1990.

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E X P E R T SYSTEMS FOR E N V I R O N M E N T A L APPLICATIONS

F i g u r e 1. An ASAP Q u e s t i o n - S c r e e n

F i g u r e 2.

ASAP H y p e r t e x t

Hushon; Expert Systems for Environmental Applications ACS Symposium Series; American Chemical Society: Washington, DC, 1990.

10.

S C H M U L L E R AND MORLINO

The Activated Sludge Advisor Prototype

i n c l u d i n g p r e - t r e a t m e n t , p r i m a r y t r e a t m e n t , secondary t r e a t m e n t , and d i s p o s a l o f removed w a s t e s . Such a system might someday be i n t e r f a c e d t o d e v i c e s f o r a u t o m a t i c p r o c e s s c o n t r o l , thus automating many o f the o p e r a t i o n s o f a wastewater p l a n t .

Downloaded by NATL UNIV OF SINGAPORE on May 5, 2018 | https://pubs.acs.org Publication Date: July 5, 1990 | doi: 10.1021/bk-1990-0431.ch010

Literature Cited 1.

Operation of Wastewater Treatment Plants: A Field Study Training Program, Volumes 1 and 2, U. S. Environmental Protection Agency, Office of Water Program Operations, 1988.

2.

Shafer, D. PC AI 1988, 2(2), 37-39.

RECEIVED

April 13, 1990

Hushon; Expert Systems for Environmental Applications ACS Symposium Series; American Chemical Society: Washington, DC, 1990.

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